Re: [PATCH 02/18] powerpc: remove arguments from fault handler functions
From: Christophe Leroy <hidden>
Date: 2020-11-06 08:02:23
Le 05/11/2020 à 15:34, Nicholas Piggin a écrit :
quoted hunk ↗ jump to hunk
Make mm fault handlers all just take the pt_regs * argument and load DAR/DSISR from that. Make those that return a value return long. This is done to make the function signatures match other handlers, which will help with a future patch to add wrappers. Explicit arguments could be added for performance but that would require more wrapper macro variants. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> --- arch/powerpc/include/asm/asm-prototypes.h | 4 ++-- arch/powerpc/include/asm/bug.h | 4 ++-- arch/powerpc/kernel/exceptions-64e.S | 2 -- arch/powerpc/kernel/exceptions-64s.S | 14 ++------------ arch/powerpc/kernel/head_40x.S | 10 +++++----- arch/powerpc/kernel/head_8xx.S | 6 +++--- arch/powerpc/kernel/head_book3s_32.S | 6 ++---- arch/powerpc/kernel/head_booke.h | 4 +--- arch/powerpc/mm/book3s64/hash_utils.c | 8 +++++--- arch/powerpc/mm/book3s64/slb.c | 11 +++++++---- arch/powerpc/mm/fault.c | 16 +++++++++------- 11 files changed, 38 insertions(+), 47 deletions(-)diff --git a/arch/powerpc/include/asm/asm-prototypes.h b/arch/powerpc/include/asm/asm-prototypes.h index d0b832cbbec8..22c9d08fa3a4 100644 --- a/arch/powerpc/include/asm/asm-prototypes.h +++ b/arch/powerpc/include/asm/asm-prototypes.h@@ -82,8 +82,8 @@ void kernel_bad_stack(struct pt_regs *regs); void system_reset_exception(struct pt_regs *regs); void machine_check_exception(struct pt_regs *regs); void emulation_assist_interrupt(struct pt_regs *regs); -long do_slb_fault(struct pt_regs *regs, unsigned long ea); -void do_bad_slb_fault(struct pt_regs *regs, unsigned long ea, long err); +long do_slb_fault(struct pt_regs *regs); +void do_bad_slb_fault(struct pt_regs *regs); /* signals, syscalls and interrupts */ long sys_swapcontext(struct ucontext __user *old_ctx,diff --git a/arch/powerpc/include/asm/bug.h b/arch/powerpc/include/asm/bug.h index d714d83bbc7c..2fa0cf6c6011 100644 --- a/arch/powerpc/include/asm/bug.h +++ b/arch/powerpc/include/asm/bug.h@@ -111,8 +111,8 @@ #ifndef __ASSEMBLY__ struct pt_regs; -extern int do_page_fault(struct pt_regs *, unsigned long, unsigned long); -extern int hash__do_page_fault(struct pt_regs *, unsigned long, unsigned long); +extern long do_page_fault(struct pt_regs *); +extern long hash__do_page_fault(struct pt_regs *);
extern is pointless
quoted hunk ↗ jump to hunk
