[RFC PATCH v1 3/3] powerpc/8xx: Enable CONFIG_VMAP_STACK
Christophe Leroy
christophe.leroy at c-s.fr
Tue Dec 11 22:23:56 AEDT 2018
This patch enables CONFIG_VMAP_STACK. For that, a few changes are
done in head_8xx.S to re-activation DATA MMU Translation before
accessing to the stack.
Due to the growing of exception prolog, a few rearrangement is also
done in a few exception handlers.
Signed-off-by: Christophe Leroy <christophe.leroy at c-s.fr>
---
arch/powerpc/Kconfig | 1 +
arch/powerpc/kernel/head_8xx.S | 87 +++++++++++++++++++++++++++++++++++++-----
2 files changed, 79 insertions(+), 9 deletions(-)
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 94b46624068d..323b8a1efb3e 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -180,6 +180,7 @@ config PPC
select HAVE_ARCH_MMAP_RND_COMPAT_BITS if COMPAT
select HAVE_ARCH_SECCOMP_FILTER
select HAVE_ARCH_TRACEHOOK
+ select HAVE_ARCH_VMAP_STACK if PPC_8xx
select HAVE_CBPF_JIT if !PPC64
select HAVE_STACKPROTECTOR if PPC64 && $(cc-option,-mstack-protector-guard=tls -mstack-protector-guard-reg=r13)
select HAVE_STACKPROTECTOR if PPC32 && $(cc-option,-mstack-protector-guard=tls -mstack-protector-guard-reg=r2)
diff --git a/arch/powerpc/kernel/head_8xx.S b/arch/powerpc/kernel/head_8xx.S
index 48996a424075..ded66a6fdfeb 100644
--- a/arch/powerpc/kernel/head_8xx.S
+++ b/arch/powerpc/kernel/head_8xx.S
@@ -136,6 +136,53 @@ instruction_counter:
EXCEPTION_PROLOG_1; \
EXCEPTION_PROLOG_2
+#ifdef CONFIG_VMAP_STACK
+#define EXCEPTION_PROLOG_1 \
+ mtspr SPRN_SPRG_SCRATCH2, r12; \
+ mfspr r12, SPRN_SPRG_THREAD; \
+ mfspr r11, SPRN_SRR0; \
+ stw r11, SRR0(r12); \
+ mfspr r11, SPRN_DAR; \
+ stw r11, DAR(r12); \
+ mfspr r11,SPRN_SRR1; /* check whether user or kernel */ \
+ stw r11, SRR1(r12); \
+ andi. r11,r11,MSR_PR
+
+#define EXCEPTION_PROLOG_2 \
+ li r11, MSR_KERNEL & ~(MSR_IR | MSR_RI); /* can take DTLB miss */ \
+ mtmsr r11; \
+ tovirt(r12, r12); \
+ subi r11, r1, INT_FRAME_SIZE; /* use r1 if kernel */ \
+ beq 1f; \
+ lwz r11, TASK_STACK-THREAD(r12); \
+ addi r11, r11, THREAD_SIZE - INT_FRAME_SIZE; \
+1: stw r10,_CCR(r11); /* save registers */ \
+ stw r9,GPR9(r11); \
+ mfspr r10,SPRN_SPRG_SCRATCH0; \
+ stw r10,GPR10(r11); \
+ mfspr r10,SPRN_SPRG_SCRATCH1; \
+ stw r10,GPR11(r11); \
+ mfspr r10,SPRN_SPRG_SCRATCH2; \
+ stw r10,GPR12(r11); \
+ mflr r10; \
+ stw r10,_LINK(r11); \
+ lwz r10, DAR(r12); \
+ stw r10, _DAR(r11); \
+ lwz r9, SRR1(r12); \
+ lwz r12, SRR0(r12); \
+ stw r1,GPR1(r11); \
+ stw r1,0(r11); \
+ mr r1, r11; /* set new kernel sp */ \
+ li r10,MSR_KERNEL & ~MSR_IR; /* can take exceptions */ \
+ mtmsr r10; \
+ stw r0,GPR0(r11); \
+ lis r10, STACK_FRAME_REGS_MARKER at ha; /* exception frame marker */ \
+ addi r10, r10, STACK_FRAME_REGS_MARKER at l; \
+ stw r10, 8(r11); \
+ SAVE_4GPRS(3, r11); \
+ SAVE_2GPRS(7, r11)
+
+#else
#define EXCEPTION_PROLOG_1 \
mfspr r11,SPRN_SRR1; /* check whether user or kernel */ \
andi. r11,r11,MSR_PR; \
@@ -172,6 +219,8 @@ instruction_counter:
SAVE_4GPRS(3, r11); \
SAVE_2GPRS(7, r11)
+#endif
+
/*
* Note: code which follows this uses cr0.eq (set if from kernel),
* r11, r12 (SRR0), and r9 (SRR1).
