On Sat, 2018-01-06 at 10:35 -0800, Eric Biggers wrote:
> On Sat, Jan 06, 2018 at 11:49:24AM +0000, David Woodhouse wrote:
> >
> > +/*
> > + * NOSPEC_JMP and NOSPEC_CALL macros can be used instead of a simple
> > + * indirect jmp/call which may be susceptible to the Spectre variant 2
> > + * attack.
> > + */
>
> Can be, or must be?

Can be is fine. It isn't necessarily the case that all indirect
branches MUST be changed. Although we *have* been auditing the kernel
binary and looking for them, some of them can stay as they are.

> Would it make any sense to name these INDIRECT_JMP and INDIRECT_CALL instead?
> NOSPEC_ seems to describe how it needs to be implemented on some CPUs, as
> opposed to what the user wants to do (make an indirect jump or call).

While NOSPEC_CALL explains why you're using the macro instead of just
'call'. I think this is fine. I'd rather not do too much bikeshedding
over the names.

Attachments:

smime.p7s (5.09 kB)

2018-01-06 19:53:54

by Thomas Gleixner

[permalink] [raw]

Subject: Re: [PATCH v5 05/12] x86/retpoline/ftrace: Convert ftrace assembler indirect jumps

On Sat, 6 Jan 2018, Linus Torvalds wrote:

> On Sat, Jan 6, 2018 at 3:49 AM, David Woodhouse <[email protected]> wrote:
> >
> > - call *ftrace_trace_function
> > + movl ftrace_trace_function, %ecx
> > + NOSPEC_CALL %ecx
>
> Can't we just do
>
> NOSPEC_CALL ftrace_trace_function
>
> now?
>
> [ Goes off and looks ]
>
> Oh. The AMD lfence version wants a register. Oh well.

The register load could be put into the macro itself, though we need to
supply a scratch register

NOSPEC_CALL ftrace_trace_function scratch_reg=%ecx

Whether thats much better, I don't know.

Thanks,

tglx

2018-01-06 21:09:47

by tip-bot for Vasyl Gomonovych

[permalink] [raw]

Subject: [tip:x86/pti] x86/cpufeatures: Add X86_BUG_SPECTRE_V[12]

Commit-ID: 99c6fa2511d8a683e61468be91b83f85452115fa
Gitweb: https://git.kernel.org/tip/99c6fa2511d8a683e61468be91b83f85452115fa
Author: David Woodhouse <[email protected]>
AuthorDate: Sat, 6 Jan 2018 11:49:23 +0000
Committer: Thomas Gleixner <[email protected]>
CommitDate: Sat, 6 Jan 2018 21:57:19 +0100

x86/cpufeatures: Add X86_BUG_SPECTRE_V[12]

Add the bug bits for spectre v1/2 and force them unconditionally for all
cpus.

Signed-off-by: David Woodhouse <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Cc: [email protected]
Cc: Rik van Riel <[email protected]>
Cc: Andi Kleen <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Jiri Kosina <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Cc: Dave Hansen <[email protected]>
Cc: Kees Cook <[email protected]>
Cc: Tim Chen <[email protected]>
Cc: Greg Kroah-Hartman <[email protected]>
Cc: Paul Turner <[email protected]>
Cc: [email protected]
Link: https://lkml.kernel.org/r/[email protected]
---
arch/x86/include/asm/cpufeatures.h | 2 ++
arch/x86/kernel/cpu/common.c | 3 +++
2 files changed, 5 insertions(+)

diff --git a/arch/x86/include/asm/cpufeatures.h b/arch/x86/include/asm/cpufeatures.h
index 21ac898..1641c2f 100644
--- a/arch/x86/include/asm/cpufeatures.h
+++ b/arch/x86/include/asm/cpufeatures.h
@@ -342,5 +342,7 @@
#define X86_BUG_MONITOR X86_BUG(12) /* IPI required to wake up remote CPU */
#define X86_BUG_AMD_E400 X86_BUG(13) /* CPU is among the affected by Erratum 400 */
#define X86_BUG_CPU_MELTDOWN X86_BUG(14) /* CPU is affected by meltdown attack and needs kernel page table isolation */
+#define X86_BUG_SPECTRE_V1 X86_BUG(15) /* CPU is affected by Spectre variant 1 attack with conditional branches */
+#define X86_BUG_SPECTRE_V2 X86_BUG(16) /* CPU is affected by Spectre variant 2 attack with indirect branches */

