Looks like there been a copy paste mistake when added the instruction
'stbcx' twice and one was probably meant to be 'sthcx'.
Changing to 'sthcx' from 'stbcx'.
Cc: <[email protected]> # v4.13+
Fixes: 350779a29f11 ("powerpc: Handle most loads and stores in instruction emulation code")
Reported-by: Arnd Bergmann <[email protected]>
Signed-off-by: Anders Roxell <[email protected]>
---
arch/powerpc/lib/sstep.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/powerpc/lib/sstep.c b/arch/powerpc/lib/sstep.c
index bd3734d5be89..d2d29243fa6d 100644
--- a/arch/powerpc/lib/sstep.c
+++ b/arch/powerpc/lib/sstep.c
@@ -3389,7 +3389,7 @@ int emulate_loadstore(struct pt_regs *regs, struct instruction_op *op)
__put_user_asmx(op->val, ea, err, "stbcx.", cr);
break;
case 2:
- __put_user_asmx(op->val, ea, err, "stbcx.", cr);
+ __put_user_asmx(op->val, ea, err, "sthcx.", cr);
break;
#endif
case 4:
--
2.34.1
Building tinyconfig with gcc (Debian 11.2.0-16) and assembler (Debian
2.37.90.20220207) the following build error shows up:
{standard input}: Assembler messages:
{standard input}:10576: Error: unrecognized opcode: `stbcx.'
{standard input}:10680: Error: unrecognized opcode: `lharx'
{standard input}:10694: Error: unrecognized opcode: `lbarx'
Rework to add assembler directives [1] around the instruction. The
problem with this might be that we can trick a power6 into
single-stepping through an stbcx. for instance, and it will execute that
in kernel mode.
[1] https://sourceware.org/binutils/docs/as/PowerPC_002dPseudo.html#PowerPC_002dPseudo
Cc: <[email protected]>
Co-developed-by: Arnd Bergmann <[email protected]>
Signed-off-by: Arnd Bergmann <[email protected]>
Reviewed-by: Segher Boessenkool <[email protected]>
Signed-off-by: Anders Roxell <[email protected]>
---
arch/powerpc/lib/sstep.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/arch/powerpc/lib/sstep.c b/arch/powerpc/lib/sstep.c
index d2d29243fa6d..f3ed80513a90 100644
--- a/arch/powerpc/lib/sstep.c
+++ b/arch/powerpc/lib/sstep.c
@@ -1097,7 +1097,10 @@ NOKPROBE_SYMBOL(emulate_dcbz);
#define __put_user_asmx(x, addr, err, op, cr) \
__asm__ __volatile__( \
+ ".machine push\n" \
+ ".machine power8\n" \
"1: " op " %2,0,%3\n" \
+ ".machine pop\n" \
" mfcr %1\n" \
"2:\n" \
".section .fixup,\"ax\"\n" \
@@ -1110,7 +1113,10 @@ NOKPROBE_SYMBOL(emulate_dcbz);
#define __get_user_asmx(x, addr, err, op) \
__asm__ __volatile__( \
+ ".machine push\n" \
+ ".machine power8\n" \
"1: "op" %1,0,%2\n" \
+ ".machine pop\n" \
"2:\n" \
".section .fixup,\"ax\"\n" \
"3: li %0,%3\n" \
--
2.34.1
Building tinyconfig with gcc (Debian 11.2.0-16) and assembler (Debian
2.37.90.20220207) the following build error shows up:
{standard input}: Assembler messages:
{standard input}:1190: Error: unrecognized opcode: `stbcix'
{standard input}:1433: Error: unrecognized opcode: `lwzcix'
{standard input}:1453: Error: unrecognized opcode: `stbcix'
{standard input}:1460: Error: unrecognized opcode: `stwcix'
{standard input}:1596: Error: unrecognized opcode: `stbcix'
...
Rework to add assembler directives [1] around the instruction. Going
through the them one by one shows that the changes should be safe. Like
__get_user_atomic_128_aligned() is only called in p9_hmi_special_emu(),
which according to the name is specific to power9. And __raw_rm_read*()
are only called in things that are powernv or book3s_hv specific.
