| Message ID | 1381160903-1248-2-git-send-email-victor.kamensky@linaro.org |
|---|---|
| State | Accepted |
| Commit | a1af3474487cc3b8731b990dceac6b6aad7f3ed8 |
| Headers | show |
On Mon, Oct 07, 2013 at 04:48:23PM +0100, Victor Kamensky wrote: > In order for ASID macro to be used as expression passed to > inline asm as 'r' operand it needs to give 32 bit unsigned result, > not unsigned 64bit expression. > > Otherwise when 64bit ASID is passed to inline assembler statement > as 'r' operand (32bit) compiler behavior is not well specified. > For example when __flush_tlb_mm function compiled in big endian > case, and ASID is passed to tlb_op macro directly, 0 will be passed > as 'mcr 15, 0, r4, cr8, cr3, {2}' argument in r4, unless ASID > macro changed to produce 32 bit result. > > Signed-off-by: Victor Kamensky <victor.kamensky@linaro.org> > --- > arch/arm/include/asm/mmu.h | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/arch/arm/include/asm/mmu.h b/arch/arm/include/asm/mmu.h > index 6f18da0..64fd151 100644 > --- a/arch/arm/include/asm/mmu.h > +++ b/arch/arm/include/asm/mmu.h > @@ -16,7 +16,7 @@ typedef struct { > #ifdef CONFIG_CPU_HAS_ASID > #define ASID_BITS 8 > #define ASID_MASK ((~0ULL) << ASID_BITS) > -#define ASID(mm) ((mm)->context.id.counter & ~ASID_MASK) > +#define ASID(mm) ((unsigned int)((mm)->context.id.counter & ~ASID_MASK)) > #else > #define ASID(mm) (0) > #endif Acked-by: Will Deacon <will.deacon@arm.com> Cheers, Will
On Mon, Oct 07, 2013 at 08:48:23AM -0700, Victor Kamensky wrote: > -#define ASID(mm) ((mm)->context.id.counter & ~ASID_MASK) > +#define ASID(mm) ((unsigned int)((mm)->context.id.counter & ~ASID_MASK)) Not a big problem, but "unsigned" is sufficient as per my suggestion. See: http://en.wikipedia.org/wiki/C_data_types or look it up in the C standards. :) I'll take it either way.
On 7 October 2013 08:52, Russell King - ARM Linux <linux@arm.linux.org.uk> wrote: > On Mon, Oct 07, 2013 at 08:48:23AM -0700, Victor Kamensky wrote: >> -#define ASID(mm) ((mm)->context.id.counter & ~ASID_MASK) >> +#define ASID(mm) ((unsigned int)((mm)->context.id.counter & ~ASID_MASK)) > > Not a big problem, but "unsigned" is sufficient as per my suggestion. > See: > > http://en.wikipedia.org/wiki/C_data_types > > or look it up in the C standards. :) I'll take it either way. Understood, I just tried to be consistent with the rest of file - 'unsigned int' was used just few lines above place that got changed. Thanks, Victor
diff --git a/arch/arm/include/asm/mmu.h b/arch/arm/include/asm/mmu.h index 6f18da0..64fd151 100644 --- a/arch/arm/include/asm/mmu.h +++ b/arch/arm/include/asm/mmu.h @@ -16,7 +16,7 @@ typedef struct { #ifdef CONFIG_CPU_HAS_ASID #define ASID_BITS 8 #define ASID_MASK ((~0ULL) << ASID_BITS) -#define ASID(mm) ((mm)->context.id.counter & ~ASID_MASK) +#define ASID(mm) ((unsigned int)((mm)->context.id.counter & ~ASID_MASK)) #else #define ASID(mm) (0) #endif
In order for ASID macro to be used as expression passed to inline asm as 'r' operand it needs to give 32 bit unsigned result, not unsigned 64bit expression. Otherwise when 64bit ASID is passed to inline assembler statement as 'r' operand (32bit) compiler behavior is not well specified. For example when __flush_tlb_mm function compiled in big endian case, and ASID is passed to tlb_op macro directly, 0 will be passed as 'mcr 15, 0, r4, cr8, cr3, {2}' argument in r4, unless ASID macro changed to produce 32 bit result. Signed-off-by: Victor Kamensky <victor.kamensky@linaro.org> --- arch/arm/include/asm/mmu.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)