2024-06-07 11:17:15

by Borislav Petkov

Subject: [PATCH v1 00/14] x86/alternatives: Nest them

From: "Borislav Petkov (AMD)" <[email protected]>

Hi,

here's the next revision

[ v1 - the last one was v0 even if not denoted as such:
https://lore.kernel.org/r/[email protected] ]

of the alternatives nesting patchset.

All feedback has been incorporated and testing with it still looks good.

Thx.

Changelog:

v0:
---

this is basically peterz's idea to nest the alternative macros with
a fix to an issue I encountered while testing.

For ease of bisection, the old macros are converted to the new, nested
variants in a step-by-step manner so that in case an issue is
encountered during testing, one can pinpoint the place where it fails
easier. Because debugging alternatives is a serious pain.

Testing here on my farm looks good but who knows what happens out there,
in the wild.

Thx.

Borislav Petkov (AMD) (13):
x86/alternative: Zap alternative_ternary()
x86/alternative: Convert alternative()
x86/alternative: Convert alternative_2()
x86/alternative: Convert alternative_input()
x86/alternative: Convert alternative_io()
x86/alternative: Convert alternative_call()
x86/alternative: Convert alternative_call_2()
x86/alternative: Convert ALTERNATIVE_TERNARY()
x86/alternative: Convert ALTERNATIVE_3()
x86/alternative: Convert the asm ALTERNATIVE() macro
x86/alternative: Convert the asm ALTERNATIVE_2() macro
x86/alternative: Convert the asm ALTERNATIVE_3() macro
x86/alternative: Replace the old macros

Peter Zijlstra (1):
x86/alternatives: Add nested alternatives macros

arch/x86/include/asm/alternative.h | 225 +++++++++--------------------
arch/x86/kernel/alternative.c | 20 ++-
arch/x86/kernel/fpu/xstate.h | 14 +-
tools/objtool/arch/x86/special.c | 23 +++
tools/objtool/special.c | 16 +-
5 files changed, 125 insertions(+), 173 deletions(-)

--
2.43.0

2024-06-07 11:17:24

by Borislav Petkov

Subject: [PATCH v1 01/14] x86/alternative: Zap alternative_ternary()

From: "Borislav Petkov (AMD)" <[email protected]>

Unused.

Signed-off-by: Borislav Petkov (AMD) <[email protected]>
---
arch/x86/include/asm/alternative.h | 3 ---
1 file changed, 3 deletions(-)

diff --git a/arch/x86/include/asm/alternative.h b/arch/x86/include/asm/alternative.h
index ba99ef75f56c..6db78909180a 100644
--- a/arch/x86/include/asm/alternative.h
+++ b/arch/x86/include/asm/alternative.h
@@ -271,9 +271,6 @@ static inline int alternatives_text_reserved(void *start, void *end)
#define alternative_2(oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2) \
asm_inline volatile(ALTERNATIVE_2(oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2) ::: "memory")

-#define alternative_ternary(oldinstr, ft_flags, newinstr_yes, newinstr_no) \
- asm_inline volatile(ALTERNATIVE_TERNARY(oldinstr, ft_flags, newinstr_yes, newinstr_no) ::: "memory")
-
/*
* Alternative inline assembly with input.
*
--
2.43.0

2024-06-07 11:18:02

by Borislav Petkov

Subject: [PATCH v1 02/14] x86/alternatives: Add nested alternatives macros

From: Peter Zijlstra <[email protected]>

Instead of making increasingly complicated ALTERNATIVE_n()
implementations, use a nested alternative expression.

The only difference between:

ALTERNATIVE_2(oldinst, newinst1, flag1, newinst2, flag2)

and

ALTERNATIVE(ALTERNATIVE(oldinst, newinst1, flag1),
newinst2, flag2)

is that the outer alternative can add additional padding when the inner
alternative is the shorter one, which then results in
alt_instr::instrlen being inconsistent.

However, this is easily remedied since the alt_instr entries will be
consecutive and it is trivial to compute the max(alt_instr::instrlen) at
runtime while patching.

Specifically, after this the ALTERNATIVE_2 macro, after CPP expansion
(and manual layout), looks like this:

.macro ALTERNATIVE_2 oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2
740:
740: \oldinstr ;
741: .skip -(((744f-743f)-(741b-740b)) > 0) * ((744f-743f)-(741b-740b)),0x90 ;
742: .pushsection .altinstructions,"a" ;
altinstr_entry 740b,743f,\ft_flags1,742b-740b,744f-743f ;
.popsection ;
.pushsection .altinstr_replacement,"ax" ;
743: \newinstr1 ;
744: .popsection ; ;
741: .skip -(((744f-743f)-(741b-740b)) > 0) * ((744f-743f)-(741b-740b)),0x90 ;
742: .pushsection .altinstructions,"a" ;
altinstr_entry 740b,743f,\ft_flags2,742b-740b,744f-743f ;
.popsection ;
.pushsection .altinstr_replacement,"ax" ;
743: \newinstr2 ;
744: .popsection ;
.endm

The only label that is ambiguous is 740, however they all reference the
same spot, so that doesn't matter.

NOTE: obviously only @oldinstr may be an alternative; making @newinstr
an alternative would mean patching .altinstr_replacement which very
likely isn't what is intended, also the labels will be confused in that
case.

[ bp: Debug an issue where it would match the wrong two insns and
and consider them nested due to the same signed offsets in the
.alternative section and use instr_va() to compare the full virtual
addresses instead.

- Use new labels to denote that the new, nested
alternatives are being used when staring at preprocessed output.

- Use the %c constraint everywhere instead of %P and document the
difference for future reference. ]

Signed-off-by: Peter Zijlstra <[email protected]>
Co-developed-by: Borislav Petkov (AMD) <[email protected]>
Signed-off-by: Borislav Petkov (AMD) <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]
---
arch/x86/include/asm/alternative.h | 120 ++++++++++++++++++++++++++++-
arch/x86/kernel/alternative.c | 20 ++++-
tools/objtool/arch/x86/special.c | 23 ++++++
tools/objtool/special.c | 16 ++--
4 files changed, 167 insertions(+), 12 deletions(-)

diff --git a/arch/x86/include/asm/alternative.h b/arch/x86/include/asm/alternative.h
index 6db78909180a..7d9ebc516bde 100644
--- a/arch/x86/include/asm/alternative.h
+++ b/arch/x86/include/asm/alternative.h
@@ -161,8 +161,13 @@ static inline int alternatives_text_reserved(void *start, void *end)

#define alt_end_marker "663"
#define alt_slen "662b-661b"
+#define n_alt_slen "772b-771b"
+
#define alt_total_slen alt_end_marker"b-661b"
+#define n_alt_total_slen "773b-771b"
+
#define alt_rlen(num) e_replacement(num)"f-"b_replacement(num)"f"
+#define n_alt_rlen "775f-774f"

#define OLDINSTR(oldinstr, num) \
"# ALT: oldnstr\n" \
@@ -172,6 +177,14 @@ static inline int alternatives_text_reserved(void *start, void *end)
"((" alt_rlen(num) ")-(" alt_slen ")),0x90\n" \
alt_end_marker ":\n"

+#define N_OLDINSTR(oldinstr) \
+ "# N_ALT: oldinstr\n" \
+ "771:\n\t" oldinstr "\n772:\n" \
+ "# N_ALT: padding\n" \
+ ".skip -(((" n_alt_rlen ")-(" n_alt_slen ")) > 0) * " \
+ "((" n_alt_rlen ")-(" n_alt_slen ")),0x90\n" \
+ "773:\n"
+
/*
* gas compatible max based on the idea from:
* http://graphics.stanford.edu/~seander/bithacks.html#IntegerMinOrMax
@@ -209,10 +222,25 @@ static inline int alternatives_text_reserved(void *start, void *end)
" .byte " alt_total_slen "\n" /* source len */ \
" .byte " alt_rlen(num) "\n" /* replacement len */

+#define N_ALTINSTR_ENTRY(ft_flags) \
+ ".pushsection .altinstructions,\"a\"\n" \
+ " .long 771b - .\n" /* label */ \
+ " .long 774f - .\n" /* new instruction */ \
+ " .4byte " __stringify(ft_flags) "\n" /* feature + flags */ \
+ " .byte " n_alt_total_slen "\n" /* source len */ \
+ " .byte " n_alt_rlen "\n" /* replacement len */ \
+ ".popsection\n"
+
#define ALTINSTR_REPLACEMENT(newinstr, num) /* replacement */ \
"# ALT: replacement " #num "\n" \
b_replacement(num)":\n\t" newinstr "\n" e_replacement(num) ":\n"

+#define N_ALTINSTR_REPLACEMENT(newinstr) /* replacement */ \
+ ".pushsection .altinstr_replacement, \"ax\"\n" \
+ "# N_ALT: replacement\n" \
+ "774:\n\t" newinstr "\n775:\n" \
+ ".popsection\n"
+
/* alternative assembly primitive: */
#define ALTERNATIVE(oldinstr, newinstr, ft_flags) \
OLDINSTR(oldinstr, 1) \
@@ -223,6 +251,12 @@ static inline int alternatives_text_reserved(void *start, void *end)
ALTINSTR_REPLACEMENT(newinstr, 1) \
".popsection\n"

+/* Nested alternatives macro variant */
+#define N_ALTERNATIVE(oldinstr, newinstr, ft_flags) \
+ N_OLDINSTR(oldinstr) \
+ N_ALTINSTR_ENTRY(ft_flags) \
+ N_ALTINSTR_REPLACEMENT(newinstr)
+
#define ALTERNATIVE_2(oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2) \
OLDINSTR_2(oldinstr, 1, 2) \
".pushsection .altinstructions,\"a\"\n" \
@@ -234,11 +268,21 @@ static inline int alternatives_text_reserved(void *start, void *end)
ALTINSTR_REPLACEMENT(newinstr2, 2) \
".popsection\n"

+#define N_ALTERNATIVE_2(oldinst, newinst1, flag1, newinst2, flag2) \
+ N_ALTERNATIVE(N_ALTERNATIVE(oldinst, newinst1, flag1), \
+ newinst2, flag2)
+
/* If @feature is set, patch in @newinstr_yes, otherwise @newinstr_no. */
#define ALTERNATIVE_TERNARY(oldinstr, ft_flags, newinstr_yes, newinstr_no) \
ALTERNATIVE_2(oldinstr, newinstr_no, X86_FEATURE_ALWAYS, \
newinstr_yes, ft_flags)

+/* If @feature is set, patch in @newinstr_yes, otherwise @newinstr_no. */
+#define N_ALTERNATIVE_TERNARY(oldinstr, ft_flags, newinstr_yes, newinstr_no) \
+ N_ALTERNATIVE_2(oldinstr, newinstr_no, X86_FEATURE_ALWAYS, \
+ newinstr_yes, ft_flags)
+
+
#define ALTERNATIVE_3(oldinsn, newinsn1, ft_flags1, newinsn2, ft_flags2, \
newinsn3, ft_flags3) \
OLDINSTR_3(oldinsn, 1, 2, 3) \
@@ -253,6 +297,12 @@ static inline int alternatives_text_reserved(void *start, void *end)
ALTINSTR_REPLACEMENT(newinsn3, 3) \
".popsection\n"

+
+#define N_ALTERNATIVE_3(oldinst, newinst1, flag1, newinst2, flag2, \
+ newinst3, flag3) \
+ N_ALTERNATIVE(N_ALTERNATIVE_2(oldinst, newinst1, flag1, newinst2, flag2), \
+ newinst3, flag3)
+
/*
* Alternative instructions for different CPU types or capabilities.
*
@@ -271,6 +321,12 @@ static inline int alternatives_text_reserved(void *start, void *end)
#define alternative_2(oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2) \
asm_inline volatile(ALTERNATIVE_2(oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2) ::: "memory")

+#define n_alternative(oldinstr, newinstr, ft_flags) \
+ asm_inline volatile (N_ALTERNATIVE(oldinstr, newinstr, ft_flags) : : : "memory")
+
+#define n_alternative_2(oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2) \
+ asm_inline volatile(N_ALTERNATIVE_2(oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2) ::: "memory")
+
/*
* Alternative inline assembly with input.
*
@@ -288,11 +344,32 @@ static inline int alternatives_text_reserved(void *start, void *end)
asm_inline volatile (ALTERNATIVE(oldinstr, newinstr, ft_flags) \
: output : "i" (0), ## input)

-/* Like alternative_io, but for replacing a direct call with another one. */
+#define n_alternative_io(oldinstr, newinstr, ft_flags, output, input...) \
+ asm_inline volatile (N_ALTERNATIVE(oldinstr, newinstr, ft_flags) \
+ : output : "i" (0), ## input)
+
+/*
+ * Like alternative_io, but for replacing a direct call with another one.
+ *
+ * Use the %c operand modifier which is the generic way to print a bare
+ * constant expression with all syntax-specific punctuation omitted. %P
+ * is the x86-specific variant which can handle constants too, for
+ * historical reasons, but it should be used primarily for PIC
+ * references: i.e., if used for a function, it would add the PLT
+ * suffix.
+ */
#define alternative_call(oldfunc, newfunc, ft_flags, output, input...) \
asm_inline volatile (ALTERNATIVE("call %c[old]", "call %c[new]", ft_flags) \
: output : [old] "i" (oldfunc), [new] "i" (newfunc), ## input)

