Messages in this thread Patch in this message | | | From | Christophe Leroy <> | Subject | [PATCH v3 11/41] powerpc/32: Use fast instruction to set MSR RI in exception prolog on 8xx | Date | Fri, 12 Mar 2021 12:50:20 +0000 (UTC) |
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8xx has registers SPRN_NRI, SPRN_EID and SPRN_EIE for changing MSR EE and RI.
Use SPRN_EID in exception prolog to set RI.
On an 8xx, it reduces the null_syscall test by 3 cycles.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> --- arch/powerpc/kernel/head_32.h | 2 ++ 1 file changed, 2 insertions(+)
diff --git a/arch/powerpc/kernel/head_32.h b/arch/powerpc/kernel/head_32.h index ac6b391f1493..25ee6b26ef5a 100644 --- a/arch/powerpc/kernel/head_32.h +++ b/arch/powerpc/kernel/head_32.h @@ -107,6 +107,8 @@ #endif #ifdef CONFIG_40x rlwinm r9,r9,0,14,12 /* clear MSR_WE (necessary?) */ +#elif defined(CONFIG_PPC_8xx) + mtspr SPRN_EID, r2 /* Set MSR_RI */ #else #ifdef CONFIG_VMAP_STACK li r10, MSR_KERNEL & ~MSR_IR /* can take exceptions */ -- 2.25.0
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