#endif /* _ASM_X86_CPUFEATURES_H */
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index 2d3bd22..372ba3f 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -902,6 +902,9 @@ static void __init early_identify_cpu(struct cpuinfo_x86 *c)
if (c->x86_vendor != X86_VENDOR_AMD)
setup_force_cpu_bug(X86_BUG_CPU_MELTDOWN);

+ setup_force_cpu_bug(X86_BUG_SPECTRE_V1);
+ setup_force_cpu_bug(X86_BUG_SPECTRE_V2);
+
fpu__init_system(c);

#ifdef CONFIG_X86_32

2018-01-06 21:17:17

by Andrew Cooper

[permalink] [raw]

Subject: Re: [PATCH v5 02/12] x86/retpoline: Add initial retpoline support

On 06/01/18 11:49, David Woodhouse wrote:
> diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
> index 372ba3f..40e6e54 100644
> --- a/arch/x86/kernel/cpu/common.c
> +++ b/arch/x86/kernel/cpu/common.c
> @@ -904,6 +904,11 @@ static void __init early_identify_cpu(struct cpuinfo_x86 *c)
>
> setup_force_cpu_bug(X86_BUG_SPECTRE_V1);
> setup_force_cpu_bug(X86_BUG_SPECTRE_V2);
> +#ifdef CONFIG_RETPOLINE
> + setup_force_cpu_cap(X86_FEATURE_RETPOLINE);
> + if (c->x86_vendor == X86_VENDOR_AMD)
> + setup_force_cpu_cap(X86_FEATURE_RETPOLINE_AMD);

This isn't safe. It needs to be dependant on finding that LFENCEs are
actually dispatch serialising.

In particular, when virtualised, you'll most likely be saddled with the
hypervisors choice of setting, in which case you need to use retpoline
as a fallback.

~Andrew

> +#endif
>
> fpu__init_system(c);
>
>

2018-01-06 21:22:52

On Sat, 2018-01-06 at 21:34 +0000, Andrew Cooper wrote:
> On 06/01/18 21:23, Thomas Gleixner wrote:
> >
> > On Sat, 6 Jan 2018, Andrew Cooper wrote:
> > >
> > > On 06/01/18 11:49, David Woodhouse wrote:
> > > >
> > > > diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
> > > > index 372ba3f..40e6e54 100644
> > > > --- a/arch/x86/kernel/cpu/common.c
> > > > +++ b/arch/x86/kernel/cpu/common.c
> > > > @@ -904,6 +904,11 @@ static void __init early_identify_cpu(struct cpuinfo_x86 *c)
> > > >
> > > > setup_force_cpu_bug(X86_BUG_SPECTRE_V1);
> > > > setup_force_cpu_bug(X86_BUG_SPECTRE_V2);
> > > > +#ifdef CONFIG_RETPOLINE
> > > > + setup_force_cpu_cap(X86_FEATURE_RETPOLINE);
> > > > + if (c->x86_vendor == X86_VENDOR_AMD)
> > > > + setup_force_cpu_cap(X86_FEATURE_RETPOLINE_AMD);
> > > This isn't safe. It needs to be dependant on finding that LFENCEs are
> > > actually dispatch serialising.
> > >
> > > In particular, when virtualised, you'll most likely be saddled with the
> > > hypervisors choice of setting, in which case you need to use retpoline
> > > as a fallback.
> > On bare metal we are sure, the virtualization part is a different question.
> Leaving virtualisation to one side, how does this cope with pre-SSE2
> hardware?

Either way, I've rebased my retpoline tree on top of tip/x86/pti with
Tom's patches, but I *haven't* enabled X86_FEATURE_RETPOLINE_AMD. AMD
can use the standard retpoline implementation until this question is
resolved.

Attachments:

smime.p7s (5.09 kB)

2018-01-07 00:10:49

On Sun, 2018-01-07 at 00:10 +0000, David Woodhouse wrote:
> Arjan pointed out that CONFIG_TRIM_UNUSED_SYMBOLS *really* doesn't like
> the dot in the symbols that GCC uses for the thunks.
>
> This seems to work, although my eyes are bleeding just a little bit.
>
> Given this, and the hack we already needed for MODVERSIONS, I wonder if
> a better approach might be to export the thunks using underscores in
> place of the dots, which is a relatively simple abuse of
> __EXPORT_SYMBOL(__x86_indirect_thunk_foo,__x86.indirect_thunk.foo,),
> and then have a hack either when generating or loading modules to do
> the same replacement.

