| Message ID | 1331829132-9762-2-git-send-email-dave.martin@linaro.org |
|---|---|
| State | Accepted |
| Headers | show |
On Thu, 15 Mar 2012, Dave Martin wrote: > The existing __mem_to_opcode_thumb32() is incorrect for BE32 > platforms. However, these don't support Thumb-2 kernels, so this > option is not so relevant for those platforms anyway. > > This operation is complicated by the lack of unaligned memory > access support prior to ARMv6. > > Rather than provide a "working" macro which will probably won't get > used (or worse, will get misused), this patch removes the macro for > BE32 kernels. People manipulating Thumb opcodes prior to ARMv6 > should almost certainly be splitting these operations into > halfwords anyway, using __opcode_thumb32_{first,second,compose}() > and the 16-bit opcode transformations. > > Signed-off-by: Dave Martin <dave.martin@linaro.org> Acked-by: Nicolas Pitre <nico@linaro.org> > +/* > + * On BE32 systems, using 32-bit accesses to store Thumb instructions will not > + * work in all cases, due to alignment constraints. For now, a correct > + * version is not proivided for BE32. s/proivided/provided/ Nicolas
diff --git a/arch/arm/include/asm/opcodes.h b/arch/arm/include/asm/opcodes.h index 19c48de..cf877c8 100644 --- a/arch/arm/include/asm/opcodes.h +++ b/arch/arm/include/asm/opcodes.h @@ -49,18 +49,31 @@ extern asmlinkage unsigned int arm_check_condition(u32 opcode, u32 psr); #include <linux/swab.h> #ifdef CONFIG_CPU_ENDIAN_BE8 + #define __opcode_to_mem_arm(x) swab32(x) #define __opcode_to_mem_thumb16(x) swab16(x) #define __opcode_to_mem_thumb32(x) swahb32(x) -#else + +#else /* ! CONFIG_CPU_ENDIAN_BE8 */ + #define __opcode_to_mem_arm(x) ((u32)(x)) #define __opcode_to_mem_thumb16(x) ((u16)(x)) +#ifndef CONFIG_CPU_ENDIAN_BE32 +/* + * On BE32 systems, using 32-bit accesses to store Thumb instructions will not + * work in all cases, due to alignment constraints. For now, a correct + * version is not proivided for BE32. + */ #define __opcode_to_mem_thumb32(x) swahw32(x) #endif +#endif /* ! CONFIG_CPU_ENDIAN_BE8 */ + #define __mem_to_opcode_arm(x) __opcode_to_mem_arm(x) #define __mem_to_opcode_thumb16(x) __opcode_to_mem_thumb16(x) +#ifndef CONFIG_CPU_ENDIAN_BE32 #define __mem_to_opcode_thumb32(x) __opcode_to_mem_thumb32(x) +#endif /* Operations specific to Thumb opcodes */
The existing __mem_to_opcode_thumb32() is incorrect for BE32 platforms. However, these don't support Thumb-2 kernels, so this option is not so relevant for those platforms anyway. This operation is complicated by the lack of unaligned memory access support prior to ARMv6. Rather than provide a "working" macro which will probably won't get used (or worse, will get misused), this patch removes the macro for BE32 kernels. People manipulating Thumb opcodes prior to ARMv6 should almost certainly be splitting these operations into halfwords anyway, using __opcode_thumb32_{first,second,compose}() and the 16-bit opcode transformations. Signed-off-by: Dave Martin <dave.martin@linaro.org> --- arch/arm/include/asm/opcodes.h | 15 ++++++++++++++- 1 files changed, 14 insertions(+), 1 deletions(-)