+#define n_alternative_input(oldinstr, newinstr, ft_flags, input...) \
+ asm_inline volatile (N_ALTERNATIVE(oldinstr, newinstr, ft_flags) \
+ : : "i" (0), ## input)
+
+#define n_alternative_call(oldfunc, newfunc, ft_flags, output, input...) \
+ asm_inline volatile (N_ALTERNATIVE("call %c[old]", "call %c[new]", ft_flags) \
+ : output : [old] "i" (oldfunc), [new] "i" (newfunc), ## input)
+
/*
* Like alternative_call, but there are two features and respective functions.
* If CPU has feature2, function2 is used.
@@ -307,6 +384,15 @@ static inline int alternatives_text_reserved(void *start, void *end)
: [old] "i" (oldfunc), [new1] "i" (newfunc1), \
[new2] "i" (newfunc2), ## input)

+#define n_alternative_call_2(oldfunc, newfunc1, ft_flags1, newfunc2, ft_flags2, \
+ output, input...) \
+ asm_inline volatile (N_ALTERNATIVE_2("call %c[old]", "call %c[new1]", ft_flags1,\
+ "call %c[new2]", ft_flags2) \
+ : output, ASM_CALL_CONSTRAINT \
+ : [old] "i" (oldfunc), [new1] "i" (newfunc1), \
+ [new2] "i" (newfunc2), ## input)
+
+
/*
* use this macro(s) if you need more than one output parameter
* in alternative_io
@@ -403,6 +489,27 @@ void nop_func(void);
.popsection
.endm

+#define __N_ALTERNATIVE(oldinst, newinst, flag) \
+740: \
+ oldinst ; \
+741: \
+ .skip -(((744f-743f)-(741b-740b)) > 0) * ((744f-743f)-(741b-740b)),0x90 ;\
+742: \
+ .pushsection .altinstructions,"a" ; \
+ altinstr_entry 740b,743f,flag,742b-740b,744f-743f ; \
+ .popsection ; \
+ .pushsection .altinstr_replacement,"ax" ; \
+743: \
+ newinst ; \
+744: \
+ .popsection ;
+
+
+.macro N_ALTERNATIVE oldinstr, newinstr, ft_flags
+ __N_ALTERNATIVE(\oldinstr, \newinstr, \ft_flags)
+.endm
+
+
#define old_len 141b-140b
#define new_len1 144f-143f
#define new_len2 145f-144f
@@ -417,7 +524,6 @@ void nop_func(void);
#define alt_max_2(a, b) ((a) ^ (((a) ^ (b)) & -(-((a) < (b)))))
#define alt_max_3(a, b, c) (alt_max_2(alt_max_2(a, b), c))

-
/*
* Same as ALTERNATIVE macro above but for two alternatives. If CPU
* has @feature1, it replaces @oldinstr with @newinstr1. If CPU has
@@ -445,6 +551,11 @@ void nop_func(void);
.popsection
.endm

+.macro N_ALTERNATIVE_2 oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2
+ __N_ALTERNATIVE(__N_ALTERNATIVE(\oldinstr, \newinstr1, \ft_flags1),
+ \newinstr2, \ft_flags2)
+.endm
+
.macro ALTERNATIVE_3 oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2, newinstr3, ft_flags3
140:
\oldinstr
@@ -470,6 +581,11 @@ void nop_func(void);
.popsection
.endm

+.macro N_ALTERNATIVE_3 oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2, newinstr3, ft_flags3
+ __N_ALTERNATIVE(N_ALTERNATIVE_2(\oldinstr, \newinstr1, \ft_flags1, \newinstr2, \ft_flags2),
+ \newinstr3, \ft_flags3)
+.endm
+
/* If @feature is set, patch in @newinstr_yes, otherwise @newinstr_no. */
#define ALTERNATIVE_TERNARY(oldinstr, ft_flags, newinstr_yes, newinstr_no) \
ALTERNATIVE_2 oldinstr, newinstr_no, X86_FEATURE_ALWAYS, \
diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c
index 89de61243272..37596a417094 100644
--- a/arch/x86/kernel/alternative.c
+++ b/arch/x86/kernel/alternative.c
@@ -432,6 +432,11 @@ static int alt_replace_call(u8 *instr, u8 *insn_buff, struct alt_instr *a)
return 5;
}

+static inline u8 * instr_va(struct alt_instr *i)
+{
+ return (u8 *)&i->instr_offset + i->instr_offset;
+}
+
/*
* Replace instructions with better alternatives for this CPU type. This runs
* before SMP is initialized to avoid SMP problems with self modifying code.
@@ -447,7 +452,7 @@ void __init_or_module noinline apply_alternatives(struct alt_instr *start,
{
u8 insn_buff[MAX_PATCH_LEN];
u8 *instr, *replacement;
- struct alt_instr *a;
+ struct alt_instr *a, *b;

DPRINTK(ALT, "alt table %px, -> %px", start, end);

@@ -473,7 +478,18 @@ void __init_or_module noinline apply_alternatives(struct alt_instr *start,
for (a = start; a < end; a++) {
int insn_buff_sz = 0;

- instr = (u8 *)&a->instr_offset + a->instr_offset;
+ /*
+ * In case of nested ALTERNATIVE()s the outer alternative might
+ * add more padding. To ensure consistent patching find the max
+ * padding for all alt_instr entries for this site (nested
+ * alternatives result in consecutive entries).
+ */
+ for (b = a+1; b < end && instr_va(b) == instr_va(a); b++) {
+ u8 len = max(a->instrlen, b->instrlen);
+ a->instrlen = b->instrlen = len;
+ }
+
+ instr = instr_va(a);
replacement = (u8 *)&a->repl_offset + a->repl_offset;
BUG_ON(a->instrlen > sizeof(insn_buff));
BUG_ON(a->cpuid >= (NCAPINTS + NBUGINTS) * 32);
diff --git a/tools/objtool/arch/x86/special.c b/tools/objtool/arch/x86/special.c
index 4134d27c696b..4ea0f9815fda 100644
--- a/tools/objtool/arch/x86/special.c
+++ b/tools/objtool/arch/x86/special.c
@@ -9,6 +9,29 @@

void arch_handle_alternative(unsigned short feature, struct special_alt *alt)
{
+ static struct special_alt *group, *prev;
+
+ /*
+ * Recompute orig_len for nested ALTERNATIVE()s.
+ */
+ if (group && group->orig_sec == alt->orig_sec &&
+ group->orig_off == alt->orig_off) {
+
+ struct special_alt *iter = group;
+ for (;;) {
+ unsigned int len = max(iter->orig_len, alt->orig_len);
+ iter->orig_len = alt->orig_len = len;
+
+ if (iter == prev)
+ break;
+
+ iter = list_next_entry(iter, list);
+ }
+
+ } else group = alt;
+
+ prev = alt;
+
switch (feature) {
case X86_FEATURE_SMAP:
/*
diff --git a/tools/objtool/special.c b/tools/objtool/special.c
index 91b1950f5bd8..097a69db82a0 100644
--- a/tools/objtool/special.c
+++ b/tools/objtool/special.c
@@ -84,6 +84,14 @@ static int get_alt_entry(struct elf *elf, const struct special_entry *entry,
entry->new_len);
}

+ orig_reloc = find_reloc_by_dest(elf, sec, offset + entry->orig);
+ if (!orig_reloc) {
+ WARN_FUNC("can't find orig reloc", sec, offset + entry->orig);
+ return -1;
+ }
+
+ reloc_to_sec_off(orig_reloc, &alt->orig_sec, &alt->orig_off);
+
if (entry->feature) {
unsigned short feature;

@@ -94,14 +102,6 @@ static int get_alt_entry(struct elf *elf, const struct special_entry *entry,
arch_handle_alternative(feature, alt);
}

- orig_reloc = find_reloc_by_dest(elf, sec, offset + entry->orig);
- if (!orig_reloc) {
- WARN_FUNC("can't find orig reloc", sec, offset + entry->orig);
- return -1;
- }
-
- reloc_to_sec_off(orig_reloc, &alt->orig_sec, &alt->orig_off);
-
if (!entry->group || alt->new_len) {
new_reloc = find_reloc_by_dest(elf, sec, offset + entry->new);
if (!new_reloc) {
--
2.43.0

2024-06-07 11:18:18

by Borislav Petkov

Subject: [PATCH v1 04/14] x86/alternative: Convert alternative_2()

From: "Borislav Petkov (AMD)" <[email protected]>

Signed-off-by: Borislav Petkov (AMD) <[email protected]>
---
arch/x86/include/asm/alternative.h | 3 ---
1 file changed, 3 deletions(-)

diff --git a/arch/x86/include/asm/alternative.h b/arch/x86/include/asm/alternative.h
index c05bff2e3626..21ead5dea15a 100644
--- a/arch/x86/include/asm/alternative.h
+++ b/arch/x86/include/asm/alternative.h
@@ -319,9 +319,6 @@ static inline int alternatives_text_reserved(void *start, void *end)
asm_inline volatile(N_ALTERNATIVE(oldinstr, newinstr, ft_flags) : : : "memory")

#define alternative_2(oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2) \
- asm_inline volatile(ALTERNATIVE_2(oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2) ::: "memory")
-
-#define n_alternative_2(oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2) \
asm_inline volatile(N_ALTERNATIVE_2(oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2) ::: "memory")

/*
--
2.43.0

2024-06-07 11:18:24

by Borislav Petkov

Subject: [PATCH v1 03/14] x86/alternative: Convert alternative()

From: "Borislav Petkov (AMD)" <[email protected]>

Split conversion deliberately into minimal pieces to ease bisection
because debugging alternatives is a nightmare.

Signed-off-by: Borislav Petkov (AMD) <[email protected]>
---
arch/x86/include/asm/alternative.h | 5 +----
1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/arch/x86/include/asm/alternative.h b/arch/x86/include/asm/alternative.h
index 7d9ebc516bde..c05bff2e3626 100644
--- a/arch/x86/include/asm/alternative.h
+++ b/arch/x86/include/asm/alternative.h
@@ -316,14 +316,11 @@ static inline int alternatives_text_reserved(void *start, void *end)
* without volatile and memory clobber.
*/
#define alternative(oldinstr, newinstr, ft_flags) \
- asm_inline volatile (ALTERNATIVE(oldinstr, newinstr, ft_flags) : : : "memory")
+ asm_inline volatile(N_ALTERNATIVE(oldinstr, newinstr, ft_flags) : : : "memory")

#define alternative_2(oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2) \
asm_inline volatile(ALTERNATIVE_2(oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2) ::: "memory")

-#define n_alternative(oldinstr, newinstr, ft_flags) \
- asm_inline volatile (N_ALTERNATIVE(oldinstr, newinstr, ft_flags) : : : "memory")
-
#define n_alternative_2(oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2) \
asm_inline volatile(N_ALTERNATIVE_2(oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2) ::: "memory")

--
2.43.0

2024-06-07 11:18:48

by Borislav Petkov

Subject: [PATCH v1 05/14] x86/alternative: Convert alternative_input()

From: "Borislav Petkov (AMD)" <[email protected]>

Signed-off-by: Borislav Petkov (AMD) <[email protected]>
---
arch/x86/include/asm/alternative.h | 6 +-----
1 file changed, 1 insertion(+), 5 deletions(-)

diff --git a/arch/x86/include/asm/alternative.h b/arch/x86/include/asm/alternative.h
index 21ead5dea15a..428d6efeb333 100644
--- a/arch/x86/include/asm/alternative.h
+++ b/arch/x86/include/asm/alternative.h
@@ -330,7 +330,7 @@ static inline int alternatives_text_reserved(void *start, void *end)
* Leaving an unused argument 0 to keep API compatibility.
*/
#define alternative_input(oldinstr, newinstr, ft_flags, input...) \
- asm_inline volatile (ALTERNATIVE(oldinstr, newinstr, ft_flags) \
+ asm_inline volatile(N_ALTERNATIVE(oldinstr, newinstr, ft_flags) \
: : "i" (0), ## input)

/* Like alternative_input, but with a single output argument */
@@ -356,10 +356,6 @@ static inline int alternatives_text_reserved(void *start, void *end)
asm_inline volatile (ALTERNATIVE("call %c[old]", "call %c[new]", ft_flags) \
: output : [old] "i" (oldfunc), [new] "i" (newfunc), ## input)

-#define n_alternative_input(oldinstr, newinstr, ft_flags, input...) \
- asm_inline volatile (N_ALTERNATIVE(oldinstr, newinstr, ft_flags) \
- : : "i" (0), ## input)
-
#define n_alternative_call(oldfunc, newfunc, ft_flags, output, input...) \
asm_inline volatile (N_ALTERNATIVE("call %c[old]", "call %c[new]", ft_flags) \
: output : [old] "i" (oldfunc), [new] "i" (newfunc), ## input)
--
2.43.0

2024-06-07 11:18:56

by Borislav Petkov

Subject: [PATCH v1 06/14] x86/alternative: Convert alternative_io()

