[PATCH 03/18] powerpc: bad_page_fault, do_break get registers from regs
Christophe Leroy
christophe.leroy at csgroup.eu
Fri Nov 6 19:14:02 AEDT 2020
Le 05/11/2020 à 15:34, Nicholas Piggin a écrit :
> This also moves the 32s DABR match to C.
Is there a real benefit doing this ?
>
> Similar to the previous patch this makes interrupt handler function
> types more regular so they can be wrapped with the next patch.
>
> bad_page_fault and do_break are not performance critical.
>
> Signed-off-by: Nicholas Piggin <npiggin at gmail.com>
> ---
> arch/powerpc/include/asm/bug.h | 2 +-
> arch/powerpc/include/asm/debug.h | 3 +--
> arch/powerpc/kernel/entry_32.S | 14 ++++----------
> arch/powerpc/kernel/exceptions-64e.S | 3 +--
> arch/powerpc/kernel/exceptions-64s.S | 3 +--
> arch/powerpc/kernel/head_8xx.S | 5 ++---
> arch/powerpc/kernel/process.c | 7 +++----
> arch/powerpc/kernel/traps.c | 2 +-
> arch/powerpc/mm/book3s64/hash_utils.c | 4 ++--
> arch/powerpc/mm/book3s64/slb.c | 2 +-
> arch/powerpc/mm/fault.c | 14 +++++++-------
> arch/powerpc/platforms/8xx/machine_check.c | 2 +-
> 12 files changed, 25 insertions(+), 36 deletions(-)
>
> diff --git a/arch/powerpc/include/asm/bug.h b/arch/powerpc/include/asm/bug.h
> index 2fa0cf6c6011..4af6c3835eb2 100644
> --- a/arch/powerpc/include/asm/bug.h
> +++ b/arch/powerpc/include/asm/bug.h
> @@ -113,7 +113,7 @@
> struct pt_regs;
> extern long do_page_fault(struct pt_regs *);
> extern long hash__do_page_fault(struct pt_regs *);
> -extern void bad_page_fault(struct pt_regs *, unsigned long, int);
> +extern void bad_page_fault(struct pt_regs *, int);
pointless extern
Christophe
> extern void _exception(int, struct pt_regs *, int, unsigned long);
> extern void _exception_pkey(struct pt_regs *, unsigned long, int);
> extern void die(const char *, struct pt_regs *, long);
> diff --git a/arch/powerpc/include/asm/debug.h b/arch/powerpc/include/asm/debug.h
> index ec57daf87f40..0550eceab3ca 100644
> --- a/arch/powerpc/include/asm/debug.h
> +++ b/arch/powerpc/include/asm/debug.h
> @@ -52,8 +52,7 @@ extern void do_send_trap(struct pt_regs *regs, unsigned long address,
> unsigned long error_code, int brkpt);
> #else
>
> -extern void do_break(struct pt_regs *regs, unsigned long address,
> - unsigned long error_code);
> +void do_break(struct pt_regs *regs);
> #endif
>
> #endif /* _ASM_POWERPC_DEBUG_H */
> diff --git a/arch/powerpc/kernel/entry_32.S b/arch/powerpc/kernel/entry_32.S
> index 8cdc8bcde703..eb97df234a0c 100644
> --- a/arch/powerpc/kernel/entry_32.S
> +++ b/arch/powerpc/kernel/entry_32.S
> @@ -657,10 +657,6 @@ ppc_swapcontext:
> .globl handle_page_fault
> handle_page_fault:
> addi r3,r1,STACK_FRAME_OVERHEAD
> -#ifdef CONFIG_PPC_BOOK3S_32
> - andis. r0,r5,DSISR_DABRMATCH at h
> - bne- handle_dabr_fault
> -#endif
> bl do_page_fault
> cmpwi r3,0
> beq+ ret_from_except
> @@ -668,19 +664,17 @@ handle_page_fault:
> lwz r0,_TRAP(r1)
> clrrwi r0,r0,1
> stw r0,_TRAP(r1)
> - mr r5,r3
> + mr r4,r3 /* err arg for bad_page_fault */
> addi r3,r1,STACK_FRAME_OVERHEAD
> - lwz r4,_DAR(r1)
> +#ifdef CONFIG_PPC_BOOK3S_32
> + blt handle_dabr_fault
> +#endif
> bl bad_page_fault
> b ret_from_except_full
>
> #ifdef CONFIG_PPC_BOOK3S_32
> /* We have a data breakpoint exception - handle it */
> handle_dabr_fault:
> - SAVE_NVGPRS(r1)
