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.le...@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