From: "Borislav Petkov (AMD)" <[email protected]>

Signed-off-by: Borislav Petkov (AMD) <[email protected]>
---
arch/x86/include/asm/alternative.h | 6 +-----
1 file changed, 1 insertion(+), 5 deletions(-)

diff --git a/arch/x86/include/asm/alternative.h b/arch/x86/include/asm/alternative.h
index 428d6efeb333..6a746811c602 100644
--- a/arch/x86/include/asm/alternative.h
+++ b/arch/x86/include/asm/alternative.h
@@ -335,11 +335,7 @@ static inline int alternatives_text_reserved(void *start, void *end)

/* Like alternative_input, but with a single output argument */
#define alternative_io(oldinstr, newinstr, ft_flags, output, input...) \
- asm_inline volatile (ALTERNATIVE(oldinstr, newinstr, ft_flags) \
- : output : "i" (0), ## input)
-
-#define n_alternative_io(oldinstr, newinstr, ft_flags, output, input...) \
- asm_inline volatile (N_ALTERNATIVE(oldinstr, newinstr, ft_flags) \
+ asm_inline volatile(N_ALTERNATIVE(oldinstr, newinstr, ft_flags) \
: output : "i" (0), ## input)

/*
--
2.43.0

2024-06-07 11:19:06

by Borislav Petkov

Subject: [PATCH v1 07/14] x86/alternative: Convert alternative_call()

From: "Borislav Petkov (AMD)" <[email protected]>

Signed-off-by: Borislav Petkov (AMD) <[email protected]>
---
arch/x86/include/asm/alternative.h | 6 +-----
1 file changed, 1 insertion(+), 5 deletions(-)

diff --git a/arch/x86/include/asm/alternative.h b/arch/x86/include/asm/alternative.h
index 6a746811c602..b6597574fa43 100644
--- a/arch/x86/include/asm/alternative.h
+++ b/arch/x86/include/asm/alternative.h
@@ -349,11 +349,7 @@ static inline int alternatives_text_reserved(void *start, void *end)
* suffix.
*/
#define alternative_call(oldfunc, newfunc, ft_flags, output, input...) \
- asm_inline volatile (ALTERNATIVE("call %c[old]", "call %c[new]", ft_flags) \
- : output : [old] "i" (oldfunc), [new] "i" (newfunc), ## input)
-
-#define n_alternative_call(oldfunc, newfunc, ft_flags, output, input...) \
- asm_inline volatile (N_ALTERNATIVE("call %c[old]", "call %c[new]", ft_flags) \
+ asm_inline volatile(N_ALTERNATIVE("call %c[old]", "call %c[new]", ft_flags) \
: output : [old] "i" (oldfunc), [new] "i" (newfunc), ## input)

/*
--
2.43.0

2024-06-07 11:19:21

by Borislav Petkov

Subject: [PATCH v1 08/14] x86/alternative: Convert alternative_call_2()

From: "Borislav Petkov (AMD)" <[email protected]>

Signed-off-by: Borislav Petkov (AMD) <[email protected]>
---
arch/x86/include/asm/alternative.h | 21 ++++++---------------
1 file changed, 6 insertions(+), 15 deletions(-)

diff --git a/arch/x86/include/asm/alternative.h b/arch/x86/include/asm/alternative.h
index b6597574fa43..bc260f27d7f1 100644
--- a/arch/x86/include/asm/alternative.h
+++ b/arch/x86/include/asm/alternative.h
@@ -358,23 +358,14 @@ static inline int alternatives_text_reserved(void *start, void *end)
* Otherwise, if CPU has feature1, function1 is used.
* Otherwise, old function is used.
*/
-#define alternative_call_2(oldfunc, newfunc1, ft_flags1, newfunc2, ft_flags2, \
- output, input...) \
- asm_inline volatile (ALTERNATIVE_2("call %c[old]", "call %c[new1]", ft_flags1, \
- "call %c[new2]", ft_flags2) \
- : output, ASM_CALL_CONSTRAINT \
- : [old] "i" (oldfunc), [new1] "i" (newfunc1), \
+#define alternative_call_2(oldfunc, newfunc1, ft_flags1, newfunc2, ft_flags2, \
+ output, input...) \
+ asm_inline volatile(N_ALTERNATIVE_2("call %c[old]", "call %c[new1]", ft_flags1, \
+ "call %c[new2]", ft_flags2) \
+ : output, ASM_CALL_CONSTRAINT \
+ : [old] "i" (oldfunc), [new1] "i" (newfunc1), \
[new2] "i" (newfunc2), ## input)

-#define n_alternative_call_2(oldfunc, newfunc1, ft_flags1, newfunc2, ft_flags2, \
- output, input...) \
- asm_inline volatile (N_ALTERNATIVE_2("call %c[old]", "call %c[new1]", ft_flags1,\
- "call %c[new2]", ft_flags2) \
- : output, ASM_CALL_CONSTRAINT \
- : [old] "i" (oldfunc), [new1] "i" (newfunc1), \
- [new2] "i" (newfunc2), ## input)
-
-
/*
* use this macro(s) if you need more than one output parameter
* in alternative_io
--
2.43.0

2024-06-07 11:19:34

by Borislav Petkov

Subject: [PATCH v1 09/14] x86/alternative: Convert ALTERNATIVE_TERNARY()

From: "Borislav Petkov (AMD)" <[email protected]>

The C macro.

Signed-off-by: Borislav Petkov (AMD) <[email protected]>
---
arch/x86/include/asm/alternative.h | 6 ------
1 file changed, 6 deletions(-)

diff --git a/arch/x86/include/asm/alternative.h b/arch/x86/include/asm/alternative.h
index bc260f27d7f1..007baab32c14 100644
--- a/arch/x86/include/asm/alternative.h
+++ b/arch/x86/include/asm/alternative.h
@@ -274,15 +274,9 @@ static inline int alternatives_text_reserved(void *start, void *end)

/* If @feature is set, patch in @newinstr_yes, otherwise @newinstr_no. */
#define ALTERNATIVE_TERNARY(oldinstr, ft_flags, newinstr_yes, newinstr_no) \
- ALTERNATIVE_2(oldinstr, newinstr_no, X86_FEATURE_ALWAYS, \
- newinstr_yes, ft_flags)
-
-/* If @feature is set, patch in @newinstr_yes, otherwise @newinstr_no. */
-#define N_ALTERNATIVE_TERNARY(oldinstr, ft_flags, newinstr_yes, newinstr_no) \
N_ALTERNATIVE_2(oldinstr, newinstr_no, X86_FEATURE_ALWAYS, \
newinstr_yes, ft_flags)

-
#define ALTERNATIVE_3(oldinsn, newinsn1, ft_flags1, newinsn2, ft_flags2, \
newinsn3, ft_flags3) \
OLDINSTR_3(oldinsn, 1, 2, 3) \
--
2.43.0

2024-06-07 11:19:46

by Borislav Petkov

Subject: [PATCH v1 10/14] x86/alternative: Convert ALTERNATIVE_3()

From: "Borislav Petkov (AMD)" <[email protected]>

Zap the hack of using an ALTERNATIVE_3() internal label, as suggested by
bgerst:

https://lore.kernel.org/r/CAMzpN2i4oJ-Dv0qO46Fd-DxNv5z9=x%2BvO%[email protected]

in favor of a label local to this macro only, as it should be done.

Signed-off-by: Borislav Petkov (AMD) <[email protected]>
---
arch/x86/include/asm/alternative.h | 24 ++++--------------------
arch/x86/kernel/fpu/xstate.h | 14 +++++---------
2 files changed, 9 insertions(+), 29 deletions(-)

diff --git a/arch/x86/include/asm/alternative.h b/arch/x86/include/asm/alternative.h
index 007baab32c14..fba12ad237e2 100644
--- a/arch/x86/include/asm/alternative.h
+++ b/arch/x86/include/asm/alternative.h
@@ -277,26 +277,10 @@ static inline int alternatives_text_reserved(void *start, void *end)
N_ALTERNATIVE_2(oldinstr, newinstr_no, X86_FEATURE_ALWAYS, \
newinstr_yes, ft_flags)

-#define ALTERNATIVE_3(oldinsn, newinsn1, ft_flags1, newinsn2, ft_flags2, \
- newinsn3, ft_flags3) \
- OLDINSTR_3(oldinsn, 1, 2, 3) \
- ".pushsection .altinstructions,\"a\"\n" \
- ALTINSTR_ENTRY(ft_flags1, 1) \
- ALTINSTR_ENTRY(ft_flags2, 2) \
- ALTINSTR_ENTRY(ft_flags3, 3) \
- ".popsection\n" \
- ".pushsection .altinstr_replacement, \"ax\"\n" \
- ALTINSTR_REPLACEMENT(newinsn1, 1) \
- ALTINSTR_REPLACEMENT(newinsn2, 2) \
- ALTINSTR_REPLACEMENT(newinsn3, 3) \
- ".popsection\n"
-
-
-#define N_ALTERNATIVE_3(oldinst, newinst1, flag1, newinst2, flag2, \
- newinst3, flag3) \
- N_ALTERNATIVE(N_ALTERNATIVE_2(oldinst, newinst1, flag1, newinst2, flag2), \
- newinst3, flag3)
-
+#define ALTERNATIVE_3(oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2, \
+ newinstr3, ft_flags3) \
+ N_ALTERNATIVE(N_ALTERNATIVE_2(oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2), \
+ newinstr3, ft_flags3)
/*
* Alternative instructions for different CPU types or capabilities.
*
diff --git a/arch/x86/kernel/fpu/xstate.h b/arch/x86/kernel/fpu/xstate.h
index 05df04f39628..2ee0b9c53dcc 100644
--- a/arch/x86/kernel/fpu/xstate.h
+++ b/arch/x86/kernel/fpu/xstate.h
@@ -106,21 +106,17 @@ static inline u64 xfeatures_mask_independent(void)
* Otherwise, if XSAVEOPT is enabled, XSAVEOPT replaces XSAVE because XSAVEOPT
* supports modified optimization which is not supported by XSAVE.
*
- * We use XSAVE as a fallback.
- *
- * The 661 label is defined in the ALTERNATIVE* macros as the address of the
- * original instruction which gets replaced. We need to use it here as the
- * address of the instruction where we might get an exception at.
+ * Use XSAVE as a fallback.
*/
#define XSTATE_XSAVE(st, lmask, hmask, err) \
- asm volatile(ALTERNATIVE_3(XSAVE, \
+ asm volatile("1: " ALTERNATIVE_3(XSAVE, \
XSAVEOPT, X86_FEATURE_XSAVEOPT, \
XSAVEC, X86_FEATURE_XSAVEC, \
XSAVES, X86_FEATURE_XSAVES) \
"\n" \
"xor %[err], %[err]\n" \
"3:\n" \
- _ASM_EXTABLE_TYPE_REG(661b, 3b, EX_TYPE_EFAULT_REG, %[err]) \
+ _ASM_EXTABLE_TYPE_REG(1b, 3b, EX_TYPE_EFAULT_REG, %[err]) \
: [err] "=r" (err) \
: "D" (st), "m" (*st), "a" (lmask), "d" (hmask) \
: "memory")
@@ -130,11 +126,11 @@ static inline u64 xfeatures_mask_independent(void)
* XSAVE area format.
*/
#define XSTATE_XRESTORE(st, lmask, hmask) \
- asm volatile(ALTERNATIVE(XRSTOR, \
+ asm volatile("1: " ALTERNATIVE(XRSTOR, \
XRSTORS, X86_FEATURE_XSAVES) \
"\n" \
"3:\n" \
- _ASM_EXTABLE_TYPE(661b, 3b, EX_TYPE_FPU_RESTORE) \
+ _ASM_EXTABLE_TYPE(1b, 3b, EX_TYPE_FPU_RESTORE) \
: \
: "D" (st), "m" (*st), "a" (lmask), "d" (hmask) \
: "memory")
--
2.43.0

2024-06-07 11:20:14

by Borislav Petkov

Subject: [PATCH v1 12/14] x86/alternative: Convert the asm ALTERNATIVE_2() macro

From: "Borislav Petkov (AMD)" <[email protected]>

Signed-off-by: Borislav Petkov (AMD) <[email protected]>
---
arch/x86/include/asm/alternative.h | 22 ----------------------
1 file changed, 22 deletions(-)

diff --git a/arch/x86/include/asm/alternative.h b/arch/x86/include/asm/alternative.h
index 31b9a47b9df9..28e07a038964 100644
--- a/arch/x86/include/asm/alternative.h
+++ b/arch/x86/include/asm/alternative.h
@@ -461,28 +461,6 @@ void nop_func(void);
* @feature2, it replaces @oldinstr with @feature2.
*/
.macro ALTERNATIVE_2 oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2
-140:
- \oldinstr
-141:
- .skip -((alt_max_2(new_len1, new_len2) - (old_len)) > 0) * \
- (alt_max_2(new_len1, new_len2) - (old_len)),0x90
-142:
-
- .pushsection .altinstructions,"a"
- altinstr_entry 140b,143f,\ft_flags1,142b-140b,144f-143f
- altinstr_entry 140b,144f,\ft_flags2,142b-140b,145f-144f
- .popsection
-
- .pushsection .altinstr_replacement,"ax"
-143:
- \newinstr1
-144:
- \newinstr2
-145:
- .popsection
-.endm
-
-.macro N_ALTERNATIVE_2 oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2
__N_ALTERNATIVE(__N_ALTERNATIVE(\oldinstr, \newinstr1, \ft_flags1),
\newinstr2, \ft_flags2)
.endm
--
2.43.0

