[PATCH v3 34/41] powerpc/32: Save remaining registers in exception prolog
From: Christophe Leroy <hidden>
Date: 2021-03-12 12:51:50
Also in:
lkml
Subsystem:
linux for powerpc (32-bit and 64-bit), the rest · Maintainers:
Madhavan Srinivasan, Michael Ellerman, Linus Torvalds
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 <redacted> --- arch/powerpc/kernel/entry_32.S | 27 ++++----------------------- arch/powerpc/kernel/head_32.h | 12 ++++++++++++ arch/powerpc/kernel/head_booke.h | 12 ++++++++++++ 3 files changed, 28 insertions(+), 23 deletions(-)
diff --git a/arch/powerpc/kernel/entry_32.S b/arch/powerpc/kernel/entry_32.S
index bcf8452ebb58..46b3854e7318 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. r12,r9,MSR_PR + addi r12,r2,THREAD beq 2f - addi r2, r12, -THREAD #ifdef CONFIG_PPC_BOOK3S_32 kuep_lock r11, r12 #endif
@@ -78,8 +60,7 @@ 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
@@ -293,7 +274,7 @@ fast_exception_return: 2: REST_4GPRS(3, r11) lwz r10,_CCR(r11) - REST_GPR(1, r11) + REST_2GPRS(1, r11) mtcr r10 lwz r10,_LINK(r11) mtlr r10
diff --git a/arch/powerpc/kernel/head_32.h b/arch/powerpc/kernel/head_32.h
index ba20bfabdf63..80e45c800496 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 r10 + mfspr r2,SPRN_SPRG_THREAD + stw r10,_CTR(r1) + tovirt(r2, r2) + mfspr r10,SPRN_XER + addi r2, r2, -THREAD + stw r10,_XER(r1) + addi r3,r1,STACK_FRAME_OVERHEAD .endm .macro prepare_transfer_to_handler
diff --git a/arch/powerpc/kernel/head_booke.h b/arch/powerpc/kernel/head_booke.h
index 4d583fbef0b6..7f3dd5fae51d 100644
--- a/arch/powerpc/kernel/head_booke.h
+++ b/arch/powerpc/kernel/head_booke.h@@ -89,6 +89,18 @@ END_BTB_FLUSH_SECTION 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 r10 + mfspr r2,SPRN_SPRG_THREAD + stw r10,_CTR(r1) + tovirt(r2, r2) + mfspr r10,SPRN_XER + addi r2, r2, -THREAD + stw r10,_XER(r1) + addi r3,r1,STACK_FRAME_OVERHEAD .endm .macro prepare_transfer_to_handler
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2.25.0