[1] https://sourceware.org/binutils/docs/as/PowerPC_002dPseudo.html#PowerPC_002dPseudo
Cc: <[email protected]>
Co-developed-by: Arnd Bergmann <[email protected]>
Signed-off-by: Arnd Bergmann <[email protected]>
Reviewed-by: Segher Boessenkool <[email protected]>
Signed-off-by: Anders Roxell <[email protected]>
---
arch/powerpc/include/asm/io.h | 40 ++++++++++++++++++++++------
arch/powerpc/include/asm/uaccess.h | 3 +++
arch/powerpc/platforms/powernv/rng.c | 6 ++++-
3 files changed, 40 insertions(+), 9 deletions(-)
diff --git a/arch/powerpc/include/asm/io.h b/arch/powerpc/include/asm/io.h
index beba4979bff9..fee979d3a1aa 100644
--- a/arch/powerpc/include/asm/io.h
+++ b/arch/powerpc/include/asm/io.h
@@ -359,25 +359,37 @@ static inline void __raw_writeq_be(unsigned long v, volatile void __iomem *addr)
*/
static inline void __raw_rm_writeb(u8 val, volatile void __iomem *paddr)
{
- __asm__ __volatile__("stbcix %0,0,%1"
+ __asm__ __volatile__(".machine push; \
+ .machine power6; \
+ stbcix %0,0,%1; \
+ .machine pop;"
: : "r" (val), "r" (paddr) : "memory");
}
static inline void __raw_rm_writew(u16 val, volatile void __iomem *paddr)
{
- __asm__ __volatile__("sthcix %0,0,%1"
+ __asm__ __volatile__(".machine push; \
+ .machine power6; \
+ sthcix %0,0,%1; \
+ .machine pop;"
: : "r" (val), "r" (paddr) : "memory");
}
static inline void __raw_rm_writel(u32 val, volatile void __iomem *paddr)
{
- __asm__ __volatile__("stwcix %0,0,%1"
+ __asm__ __volatile__(".machine push; \
+ .machine power6; \
+ stwcix %0,0,%1; \
+ .machine pop;"
: : "r" (val), "r" (paddr) : "memory");
}
static inline void __raw_rm_writeq(u64 val, volatile void __iomem *paddr)
{
- __asm__ __volatile__("stdcix %0,0,%1"
+ __asm__ __volatile__(".machine push; \
+ .machine power6; \
+ stdcix %0,0,%1; \
+ .machine pop;"
: : "r" (val), "r" (paddr) : "memory");
}
@@ -389,7 +401,10 @@ static inline void __raw_rm_writeq_be(u64 val, volatile void __iomem *paddr)
static inline u8 __raw_rm_readb(volatile void __iomem *paddr)
{
u8 ret;
- __asm__ __volatile__("lbzcix %0,0, %1"
+ __asm__ __volatile__(".machine push; \
+ .machine power6; \
+ lbzcix %0,0, %1; \
+ .machine pop;"
: "=r" (ret) : "r" (paddr) : "memory");
return ret;
}
@@ -397,7 +412,10 @@ static inline u8 __raw_rm_readb(volatile void __iomem *paddr)
static inline u16 __raw_rm_readw(volatile void __iomem *paddr)
{
u16 ret;
- __asm__ __volatile__("lhzcix %0,0, %1"
+ __asm__ __volatile__(".machine push; \
+ .machine power6; \
+ lhzcix %0,0, %1; \
+ .machine pop;"
: "=r" (ret) : "r" (paddr) : "memory");
return ret;
}
@@ -405,7 +423,10 @@ static inline u16 __raw_rm_readw(volatile void __iomem *paddr)
static inline u32 __raw_rm_readl(volatile void __iomem *paddr)
{
u32 ret;
- __asm__ __volatile__("lwzcix %0,0, %1"
+ __asm__ __volatile__(".machine push; \
+ .machine power6; \
+ lwzcix %0,0, %1; \
+ .machine pop;"
: "=r" (ret) : "r" (paddr) : "memory");
return ret;
}
@@ -413,7 +434,10 @@ static inline u32 __raw_rm_readl(volatile void __iomem *paddr)
static inline u64 __raw_rm_readq(volatile void __iomem *paddr)
{
u64 ret;
- __asm__ __volatile__("ldcix %0,0, %1"
+ __asm__ __volatile__(".machine push; \
+ .machine power6; \
+ ldcix %0,0, %1; \
+ .machine pop;"
: "=r" (ret) : "r" (paddr) : "memory");
return ret;
}
diff --git a/arch/powerpc/include/asm/uaccess.h b/arch/powerpc/include/asm/uaccess.h
index 63316100080c..4a35423f766d 100644
--- a/arch/powerpc/include/asm/uaccess.h
+++ b/arch/powerpc/include/asm/uaccess.h
@@ -125,8 +125,11 @@ do { \
*/
#define __get_user_atomic_128_aligned(kaddr, uaddr, err) \
__asm__ __volatile__( \
+ ".machine push\n" \
+ ".machine altivec\n" \
"1: lvx 0,0,%1 # get user\n" \
" stvx 0,0,%2 # put kernel\n" \
+ ".machine pop\n" \
"2:\n" \
".section .fixup,\"ax\"\n" \
"3: li %0,%3\n" \
diff --git a/arch/powerpc/platforms/powernv/rng.c b/arch/powerpc/platforms/powernv/rng.c
index b4386714494a..e3d44b36ae98 100644
--- a/arch/powerpc/platforms/powernv/rng.c
+++ b/arch/powerpc/platforms/powernv/rng.c
@@ -43,7 +43,11 @@ static unsigned long rng_whiten(struct powernv_rng *rng, unsigned long val)
unsigned long parity;
/* Calculate the parity of the value */
- asm ("popcntd %0,%1" : "=r" (parity) : "r" (val));
+ asm (".machine push; \
+ .machine power7; \
+ popcntd %0,%1; \
+ .machine pop;"
+ : "=r" (parity) : "r" (val));
/* xor our value with the previous mask */
val ^= rng->mask;
--
2.34.1
On Thu, 24 Feb 2022 17:22:13 +0100, Anders Roxell wrote:
> Looks like there been a copy paste mistake when added the instruction
> 'stbcx' twice and one was probably meant to be 'sthcx'.
> Changing to 'sthcx' from 'stbcx'.
>
>
Applied to powerpc/next.
[1/3] powerpc: lib: sstep: fix 'sthcx' instruction
https://git.kernel.org/powerpc/c/a633cb1edddaa643fadc70abc88f89a408fa834a
[2/3] powerpc: fix build errors
https://git.kernel.org/powerpc/c/8667d0d64dd1f84fd41b5897fd87fa9113ae05e3
[3/3] powerpc: lib: sstep: fix build errors
https://git.kernel.org/powerpc/c/8219d31effa7be5dbc7ff915d7970672e028c701
cheers