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Subject[RFC PATCH v1 23/41] powerpc/32: Always save non volatile registers on exception entry
Date
In preparation of handling exception entry and exit in C,
in order to simplify the handling, always save non volatile registers
when entering an exception.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
---
arch/powerpc/include/asm/ptrace.h | 13 ++++---------
arch/powerpc/kernel/entry_32.S | 13 +------------
arch/powerpc/kernel/head_32.h | 3 +--
arch/powerpc/kernel/head_booke.h | 2 +-
4 files changed, 7 insertions(+), 24 deletions(-)

diff --git a/arch/powerpc/include/asm/ptrace.h b/arch/powerpc/include/asm/ptrace.h
index 2c842b11a924..979bd0d4d371 100644
--- a/arch/powerpc/include/asm/ptrace.h
+++ b/arch/powerpc/include/asm/ptrace.h
@@ -194,7 +194,6 @@ static inline void regs_set_return_value(struct pt_regs *regs, unsigned long rc)
#define FULL_REGS(regs) (((regs)->trap & 1) == 0)
#define SET_FULL_REGS(regs) ((regs)->trap |= 1)
#endif
-#define CHECK_FULL_REGS(regs) BUG_ON(!FULL_REGS(regs))
#define NV_REG_POISON 0xdeadbeefdeadbeefUL
#else
/*
@@ -204,20 +203,16 @@ static inline void regs_set_return_value(struct pt_regs *regs, unsigned long rc)
* On 4xx we use the next bit to indicate whether the exception
* is a critical exception (1 means it is).
*/
-#define TRAP_FLAGS_MASK 0x1F
+#define TRAP_FLAGS_MASK 0x1e
#define TRAP(regs) ((regs)->trap & ~TRAP_FLAGS_MASK)
-#define FULL_REGS(regs) (((regs)->trap & 1) == 0)
-#define SET_FULL_REGS(regs) ((regs)->trap |= 1)
+#define FULL_REGS(regs) true
+#define SET_FULL_REGS(regs) do { } while (0)
#define IS_CRITICAL_EXC(regs) (((regs)->trap & 2) != 0)
#define IS_MCHECK_EXC(regs) (((regs)->trap & 4) != 0)
#define IS_DEBUG_EXC(regs) (((regs)->trap & 8) != 0)
#define NV_REG_POISON 0xdeadbeef
-#define CHECK_FULL_REGS(regs) \
-do { \
- if ((regs)->trap & 1) \
- printk(KERN_CRIT "%s: partial register set\n", __func__); \
-} while (0)
#endif /* __powerpc64__ */
+#define CHECK_FULL_REGS(regs) BUG_ON(!FULL_REGS(regs))

static inline void set_trap(struct pt_regs *regs, unsigned long val)
{
diff --git a/arch/powerpc/kernel/entry_32.S b/arch/powerpc/kernel/entry_32.S
index e448ee3f5f15..bbce2de4c6a8 100644
--- a/arch/powerpc/kernel/entry_32.S
+++ b/arch/powerpc/kernel/entry_32.S
@@ -81,12 +81,12 @@ _ASM_NOKPROBE_SYMBOL(crit_transfer_to_handler)
*/
.globl transfer_to_handler_full
transfer_to_handler_full:
- SAVE_NVGPRS(r11)
_ASM_NOKPROBE_SYMBOL(transfer_to_handler_full)
/* fall through */

.globl transfer_to_handler
transfer_to_handler:
+ SAVE_NVGPRS(r11)
stw r2,GPR2(r11)
stw r12,_NIP(r11)
stw r9,_MSR(r11)
@@ -234,10 +234,6 @@ handle_page_fault:
bl do_page_fault
cmpwi r3,0
beq+ ret_from_except
- SAVE_NVGPRS(r1)
- lwz r0,_TRAP(r1)
- clrrwi r0,r0,1
- stw r0,_TRAP(r1)
mr r4,r3 /* err arg for bad_page_fault */
addi r3,r1,STACK_FRAME_OVERHEAD
bl __bad_page_fault
@@ -810,13 +806,6 @@ recheck:
do_user_signal: /* r10 contains MSR_KERNEL here */
ori r10,r10,MSR_EE
mtmsr r10 /* hard-enable interrupts */
- /* save r13-r31 in the exception frame, if not already done */
- lwz r3,_TRAP(r1)
- andi. r0,r3,1
- beq 2f
- SAVE_NVGPRS(r1)
- rlwinm r3,r3,0,0,30
- stw r3,_TRAP(r1)
2: addi r3,r1,STACK_FRAME_OVERHEAD
mr r4,r9
bl do_notify_resume
diff --git a/arch/powerpc/kernel/head_32.h b/arch/powerpc/kernel/head_32.h
index e09585b88ba7..087445e45489 100644
--- a/arch/powerpc/kernel/head_32.h
+++ b/arch/powerpc/kernel/head_32.h
@@ -198,7 +198,7 @@ _ASM_NOKPROBE_SYMBOL(\name\()_virt)
ret_from_except_full)

#define EXC_XFER_LITE(n, hdlr) \
- EXC_XFER_TEMPLATE(hdlr, n+1, MSR_KERNEL, transfer_to_handler, \
+ EXC_XFER_TEMPLATE(hdlr, n, MSR_KERNEL, transfer_to_handler, \
ret_from_except)

.macro vmap_stack_overflow_exception
@@ -215,7 +215,6 @@ _ASM_NOKPROBE_SYMBOL(\name\()_virt)
lwz r1, emergency_ctx@l(r1)
addi r1, r1, THREAD_SIZE - INT_FRAME_SIZE
EXCEPTION_PROLOG_2 vmap_stack_overflow
- SAVE_NVGPRS(r11)
addi r3, r1, STACK_FRAME_OVERHEAD
EXC_XFER_STD(0, stack_overflow_exception)
.endm
diff --git a/arch/powerpc/kernel/head_booke.h b/arch/powerpc/kernel/head_booke.h
index 4286f04648f8..c88c1c474381 100644
--- a/arch/powerpc/kernel/head_booke.h
+++ b/arch/powerpc/kernel/head_booke.h
@@ -331,7 +331,7 @@ ALT_FTR_SECTION_END_IFSET(CPU_FTR_EMB_HV)
ret_from_except_full)

#define EXC_XFER_LITE(n, hdlr) \
- EXC_XFER_TEMPLATE(hdlr, n+1, MSR_KERNEL, transfer_to_handler, \
+ EXC_XFER_TEMPLATE(hdlr, n, MSR_KERNEL, transfer_to_handler, \
ret_from_except)

/* Check for a single step debug exception while in an exception
--
2.25.0
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