> - lwz r0,_TRAP(r1)
> - clrrwi r0,r0,1
> - stw r0,_TRAP(r1)
> bl do_break
> b ret_from_except_full
> #endif
> diff --git a/arch/powerpc/kernel/exceptions-64e.S b/arch/powerpc/kernel/exceptions-64e.S
> index 25fa7d5a643c..dc728bb1c89a 100644
> --- a/arch/powerpc/kernel/exceptions-64e.S
> +++ b/arch/powerpc/kernel/exceptions-64e.S
> @@ -1018,9 +1018,8 @@ storage_fault_common:
> bne- 1f
> b ret_from_except_lite
> 1: bl save_nvgprs
> - mr r5,r3
> + mr r4,r3
> addi r3,r1,STACK_FRAME_OVERHEAD
> - ld r4,_DAR(r1)
> bl bad_page_fault
> b ret_from_except
>
> diff --git a/arch/powerpc/kernel/exceptions-64s.S b/arch/powerpc/kernel/exceptions-64s.S
> index 1f34cfd1887c..e6558c4d3f81 100644
> --- a/arch/powerpc/kernel/exceptions-64s.S
> +++ b/arch/powerpc/kernel/exceptions-64s.S
> @@ -2135,8 +2135,7 @@ EXC_COMMON_BEGIN(h_data_storage_common)
> GEN_COMMON h_data_storage
> addi r3,r1,STACK_FRAME_OVERHEAD
> BEGIN_MMU_FTR_SECTION
> - ld r4,_DAR(r1)
> - li r5,SIGSEGV
> + li r4,SIGSEGV
> bl bad_page_fault
> MMU_FTR_SECTION_ELSE
> bl unknown_exception
> diff --git a/arch/powerpc/kernel/head_8xx.S b/arch/powerpc/kernel/head_8xx.S
> index 0cd95b633e2b..13eda7154695 100644
> --- a/arch/powerpc/kernel/head_8xx.S
> +++ b/arch/powerpc/kernel/head_8xx.S
> @@ -408,10 +408,9 @@ do_databreakpoint:
> addi r3,r1,STACK_FRAME_OVERHEAD
> mfspr r4,SPRN_BAR
> stw r4,_DAR(r11)
> -#ifdef CONFIG_VMAP_STACK
> - lwz r5,_DSISR(r11)
> -#else
> +#ifndef CONFIG_VMAP_STACK
> mfspr r5,SPRN_DSISR
> + stw r5,_DSISR(r11)
> #endif
> EXC_XFER_STD(0x1c00, do_break)
>
> diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
> index d421a2c7f822..0bdd3ed653df 100644
> --- a/arch/powerpc/kernel/process.c
> +++ b/arch/powerpc/kernel/process.c
> @@ -660,11 +660,10 @@ static void do_break_handler(struct pt_regs *regs)
> }
> }
>
> -void do_break (struct pt_regs *regs, unsigned long address,
> - unsigned long error_code)
> +void do_break(struct pt_regs *regs)
> {
> current->thread.trap_nr = TRAP_HWBKPT;
> - if (notify_die(DIE_DABR_MATCH, "dabr_match", regs, error_code,
> + if (notify_die(DIE_DABR_MATCH, "dabr_match", regs, regs->dsisr,
> 11, SIGSEGV) == NOTIFY_STOP)
> return;
>
> @@ -682,7 +681,7 @@ void do_break (struct pt_regs *regs, unsigned long address,
> do_break_handler(regs);
>
> /* Deliver the signal to userspace */
> - force_sig_fault(SIGTRAP, TRAP_HWBKPT, (void __user *)address);
> + force_sig_fault(SIGTRAP, TRAP_HWBKPT, (void __user *)regs->dar);
> }
> #endif /* CONFIG_PPC_ADV_DEBUG_REGS */
>
> diff --git a/arch/powerpc/kernel/traps.c b/arch/powerpc/kernel/traps.c
> index 5006dcbe1d9f..902fcbd1a778 100644
> --- a/arch/powerpc/kernel/traps.c
> +++ b/arch/powerpc/kernel/traps.c
> @@ -1641,7 +1641,7 @@ void alignment_exception(struct pt_regs *regs)
> if (user_mode(regs))
> _exception(sig, regs, code, regs->dar);
> else
> - bad_page_fault(regs, regs->dar, sig);
> + bad_page_fault(regs, sig);
>
> bail:
> exception_exit(prev_state);
> diff --git a/arch/powerpc/mm/book3s64/hash_utils.c b/arch/powerpc/mm/book3s64/hash_utils.c
> index 0f0bd4af4b2d..731518e7d56f 100644
> --- a/arch/powerpc/mm/book3s64/hash_utils.c
> +++ b/arch/powerpc/mm/book3s64/hash_utils.c
> @@ -1537,7 +1537,7 @@ long do_hash_fault(struct pt_regs *regs)
> * the access, or panic if there isn't a handler.