Alternatively, and much simpler... HJ (or Igor), please can we change
the GCC patches so that the __x86.indirect_thunk.rxx symbols don't have
those awful dots in them? They are causing *lots* of pain.

Or we could build *modules* with the inline thunk and lose the ability
to ALTERNATIVE it away, I suppose.

> diff --git a/arch/x86/lib/retpoline.S b/arch/x86/lib/retpoline.S
> index ccb117a4588b..64d7a45ea954 100644
> --- a/arch/x86/lib/retpoline.S
> +++ b/arch/x86/lib/retpoline.S
> @@ -8,7 +8,13 @@
> #include
> #include
>
> -.macro THUNK reg
> +#ifdef CONFIG_TRIM_UNUSED_KSYMS
> +#define EXPORT_REG(reg) __is_defined(__KSYM___x86_indirect_thunk_ ## reg)
> +#else
> +#define EXPORT_REG(reg) 1
> +#endif
> +
> +.macro THUNK reg export
> .section .text.__x86.indirect_thunk.\reg
>
> ENTRY(__x86.indirect_thunk.\reg)
> @@ -16,15 +22,33 @@ ENTRY(__x86.indirect_thunk.\reg)
> NOSPEC_JMP %\reg
> CFI_ENDPROC
> ENDPROC(__x86.indirect_thunk.\reg)
> -EXPORT_SYMBOL(__x86.indirect_thunk.\reg)
> +
> +.if \export
> + EXPORT_SYMBOL_FORCE(__x86.indirect_thunk.\reg)
> +.endif
> .endm
>
> -#ifdef CONFIG_64BIT
> -.irp reg rax rbx rcx rdx rsi rdi rbp r8 r9 r10 r11 r12 r13 r14 r15
> - THUNK \reg
> -.endr
> +#ifdef __KSYM_DEPS__
> +#define GENERATE_THUNK(reg) EXPORT_SYMBOL(__x86.indirect_thunk. ## reg)
> #else
> -.irp reg eax ebx ecx edx esi edi ebp
> - THUNK \reg
> -.endr
> +#define GENERATE_THUNK(reg) THUNK reg EXPORT_REG(reg)
> +#endif
> +
> +GENERATE_THUNK(_ASM_AX)
> +GENERATE_THUNK(_ASM_BX)
> +GENERATE_THUNK(_ASM_CX)
> +GENERATE_THUNK(_ASM_DX)
> +GENERATE_THUNK(_ASM_SI)
> +GENERATE_THUNK(_ASM_DI)
> +GENERATE_THUNK(_ASM_BP)
> +GENERATE_THUNK(_ASM_SP)
> +#ifdef CONFIG_64BIT
> +GENERATE_THUNK(r8)
> +GENERATE_THUNK(r9)
> +GENERATE_THUNK(r10)
> +GENERATE_THUNK(r11)
> +GENERATE_THUNK(r12)
> +GENERATE_THUNK(r13)
> +GENERATE_THUNK(r14)
> +GENERATE_THUNK(r15)
> #endif
> diff --git a/include/asm-generic/export.h b/include/asm-generic/export.h
> index 719db1968d81..b13bb65e2530 100644
> --- a/include/asm-generic/export.h
> +++ b/include/asm-generic/export.h
> @@ -63,33 +63,33 @@ KSYM(__kcrctab_\name):
>
> #if defined(__KSYM_DEPS__)
>
> -#define __EXPORT_SYMBOL(sym, val, sec) === __KSYM_##sym ===
> +#define __EXPORT_SYMBOL(sym, val, sec, force) === __KSYM_##sym ===
>
> #elif defined(CONFIG_TRIM_UNUSED_KSYMS)
>
> #include
> #include
>
> -#define __EXPORT_SYMBOL(sym, val, sec) \
> - __cond_export_sym(sym, val, sec, __is_defined(__KSYM_##sym))
> +#define __EXPORT_SYMBOL(sym, val, sec, force) \
> + __cond_export_sym(sym, val, sec, __or(force, __is_defined(__KSYM_##sym)))
> #define __cond_export_sym(sym, val, sec, conf) \
> ___cond_export_sym(sym, val, sec, conf)
> #define ___cond_export_sym(sym, val, sec, enabled) \
> __cond_export_sym_##enabled(sym, val, sec)
> #define __cond_export_sym_1(sym, val, sec) ___EXPORT_SYMBOL sym, val, sec
> #define __cond_export_sym_0(sym, val, sec) /* nothing */
> -
> #else
> -#define __EXPORT_SYMBOL(sym, val, sec) ___EXPORT_SYMBOL sym, val, sec
> +#define __EXPORT_SYMBOL(sym, val, sec, force) ___EXPORT_SYMBOL sym, val, sec
> #endif
>
> #define EXPORT_SYMBOL(name) \
> - __EXPORT_SYMBOL(name, KSYM_FUNC(KSYM(name)),)
> + __EXPORT_SYMBOL(name, KSYM_FUNC(KSYM(name)), , 0)
> #define EXPORT_SYMBOL_GPL(name) \
> - __EXPORT_SYMBOL(name, KSYM_FUNC(KSYM(name)), _gpl)
> + __EXPORT_SYMBOL(name, KSYM_FUNC(KSYM(name)), _gpl, 0)
> #define EXPORT_DATA_SYMBOL(name) \
> - __EXPORT_SYMBOL(name, KSYM(name),)
> + __EXPORT_SYMBOL(name, KSYM(name), , 0)
> #define EXPORT_DATA_SYMBOL_GPL(name) \
> - __EXPORT_SYMBOL(name, KSYM(name),_gpl)
> -
> + __EXPORT_SYMBOL(name, KSYM(name), _gpl, 0)
> +#define EXPORT_SYMBOL_FORCE(name) \
> + __EXPORT_SYMBOL(name, KSYM(name), , 1)
> #endif
> diff --git a/scripts/adjust_autoksyms.sh b/scripts/adjust_autoksyms.sh
> index 513da1a4a2da..991cd136291b 100755
> --- a/scripts/adjust_autoksyms.sh
> +++ b/scripts/adjust_autoksyms.sh
> @@ -60,7 +60,7 @@ cat > "$new_ksyms_file" << EOT
>
> EOT
> [ "$(ls -A "$MODVERDIR")" ] &&
> -sed -ns -e '3{s/ /\n/g;/^$/!p;}' "$MODVERDIR"/*.mod | sort -u |
> +sed -ns -e '3{s/ /\n/g;/^$/!p;}' "$MODVERDIR"/*.mod | sort -u | tr . _ |
> while read sym; do
> if [ -n "$CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIX" ]; then
> sym="${sym#_}"

