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: stable@vger.kernel.org # v4.13+ Fixes: 350779a29f11 ("powerpc: Handle most loads and stores in instruction emulation code") Reported-by: Arnd Bergmann arnd@arndb.de Signed-off-by: Anders Roxell anders.roxell@linaro.org --- 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:
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_002d...
Cc: stable@vger.kernel.org Co-developed-by: Arnd Bergmann arnd@arndb.de Signed-off-by: Arnd Bergmann arnd@arndb.de Reviewed-by: Segher Boessenkool segher@kernel.crashing.org Signed-off-by: Anders Roxell anders.roxell@linaro.org --- 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;
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_002d...
Cc: stable@vger.kernel.org Co-developed-by: Arnd Bergmann arnd@arndb.de Signed-off-by: Arnd Bergmann arnd@arndb.de Reviewed-by: Segher Boessenkool segher@kernel.crashing.org Signed-off-by: Anders Roxell anders.roxell@linaro.org --- 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" \
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
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