linux-kernel - [PATCH v3 03/15] powerpc/32: save DEAR/DAR before calling handle_page

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Message-Id: <c3c2b4de8794815d35d88c679f22a49fd8a9e0b7.1568106758.git.christophe.leroy@c-s.fr>
Date:   Tue, 10 Sep 2019 09:16:22 +0000 (UTC)
From:   Christophe Leroy <christophe.leroy@....fr>
To:     Benjamin Herrenschmidt <benh@...nel.crashing.org>,
        Paul Mackerras <paulus@...ba.org>,
        Michael Ellerman <mpe@...erman.id.au>, npiggin@...il.com,
        dja@...ens.net
Cc:     linux-kernel@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org,
        linux-mm@...ck.org
Subject: [PATCH v3 03/15] powerpc/32: save DEAR/DAR before calling
 handle_page_fault

handle_page_fault() is the only function that save DAR/DEAR itself.

Save DAR/DEAR before calling handle_page_fault() to prepare for
VMAP stack which will require to save even before.

Signed-off-by: Christophe Leroy <christophe.leroy@....fr>
---
 arch/powerpc/kernel/entry_32.S       | 1 -
 arch/powerpc/kernel/head_32.S        | 2 ++
 arch/powerpc/kernel/head_40x.S       | 2 ++
 arch/powerpc/kernel/head_8xx.S       | 2 ++
 arch/powerpc/kernel/head_booke.h     | 2 ++
 arch/powerpc/kernel/head_fsl_booke.S | 1 +
 6 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/kernel/entry_32.S b/arch/powerpc/kernel/entry_32.S
index 6273b4862482..317ad9df8ba8 100644
--- a/arch/powerpc/kernel/entry_32.S
+++ b/arch/powerpc/kernel/entry_32.S
@@ -621,7 +621,6 @@ ppc_swapcontext:
  */
 	.globl	handle_page_fault
 handle_page_fault:
-	stw	r4,_DAR(r1)
 	addi	r3,r1,STACK_FRAME_OVERHEAD
 #ifdef CONFIG_PPC_BOOK3S_32
 	andis.  r0,r5,DSISR_DABRMATCH@h
diff --git a/arch/powerpc/kernel/head_32.S b/arch/powerpc/kernel/head_32.S
index 9e868567b716..bebb49d877f2 100644
--- a/arch/powerpc/kernel/head_32.S
+++ b/arch/powerpc/kernel/head_32.S
@@ -310,6 +310,7 @@ BEGIN_MMU_FTR_SECTION
 END_MMU_FTR_SECTION_IFSET(MMU_FTR_HPTE_TABLE)
 1:	lwz	r5,_DSISR(r11)		/* get DSISR value */
 	mfspr	r4,SPRN_DAR
+	stw	r4, _DAR(r11)
 	EXC_XFER_LITE(0x300, handle_page_fault)
 
 
@@ -327,6 +328,7 @@ BEGIN_MMU_FTR_SECTION
 END_MMU_FTR_SECTION_IFSET(MMU_FTR_HPTE_TABLE)
 1:	mr	r4,r12
 	andis.	r5,r9,DSISR_SRR1_MATCH_32S@h /* Filter relevant SRR1 bits */
+	stw	r4, _DAR(r11)
 	EXC_XFER_LITE(0x400, handle_page_fault)
 
 /* External interrupt */
diff --git a/arch/powerpc/kernel/head_40x.S b/arch/powerpc/kernel/head_40x.S
index 585ea1976550..9bb663977e84 100644
--- a/arch/powerpc/kernel/head_40x.S
+++ b/arch/powerpc/kernel/head_40x.S
@@ -313,6 +313,7 @@ _ENTRY(saved_ksp_limit)
 	START_EXCEPTION(0x0400, InstructionAccess)
 	EXCEPTION_PROLOG
 	mr	r4,r12			/* Pass SRR0 as arg2 */
+	stw	r4, _DEAR(r11)
 	li	r5,0			/* Pass zero as arg3 */
 	EXC_XFER_LITE(0x400, handle_page_fault)
 