Attachments:

smime.p7s (5.09 kB)

2018-01-07 15:09:52

by Lu, Hongjiu

[permalink] [raw]

Subject: RE: [RFC PATCH 13/12] Retpoline vs. CONFIG_TRIM_UNUSED_SYMBOLS

Sure, I can use __x86_indirect_thunk_rax.

H.J.

> -----Original Message-----
> From: David Woodhouse [mailto:[email protected]]
> Sent: Sunday, January 07, 2018 12:03 AM
> To: Andi Kleen <[email protected]>; Van De Ven, Arjan
> <[email protected]>; Lu, Hongjiu <[email protected]>;
> Tsimbalist, Igor V <[email protected]>
> Cc: Paul Turner <[email protected]>; LKML <[email protected]>;
> Linus Torvalds <[email protected]>; Greg Kroah-Hartman
> <[email protected]>; Tim Chen <[email protected]>;
> Hansen, Dave <[email protected]>; [email protected]; Kees Cook
> <[email protected]>; Rik van Riel <[email protected]>; Peter Zijlstra
> <[email protected]>; Andy Lutomirski <[email protected]>; Jiri
> Kosina <[email protected]>; [email protected]
> Subject: Re: [RFC PATCH 13/12] Retpoline vs.
> CONFIG_TRIM_UNUSED_SYMBOLS
>
> On Sun, 2018-01-07 at 00:10 +0000, David Woodhouse wrote:
> > Arjan pointed out that CONFIG_TRIM_UNUSED_SYMBOLS *really*
> doesn't like
> > the dot in the symbols that GCC uses for the thunks.
> >
> > This seems to work, although my eyes are bleeding just a little bit.
> >
> > Given this, and the hack we already needed for MODVERSIONS, I wonder if
> > a better approach might be to export the thunks using underscores in
> > place of the dots, which is a relatively simple abuse of
> >
> __EXPORT_SYMBOL(__x86_indirect_thunk_foo,__x86.indirect_thunk.foo,),
> > and then have a hack either when generating or loading modules to do
> > the same replacement.
>
> Alternatively, and much simpler... HJ (or Igor), please can we change
> the GCC patches so that the __x86.indirect_thunk.rxx symbols don't have
> those awful dots in them? They are causing *lots* of pain.
>
> Or we could build *modules* with the inline thunk and lose the ability
> to ALTERNATIVE it away, I suppose.
>
> > diff --git a/arch/x86/lib/retpoline.S b/arch/x86/lib/retpoline.S
> > index ccb117a4588b..64d7a45ea954 100644
> > --- a/arch/x86/lib/retpoline.S
> > +++ b/arch/x86/lib/retpoline.S
> > @@ -8,7 +8,13 @@
> > #include
> > #include
> >
> > -.macro THUNK reg
> > +#ifdef CONFIG_TRIM_UNUSED_KSYMS
> > +#define EXPORT_REG(reg)
> __is_defined(__KSYM___x86_indirect_thunk_ ## reg)
> > +#else
> > +#define EXPORT_REG(reg) 1
> > +#endif
> > +
> > +.macro THUNK reg export
> > .section .text.__x86.indirect_thunk.\reg
> >
> > ENTRY(__x86.indirect_thunk.\reg)
> > @@ -16,15 +22,33 @@ ENTRY(__x86.indirect_thunk.\reg)
> > NOSPEC_JMP %\reg
> > CFI_ENDPROC
> > ENDPROC(__x86.indirect_thunk.\reg)
> > -EXPORT_SYMBOL(__x86.indirect_thunk.\reg)
> > +
> > +.if \export
> > + EXPORT_SYMBOL_FORCE(__x86.indirect_thunk.\reg)
> > +.endif
> > .endm
> >
> > -#ifdef CONFIG_64BIT
> > -.irp reg rax rbx rcx rdx rsi rdi rbp r8 r9 r10 r11 r12 r13 r14 r15
> > - THUNK \reg
> > -.endr
> > +#ifdef __KSYM_DEPS__
> > +#define GENERATE_THUNK(reg) EXPORT_SYMBOL(__x86.indirect_thunk.
> ## reg)
> > #else
> > -.irp reg eax ebx ecx edx esi edi ebp