2024-06-07 11:20:27

by Borislav Petkov

Subject: [PATCH v1 13/14] x86/alternative: Convert the asm ALTERNATIVE_3() macro

From: "Borislav Petkov (AMD)" <[email protected]>

Signed-off-by: Borislav Petkov (AMD) <[email protected]>
---
arch/x86/include/asm/alternative.h | 25 -------------------------
1 file changed, 25 deletions(-)

diff --git a/arch/x86/include/asm/alternative.h b/arch/x86/include/asm/alternative.h
index 28e07a038964..5278cfb1f745 100644
--- a/arch/x86/include/asm/alternative.h
+++ b/arch/x86/include/asm/alternative.h
@@ -466,31 +466,6 @@ void nop_func(void);
.endm

.macro ALTERNATIVE_3 oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2, newinstr3, ft_flags3
-140:
- \oldinstr
-141:
- .skip -((alt_max_3(new_len1, new_len2, new_len3) - (old_len)) > 0) * \
- (alt_max_3(new_len1, new_len2, new_len3) - (old_len)),0x90
-142:
-
- .pushsection .altinstructions,"a"
- altinstr_entry 140b,143f,\ft_flags1,142b-140b,144f-143f
- altinstr_entry 140b,144f,\ft_flags2,142b-140b,145f-144f
- altinstr_entry 140b,145f,\ft_flags3,142b-140b,146f-145f
- .popsection
-
- .pushsection .altinstr_replacement,"ax"
-143:
- \newinstr1
-144:
- \newinstr2
-145:
- \newinstr3
-146:
- .popsection
-.endm
-
-.macro N_ALTERNATIVE_3 oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2, newinstr3, ft_flags3
__N_ALTERNATIVE(N_ALTERNATIVE_2(\oldinstr, \newinstr1, \ft_flags1, \newinstr2, \ft_flags2),
\newinstr3, \ft_flags3)
.endm
--
2.43.0

2024-06-07 11:20:43

by Borislav Petkov

Subject: [PATCH v1 14/14] x86/alternative: Replace the old macros

From: "Borislav Petkov (AMD)" <[email protected]>

Now that the new macros have been gradually put in place, replace the
old ones. Leave the new label numbers starting at 7xx as a hint that the
new nested alternatives are being used now.

Signed-off-by: Borislav Petkov (AMD) <[email protected]>
---
arch/x86/include/asm/alternative.h | 144 +++++++----------------------
1 file changed, 32 insertions(+), 112 deletions(-)

diff --git a/arch/x86/include/asm/alternative.h b/arch/x86/include/asm/alternative.h
index 5278cfb1f745..4973edbe9289 100644
--- a/arch/x86/include/asm/alternative.h
+++ b/arch/x86/include/asm/alternative.h
@@ -156,131 +156,51 @@ static inline int alternatives_text_reserved(void *start, void *end)

#define ALT_CALL_INSTR "call BUG_func"

-#define b_replacement(num) "664"#num
-#define e_replacement(num) "665"#num
+#define alt_slen "772b-771b"
+#define alt_total_slen "773b-771b"
+#define alt_rlen "775f-774f"

-#define alt_end_marker "663"
-#define alt_slen "662b-661b"
-#define n_alt_slen "772b-771b"
-
-#define alt_total_slen alt_end_marker"b-661b"
-#define n_alt_total_slen "773b-771b"
-
-#define alt_rlen(num) e_replacement(num)"f-"b_replacement(num)"f"
-#define n_alt_rlen "775f-774f"
-
-#define OLDINSTR(oldinstr, num) \
- "# ALT: oldnstr\n" \
- "661:\n\t" oldinstr "\n662:\n" \
- "# ALT: padding\n" \
- ".skip -(((" alt_rlen(num) ")-(" alt_slen ")) > 0) * " \
- "((" alt_rlen(num) ")-(" alt_slen ")),0x90\n" \
- alt_end_marker ":\n"
-
-#define N_OLDINSTR(oldinstr) \
- "# N_ALT: oldinstr\n" \
+#define OLDINSTR(oldinstr) \
+ "# ALT: oldinstr\n" \
"771:\n\t" oldinstr "\n772:\n" \
- "# N_ALT: padding\n" \
- ".skip -(((" n_alt_rlen ")-(" n_alt_slen ")) > 0) * " \
- "((" n_alt_rlen ")-(" n_alt_slen ")),0x90\n" \
+ "# ALT: padding\n" \
+ ".skip -(((" alt_rlen ")-(" alt_slen ")) > 0) * " \
+ "((" alt_rlen ")-(" alt_slen ")),0x90\n" \
"773:\n"

-/*
- * gas compatible max based on the idea from:
- * http://graphics.stanford.edu/~seander/bithacks.html#IntegerMinOrMax
- *
- * The additional "-" is needed because gas uses a "true" value of -1.
- */
-#define alt_max_short(a, b) "((" a ") ^ (((" a ") ^ (" b ")) & -(-((" a ") < (" b ")))))"
-
-/*
- * Pad the second replacement alternative with additional NOPs if it is
- * additionally longer than the first replacement alternative.
- */
-#define OLDINSTR_2(oldinstr, num1, num2) \
- "# ALT: oldinstr2\n" \
- "661:\n\t" oldinstr "\n662:\n" \
- "# ALT: padding2\n" \
- ".skip -((" alt_max_short(alt_rlen(num1), alt_rlen(num2)) " - (" alt_slen ")) > 0) * " \
- "(" alt_max_short(alt_rlen(num1), alt_rlen(num2)) " - (" alt_slen ")), 0x90\n" \
- alt_end_marker ":\n"
-
-#define OLDINSTR_3(oldinsn, n1, n2, n3) \
- "# ALT: oldinstr3\n" \
- "661:\n\t" oldinsn "\n662:\n" \
- "# ALT: padding3\n" \
- ".skip -((" alt_max_short(alt_max_short(alt_rlen(n1), alt_rlen(n2)), alt_rlen(n3)) \
- " - (" alt_slen ")) > 0) * " \
- "(" alt_max_short(alt_max_short(alt_rlen(n1), alt_rlen(n2)), alt_rlen(n3)) \
- " - (" alt_slen ")), 0x90\n" \
- alt_end_marker ":\n"
-
-#define ALTINSTR_ENTRY(ft_flags, num) \
- " .long 661b - .\n" /* label */ \
- " .long " b_replacement(num)"f - .\n" /* new instruction */ \
- " .4byte " __stringify(ft_flags) "\n" /* feature + flags */ \
- " .byte " alt_total_slen "\n" /* source len */ \
- " .byte " alt_rlen(num) "\n" /* replacement len */
-
-#define N_ALTINSTR_ENTRY(ft_flags) \
+#define ALTINSTR_ENTRY(ft_flags) \
".pushsection .altinstructions,\"a\"\n" \
" .long 771b - .\n" /* label */ \
" .long 774f - .\n" /* new instruction */ \
" .4byte " __stringify(ft_flags) "\n" /* feature + flags */ \
- " .byte " n_alt_total_slen "\n" /* source len */ \
- " .byte " n_alt_rlen "\n" /* replacement len */ \
+ " .byte " alt_total_slen "\n" /* source len */ \
+ " .byte " alt_rlen "\n" /* replacement len */ \
".popsection\n"

-#define ALTINSTR_REPLACEMENT(newinstr, num) /* replacement */ \
- "# ALT: replacement " #num "\n" \
- b_replacement(num)":\n\t" newinstr "\n" e_replacement(num) ":\n"
-
-#define N_ALTINSTR_REPLACEMENT(newinstr) /* replacement */ \
- ".pushsection .altinstr_replacement, \"ax\"\n" \
- "# N_ALT: replacement\n" \
- "774:\n\t" newinstr "\n775:\n" \
+#define ALTINSTR_REPLACEMENT(newinstr) /* replacement */ \
+ ".pushsection .altinstr_replacement, \"ax\"\n" \
+ "# ALT: replacement\n" \
+ "774:\n\t" newinstr "\n775:\n" \
".popsection\n"

/* alternative assembly primitive: */
#define ALTERNATIVE(oldinstr, newinstr, ft_flags) \
- OLDINSTR(oldinstr, 1) \
- ".pushsection .altinstructions,\"a\"\n" \
- ALTINSTR_ENTRY(ft_flags, 1) \
- ".popsection\n" \
- ".pushsection .altinstr_replacement, \"ax\"\n" \
- ALTINSTR_REPLACEMENT(newinstr, 1) \
- ".popsection\n"
-
-/* Nested alternatives macro variant */
-#define N_ALTERNATIVE(oldinstr, newinstr, ft_flags) \
- N_OLDINSTR(oldinstr) \
- N_ALTINSTR_ENTRY(ft_flags) \
- N_ALTINSTR_REPLACEMENT(newinstr)
+ OLDINSTR(oldinstr) \
+ ALTINSTR_ENTRY(ft_flags) \
+ ALTINSTR_REPLACEMENT(newinstr)

#define ALTERNATIVE_2(oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2) \
- OLDINSTR_2(oldinstr, 1, 2) \
- ".pushsection .altinstructions,\"a\"\n" \
- ALTINSTR_ENTRY(ft_flags1, 1) \
- ALTINSTR_ENTRY(ft_flags2, 2) \
- ".popsection\n" \
- ".pushsection .altinstr_replacement, \"ax\"\n" \
- ALTINSTR_REPLACEMENT(newinstr1, 1) \
- ALTINSTR_REPLACEMENT(newinstr2, 2) \
- ".popsection\n"
-
-#define N_ALTERNATIVE_2(oldinst, newinst1, flag1, newinst2, flag2) \
- N_ALTERNATIVE(N_ALTERNATIVE(oldinst, newinst1, flag1), \
- newinst2, flag2)
+ ALTERNATIVE(ALTERNATIVE(oldinstr, newinstr1, ft_flags1), newinstr2, ft_flags2)

/* If @feature is set, patch in @newinstr_yes, otherwise @newinstr_no. */
#define ALTERNATIVE_TERNARY(oldinstr, ft_flags, newinstr_yes, newinstr_no) \
- N_ALTERNATIVE_2(oldinstr, newinstr_no, X86_FEATURE_ALWAYS, \
- newinstr_yes, ft_flags)
+ ALTERNATIVE_2(oldinstr, newinstr_no, X86_FEATURE_ALWAYS, newinstr_yes, ft_flags)

#define ALTERNATIVE_3(oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2, \
newinstr3, ft_flags3) \
- N_ALTERNATIVE(N_ALTERNATIVE_2(oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2), \
+ ALTERNATIVE(ALTERNATIVE_2(oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2), \
newinstr3, ft_flags3)
+
/*
* Alternative instructions for different CPU types or capabilities.
*
@@ -294,10 +214,10 @@ static inline int alternatives_text_reserved(void *start, void *end)
* without volatile and memory clobber.
*/
#define alternative(oldinstr, newinstr, ft_flags) \
- asm_inline volatile(N_ALTERNATIVE(oldinstr, newinstr, ft_flags) : : : "memory")
+ asm_inline volatile(ALTERNATIVE(oldinstr, newinstr, ft_flags) : : : "memory")

#define alternative_2(oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2) \
- asm_inline volatile(N_ALTERNATIVE_2(oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2) ::: "memory")
+ asm_inline volatile(ALTERNATIVE_2(oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2) ::: "memory")

/*
* Alternative inline assembly with input.
@@ -308,12 +228,12 @@ static inline int alternatives_text_reserved(void *start, void *end)
* Leaving an unused argument 0 to keep API compatibility.
*/
#define alternative_input(oldinstr, newinstr, ft_flags, input...) \
- asm_inline volatile(N_ALTERNATIVE(oldinstr, newinstr, ft_flags) \
+ asm_inline volatile(ALTERNATIVE(oldinstr, newinstr, ft_flags) \
: : "i" (0), ## input)

/* Like alternative_input, but with a single output argument */
#define alternative_io(oldinstr, newinstr, ft_flags, output, input...) \
- asm_inline volatile(N_ALTERNATIVE(oldinstr, newinstr, ft_flags) \
+ asm_inline volatile(ALTERNATIVE(oldinstr, newinstr, ft_flags) \
: output : "i" (0), ## input)

/*
@@ -327,7 +247,7 @@ static inline int alternatives_text_reserved(void *start, void *end)
* suffix.
*/
#define alternative_call(oldfunc, newfunc, ft_flags, output, input...) \
- asm_inline volatile(N_ALTERNATIVE("call %c[old]", "call %c[new]", ft_flags) \
+ asm_inline volatile(ALTERNATIVE("call %c[old]", "call %c[new]", ft_flags) \
: output : [old] "i" (oldfunc), [new] "i" (newfunc), ## input)

