Messages in this thread Patch in this message | | | From | Christophe Leroy <> | Subject | [PATCH v3 2/2] powerpc: Don't user thread struct for saving SRR0/1 on syscall. | Date | Fri, 31 Jan 2020 11:34:55 +0000 (UTC) |
| |
CR0 can be saved later, and CTR can also be used for saving.
Keep SRR1 in r9 and stash SRR0 in CTR, this avoids using thread_struct in memory for that.
Saves 3 cycles (ie 1%) in null_syscall selftest on 8xx.
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> --- v3: New --- arch/powerpc/kernel/head_32.h | 16 +++++++--------- 1 file changed, 7 insertions(+), 9 deletions(-)
diff --git a/arch/powerpc/kernel/head_32.h b/arch/powerpc/kernel/head_32.h index 0e7bf28fe53a..4a1faeded069 100644 --- a/arch/powerpc/kernel/head_32.h +++ b/arch/powerpc/kernel/head_32.h @@ -114,28 +114,23 @@ mfspr r9, SPRN_SRR1 #ifdef CONFIG_VMAP_STACK mfspr r11, SPRN_SRR0 - stw r11, SRR0(r12) - stw r9, SRR1(r12) + mtctr r11 #endif - mfcr r10 andi. r11, r9, MSR_PR lwz r11,TASK_STACK-THREAD(r12) beq- 99f - rlwinm r10,r10,0,4,2 /* Clear SO bit in CR */ addi r11, r11, THREAD_SIZE - INT_FRAME_SIZE #ifdef CONFIG_VMAP_STACK - li r9, MSR_KERNEL & ~(MSR_IR | MSR_RI) /* can take DTLB miss */ - mtmsr r9 + li r10, MSR_KERNEL & ~(MSR_IR | MSR_RI) /* can take DTLB miss */ + mtmsr r10 isync #endif tovirt_vmstack r12, r12 tophys_novmstack r11, r11 - stw r10,_CCR(r11) /* save registers */ mflr r10 stw r10, _LINK(r11) #ifdef CONFIG_VMAP_STACK - lwz r10, SRR0(r12) - lwz r9, SRR1(r12) + mfctr r10 #else mfspr r10,SPRN_SRR0 #endif @@ -143,6 +138,9 @@ stw r1,0(r11) tovirt_novmstack r1, r11 /* set new kernel sp */ stw r10,_NIP(r11) + mfcr r10 + rlwinm r10,r10,0,4,2 /* Clear SO bit in CR */ + stw r10,_CCR(r11) /* save registers */ #ifdef CONFIG_40x rlwinm r9,r9,0,14,12 /* clear MSR_WE (necessary?) */ #else -- 2.25.0
| |