@@ -226,8 +275,12 @@ i##n: \
. = 0x200
MachineCheck:
EXCEPTION_PROLOG
+#ifdef CONFIG_VMAP_STACK
+ lwz r4, _DAR(r11)
+#else
mfspr r4,SPRN_DAR
stw r4,_DAR(r11)
+#endif
li r5,RPN_PATTERN
mtspr SPRN_DAR,r5 /* Tag DAR, to be used in DTLB Error */
mfspr r5,SPRN_DSISR
@@ -254,8 +307,12 @@ InstructionAccess:
. = 0x600
Alignment:
EXCEPTION_PROLOG
+#ifdef CONFIG_VMAP_STACK
+ lwz r4, _DAR(r11)
+#else
mfspr r4,SPRN_DAR
stw r4,_DAR(r11)
+#endif
li r5,RPN_PATTERN
mtspr SPRN_DAR,r5 /* Tag DAR, to be used in DTLB Error */
mfspr r5,SPRN_DSISR
@@ -573,20 +630,31 @@ DataTLBError:
beq- FixupDAR /* must be a buggy dcbX, icbi insn. */
DARFixed:/* Return from dcbx instruction bug workaround */
EXCEPTION_PROLOG_1
+#ifdef CONFIG_VMAP_STACK
+ li r11, RPN_PATTERN
+ mtspr SPRN_DAR, r11 /* Tag DAR, to be used in DTLB Error */
+#endif
EXCEPTION_PROLOG_2
mfspr r5,SPRN_DSISR
stw r5,_DSISR(r11)
+#ifdef CONFIG_VMAP_STACK
+ lwz r4, _DAR(r11)
+#else
mfspr r4,SPRN_DAR
+#endif
andis. r10,r5,DSISR_NOHPTE at h
beq+ 1f
tlbie r4
dtlbie:
-1: li r10,RPN_PATTERN
+1:
+#ifndef CONFIG_VMAP_STACK
+ li r10, RPN_PATTERN
mtspr SPRN_DAR,r10 /* Tag DAR, to be used in DTLB Error */
+#endif
/* 0x300 is DataAccess exception, needed by bad_page_fault() */
EXC_XFER_LITE(0x300, handle_page_fault)
- EXCEPTION(0x1500, Trap_15, unknown_exception, EXC_XFER_EE)
+/* EXCEPTION(0x1500, Trap_15, unknown_exception, EXC_XFER_EE)*/
EXCEPTION(0x1600, Trap_16, unknown_exception, EXC_XFER_EE)
EXCEPTION(0x1700, Trap_17, unknown_exception, EXC_XFER_EE)
EXCEPTION(0x1800, Trap_18, unknown_exception, EXC_XFER_EE)
@@ -598,6 +666,12 @@ dtlbie:
* support of breakpoints and such. Someday I will get around to
* using them.
*/
+11:
+ mtcr r10
+ mfspr r10, SPRN_SPRG_SCRATCH0
+ mfspr r11, SPRN_SPRG_SCRATCH1
+ rfi
+
. = 0x1c00
DataBreakpoint:
mtspr SPRN_SPRG_SCRATCH0, r10
@@ -606,8 +680,8 @@ DataBreakpoint:
mfspr r11, SPRN_SRR0
cmplwi cr0, r11, (dtlbie - PAGE_OFFSET)@l
cmplwi cr7, r11, (itlbie - PAGE_OFFSET)@l
- beq- cr0, 11f
- beq- cr7, 11f
+ beq- cr0, 11b
+ beq- cr7, 11b
EXCEPTION_PROLOG_1
EXCEPTION_PROLOG_2
addi r3,r1,STACK_FRAME_OVERHEAD
@@ -615,11 +689,6 @@ DataBreakpoint:
stw r4,_DAR(r11)
mfspr r5,SPRN_DSISR
EXC_XFER_EE(0x1c00, do_break)
-11:
- mtcr r10
- mfspr r10, SPRN_SPRG_SCRATCH0
- mfspr r11, SPRN_SPRG_SCRATCH1
- rfi
#ifdef CONFIG_PERF_EVENTS
. = 0x1d00
--
2.13.3
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