Messages in this thread Patch in this message | | | From | Christophe Leroy <> | Subject | [PATCH 3/3] powerpc/32s: Allow constant folding in mtsr()/mfsr() | Date | Sat, 6 Feb 2021 11:47:28 +0000 (UTC) |
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On the same way as we did in wrtee(), add an alternative using mtsr/mfsr instructions instead of mtsrin/mfsrin when the segment register can be determined at compile time.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> --- arch/powerpc/include/asm/reg.h | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-)
diff --git a/arch/powerpc/include/asm/reg.h b/arch/powerpc/include/asm/reg.h index eeab7e7dc699..da103e92c112 100644 --- a/arch/powerpc/include/asm/reg.h +++ b/arch/powerpc/include/asm/reg.h @@ -1418,14 +1418,20 @@ static inline u32 mfsr(u32 idx) { u32 val; - asm volatile("mfsrin %0, %1" : "=r" (val): "r" (idx)); + if (__builtin_constant_p(idx)) + asm volatile("mfsr %0, %1" : "=r" (val): "i" (idx >> 28)); + else + asm volatile("mfsrin %0, %1" : "=r" (val): "r" (idx)); return val; } static inline void mtsr(u32 val, u32 idx) { - asm volatile("mtsrin %0, %1" : : "r" (val), "r" (idx)); + if (__builtin_constant_p(idx)) + asm volatile("mtsr %1, %0" : : "r" (val), "i" (idx >> 28)); + else + asm volatile("mtsrin %0, %1" : : "r" (val), "r" (idx)); } #endif -- 2.25.0
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