lkml.org 
[lkml]   [2021]   [Mar]   [12]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH v3 11/41] powerpc/32: Use fast instruction to set MSR RI in exception prolog on 8xx
    Date
    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
    \
     
     \ /
      Last update: 2021-03-12 14:09    [W:4.784 / U:0.896 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site