[PATCH v2 03/19] powerpc: bad_page_fault, do_break get registers from regs
Nicholas Piggin
npiggin at gmail.com
Mon Nov 16 12:52:05 AEDT 2020
Excerpts from Christophe Leroy's message of November 15, 2020 5:07 am:
> Hi,
>
> Quoting Nicholas Piggin <npiggin at gmail.com>:
>
>> This also moves the 32s DABR match to C.
>
> I'm still not happy with that. What about the following instead ?
This seems quite clean. I'll pull it into the series and see how it looks.
Thanks,
Nick
>
> diff --git a/arch/powerpc/kernel/entry_32.S b/arch/powerpc/kernel/entry_32.S
> index 8cdc8bcde703..6253c4acb46d 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
> @@ -674,17 +670,6 @@ handle_page_fault:
> 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
> -
> /*
> * This routine switches between two different tasks. The process
> * state of one is saved on its kernel stack. Then the state
> diff --git a/arch/powerpc/kernel/head_book3s_32.S
> b/arch/powerpc/kernel/head_book3s_32.S
> index 9381aa867591..5cc71482b35f 100644
> --- a/arch/powerpc/kernel/head_book3s_32.S
> +++ b/arch/powerpc/kernel/head_book3s_32.S
> @@ -684,7 +684,10 @@ handle_page_fault_tramp_1:
> lwz r5, _DSISR(r11)
> /* fall through */
> handle_page_fault_tramp_2:
> + andis. r0, r5, DSISR_DABRMATCH at h
> + bne- 1f
> EXC_XFER_LITE(0x300, handle_page_fault)
> +1: EXC_XFER_STD(0x300, do_break)
>
> #ifdef CONFIG_VMAP_STACK
> .macro save_regs_thread thread
> ---
> Christophe
>
>>
>> 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 897bad6b6bbb..49162faba33f 100644
>> --- a/arch/powerpc/include/asm/bug.h
>> +++ b/arch/powerpc/include/asm/bug.h
>> @@ -113,7 +113,7 @@
>> struct pt_regs;
>> long do_page_fault(struct pt_regs *);
>> long hash__do_page_fault(struct pt_regs *);
>> -extern void bad_page_fault(struct pt_regs *, unsigned long, int);
>> +void bad_page_fault(struct pt_regs *, int);
>> 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..db73b373e76c 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;
>> --
>> 2.23.0
>
>
>
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