> > - THUNK \reg
> > -.endr
> > +#define GENERATE_THUNK(reg) THUNK reg EXPORT_REG(reg)
> > +#endif
> > +
> > +GENERATE_THUNK(_ASM_AX)
> > +GENERATE_THUNK(_ASM_BX)
> > +GENERATE_THUNK(_ASM_CX)
> > +GENERATE_THUNK(_ASM_DX)
> > +GENERATE_THUNK(_ASM_SI)
> > +GENERATE_THUNK(_ASM_DI)
> > +GENERATE_THUNK(_ASM_BP)
> > +GENERATE_THUNK(_ASM_SP)
> > +#ifdef CONFIG_64BIT
> > +GENERATE_THUNK(r8)
> > +GENERATE_THUNK(r9)
> > +GENERATE_THUNK(r10)
> > +GENERATE_THUNK(r11)
> > +GENERATE_THUNK(r12)
> > +GENERATE_THUNK(r13)
> > +GENERATE_THUNK(r14)
> > +GENERATE_THUNK(r15)
> > #endif
> > diff --git a/include/asm-generic/export.h b/include/asm-generic/export.h
> > index 719db1968d81..b13bb65e2530 100644
> > --- a/include/asm-generic/export.h
> > +++ b/include/asm-generic/export.h
> > @@ -63,33 +63,33 @@ KSYM(__kcrctab_\name):
> >
> > #if defined(__KSYM_DEPS__)
> >
> > -#define __EXPORT_SYMBOL(sym, val, sec) === __KSYM_##sym ===
> > +#define __EXPORT_SYMBOL(sym, val, sec, force) === __KSYM_##sym
> ===
> >
> > #elif defined(CONFIG_TRIM_UNUSED_KSYMS)
> >
> > #include
> > #include
> >
> > -#define __EXPORT_SYMBOL(sym, val, sec) \
> > - __cond_export_sym(sym, val, sec, __is_defined(__KSYM_##sym))
> > +#define __EXPORT_SYMBOL(sym, val, sec, force) \
> > + __cond_export_sym(sym, val, sec, __or(force,
> __is_defined(__KSYM_##sym)))
> > #define __cond_export_sym(sym, val, sec, conf) \
> > ___cond_export_sym(sym, val, sec, conf)
> > #define ___cond_export_sym(sym, val, sec, enabled) \
> > __cond_export_sym_##enabled(sym, val, sec)
> > #define __cond_export_sym_1(sym, val, sec) ___EXPORT_SYMBOL sym,
> val, sec
> > #define __cond_export_sym_0(sym, val, sec) /* nothing */
> > -
> > #else
> > -#define __EXPORT_SYMBOL(sym, val, sec) ___EXPORT_SYMBOL sym, val,
> sec
> > +#define __EXPORT_SYMBOL(sym, val, sec, force) ___EXPORT_SYMBOL
> sym, val, sec
> > #endif
> >
> > #define EXPORT_SYMBOL(name) \
> > - __EXPORT_SYMBOL(name, KSYM_FUNC(KSYM(name)),)
> > + __EXPORT_SYMBOL(name, KSYM_FUNC(KSYM(name)), , 0)
> > #define EXPORT_SYMBOL_GPL(name) \
> > - __EXPORT_SYMBOL(name, KSYM_FUNC(KSYM(name)), _gpl)
> > + __EXPORT_SYMBOL(name, KSYM_FUNC(KSYM(name)), _gpl, 0)
> > #define EXPORT_DATA_SYMBOL(name) \
> > - __EXPORT_SYMBOL(name, KSYM(name),)
> > + __EXPORT_SYMBOL(name, KSYM(name), , 0)
> > #define EXPORT_DATA_SYMBOL_GPL(name)
> \
> > - __EXPORT_SYMBOL(name, KSYM(name),_gpl)
> > -
> > + __EXPORT_SYMBOL(name, KSYM(name), _gpl, 0)
> > +#define EXPORT_SYMBOL_FORCE(name) \
> > + __EXPORT_SYMBOL(name, KSYM(name), , 1)
> > #endif
> > diff --git a/scripts/adjust_autoksyms.sh b/scripts/adjust_autoksyms.sh
> > index 513da1a4a2da..991cd136291b 100755
> > --- a/scripts/adjust_autoksyms.sh
> > +++ b/scripts/adjust_autoksyms.sh
> > @@ -60,7 +60,7 @@ cat > "$new_ksyms_file" << EOT
> >
> > EOT
> > [ "$(ls -A "$MODVERDIR")" ] &&
> > -sed -ns -e '3{s/ /\n/g;/^$/!p;}' "$MODVERDIR"/*.mod | sort -u |
> > +sed -ns -e '3{s/ /\n/g;/^$/!p;}' "$MODVERDIR"/*.mod | sort -u | tr . _ |
> > while read sym; do
> > if [ -n "$CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIX" ]; then
> > sym="${sym#_}"

