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| author | Nicholas Piggin <npiggin@gmail.com> | 2020-06-11 18:12:03 +1000 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2020-07-22 23:00:27 +1000 |
| commit | 7fa95f9adaee7e5cbb195d3359741120829e488b (patch) | |
| tree | 1ca2d65102ad2c5223afe9a78e3105836982479f /arch/powerpc/include/asm/setup.h | |
| parent | b2dc2977cba48990df45e0a96150663d4f342700 (diff) | |
| download | lwn-7fa95f9adaee7e5cbb195d3359741120829e488b.tar.gz lwn-7fa95f9adaee7e5cbb195d3359741120829e488b.zip | |
powerpc/64s: system call support for scv/rfscv instructions
Add support for the scv instruction on POWER9 and later CPUs.
For now this implements the zeroth scv vector 'scv 0', as identical to
'sc' system calls, with the exception that LR is not preserved, nor
are volatile CR registers, and error is not indicated with CR0[SO],
but by returning a negative errno.
rfscv is implemented to return from scv type system calls. It can not
be used to return from sc system calls because those are defined to
preserve LR.
getpid syscall throughput on POWER9 is improved by 26% (428 to 318
cycles), largely due to reducing mtmsr and mtspr.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
[mpe: Fix ppc64e build]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200611081203.995112-3-npiggin@gmail.com
Diffstat (limited to 'arch/powerpc/include/asm/setup.h')
| -rw-r--r-- | arch/powerpc/include/asm/setup.h | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/arch/powerpc/include/asm/setup.h b/arch/powerpc/include/asm/setup.h index 65676e2325b8..9efbddee2bca 100644 --- a/arch/powerpc/include/asm/setup.h +++ b/arch/powerpc/include/asm/setup.h @@ -30,12 +30,12 @@ void setup_panic(void); #define ARCH_PANIC_TIMEOUT 180 #ifdef CONFIG_PPC_PSERIES -extern void pseries_enable_reloc_on_exc(void); +extern bool pseries_enable_reloc_on_exc(void); extern void pseries_disable_reloc_on_exc(void); extern void pseries_big_endian_exceptions(void); extern void pseries_little_endian_exceptions(void); #else -static inline void pseries_enable_reloc_on_exc(void) {} +static inline bool pseries_enable_reloc_on_exc(void) { return false; } static inline void pseries_disable_reloc_on_exc(void) {} static inline void pseries_big_endian_exceptions(void) {} static inline void pseries_little_endian_exceptions(void) {} |