extern void bad_page_fault(struct pt_regs *, unsigned long, int); extern void _exception(int, struct pt_regs *, int, unsigned long); extern void _exception_pkey(struct pt_regs *, unsigned long, int);diff --git a/arch/powerpc/kernel/exceptions-64e.S b/arch/powerpc/kernel/exceptions-64e.S index f579ce46eef2..25fa7d5a643c 100644 --- a/arch/powerpc/kernel/exceptions-64e.S +++ b/arch/powerpc/kernel/exceptions-64e.S@@ -1011,8 +1011,6 @@ storage_fault_common: std r14,_DAR(r1) std r15,_DSISR(r1) addi r3,r1,STACK_FRAME_OVERHEAD - mr r4,r14 - mr r5,r15 ld r14,PACA_EXGEN+EX_R14(r13) ld r15,PACA_EXGEN+EX_R15(r13) bl do_page_faultdiff --git a/arch/powerpc/kernel/exceptions-64s.S b/arch/powerpc/kernel/exceptions-64s.S index f830b893fe03..1f34cfd1887c 100644 --- a/arch/powerpc/kernel/exceptions-64s.S +++ b/arch/powerpc/kernel/exceptions-64s.S@@ -1437,8 +1437,6 @@ EXC_VIRT_BEGIN(data_access, 0x4300, 0x80) EXC_VIRT_END(data_access, 0x4300, 0x80) EXC_COMMON_BEGIN(data_access_common) GEN_COMMON data_access - ld r4,_DAR(r1) - ld r5,_DSISR(r1) addi r3,r1,STACK_FRAME_OVERHEAD BEGIN_MMU_FTR_SECTION bl do_hash_fault@@ -1491,10 +1489,9 @@ EXC_VIRT_BEGIN(data_access_slb, 0x4380, 0x80) EXC_VIRT_END(data_access_slb, 0x4380, 0x80) EXC_COMMON_BEGIN(data_access_slb_common) GEN_COMMON data_access_slb - ld r4,_DAR(r1) - addi r3,r1,STACK_FRAME_OVERHEAD BEGIN_MMU_FTR_SECTION /* HPT case, do SLB fault */ + addi r3,r1,STACK_FRAME_OVERHEAD bl do_slb_fault cmpdi r3,0 bne- 1f@@ -1506,8 +1503,6 @@ MMU_FTR_SECTION_ELSE ALT_MMU_FTR_SECTION_END_IFCLR(MMU_FTR_TYPE_RADIX) std r3,RESULT(r1) RECONCILE_IRQ_STATE(r10, r11) - ld r4,_DAR(r1) - ld r5,RESULT(r1) addi r3,r1,STACK_FRAME_OVERHEAD bl do_bad_slb_fault b interrupt_return@@ -1542,8 +1537,6 @@ EXC_VIRT_BEGIN(instruction_access, 0x4400, 0x80) EXC_VIRT_END(instruction_access, 0x4400, 0x80) EXC_COMMON_BEGIN(instruction_access_common) GEN_COMMON instruction_access - ld r4,_DAR(r1) - ld r5,_DSISR(r1) addi r3,r1,STACK_FRAME_OVERHEAD BEGIN_MMU_FTR_SECTION bl do_hash_fault@@ -1587,10 +1580,9 @@ EXC_VIRT_BEGIN(instruction_access_slb, 0x4480, 0x80) EXC_VIRT_END(instruction_access_slb, 0x4480, 0x80) EXC_COMMON_BEGIN(instruction_access_slb_common) GEN_COMMON instruction_access_slb - ld r4,_DAR(r1) - addi r3,r1,STACK_FRAME_OVERHEAD BEGIN_MMU_FTR_SECTION /* HPT case, do SLB fault */ + addi r3,r1,STACK_FRAME_OVERHEAD bl do_slb_fault cmpdi r3,0 bne- 1f@@ -1602,8 +1594,6 @@ MMU_FTR_SECTION_ELSE ALT_MMU_FTR_SECTION_END_IFCLR(MMU_FTR_TYPE_RADIX) std r3,RESULT(r1) RECONCILE_IRQ_STATE(r10, r11) - ld r4,_DAR(r1) - ld r5,RESULT(r1) addi r3,r1,STACK_FRAME_OVERHEAD bl do_bad_slb_fault b interrupt_returndiff --git a/arch/powerpc/kernel/head_40x.S b/arch/powerpc/kernel/head_40x.S index 44c9018aed1b..ea31f75e9692 100644 --- a/arch/powerpc/kernel/head_40x.S +++ b/arch/powerpc/kernel/head_40x.S@@ -179,9 +179,9 @@ _ENTRY(saved_ksp_limit) */ START_EXCEPTION(0x0300, DataStorage) EXCEPTION_PROLOG - mfspr r5, SPRN_ESR /* Grab the ESR, save it, pass arg3 */ + mfspr r5, SPRN_ESR /* Grab the ESR, save it */ stw r5, _ESR(r11) - mfspr r4, SPRN_DEAR /* Grab the DEAR, save it, pass arg2 */ + mfspr r4, SPRN_DEAR /* Grab the DEAR, save it */ stw r4, _DEAR(r11) EXC_XFER_LITE(0x300, handle_page_fault)@@ -191,9 +191,9 @@ _ENTRY(saved_ksp_limit) */ START_EXCEPTION(0x0400, InstructionAccess) EXCEPTION_PROLOG - mr r4,r12 /* Pass SRR0 as arg2 */ - stw r4, _DEAR(r11) - li r5,0 /* Pass zero as arg3 */ + li r5,0 + stw r5, _ESR(r11) /* Zero ESR */ + stw r12, _DEAR(r11) /* SRR0 as DEAR */