/*
@@ -338,7 +258,7 @@ static inline int alternatives_text_reserved(void *start, void *end)
*/
#define alternative_call_2(oldfunc, newfunc1, ft_flags1, newfunc2, ft_flags2, \
output, input...) \
- asm_inline volatile(N_ALTERNATIVE_2("call %c[old]", "call %c[new1]", ft_flags1, \
+ asm_inline volatile(ALTERNATIVE_2("call %c[old]", "call %c[new1]", ft_flags1, \
"call %c[new2]", ft_flags2) \
: output, ASM_CALL_CONSTRAINT \
: [old] "i" (oldfunc), [new1] "i" (newfunc1), \
@@ -422,7 +342,7 @@ void nop_func(void);
* @newinstr. ".skip" directive takes care of proper instruction padding
* in case @newinstr is longer than @oldinstr.
*/
-#define __N_ALTERNATIVE(oldinst, newinst, flag) \
+#define __ALTERNATIVE(oldinst, newinst, flag) \
740: \
oldinst ; \
741: \
@@ -438,7 +358,7 @@ void nop_func(void);
.popsection ;

.macro ALTERNATIVE oldinstr, newinstr, ft_flags
- __N_ALTERNATIVE(\oldinstr, \newinstr, \ft_flags)
+ __ALTERNATIVE(\oldinstr, \newinstr, \ft_flags)
.endm

#define old_len 141b-140b
@@ -461,12 +381,12 @@ void nop_func(void);
* @feature2, it replaces @oldinstr with @feature2.
*/
.macro ALTERNATIVE_2 oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2
- __N_ALTERNATIVE(__N_ALTERNATIVE(\oldinstr, \newinstr1, \ft_flags1),
+ __ALTERNATIVE(__ALTERNATIVE(\oldinstr, \newinstr1, \ft_flags1),
\newinstr2, \ft_flags2)
.endm

.macro ALTERNATIVE_3 oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2, newinstr3, ft_flags3
- __N_ALTERNATIVE(N_ALTERNATIVE_2(\oldinstr, \newinstr1, \ft_flags1, \newinstr2, \ft_flags2),
+ __ALTERNATIVE(ALTERNATIVE_2(\oldinstr, \newinstr1, \ft_flags1, \newinstr2, \ft_flags2),
\newinstr3, \ft_flags3)
.endm

--
2.43.0

2024-06-07 11:21:02

by Borislav Petkov

Subject: [PATCH v1 11/14] x86/alternative: Convert the asm ALTERNATIVE() macro

From: "Borislav Petkov (AMD)" <[email protected]>

Signed-off-by: Borislav Petkov (AMD) <[email protected]>
---
arch/x86/include/asm/alternative.h | 22 +---------------------
1 file changed, 1 insertion(+), 21 deletions(-)

diff --git a/arch/x86/include/asm/alternative.h b/arch/x86/include/asm/alternative.h
index fba12ad237e2..31b9a47b9df9 100644
--- a/arch/x86/include/asm/alternative.h
+++ b/arch/x86/include/asm/alternative.h
@@ -422,24 +422,6 @@ void nop_func(void);
* @newinstr. ".skip" directive takes care of proper instruction padding
* in case @newinstr is longer than @oldinstr.
*/
-.macro ALTERNATIVE oldinstr, newinstr, ft_flags
-140:
- \oldinstr
-141:
- .skip -(((144f-143f)-(141b-140b)) > 0) * ((144f-143f)-(141b-140b)),0x90
-142:
-
- .pushsection .altinstructions,"a"
- altinstr_entry 140b,143f,\ft_flags,142b-140b,144f-143f
- .popsection
-
- .pushsection .altinstr_replacement,"ax"
-143:
- \newinstr
-144:
- .popsection
-.endm
-
#define __N_ALTERNATIVE(oldinst, newinst, flag) \
740: \
oldinst ; \
@@ -455,12 +437,10 @@ void nop_func(void);
744: \
.popsection ;

-
-.macro N_ALTERNATIVE oldinstr, newinstr, ft_flags
+.macro ALTERNATIVE oldinstr, newinstr, ft_flags
__N_ALTERNATIVE(\oldinstr, \newinstr, \ft_flags)
.endm

-
#define old_len 141b-140b
#define new_len1 144f-143f
#define new_len2 145f-144f
--
2.43.0

2024-06-11 14:06:50

by Borislav Petkov

Subject: Re: [PATCH v1 00/14] x86/alternatives: Nest them

On June 11, 2024 3:26:09 PM GMT+02:00, Peter Zijlstra <[email protected]> wrote:
>On Fri, Jun 07, 2024 at 01:16:47PM +0200, Borislav Petkov wrote:
>
>> Borislav Petkov (AMD) (13):
>> x86/alternative: Zap alternative_ternary()
>> x86/alternative: Convert alternative()
>> x86/alternative: Convert alternative_2()
>> x86/alternative: Convert alternative_input()
>> x86/alternative: Convert alternative_io()
>> x86/alternative: Convert alternative_call()
>> x86/alternative: Convert alternative_call_2()
>> x86/alternative: Convert ALTERNATIVE_TERNARY()
>> x86/alternative: Convert ALTERNATIVE_3()
>> x86/alternative: Convert the asm ALTERNATIVE() macro
>> x86/alternative: Convert the asm ALTERNATIVE_2() macro
>> x86/alternative: Convert the asm ALTERNATIVE_3() macro
>> x86/alternative: Replace the old macros
>>
>> Peter Zijlstra (1):
>> x86/alternatives: Add nested alternatives macros
>>
>> arch/x86/include/asm/alternative.h | 225 +++++++++--------------------
>> arch/x86/kernel/alternative.c | 20 ++-
>> arch/x86/kernel/fpu/xstate.h | 14 +-
>> tools/objtool/arch/x86/special.c | 23 +++
>> tools/objtool/special.c | 16 +-
>> 5 files changed, 125 insertions(+), 173 deletions(-)
>
>The whole back and forth with the n_foo things ia weird, but sure, have
>at.
>
>Acked-by: Peter Zijlstra (Intel) <[email protected]>

Thanks, yeah it is in the 0th mail:

"For ease of bisection, the old macros are converted to the new, nested
variants in a step-by-step manner so that in case an issue is
encountered during testing, one can pinpoint the place where it fails
easier. Because debugging alternatives is a serious pain."

If you remember, your original patch had this issue where it would confuse two back-to-back .altinstr entries for nested because you were comparing only the offsets and they happened to be equal, by l

Now debugging *that* was insane and I managed to find the issue only when I started converting each place one-by-one and booting each one step.

That's why this superficial split is all about. We will appreciate it later. I hope not but if something explodes, bisection will be a lot easier this way.

I hope this makes sense.


--
Sent from a small device: formatting sucks and brevity is inevitable.

2024-06-11 14:46:58

by Peter Zijlstra

Subject: Re: [PATCH v1 00/14] x86/alternatives: Nest them

On Fri, Jun 07, 2024 at 01:16:47PM +0200, Borislav Petkov wrote:

> Borislav Petkov (AMD) (13):
> x86/alternative: Zap alternative_ternary()
> x86/alternative: Convert alternative()
> x86/alternative: Convert alternative_2()
> x86/alternative: Convert alternative_input()
> x86/alternative: Convert alternative_io()
> x86/alternative: Convert alternative_call()
> x86/alternative: Convert alternative_call_2()
> x86/alternative: Convert ALTERNATIVE_TERNARY()
> x86/alternative: Convert ALTERNATIVE_3()
> x86/alternative: Convert the asm ALTERNATIVE() macro
> x86/alternative: Convert the asm ALTERNATIVE_2() macro
> x86/alternative: Convert the asm ALTERNATIVE_3() macro
> x86/alternative: Replace the old macros
>
> Peter Zijlstra (1):
> x86/alternatives: Add nested alternatives macros
>
> arch/x86/include/asm/alternative.h | 225 +++++++++--------------------
> arch/x86/kernel/alternative.c | 20 ++-
> arch/x86/kernel/fpu/xstate.h | 14 +-
> tools/objtool/arch/x86/special.c | 23 +++
> tools/objtool/special.c | 16 +-
> 5 files changed, 125 insertions(+), 173 deletions(-)

The whole back and forth with the n_foo things ia weird, but sure, have
at.

Acked-by: Peter Zijlstra (Intel) <[email protected]>

2024-06-11 16:15:02

by Peter Zijlstra

Subject: Re: [PATCH v1 14/14] x86/alternative: Replace the old macros

On Fri, Jun 07, 2024 at 01:17:01PM +0200, Borislav Petkov wrote:
> From: "Borislav Petkov (AMD)" <[email protected]>
>
> Now that the new macros have been gradually put in place, replace the
> old ones. Leave the new label numbers starting at 7xx as a hint that the
> new nested alternatives are being used now.

You forgot to kill alt_max_[23]().

2024-06-11 16:54:40

by tip-bot2 for Alexey Makhalov

Subject: [tip: x86/alternatives] x86/alternative: Convert the asm ALTERNATIVE_2() macro

The following commit has been merged into the x86/alternatives branch of tip:

Commit-ID: 08a621fcf4a4a4d765315ffe6a28f5d31e8237b2
Gitweb: https://git.kernel.org/tip/08a621fcf4a4a4d765315ffe6a28f5d31e8237b2
Author: Borislav Petkov (AMD) <[email protected]>
AuthorDate: Fri, 07 Jun 2024 13:16:59 +02:00
Committer: Borislav Petkov (AMD) <[email protected]>
CommitterDate: Tue, 11 Jun 2024 18:27:14 +02:00

x86/alternative: Convert the asm ALTERNATIVE_2() macro

Signed-off-by: Borislav Petkov (AMD) <[email protected]>
Acked-by: Peter Zijlstra (Intel) <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
---
arch/x86/include/asm/alternative.h | 22 ----------------------
1 file changed, 22 deletions(-)

diff --git a/arch/x86/include/asm/alternative.h b/arch/x86/include/asm/alternative.h
index 31b9a47..28e07a0 100644
--- a/arch/x86/include/asm/alternative.h
+++ b/arch/x86/include/asm/alternative.h
@@ -461,28 +461,6 @@ void nop_func(void);
* @feature2, it replaces @oldinstr with @feature2.
*/
.macro ALTERNATIVE_2 oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2
-140:
- \oldinstr
-141:
- .skip -((alt_max_2(new_len1, new_len2) - (old_len)) > 0) * \
- (alt_max_2(new_len1, new_len2) - (old_len)),0x90
-142:
-
- .pushsection .altinstructions,"a"
- altinstr_entry 140b,143f,\ft_flags1,142b-140b,144f-143f
- altinstr_entry 140b,144f,\ft_flags2,142b-140b,145f-144f
- .popsection
-
- .pushsection .altinstr_replacement,"ax"
-143:
- \newinstr1
-144:
- \newinstr2
-145:
- .popsection
-.endm
-
-.macro N_ALTERNATIVE_2 oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2
__N_ALTERNATIVE(__N_ALTERNATIVE(\oldinstr, \newinstr1, \ft_flags1),
\newinstr2, \ft_flags2)
.endm

2024-06-11 16:54:51

by tip-bot2 for Alexey Makhalov

Subject: [tip: x86/alternatives] x86/alternative: Convert the asm ALTERNATIVE() macro

The following commit has been merged into the x86/alternatives branch of tip:

Commit-ID: a6c7a6a18b10a4ac0913e7abdbdce928a2601bdb
Gitweb: https://git.kernel.org/tip/a6c7a6a18b10a4ac0913e7abdbdce928a2601bdb
Author: Borislav Petkov (AMD) <[email protected]>
AuthorDate: Fri, 07 Jun 2024 13:16:58 +02:00
Committer: Borislav Petkov (AMD) <[email protected]>
CommitterDate: Tue, 11 Jun 2024 18:25:00 +02:00

x86/alternative: Convert the asm ALTERNATIVE() macro

Signed-off-by: Borislav Petkov (AMD) <[email protected]>
Acked-by: Peter Zijlstra (Intel) <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
---
arch/x86/include/asm/alternative.h | 22 +---------------------
1 file changed, 1 insertion(+), 21 deletions(-)

diff --git a/arch/x86/include/asm/alternative.h b/arch/x86/include/asm/alternative.h
index fba12ad..31b9a47 100644
--- a/arch/x86/include/asm/alternative.h
+++ b/arch/x86/include/asm/alternative.h
@@ -422,24 +422,6 @@ void nop_func(void);
* @newinstr. ".skip" directive takes care of proper instruction padding
* in case @newinstr is longer than @oldinstr.
*/
-.macro ALTERNATIVE oldinstr, newinstr, ft_flags
-140:
- \oldinstr
-141:
- .skip -(((144f-143f)-(141b-140b)) > 0) * ((144f-143f)-(141b-140b)),0x90
-142:
-
- .pushsection .altinstructions,"a"
- altinstr_entry 140b,143f,\ft_flags,142b-140b,144f-143f
- .popsection
-
- .pushsection .altinstr_replacement,"ax"
-143:
- \newinstr
-144:
- .popsection
-.endm
-
#define __N_ALTERNATIVE(oldinst, newinst, flag) \
740: \
oldinst ; \
@@ -455,12 +437,10 @@ void nop_func(void);
744: \
.popsection ;

-
-.macro N_ALTERNATIVE oldinstr, newinstr, ft_flags
+.macro ALTERNATIVE oldinstr, newinstr, ft_flags
__N_ALTERNATIVE(\oldinstr, \newinstr, \ft_flags)
.endm

-
#define old_len 141b-140b
#define new_len1 144f-143f
#define new_len2 145f-144f