> */
> if (unlikely(in_nmi())) {
> - bad_page_fault(regs, ea, SIGSEGV);
> + bad_page_fault(regs, SIGSEGV);
> return 0;
> }
>
> @@ -1576,7 +1576,7 @@ long do_hash_fault(struct pt_regs *regs)
> else
> _exception(SIGBUS, regs, BUS_ADRERR, ea);
> } else {
> - bad_page_fault(regs, ea, SIGBUS);
> + bad_page_fault(regs, SIGBUS);
> }
> err = 0;
>
> diff --git a/arch/powerpc/mm/book3s64/slb.c b/arch/powerpc/mm/book3s64/slb.c
> index cc34d50874c1..ae89ad516247 100644
> --- a/arch/powerpc/mm/book3s64/slb.c
> +++ b/arch/powerpc/mm/book3s64/slb.c
> @@ -898,7 +898,7 @@ void do_bad_slb_fault(struct pt_regs *regs)
> if (user_mode(regs))
> _exception(SIGSEGV, regs, SEGV_BNDERR, regs->dar);
> else
> - bad_page_fault(regs, regs->dar, SIGSEGV);
> + bad_page_fault(regs, SIGSEGV);
> } else if (err == -EINVAL) {
> unrecoverable_exception(regs);
> } else {
> diff --git a/arch/powerpc/mm/fault.c b/arch/powerpc/mm/fault.c
> index 390a296b16a3..49fbe564ea2b 100644
> --- a/arch/powerpc/mm/fault.c
> +++ b/arch/powerpc/mm/fault.c
> @@ -375,7 +375,7 @@ static void sanity_check_fault(bool is_write, bool is_user,
> #elif defined(CONFIG_PPC_BOOK3E_64)
> #define page_fault_is_bad(__err) ((__err) & DSISR_BAD_FAULT_64S)
> #else
> -#define page_fault_is_bad(__err) ((__err) & DSISR_BAD_FAULT_32S)
> +#define page_fault_is_bad(__err) ((__err) & DSISR_BAD_FAULT_32S | DSISR_DABRMATCH)
> #endif
> #endif
>
> @@ -408,7 +408,7 @@ static int __do_page_fault(struct pt_regs *regs, unsigned long address,
> return 0;
>
> if (unlikely(page_fault_is_bad(error_code))) {
> - if (IS_ENABLED(CONFIG_PPC_BOOK3S_64) && (error_code & DSISR_DABRMATCH))
> + if (IS_ENABLED(CONFIG_PPC_BOOK3S) && (error_code & DSISR_DABRMATCH))
> return -1;
>
> if (is_user) {
> @@ -562,14 +562,14 @@ long do_page_fault(struct pt_regs *regs)
> /* 32 and 64e handle errors in their asm code */
> if (unlikely(err)) {
> if (err > 0) {
> - bad_page_fault(regs, address, err);
> + bad_page_fault(regs, err);
> err = 0;
> } else {
> /*
> * do_break() may change NV GPRS while handling the
> * breakpoint. Return -ve to caller to do that.
> */
> - do_break(regs, address, error_code);
> + do_break(regs);
> }
> }
> #endif
> @@ -591,14 +591,14 @@ long hash__do_page_fault(struct pt_regs *regs)
> err = __do_page_fault(regs, address, error_code);
> if (unlikely(err)) {
> if (err > 0) {
> - bad_page_fault(regs, address, err);
> + bad_page_fault(regs, err);
> err = 0;
> } else {
> /*
> * do_break() may change NV GPRS while handling the
> * breakpoint. Return -ve to caller to do that.
> */
> - do_break(regs, address, error_code);
> + do_break(regs);
> }
> }
>
> @@ -612,7 +612,7 @@ NOKPROBE_SYMBOL(hash__do_page_fault);
> * It is called from the DSI and ISI handlers in head.S and from some
> * of the procedures in traps.c.
> */
> -void bad_page_fault(struct pt_regs *regs, unsigned long address, int sig)
> +void bad_page_fault(struct pt_regs *regs, int sig)
> {
> const struct exception_table_entry *entry;
> int is_write = page_fault_is_write(regs->dsisr);
> diff --git a/arch/powerpc/platforms/8xx/machine_check.c b/arch/powerpc/platforms/8xx/machine_check.c
> index 88dedf38eccd..656365975895 100644
> --- a/arch/powerpc/platforms/8xx/machine_check.c
> +++ b/arch/powerpc/platforms/8xx/machine_check.c
> @@ -26,7 +26,7 @@ int machine_check_8xx(struct pt_regs *regs)
> * to deal with that than having a wart in the mcheck handler.
> * -- BenH
> */
> - bad_page_fault(regs, regs->dar, SIGBUS);
> + bad_page_fault(regs, SIGBUS);
> return 1;
> #else
> return 0;
>
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