@@ -676,6 +677,7 @@ DataAccess:
 	mfspr	r5,SPRN_ESR		/* Grab the ESR, save it, pass arg3 */
 	stw	r5,_ESR(r11)
 	mfspr	r4,SPRN_DEAR		/* Grab the DEAR, save it, pass arg2 */
+	stw	r4, _DEAR(r11)
 	EXC_XFER_LITE(0x300, handle_page_fault)
 
 /* Other PowerPC processors, namely those derived from the 6xx-series
diff --git a/arch/powerpc/kernel/head_8xx.S b/arch/powerpc/kernel/head_8xx.S
index dac7c0a34eea..fb284d95c76a 100644
--- a/arch/powerpc/kernel/head_8xx.S
+++ b/arch/powerpc/kernel/head_8xx.S
@@ -486,6 +486,7 @@ InstructionTLBError:
 	tlbie	r4
 	/* 0x400 is InstructionAccess exception, needed by bad_page_fault() */
 .Litlbie:
+	stw	r4, _DAR(r11)
 	EXC_XFER_LITE(0x400, handle_page_fault)
 
 /* This is the data TLB error on the MPC8xx.  This could be due to
@@ -504,6 +505,7 @@ DARFixed:/* Return from dcbx instruction bug workaround */
 	mfspr	r5,SPRN_DSISR
 	stw	r5,_DSISR(r11)
 	mfspr	r4,SPRN_DAR
+	stw	r4, _DAR(r11)
 	andis.	r10,r5,DSISR_NOHPTE@h
 	beq+	.Ldtlbie
 	tlbie	r4
diff --git a/arch/powerpc/kernel/head_booke.h b/arch/powerpc/kernel/head_booke.h
index 2ae635df9026..37fc84ed90e3 100644
--- a/arch/powerpc/kernel/head_booke.h
+++ b/arch/powerpc/kernel/head_booke.h
@@ -467,6 +467,7 @@ ALT_FTR_SECTION_END_IFSET(CPU_FTR_EMB_HV)
 	mfspr	r5,SPRN_ESR;		/* Grab the ESR and save it */	      \
 	stw	r5,_ESR(r11);						      \
 	mfspr	r4,SPRN_DEAR;		/* Grab the DEAR */		      \
+	stw	r4, _DEAR(r11);						      \
 	EXC_XFER_LITE(0x0300, handle_page_fault)
 
 #define INSTRUCTION_STORAGE_EXCEPTION					      \
@@ -475,6 +476,7 @@ ALT_FTR_SECTION_END_IFSET(CPU_FTR_EMB_HV)
 	mfspr	r5,SPRN_ESR;		/* Grab the ESR and save it */	      \
 	stw	r5,_ESR(r11);						      \
 	mr      r4,r12;                 /* Pass SRR0 as arg2 */		      \
+	stw	r4, _DEAR(r11);						      \
 	li      r5,0;                   /* Pass zero as arg3 */		      \
 	EXC_XFER_LITE(0x0400, handle_page_fault)
 
diff --git a/arch/powerpc/kernel/head_fsl_booke.S b/arch/powerpc/kernel/head_fsl_booke.S
index adf0505dbe02..442aaac292b0 100644
--- a/arch/powerpc/kernel/head_fsl_booke.S
+++ b/arch/powerpc/kernel/head_fsl_booke.S
@@ -376,6 +376,7 @@ interrupt_base:
 	mfspr	r4,SPRN_DEAR		/* Grab the DEAR, save it, pass arg2 */
 	andis.	r10,r5,(ESR_ILK|ESR_DLK)@h
 	bne	1f
+	stw	r4, _DEAR(r11)
 	EXC_XFER_LITE(0x0300, handle_page_fault)
 1:
 	addi	r3,r1,STACK_FRAME_OVERHEAD
-- 
2.13.3