| Message ID | 73d234924f6de3b3b274d5d5648e4bbea6810450.1408736066.git.geoff@infradead.org (mailing list archive) |
|---|---|
| State | New, archived |
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On Fri, Aug 22, 2014 at 08:49:16PM +0100, Geoff Levand wrote: > Add an assembler macro definition 'atomic' for performing generic > atomic operations. Also add macro definitions for atomic_add, > atomic_sub, atomic_inc, and atomic_dec. Same question as before. Why are this needed?
Hi Catalin, On Tue, 2014-08-26 at 17:05 +0100, Catalin Marinas wrote: > On Fri, Aug 22, 2014 at 08:49:16PM +0100, Geoff Levand wrote: > > Add an assembler macro definition 'atomic' for performing generic > > atomic operations. Also add macro definitions for atomic_add, > > atomic_sub, atomic_inc, and atomic_dec. > > Same question as before. Why are this needed? I use these in the smp-spin-table re-work I am doing to keep a count of CPUs in the secondary_holding_pen, but those patches are not yet ready for review. I thought I'd post this now thinking theses macros might be of use to someone else. I could just put them into the smp-spin-table series, please let me know. -Geoff
On Tue, Aug 26, 2014 at 08:40:53PM +0100, Geoff Levand wrote: > On Tue, 2014-08-26 at 17:05 +0100, Catalin Marinas wrote: > > On Fri, Aug 22, 2014 at 08:49:16PM +0100, Geoff Levand wrote: > > > Add an assembler macro definition 'atomic' for performing generic > > > atomic operations. Also add macro definitions for atomic_add, > > > atomic_sub, atomic_inc, and atomic_dec. > > > > Same question as before. Why are this needed? > > I use these in the smp-spin-table re-work I am doing to keep a > count of CPUs in the secondary_holding_pen, but those patches > are not yet ready for review. > > I thought I'd post this now thinking theses macros might be of use > to someone else. I could just put them into the smp-spin-table > series, please let me know. Keeping them all together would be better. I don't like introducing unused code.
diff --git a/arch/arm64/include/asm/assembler.h b/arch/arm64/include/asm/assembler.h index 5901480..dad3118 100644 --- a/arch/arm64/include/asm/assembler.h +++ b/arch/arm64/include/asm/assembler.h @@ -23,6 +23,39 @@ #include <asm/ptrace.h> #include <asm/thread_info.h> +/** + * macro atomic - Macros for simple atomic operations. + * + * @op: The operation to perform. + * @reg: A 32 or 64 bit register to operate on. + * @value: The value for the operation. + * @tmp1: A scratch register the same size as @reg. Defaluts to x20. + * @tmp2: A 32 bit scratch register. Defaluts to w21. + **/ + + .macro atomic op:req, reg:req, value:req, tmp1=x20, tmp2=w21 +.Latomic\@: ldxr \tmp1, [\reg] + \op \tmp1, \tmp1, \value + stxr \tmp2, \tmp1, [\reg] + cbnz \tmp2, .Latomic\@ + .endm + + .macro atomic_add reg:req, value:req, tmp1=x20, tmp2=w21 + atomic add, \reg, \value, \tmp1, \tmp2 + .endm + + .macro atomic_sub reg:req, value:req, tmp1, tmp2 + atomic sub, \reg, \value, \tmp1, \tmp2 + .endm + + .macro atomic_inc reg:req, tmp1, tmp2 + atomic add, \reg, 1, \tmp1, \tmp2 + .endm + + .macro atomic_dec reg:req, tmp1, tmp2 + atomic sub, \reg, 1, \tmp1, \tmp2 + .endm + /* * Stack pushing/popping (register pairs only). Equivalent to store decrement * before, load increment after.
Add an assembler macro definition 'atomic' for performing generic atomic operations. Also add macro definitions for atomic_add, atomic_sub, atomic_inc, and atomic_dec. Signed-off-by: Geoff Levand <geoff@infradead.org> --- arch/arm64/include/asm/assembler.h | 33 +++++++++++++++++++++++++++++++++ 1 file changed, 33 insertions(+)