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Subject[PATCH v2 35/43] powerpc/32: Save remaining registers in exception prolog
Date
Save non volatile registers, XER, CTR, MSR and NIP in exception prolog.

Also assign proper value to r2 and r3 there.

For now, recalculate thread pointer in prepare_transfer_to_handler.
It will disappear once KUAP is ported to C.

And remove the comment which is now completely wrong.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
---
arch/powerpc/kernel/entry_32.S | 25 +++----------------------
arch/powerpc/kernel/head_32.h | 12 ++++++++++++
2 files changed, 15 insertions(+), 22 deletions(-)

diff --git a/arch/powerpc/kernel/entry_32.S b/arch/powerpc/kernel/entry_32.S
index 289f111a5ac7..8fe1c3fdfa6e 100644
--- a/arch/powerpc/kernel/entry_32.S
+++ b/arch/powerpc/kernel/entry_32.S
@@ -48,29 +48,11 @@
*/
.align 12

-/*
- * This code finishes saving the registers to the exception frame
- * and jumps to the appropriate handler for the exception, turning
- * on address translation.
- * Note that we rely on the caller having set cr0.eq iff the exception
- * occurred in kernel mode (i.e. MSR:PR = 0).
- */
.globl prepare_transfer_to_handler
prepare_transfer_to_handler:
- SAVE_NVGPRS(r11)
- addi r3,r1,STACK_FRAME_OVERHEAD
- stw r2,GPR2(r11)
- stw r12,_NIP(r11)
- stw r9,_MSR(r11)
- andi. r2,r9,MSR_PR
- mfctr r12
- mfspr r2,SPRN_XER
- stw r12,_CTR(r11)
- stw r2,_XER(r11)
- mfspr r12,SPRN_SPRG_THREAD
- tovirt(r12, r12)
+ andi. r0,r9,MSR_PR
+ addi r12, r2, THREAD
beq 2f /* if from user, fix up THREAD.regs */
- addi r2, r12, -THREAD
stw r3,PT_REGS(r12)
#ifdef CONFIG_PPC_BOOK3S_32
kuep_lock r11, r12
@@ -79,8 +61,7 @@ prepare_transfer_to_handler:

/* if from kernel, check interrupted DOZE/NAP mode */
2:
- kuap_save_and_lock r11, r12, r9, r2, r6
- addi r2, r12, -THREAD
+ kuap_save_and_lock r11, r12, r9, r5, r6
#if defined(CONFIG_PPC_BOOK3S_32) || defined(CONFIG_E500)
lwz r12,TI_LOCAL_FLAGS(r2)
mtcrf 0x01,r12
diff --git a/arch/powerpc/kernel/head_32.h b/arch/powerpc/kernel/head_32.h
index ba20bfabdf63..267479072495 100644
--- a/arch/powerpc/kernel/head_32.h
+++ b/arch/powerpc/kernel/head_32.h
@@ -117,6 +117,18 @@ _ASM_NOKPROBE_SYMBOL(\name\()_virt)
stw r10,_TRAP(r1)
SAVE_4GPRS(3, r1)
SAVE_2GPRS(7, r1)
+ SAVE_NVGPRS(r1)
+ stw r2,GPR2(r1)
+ stw r12,_NIP(r1)
+ stw r9,_MSR(r1)
+ mfctr r0
+ mfspr r10,SPRN_XER
+ mfspr r2,SPRN_SPRG_THREAD
+ stw r0,_CTR(r1)
+ tovirt(r2, r2)
+ stw r10,_XER(r1)
+ addi r2, r2, -THREAD
+ addi r3,r1,STACK_FRAME_OVERHEAD
.endm

.macro prepare_transfer_to_handler
--
2.25.0
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