2024-06-11 16:54:53

by tip-bot2 for Alexey Makhalov

Subject: [tip: x86/alternatives] x86/alternative: Convert the asm ALTERNATIVE_3() macro

The following commit has been merged into the x86/alternatives branch of tip:

Commit-ID: 1a6ade825079243f08846870561aca0e1fdfb803
Gitweb: https://git.kernel.org/tip/1a6ade825079243f08846870561aca0e1fdfb803
Author: Borislav Petkov (AMD) <[email protected]>
AuthorDate: Fri, 07 Jun 2024 13:17:00 +02:00
Committer: Borislav Petkov (AMD) <[email protected]>
CommitterDate: Tue, 11 Jun 2024 18:29:26 +02:00

x86/alternative: Convert the asm ALTERNATIVE_3() macro

Signed-off-by: Borislav Petkov (AMD) <[email protected]>
Acked-by: Peter Zijlstra (Intel) <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
---
arch/x86/include/asm/alternative.h | 25 -------------------------
1 file changed, 25 deletions(-)

diff --git a/arch/x86/include/asm/alternative.h b/arch/x86/include/asm/alternative.h
index 28e07a0..5278cfb 100644
--- a/arch/x86/include/asm/alternative.h
+++ b/arch/x86/include/asm/alternative.h
@@ -466,31 +466,6 @@ void nop_func(void);
.endm

.macro ALTERNATIVE_3 oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2, newinstr3, ft_flags3
-140:
- \oldinstr
-141:
- .skip -((alt_max_3(new_len1, new_len2, new_len3) - (old_len)) > 0) * \
- (alt_max_3(new_len1, new_len2, new_len3) - (old_len)),0x90
-142:
-
- .pushsection .altinstructions,"a"
- altinstr_entry 140b,143f,\ft_flags1,142b-140b,144f-143f
- altinstr_entry 140b,144f,\ft_flags2,142b-140b,145f-144f
- altinstr_entry 140b,145f,\ft_flags3,142b-140b,146f-145f
- .popsection
-
- .pushsection .altinstr_replacement,"ax"
-143:
- \newinstr1
-144:
- \newinstr2
-145:
- \newinstr3
-146:
- .popsection
-.endm
-
-.macro N_ALTERNATIVE_3 oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2, newinstr3, ft_flags3
__N_ALTERNATIVE(N_ALTERNATIVE_2(\oldinstr, \newinstr1, \ft_flags1, \newinstr2, \ft_flags2),
\newinstr3, \ft_flags3)
.endm

2024-06-11 16:55:16

by tip-bot2 for Alexey Makhalov

Subject: [tip: x86/alternatives] x86/alternative: Convert ALTERNATIVE_3()

The following commit has been merged into the x86/alternatives branch of tip:

Commit-ID: 93694129c6e84d3013f5b2787e2ff88dd706c4f0
Gitweb: https://git.kernel.org/tip/93694129c6e84d3013f5b2787e2ff88dd706c4f0
Author: Borislav Petkov (AMD) <[email protected]>
AuthorDate: Fri, 07 Jun 2024 13:16:57 +02:00
Committer: Borislav Petkov (AMD) <[email protected]>
CommitterDate: Tue, 11 Jun 2024 18:22:41 +02:00

x86/alternative: Convert ALTERNATIVE_3()

Zap the hack of using an ALTERNATIVE_3() internal label, as suggested by
bgerst:

https://lore.kernel.org/r/CAMzpN2i4oJ-Dv0qO46Fd-DxNv5z9=x%2BvO%[email protected]

in favor of a label local to this macro only, as it should be done.

Signed-off-by: Borislav Petkov (AMD) <[email protected]>
Acked-by: Peter Zijlstra (Intel) <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
---
arch/x86/include/asm/alternative.h | 24 ++++--------------------
arch/x86/kernel/fpu/xstate.h | 14 +++++---------
2 files changed, 9 insertions(+), 29 deletions(-)

diff --git a/arch/x86/include/asm/alternative.h b/arch/x86/include/asm/alternative.h
index 007baab..fba12ad 100644
--- a/arch/x86/include/asm/alternative.h
+++ b/arch/x86/include/asm/alternative.h
@@ -277,26 +277,10 @@ static inline int alternatives_text_reserved(void *start, void *end)
N_ALTERNATIVE_2(oldinstr, newinstr_no, X86_FEATURE_ALWAYS, \
newinstr_yes, ft_flags)

-#define ALTERNATIVE_3(oldinsn, newinsn1, ft_flags1, newinsn2, ft_flags2, \
- newinsn3, ft_flags3) \
- OLDINSTR_3(oldinsn, 1, 2, 3) \
- ".pushsection .altinstructions,\"a\"\n" \
- ALTINSTR_ENTRY(ft_flags1, 1) \
- ALTINSTR_ENTRY(ft_flags2, 2) \
- ALTINSTR_ENTRY(ft_flags3, 3) \
- ".popsection\n" \
- ".pushsection .altinstr_replacement, \"ax\"\n" \
- ALTINSTR_REPLACEMENT(newinsn1, 1) \
- ALTINSTR_REPLACEMENT(newinsn2, 2) \
- ALTINSTR_REPLACEMENT(newinsn3, 3) \
- ".popsection\n"
-
-
-#define N_ALTERNATIVE_3(oldinst, newinst1, flag1, newinst2, flag2, \
- newinst3, flag3) \
- N_ALTERNATIVE(N_ALTERNATIVE_2(oldinst, newinst1, flag1, newinst2, flag2), \
- newinst3, flag3)
-
+#define ALTERNATIVE_3(oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2, \
+ newinstr3, ft_flags3) \
+ N_ALTERNATIVE(N_ALTERNATIVE_2(oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2), \
+ newinstr3, ft_flags3)
/*
* Alternative instructions for different CPU types or capabilities.
*
diff --git a/arch/x86/kernel/fpu/xstate.h b/arch/x86/kernel/fpu/xstate.h
index 05df04f..2ee0b9c 100644
--- a/arch/x86/kernel/fpu/xstate.h
+++ b/arch/x86/kernel/fpu/xstate.h
@@ -106,21 +106,17 @@ static inline u64 xfeatures_mask_independent(void)
* Otherwise, if XSAVEOPT is enabled, XSAVEOPT replaces XSAVE because XSAVEOPT
* supports modified optimization which is not supported by XSAVE.
*
- * We use XSAVE as a fallback.
- *
- * The 661 label is defined in the ALTERNATIVE* macros as the address of the
- * original instruction which gets replaced. We need to use it here as the
- * address of the instruction where we might get an exception at.
+ * Use XSAVE as a fallback.
*/
#define XSTATE_XSAVE(st, lmask, hmask, err) \
- asm volatile(ALTERNATIVE_3(XSAVE, \
+ asm volatile("1: " ALTERNATIVE_3(XSAVE, \
XSAVEOPT, X86_FEATURE_XSAVEOPT, \
XSAVEC, X86_FEATURE_XSAVEC, \
XSAVES, X86_FEATURE_XSAVES) \
"\n" \
"xor %[err], %[err]\n" \
"3:\n" \
- _ASM_EXTABLE_TYPE_REG(661b, 3b, EX_TYPE_EFAULT_REG, %[err]) \
+ _ASM_EXTABLE_TYPE_REG(1b, 3b, EX_TYPE_EFAULT_REG, %[err]) \
: [err] "=r" (err) \
: "D" (st), "m" (*st), "a" (lmask), "d" (hmask) \
: "memory")
@@ -130,11 +126,11 @@ static inline u64 xfeatures_mask_independent(void)
* XSAVE area format.
*/
#define XSTATE_XRESTORE(st, lmask, hmask) \
- asm volatile(ALTERNATIVE(XRSTOR, \
+ asm volatile("1: " ALTERNATIVE(XRSTOR, \
XRSTORS, X86_FEATURE_XSAVES) \
"\n" \
"3:\n" \
- _ASM_EXTABLE_TYPE(661b, 3b, EX_TYPE_FPU_RESTORE) \
+ _ASM_EXTABLE_TYPE(1b, 3b, EX_TYPE_FPU_RESTORE) \
: \
: "D" (st), "m" (*st), "a" (lmask), "d" (hmask) \
: "memory")

2024-06-11 16:55:35

by tip-bot2 for Alexey Makhalov

Subject: [tip: x86/alternatives] x86/alternative: Convert ALTERNATIVE_TERNARY()

The following commit has been merged into the x86/alternatives branch of tip:

Commit-ID: d2d302b1bbe28dba3bd8da855ac9c16aa5dbd00e
Gitweb: https://git.kernel.org/tip/d2d302b1bbe28dba3bd8da855ac9c16aa5dbd00e
Author: Borislav Petkov (AMD) <[email protected]>
AuthorDate: Fri, 07 Jun 2024 13:16:56 +02:00
Committer: Borislav Petkov (AMD) <[email protected]>
CommitterDate: Tue, 11 Jun 2024 18:20:41 +02:00

x86/alternative: Convert ALTERNATIVE_TERNARY()

The C macro.

Signed-off-by: Borislav Petkov (AMD) <[email protected]>
Acked-by: Peter Zijlstra (Intel) <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
---
arch/x86/include/asm/alternative.h | 6 ------
1 file changed, 6 deletions(-)

diff --git a/arch/x86/include/asm/alternative.h b/arch/x86/include/asm/alternative.h
index bc260f2..007baab 100644
--- a/arch/x86/include/asm/alternative.h
+++ b/arch/x86/include/asm/alternative.h
@@ -274,15 +274,9 @@ static inline int alternatives_text_reserved(void *start, void *end)

/* If @feature is set, patch in @newinstr_yes, otherwise @newinstr_no. */
#define ALTERNATIVE_TERNARY(oldinstr, ft_flags, newinstr_yes, newinstr_no) \
- ALTERNATIVE_2(oldinstr, newinstr_no, X86_FEATURE_ALWAYS, \
- newinstr_yes, ft_flags)
-
-/* If @feature is set, patch in @newinstr_yes, otherwise @newinstr_no. */
-#define N_ALTERNATIVE_TERNARY(oldinstr, ft_flags, newinstr_yes, newinstr_no) \
N_ALTERNATIVE_2(oldinstr, newinstr_no, X86_FEATURE_ALWAYS, \
newinstr_yes, ft_flags)

-
#define ALTERNATIVE_3(oldinsn, newinsn1, ft_flags1, newinsn2, ft_flags2, \
newinsn3, ft_flags3) \
OLDINSTR_3(oldinsn, 1, 2, 3) \

2024-06-11 16:55:48

by tip-bot2 for Alexey Makhalov

Subject: [tip: x86/alternatives] x86/alternative: Convert alternative_call_2()

The following commit has been merged into the x86/alternatives branch of tip:

Commit-ID: 719ac02347ee5f94a9f3d5c2fe84640f855432a9
Gitweb: https://git.kernel.org/tip/719ac02347ee5f94a9f3d5c2fe84640f855432a9
Author: Borislav Petkov (AMD) <[email protected]>
AuthorDate: Fri, 07 Jun 2024 13:16:55 +02:00
Committer: Borislav Petkov (AMD) <[email protected]>
CommitterDate: Tue, 11 Jun 2024 18:17:10 +02:00

x86/alternative: Convert alternative_call_2()

Signed-off-by: Borislav Petkov (AMD) <[email protected]>
Acked-by: Peter Zijlstra (Intel) <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
---
arch/x86/include/asm/alternative.h | 21 ++++++---------------
1 file changed, 6 insertions(+), 15 deletions(-)

diff --git a/arch/x86/include/asm/alternative.h b/arch/x86/include/asm/alternative.h
index b659757..bc260f2 100644
--- a/arch/x86/include/asm/alternative.h
+++ b/arch/x86/include/asm/alternative.h
@@ -358,23 +358,14 @@ static inline int alternatives_text_reserved(void *start, void *end)
* Otherwise, if CPU has feature1, function1 is used.
* Otherwise, old function is used.
*/
-#define alternative_call_2(oldfunc, newfunc1, ft_flags1, newfunc2, ft_flags2, \
- output, input...) \
- asm_inline volatile (ALTERNATIVE_2("call %c[old]", "call %c[new1]", ft_flags1, \
- "call %c[new2]", ft_flags2) \
- : output, ASM_CALL_CONSTRAINT \
- : [old] "i" (oldfunc), [new1] "i" (newfunc1), \
+#define alternative_call_2(oldfunc, newfunc1, ft_flags1, newfunc2, ft_flags2, \
+ output, input...) \
+ asm_inline volatile(N_ALTERNATIVE_2("call %c[old]", "call %c[new1]", ft_flags1, \
+ "call %c[new2]", ft_flags2) \
+ : output, ASM_CALL_CONSTRAINT \
+ : [old] "i" (oldfunc), [new1] "i" (newfunc1), \
[new2] "i" (newfunc2), ## input)

-#define n_alternative_call_2(oldfunc, newfunc1, ft_flags1, newfunc2, ft_flags2, \
- output, input...) \
- asm_inline volatile (N_ALTERNATIVE_2("call %c[old]", "call %c[new1]", ft_flags1,\
- "call %c[new2]", ft_flags2) \
- : output, ASM_CALL_CONSTRAINT \
- : [old] "i" (oldfunc), [new1] "i" (newfunc1), \
- [new2] "i" (newfunc2), ## input)
-
-
/*
* use this macro(s) if you need more than one output parameter
* in alternative_io