2018-01-07 17:32:54

On Sun, 2018-01-07 at 18:32 +0000, Lu, Hongjiu wrote:
>
> > What's the plan for these vs. official GCC? Is that stuff going to part of GCC
> > and if so, which versions of GCC will have that?
>
> If I get positive feedbacks from kernel folks with my GCC 7 patches today, I
> will submit my patches for GCC 8 today. After they are checked in, I will
> backport them to GCC 7/6/5/4.9.

I've pushed a new kernel retpoline branch tested with the changes I
made myself. Building your patch set now, both locally and at
https://koji.fedoraproject.org/koji/taskinfo?taskID=24065739

Attachments:

smime.p7s (5.09 kB)

2018-01-07 22:16:40

by David Woodhouse

[permalink] [raw]

Subject: Re: [RFC PATCH 13/12] Retpoline vs. CONFIG_TRIM_UNUSED_SYMBOLS

On Sun, 2018-01-07 at 18:32 +0000, Lu, Hongjiu wrote:
>
> If I get positive feedbacks from kernel folks with my GCC 7 patches today, I
> will submit my patches for GCC 8 today. After they are checked in, I will
> backport them to GCC 7/6/5/4.9.

To confirm: These seem to work for me and I've resent the kernel patch
series after testing with them. Thanks.

Attachments:

smime.p7s (5.09 kB)