[PATCH v5 05/17] powerpc/32: add a macro to get and/or save DAR and DSISR on stack.

From: Christophe Leroy
Date: Sat Dec 21 2019 - 03:32:34 EST


Refactor reading and saving of DAR and DSISR in exception vectors.

This will ease the implementation of VMAP stack.

Signed-off-by: Christophe Leroy <christophe.leroy@xxxxxx>
---
arch/powerpc/kernel/head_32.S | 5 +----
arch/powerpc/kernel/head_32.h | 11 +++++++++++
arch/powerpc/kernel/head_8xx.S | 23 +++++++----------------
3 files changed, 19 insertions(+), 20 deletions(-)

diff --git a/arch/powerpc/kernel/head_32.S b/arch/powerpc/kernel/head_32.S
index bebb49d877f2..449625b4ff03 100644
--- a/arch/powerpc/kernel/head_32.S
+++ b/arch/powerpc/kernel/head_32.S
@@ -339,10 +339,7 @@ END_MMU_FTR_SECTION_IFSET(MMU_FTR_HPTE_TABLE)
DO_KVM 0x600
Alignment:
EXCEPTION_PROLOG
- mfspr r4,SPRN_DAR
- stw r4,_DAR(r11)
- mfspr r5,SPRN_DSISR
- stw r5,_DSISR(r11)
+ save_dar_dsisr_on_stack r4, r5, r11
addi r3,r1,STACK_FRAME_OVERHEAD
EXC_XFER_STD(0x600, alignment_exception)

diff --git a/arch/powerpc/kernel/head_32.h b/arch/powerpc/kernel/head_32.h
index 436ffd862d2a..f19a1ab91fb5 100644
--- a/arch/powerpc/kernel/head_32.h
+++ b/arch/powerpc/kernel/head_32.h
@@ -144,6 +144,17 @@
RFI /* jump to handler, enable MMU */
.endm

+.macro save_dar_dsisr_on_stack reg1, reg2, sp
+ mfspr \reg1, SPRN_DAR
+ mfspr \reg2, SPRN_DSISR
+ stw \reg1, _DAR(\sp)
+ stw \reg2, _DSISR(\sp)
+.endm
+
+.macro get_and_save_dar_dsisr_on_stack reg1, reg2, sp
+ save_dar_dsisr_on_stack \reg1, \reg2, \sp
+.endm
+
/*
* Note: code which follows this uses cr0.eq (set if from kernel),
* r11, r12 (SRR0), and r9 (SRR1).
diff --git a/arch/powerpc/kernel/head_8xx.S b/arch/powerpc/kernel/head_8xx.S
index 175c3cfc8014..25e19af49705 100644
--- a/arch/powerpc/kernel/head_8xx.S
+++ b/arch/powerpc/kernel/head_8xx.S
@@ -128,12 +128,9 @@ instruction_counter:
. = 0x200
MachineCheck:
EXCEPTION_PROLOG
- mfspr r4,SPRN_DAR
- stw r4,_DAR(r11)
- li r5,RPN_PATTERN
- mtspr SPRN_DAR,r5 /* Tag DAR, to be used in DTLB Error */
- mfspr r5,SPRN_DSISR
- stw r5,_DSISR(r11)
+ save_dar_dsisr_on_stack r4, r5, r11
+ li r6, RPN_PATTERN
+ mtspr SPRN_DAR, r6 /* Tag DAR, to be used in DTLB Error */
addi r3,r1,STACK_FRAME_OVERHEAD
EXC_XFER_STD(0x200, machine_check_exception)

@@ -156,12 +153,9 @@ InstructionAccess:
. = 0x600
Alignment:
EXCEPTION_PROLOG
- mfspr r4,SPRN_DAR
- stw r4,_DAR(r11)
- li r5,RPN_PATTERN
- mtspr SPRN_DAR,r5 /* Tag DAR, to be used in DTLB Error */
- mfspr r5,SPRN_DSISR
- stw r5,_DSISR(r11)
+ save_dar_dsisr_on_stack r4, r5, r11
+ li r6, RPN_PATTERN
+ mtspr SPRN_DAR, r6 /* Tag DAR, to be used in DTLB Error */
addi r3,r1,STACK_FRAME_OVERHEAD
EXC_XFER_STD(0x600, alignment_exception)

@@ -502,10 +496,7 @@ DataTLBError:
DARFixed:/* Return from dcbx instruction bug workaround */
EXCEPTION_PROLOG_1
EXCEPTION_PROLOG_2
- mfspr r5,SPRN_DSISR
- stw r5,_DSISR(r11)
- mfspr r4,SPRN_DAR
- stw r4, _DAR(r11)
+ get_and_save_dar_dsisr_on_stack r4, r5, r11
andis. r10,r5,DSISR_NOHPTE@h
beq+ .Ldtlbie
tlbie r4
--
2.13.3