2024-06-11 16:56:09

by tip-bot2 for Alexey Makhalov

Subject: [tip: x86/alternatives] x86/alternative: Convert alternative_call()

The following commit has been merged into the x86/alternatives branch of tip:

Commit-ID: a880f9ef6bf7edc36753a9e40388d42ae8d7e099
Gitweb: https://git.kernel.org/tip/a880f9ef6bf7edc36753a9e40388d42ae8d7e099
Author: Borislav Petkov (AMD) <[email protected]>
AuthorDate: Fri, 07 Jun 2024 13:16:54 +02:00
Committer: Borislav Petkov (AMD) <[email protected]>
CommitterDate: Tue, 11 Jun 2024 18:15:03 +02:00

x86/alternative: Convert alternative_call()

Signed-off-by: Borislav Petkov (AMD) <[email protected]>
Acked-by: Peter Zijlstra (Intel) <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
---
arch/x86/include/asm/alternative.h | 6 +-----
1 file changed, 1 insertion(+), 5 deletions(-)

diff --git a/arch/x86/include/asm/alternative.h b/arch/x86/include/asm/alternative.h
index 6a74681..b659757 100644
--- a/arch/x86/include/asm/alternative.h
+++ b/arch/x86/include/asm/alternative.h
@@ -349,11 +349,7 @@ static inline int alternatives_text_reserved(void *start, void *end)
* suffix.
*/
#define alternative_call(oldfunc, newfunc, ft_flags, output, input...) \
- asm_inline volatile (ALTERNATIVE("call %c[old]", "call %c[new]", ft_flags) \
- : output : [old] "i" (oldfunc), [new] "i" (newfunc), ## input)
-
-#define n_alternative_call(oldfunc, newfunc, ft_flags, output, input...) \
- asm_inline volatile (N_ALTERNATIVE("call %c[old]", "call %c[new]", ft_flags) \
+ asm_inline volatile(N_ALTERNATIVE("call %c[old]", "call %c[new]", ft_flags) \
: output : [old] "i" (oldfunc), [new] "i" (newfunc), ## input)

/*

2024-06-11 16:56:14

by tip-bot2 for Alexey Makhalov

Subject: [tip: x86/alternatives] x86/alternative: Convert alternative_2()

The following commit has been merged into the x86/alternatives branch of tip:

Commit-ID: 8cb1f14b707d3d9b7d2b330c0acd62537576c6a7
Gitweb: https://git.kernel.org/tip/8cb1f14b707d3d9b7d2b330c0acd62537576c6a7
Author: Borislav Petkov (AMD) <[email protected]>
AuthorDate: Fri, 07 Jun 2024 13:16:51 +02:00
Committer: Borislav Petkov (AMD) <[email protected]>
CommitterDate: Tue, 11 Jun 2024 18:06:58 +02:00

x86/alternative: Convert alternative_2()

Signed-off-by: Borislav Petkov (AMD) <[email protected]>
Acked-by: Peter Zijlstra (Intel) <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
---
arch/x86/include/asm/alternative.h | 3 ---
1 file changed, 3 deletions(-)

diff --git a/arch/x86/include/asm/alternative.h b/arch/x86/include/asm/alternative.h
index c05bff2..21ead5d 100644
--- a/arch/x86/include/asm/alternative.h
+++ b/arch/x86/include/asm/alternative.h
@@ -319,9 +319,6 @@ static inline int alternatives_text_reserved(void *start, void *end)
asm_inline volatile(N_ALTERNATIVE(oldinstr, newinstr, ft_flags) : : : "memory")

#define alternative_2(oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2) \
- asm_inline volatile(ALTERNATIVE_2(oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2) ::: "memory")
-
-#define n_alternative_2(oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2) \
asm_inline volatile(N_ALTERNATIVE_2(oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2) ::: "memory")

/*

2024-06-11 16:56:34

by tip-bot2 for Alexey Makhalov

Subject: [tip: x86/alternatives] x86/alternative: Convert alternative_io()

The following commit has been merged into the x86/alternatives branch of tip:

Commit-ID: ad36085ee3563001cf1720eeb93c2e85715eb5cd
Gitweb: https://git.kernel.org/tip/ad36085ee3563001cf1720eeb93c2e85715eb5cd
Author: Borislav Petkov (AMD) <[email protected]>
AuthorDate: Fri, 07 Jun 2024 13:16:53 +02:00
Committer: Borislav Petkov (AMD) <[email protected]>
CommitterDate: Tue, 11 Jun 2024 18:12:29 +02:00

x86/alternative: Convert alternative_io()

Signed-off-by: Borislav Petkov (AMD) <[email protected]>
Acked-by: Peter Zijlstra (Intel) <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
---
arch/x86/include/asm/alternative.h | 6 +-----
1 file changed, 1 insertion(+), 5 deletions(-)

diff --git a/arch/x86/include/asm/alternative.h b/arch/x86/include/asm/alternative.h
index 428d6ef..6a74681 100644
--- a/arch/x86/include/asm/alternative.h
+++ b/arch/x86/include/asm/alternative.h
@@ -335,11 +335,7 @@ static inline int alternatives_text_reserved(void *start, void *end)

/* Like alternative_input, but with a single output argument */
#define alternative_io(oldinstr, newinstr, ft_flags, output, input...) \
- asm_inline volatile (ALTERNATIVE(oldinstr, newinstr, ft_flags) \
- : output : "i" (0), ## input)
-
-#define n_alternative_io(oldinstr, newinstr, ft_flags, output, input...) \
- asm_inline volatile (N_ALTERNATIVE(oldinstr, newinstr, ft_flags) \
+ asm_inline volatile(N_ALTERNATIVE(oldinstr, newinstr, ft_flags) \
: output : "i" (0), ## input)

/*

2024-06-11 16:56:58

by tip-bot2 for Alexey Makhalov

Subject: [tip: x86/alternatives] x86/alternative: Convert alternative()

The following commit has been merged into the x86/alternatives branch of tip:

Commit-ID: b94c1fe10be544070f53e4a1e5164087e446945c
Gitweb: https://git.kernel.org/tip/b94c1fe10be544070f53e4a1e5164087e446945c
Author: Borislav Petkov (AMD) <[email protected]>
AuthorDate: Fri, 07 Jun 2024 13:16:50 +02:00
Committer: Borislav Petkov (AMD) <[email protected]>
CommitterDate: Tue, 11 Jun 2024 17:14:26 +02:00

x86/alternative: Convert alternative()

Split conversion deliberately into minimal pieces to ease bisection
because debugging alternatives is a nightmare.

Signed-off-by: Borislav Petkov (AMD) <[email protected]>
Acked-by: Peter Zijlstra (Intel) <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
---
arch/x86/include/asm/alternative.h | 5 +----
1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/arch/x86/include/asm/alternative.h b/arch/x86/include/asm/alternative.h
index 7d9ebc5..c05bff2 100644
--- a/arch/x86/include/asm/alternative.h
+++ b/arch/x86/include/asm/alternative.h
@@ -316,14 +316,11 @@ static inline int alternatives_text_reserved(void *start, void *end)
* without volatile and memory clobber.
*/
#define alternative(oldinstr, newinstr, ft_flags) \
- asm_inline volatile (ALTERNATIVE(oldinstr, newinstr, ft_flags) : : : "memory")
+ asm_inline volatile(N_ALTERNATIVE(oldinstr, newinstr, ft_flags) : : : "memory")

#define alternative_2(oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2) \
asm_inline volatile(ALTERNATIVE_2(oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2) ::: "memory")

-#define n_alternative(oldinstr, newinstr, ft_flags) \
- asm_inline volatile (N_ALTERNATIVE(oldinstr, newinstr, ft_flags) : : : "memory")
-
#define n_alternative_2(oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2) \
asm_inline volatile(N_ALTERNATIVE_2(oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2) ::: "memory")

2024-06-11 17:02:59

by tip-bot2 for Alexey Makhalov

Subject: [tip: x86/alternatives] x86/alternative: Convert alternative_input()

The following commit has been merged into the x86/alternatives branch of tip:

Commit-ID: bb91576965e79d17e8e23fccdef91c4bf09d1a74
Gitweb: https://git.kernel.org/tip/bb91576965e79d17e8e23fccdef91c4bf09d1a74
Author: Borislav Petkov (AMD) <[email protected]>
AuthorDate: Fri, 07 Jun 2024 13:16:52 +02:00
Committer: Borislav Petkov (AMD) <[email protected]>
CommitterDate: Tue, 11 Jun 2024 18:09:27 +02:00

x86/alternative: Convert alternative_input()

Signed-off-by: Borislav Petkov (AMD) <[email protected]>
Acked-by: Peter Zijlstra (Intel) <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
---
arch/x86/include/asm/alternative.h | 6 +-----
1 file changed, 1 insertion(+), 5 deletions(-)

diff --git a/arch/x86/include/asm/alternative.h b/arch/x86/include/asm/alternative.h
index 21ead5d..428d6ef 100644
--- a/arch/x86/include/asm/alternative.h
+++ b/arch/x86/include/asm/alternative.h
@@ -330,7 +330,7 @@ static inline int alternatives_text_reserved(void *start, void *end)
* Leaving an unused argument 0 to keep API compatibility.
*/
#define alternative_input(oldinstr, newinstr, ft_flags, input...) \
- asm_inline volatile (ALTERNATIVE(oldinstr, newinstr, ft_flags) \
+ asm_inline volatile(N_ALTERNATIVE(oldinstr, newinstr, ft_flags) \
: : "i" (0), ## input)

/* Like alternative_input, but with a single output argument */
@@ -356,10 +356,6 @@ static inline int alternatives_text_reserved(void *start, void *end)
asm_inline volatile (ALTERNATIVE("call %c[old]", "call %c[new]", ft_flags) \
: output : [old] "i" (oldfunc), [new] "i" (newfunc), ## input)

-#define n_alternative_input(oldinstr, newinstr, ft_flags, input...) \
- asm_inline volatile (N_ALTERNATIVE(oldinstr, newinstr, ft_flags) \
- : : "i" (0), ## input)
-
#define n_alternative_call(oldfunc, newfunc, ft_flags, output, input...) \
asm_inline volatile (N_ALTERNATIVE("call %c[old]", "call %c[new]", ft_flags) \
: output : [old] "i" (oldfunc), [new] "i" (newfunc), ## input)

2024-06-11 17:05:17

by tip-bot2 for Alexey Makhalov

Subject: [tip: x86/alternatives] x86/alternative: Replace the old macros

The following commit has been merged into the x86/alternatives branch of tip:

Commit-ID: f776e41fdcc4141876ef6f297318ab04c2382eb7
Gitweb: https://git.kernel.org/tip/f776e41fdcc4141876ef6f297318ab04c2382eb7
Author: Borislav Petkov (AMD) <[email protected]>
AuthorDate: Fri, 07 Jun 2024 13:17:01 +02:00
Committer: Borislav Petkov (AMD) <[email protected]>
CommitterDate: Tue, 11 Jun 2024 18:33:23 +02:00

x86/alternative: Replace the old macros

Now that the new macros have been gradually put in place, replace the
old ones. Leave the new label numbers starting at 7xx as a hint that the
new nested alternatives are being used now.