I think we should avoid this, see below
quoted hunk ↗ jump to hunk
EXC_XFER_LITE(0x400, handle_page_fault) /* 0x0500 - External Interrupt Exception */diff --git a/arch/powerpc/kernel/head_8xx.S b/arch/powerpc/kernel/head_8xx.S index 9f359d3fba74..0cd95b633e2b 100644 --- a/arch/powerpc/kernel/head_8xx.S +++ b/arch/powerpc/kernel/head_8xx.S@@ -356,14 +356,14 @@ DataStoreTLBMiss: . = 0x1300 InstructionTLBError: EXCEPTION_PROLOG - mr r4,r12 andis. r5,r9,DSISR_SRR1_MATCH_32S@h /* Filter relevant SRR1 bits */
Could avoid this, see below
andis. r10,r9,SRR1_ISI_NOPT@h beq+ .Litlbie - tlbie r4 + tlbie r12 /* 0x400 is InstructionAccess exception, needed by bad_page_fault() */ .Litlbie: - stw r4, _DAR(r11) + stw r12, _DAR(r11) + stw r5, _DSISR(r11)
And this
quoted hunk ↗ jump to hunk
EXC_XFER_LITE(0x400, handle_page_fault) /* This is the data TLB error on the MPC8xx. This could be due todiff --git a/arch/powerpc/kernel/head_book3s_32.S b/arch/powerpc/kernel/head_book3s_32.S index 5eb9eedac920..81c69769cec6 100644 --- a/arch/powerpc/kernel/head_book3s_32.S +++ b/arch/powerpc/kernel/head_book3s_32.S@@ -369,9 +369,9 @@ BEGIN_MMU_FTR_SECTION bl hash_page END_MMU_FTR_SECTION_IFSET(MMU_FTR_HPTE_TABLE) #endif /* CONFIG_VMAP_STACK */ -1: mr r4,r12 andis. r5,r9,DSISR_SRR1_MATCH_32S@h /* Filter relevant SRR1 bits */ - stw r4, _DAR(r11) + stw r5, _DSISR(r11) + stw r12, _DAR(r11)
And this including the andis.
quoted hunk ↗ jump to hunk
EXC_XFER_LITE(0x400, handle_page_fault) /* External interrupt */@@ -698,8 +698,6 @@ handle_page_fault_tramp_1: #ifdef CONFIG_VMAP_STACK EXCEPTION_PROLOG_2 handle_dar_dsisr=1 #endif - lwz r4, _DAR(r11) - lwz r5, _DSISR(r11) /* fall through */ handle_page_fault_tramp_2: EXC_XFER_LITE(0x300, handle_page_fault)diff --git a/arch/powerpc/kernel/head_booke.h b/arch/powerpc/kernel/head_booke.h index 71c359d438b5..1da0c1d1b0a1 100644 --- a/arch/powerpc/kernel/head_booke.h +++ b/arch/powerpc/kernel/head_booke.h@@ -477,9 +477,7 @@ ALT_FTR_SECTION_END_IFSET(CPU_FTR_EMB_HV) NORMAL_EXCEPTION_PROLOG(INST_STORAGE); \ mfspr r5,SPRN_ESR; /* Grab the ESR and save it */ \ stw r5,_ESR(r11); \ - mr r4,r12; /* Pass SRR0 as arg2 */ \ - stw r4, _DEAR(r11); \ - li r5,0; /* Pass zero as arg3 */ \ + stw r12, _DEAR(r11); /* Pass SRR0 as arg2 */ \
And this
quoted hunk ↗ jump to hunk