Signed-off-by: Borislav Petkov (AMD) <[email protected]>
Acked-by: Peter Zijlstra (Intel) <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
---
arch/x86/include/asm/alternative.h | 153 +++++-----------------------
1 file changed, 32 insertions(+), 121 deletions(-)

diff --git a/arch/x86/include/asm/alternative.h b/arch/x86/include/asm/alternative.h
index 5278cfb..89fa50d 100644
--- a/arch/x86/include/asm/alternative.h
+++ b/arch/x86/include/asm/alternative.h
@@ -156,131 +156,51 @@ static inline int alternatives_text_reserved(void *start, void *end)

#define ALT_CALL_INSTR "call BUG_func"

-#define b_replacement(num) "664"#num
-#define e_replacement(num) "665"#num
+#define alt_slen "772b-771b"
+#define alt_total_slen "773b-771b"
+#define alt_rlen "775f-774f"

-#define alt_end_marker "663"
-#define alt_slen "662b-661b"
-#define n_alt_slen "772b-771b"
-
-#define alt_total_slen alt_end_marker"b-661b"
-#define n_alt_total_slen "773b-771b"
-
-#define alt_rlen(num) e_replacement(num)"f-"b_replacement(num)"f"
-#define n_alt_rlen "775f-774f"
-
-#define OLDINSTR(oldinstr, num) \
- "# ALT: oldnstr\n" \
- "661:\n\t" oldinstr "\n662:\n" \
- "# ALT: padding\n" \
- ".skip -(((" alt_rlen(num) ")-(" alt_slen ")) > 0) * " \
- "((" alt_rlen(num) ")-(" alt_slen ")),0x90\n" \
- alt_end_marker ":\n"
-
-#define N_OLDINSTR(oldinstr) \
- "# N_ALT: oldinstr\n" \
+#define OLDINSTR(oldinstr) \
+ "# ALT: oldinstr\n" \
"771:\n\t" oldinstr "\n772:\n" \
- "# N_ALT: padding\n" \
- ".skip -(((" n_alt_rlen ")-(" n_alt_slen ")) > 0) * " \
- "((" n_alt_rlen ")-(" n_alt_slen ")),0x90\n" \
+ "# ALT: padding\n" \
+ ".skip -(((" alt_rlen ")-(" alt_slen ")) > 0) * " \
+ "((" alt_rlen ")-(" alt_slen ")),0x90\n" \
"773:\n"

-/*
- * gas compatible max based on the idea from:
- * http://graphics.stanford.edu/~seander/bithacks.html#IntegerMinOrMax
- *
- * The additional "-" is needed because gas uses a "true" value of -1.
- */
-#define alt_max_short(a, b) "((" a ") ^ (((" a ") ^ (" b ")) & -(-((" a ") < (" b ")))))"
-
-/*
- * Pad the second replacement alternative with additional NOPs if it is
- * additionally longer than the first replacement alternative.
- */
-#define OLDINSTR_2(oldinstr, num1, num2) \
- "# ALT: oldinstr2\n" \
- "661:\n\t" oldinstr "\n662:\n" \
- "# ALT: padding2\n" \
- ".skip -((" alt_max_short(alt_rlen(num1), alt_rlen(num2)) " - (" alt_slen ")) > 0) * " \
- "(" alt_max_short(alt_rlen(num1), alt_rlen(num2)) " - (" alt_slen ")), 0x90\n" \
- alt_end_marker ":\n"
-
-#define OLDINSTR_3(oldinsn, n1, n2, n3) \
- "# ALT: oldinstr3\n" \
- "661:\n\t" oldinsn "\n662:\n" \
- "# ALT: padding3\n" \
- ".skip -((" alt_max_short(alt_max_short(alt_rlen(n1), alt_rlen(n2)), alt_rlen(n3)) \
- " - (" alt_slen ")) > 0) * " \
- "(" alt_max_short(alt_max_short(alt_rlen(n1), alt_rlen(n2)), alt_rlen(n3)) \
- " - (" alt_slen ")), 0x90\n" \
- alt_end_marker ":\n"
-
-#define ALTINSTR_ENTRY(ft_flags, num) \
- " .long 661b - .\n" /* label */ \
- " .long " b_replacement(num)"f - .\n" /* new instruction */ \
- " .4byte " __stringify(ft_flags) "\n" /* feature + flags */ \
- " .byte " alt_total_slen "\n" /* source len */ \
- " .byte " alt_rlen(num) "\n" /* replacement len */
-
-#define N_ALTINSTR_ENTRY(ft_flags) \
+#define ALTINSTR_ENTRY(ft_flags) \
".pushsection .altinstructions,\"a\"\n" \
" .long 771b - .\n" /* label */ \
" .long 774f - .\n" /* new instruction */ \
" .4byte " __stringify(ft_flags) "\n" /* feature + flags */ \
- " .byte " n_alt_total_slen "\n" /* source len */ \
- " .byte " n_alt_rlen "\n" /* replacement len */ \
+ " .byte " alt_total_slen "\n" /* source len */ \
+ " .byte " alt_rlen "\n" /* replacement len */ \
".popsection\n"

-#define ALTINSTR_REPLACEMENT(newinstr, num) /* replacement */ \
- "# ALT: replacement " #num "\n" \
- b_replacement(num)":\n\t" newinstr "\n" e_replacement(num) ":\n"
-
-#define N_ALTINSTR_REPLACEMENT(newinstr) /* replacement */ \
- ".pushsection .altinstr_replacement, \"ax\"\n" \
- "# N_ALT: replacement\n" \
- "774:\n\t" newinstr "\n775:\n" \
+#define ALTINSTR_REPLACEMENT(newinstr) /* replacement */ \
+ ".pushsection .altinstr_replacement, \"ax\"\n" \
+ "# ALT: replacement\n" \
+ "774:\n\t" newinstr "\n775:\n" \
".popsection\n"

/* alternative assembly primitive: */
#define ALTERNATIVE(oldinstr, newinstr, ft_flags) \
- OLDINSTR(oldinstr, 1) \
- ".pushsection .altinstructions,\"a\"\n" \
- ALTINSTR_ENTRY(ft_flags, 1) \
- ".popsection\n" \
- ".pushsection .altinstr_replacement, \"ax\"\n" \
- ALTINSTR_REPLACEMENT(newinstr, 1) \
- ".popsection\n"
-
-/* Nested alternatives macro variant */
-#define N_ALTERNATIVE(oldinstr, newinstr, ft_flags) \
- N_OLDINSTR(oldinstr) \
- N_ALTINSTR_ENTRY(ft_flags) \
- N_ALTINSTR_REPLACEMENT(newinstr)
+ OLDINSTR(oldinstr) \
+ ALTINSTR_ENTRY(ft_flags) \
+ ALTINSTR_REPLACEMENT(newinstr)

#define ALTERNATIVE_2(oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2) \
- OLDINSTR_2(oldinstr, 1, 2) \
- ".pushsection .altinstructions,\"a\"\n" \
- ALTINSTR_ENTRY(ft_flags1, 1) \
- ALTINSTR_ENTRY(ft_flags2, 2) \
- ".popsection\n" \
- ".pushsection .altinstr_replacement, \"ax\"\n" \
- ALTINSTR_REPLACEMENT(newinstr1, 1) \
- ALTINSTR_REPLACEMENT(newinstr2, 2) \
- ".popsection\n"
-
-#define N_ALTERNATIVE_2(oldinst, newinst1, flag1, newinst2, flag2) \
- N_ALTERNATIVE(N_ALTERNATIVE(oldinst, newinst1, flag1), \
- newinst2, flag2)
+ ALTERNATIVE(ALTERNATIVE(oldinstr, newinstr1, ft_flags1), newinstr2, ft_flags2)

/* If @feature is set, patch in @newinstr_yes, otherwise @newinstr_no. */
#define ALTERNATIVE_TERNARY(oldinstr, ft_flags, newinstr_yes, newinstr_no) \
- N_ALTERNATIVE_2(oldinstr, newinstr_no, X86_FEATURE_ALWAYS, \
- newinstr_yes, ft_flags)
+ ALTERNATIVE_2(oldinstr, newinstr_no, X86_FEATURE_ALWAYS, newinstr_yes, ft_flags)

#define ALTERNATIVE_3(oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2, \
newinstr3, ft_flags3) \
- N_ALTERNATIVE(N_ALTERNATIVE_2(oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2), \
+ ALTERNATIVE(ALTERNATIVE_2(oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2), \
newinstr3, ft_flags3)
+
/*
* Alternative instructions for different CPU types or capabilities.
*
@@ -294,10 +214,10 @@ static inline int alternatives_text_reserved(void *start, void *end)
* without volatile and memory clobber.
*/
#define alternative(oldinstr, newinstr, ft_flags) \
- asm_inline volatile(N_ALTERNATIVE(oldinstr, newinstr, ft_flags) : : : "memory")
+ asm_inline volatile(ALTERNATIVE(oldinstr, newinstr, ft_flags) : : : "memory")

#define alternative_2(oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2) \
- asm_inline volatile(N_ALTERNATIVE_2(oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2) ::: "memory")
+ asm_inline volatile(ALTERNATIVE_2(oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2) ::: "memory")

/*
* Alternative inline assembly with input.
@@ -308,12 +228,12 @@ static inline int alternatives_text_reserved(void *start, void *end)
* Leaving an unused argument 0 to keep API compatibility.
*/
#define alternative_input(oldinstr, newinstr, ft_flags, input...) \
- asm_inline volatile(N_ALTERNATIVE(oldinstr, newinstr, ft_flags) \
+ asm_inline volatile(ALTERNATIVE(oldinstr, newinstr, ft_flags) \
: : "i" (0), ## input)

/* Like alternative_input, but with a single output argument */
#define alternative_io(oldinstr, newinstr, ft_flags, output, input...) \
- asm_inline volatile(N_ALTERNATIVE(oldinstr, newinstr, ft_flags) \
+ asm_inline volatile(ALTERNATIVE(oldinstr, newinstr, ft_flags) \
: output : "i" (0), ## input)

/*
@@ -327,7 +247,7 @@ static inline int alternatives_text_reserved(void *start, void *end)
* suffix.
*/
#define alternative_call(oldfunc, newfunc, ft_flags, output, input...) \
- asm_inline volatile(N_ALTERNATIVE("call %c[old]", "call %c[new]", ft_flags) \
+ asm_inline volatile(ALTERNATIVE("call %c[old]", "call %c[new]", ft_flags) \
: output : [old] "i" (oldfunc), [new] "i" (newfunc), ## input)

/*
@@ -338,7 +258,7 @@ static inline int alternatives_text_reserved(void *start, void *end)
*/
#define alternative_call_2(oldfunc, newfunc1, ft_flags1, newfunc2, ft_flags2, \
output, input...) \
- asm_inline volatile(N_ALTERNATIVE_2("call %c[old]", "call %c[new1]", ft_flags1, \
+ asm_inline volatile(ALTERNATIVE_2("call %c[old]", "call %c[new1]", ft_flags1, \
"call %c[new2]", ft_flags2) \
: output, ASM_CALL_CONSTRAINT \
: [old] "i" (oldfunc), [new1] "i" (newfunc1), \
@@ -422,7 +342,7 @@ void nop_func(void);
* @newinstr. ".skip" directive takes care of proper instruction padding
* in case @newinstr is longer than @oldinstr.
*/
-#define __N_ALTERNATIVE(oldinst, newinst, flag) \
+#define __ALTERNATIVE(oldinst, newinst, flag) \
740: \
oldinst ; \
741: \
@@ -438,7 +358,7 @@ void nop_func(void);
.popsection ;

.macro ALTERNATIVE oldinstr, newinstr, ft_flags
- __N_ALTERNATIVE(\oldinstr, \newinstr, \ft_flags)
+ __ALTERNATIVE(\oldinstr, \newinstr, \ft_flags)
.endm

#define old_len 141b-140b
@@ -447,26 +367,17 @@ void nop_func(void);
#define new_len3 146f-145f

/*
- * gas compatible max based on the idea from:
- * http://graphics.stanford.edu/~seander/bithacks.html#IntegerMinOrMax
- *
- * The additional "-" is needed because gas uses a "true" value of -1.
- */
-#define alt_max_2(a, b) ((a) ^ (((a) ^ (b)) & -(-((a) < (b)))))
-#define alt_max_3(a, b, c) (alt_max_2(alt_max_2(a, b), c))
-
-/*
* Same as ALTERNATIVE macro above but for two alternatives. If CPU
* has @feature1, it replaces @oldinstr with @newinstr1. If CPU has
* @feature2, it replaces @oldinstr with @feature2.
*/
.macro ALTERNATIVE_2 oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2
- __N_ALTERNATIVE(__N_ALTERNATIVE(\oldinstr, \newinstr1, \ft_flags1),
+ __ALTERNATIVE(__ALTERNATIVE(\oldinstr, \newinstr1, \ft_flags1),
\newinstr2, \ft_flags2)
.endm

.macro ALTERNATIVE_3 oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2, newinstr3, ft_flags3
- __N_ALTERNATIVE(N_ALTERNATIVE_2(\oldinstr, \newinstr1, \ft_flags1, \newinstr2, \ft_flags2),
+ __ALTERNATIVE(ALTERNATIVE_2(\oldinstr, \newinstr1, \ft_flags1, \newinstr2, \ft_flags2),
\newinstr3, \ft_flags3)
.endm

2024-06-11 17:05:33

by tip-bot2 for Alexey Makhalov

Subject: [tip: x86/alternatives] x86/alternative: Zap alternative_ternary()

The following commit has been merged into the x86/alternatives branch of tip:

Commit-ID: 9cbf2643b3ec7866e688df35d5b28c8b07ecbe6c
Gitweb: https://git.kernel.org/tip/9cbf2643b3ec7866e688df35d5b28c8b07ecbe6c
Author: Borislav Petkov (AMD) <[email protected]>
AuthorDate: Fri, 07 Jun 2024 13:16:48 +02:00
Committer: Borislav Petkov (AMD) <[email protected]>
CommitterDate: Tue, 11 Jun 2024 17:07:35 +02:00

x86/alternative: Zap alternative_ternary()

Unused.

Signed-off-by: Borislav Petkov (AMD) <[email protected]>
Acked-by: Peter Zijlstra (Intel) <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
---
arch/x86/include/asm/alternative.h | 3 ---
1 file changed, 3 deletions(-)

diff --git a/arch/x86/include/asm/alternative.h b/arch/x86/include/asm/alternative.h
index ba99ef7..6db7890 100644
--- a/arch/x86/include/asm/alternative.h
+++ b/arch/x86/include/asm/alternative.h
@@ -271,9 +271,6 @@ static inline int alternatives_text_reserved(void *start, void *end)
#define alternative_2(oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2) \
asm_inline volatile(ALTERNATIVE_2(oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2) ::: "memory")

-#define alternative_ternary(oldinstr, ft_flags, newinstr_yes, newinstr_no) \
- asm_inline volatile(ALTERNATIVE_TERNARY(oldinstr, ft_flags, newinstr_yes, newinstr_no) ::: "memory")
-
/*
* Alternative inline assembly with input.
*