EXC_XFER_LITE(0x0400, handle_page_fault) #define ALIGNMENT_EXCEPTION \diff --git a/arch/powerpc/mm/book3s64/hash_utils.c b/arch/powerpc/mm/book3s64/hash_utils.c index bfa1b1966218..0f0bd4af4b2d 100644 --- a/arch/powerpc/mm/book3s64/hash_utils.c +++ b/arch/powerpc/mm/book3s64/hash_utils.c@@ -1510,13 +1510,15 @@ int hash_page(unsigned long ea, unsigned long access, unsigned long trap, } EXPORT_SYMBOL_GPL(hash_page); -int do_hash_fault(struct pt_regs *regs, unsigned long ea, unsigned long dsisr) +long do_hash_fault(struct pt_regs *regs) { + unsigned long ea = regs->dar; + unsigned long dsisr = regs->dsisr; unsigned long access = _PAGE_PRESENT | _PAGE_READ; unsigned long flags = 0; struct mm_struct *mm; unsigned int region_id; - int err; + long err; if (unlikely(dsisr & (DSISR_BAD_FAULT_64S | DSISR_DABRMATCH | DSISR_KEYFAULT))) goto _do_page_fault;@@ -1580,7 +1582,7 @@ int do_hash_fault(struct pt_regs *regs, unsigned long ea, unsigned long dsisr) } else if (err) { _do_page_fault: - err = hash__do_page_fault(regs, ea, dsisr); + err = hash__do_page_fault(regs); } return err;diff --git a/arch/powerpc/mm/book3s64/slb.c b/arch/powerpc/mm/book3s64/slb.c index c30fcbfa0e32..cc34d50874c1 100644 --- a/arch/powerpc/mm/book3s64/slb.c +++ b/arch/powerpc/mm/book3s64/slb.c@@ -837,8 +837,9 @@ static long slb_allocate_user(struct mm_struct *mm, unsigned long ea) return slb_insert_entry(ea, context, flags, ssize, false); } -long do_slb_fault(struct pt_regs *regs, unsigned long ea) +long do_slb_fault(struct pt_regs *regs) { + unsigned long ea = regs->dar; unsigned long id = get_region_id(ea); /* IRQs are not reconciled here, so can't check irqs_disabled */@@ -889,13 +890,15 @@ long do_slb_fault(struct pt_regs *regs, unsigned long ea) } } -void do_bad_slb_fault(struct pt_regs *regs, unsigned long ea, long err) +void do_bad_slb_fault(struct pt_regs *regs) { + int err = regs->result; + if (err == -EFAULT) { if (user_mode(regs)) - _exception(SIGSEGV, regs, SEGV_BNDERR, ea); + _exception(SIGSEGV, regs, SEGV_BNDERR, regs->dar); else - bad_page_fault(regs, ea, SIGSEGV); + bad_page_fault(regs, regs->dar, SIGSEGV); } else if (err == -EINVAL) { unrecoverable_exception(regs); } else {diff --git a/arch/powerpc/mm/fault.c b/arch/powerpc/mm/fault.c index e65a49f246ef..390a296b16a3 100644 --- a/arch/powerpc/mm/fault.c +++ b/arch/powerpc/mm/fault.c@@ -549,11 +549,12 @@ static int __do_page_fault(struct pt_regs *regs, unsigned long address, } NOKPROBE_SYMBOL(__do_page_fault); -int do_page_fault(struct pt_regs *regs, unsigned long address, - unsigned long error_code) +long do_page_fault(struct pt_regs *regs) { enum ctx_state prev_state = exception_enter(); - int err; + unsigned long address = regs->dar; + unsigned long error_code = regs->dsisr; + long err;
By doing something more or less like this (need to be tuned for bookE as well): + int is_exec = TRAP(regs) == 0x400; + unsigned long address = is_exec ? regs->ssr0 : regs->dar; + unsigned long error_code = is_exec ? (regs->ssr1 & DSISR_SRR1_MATCH_32S) : regs->dsisr;
quoted hunk ↗ jump to hunk
err = __do_page_fault(regs, address, error_code);@@ -580,11 +581,12 @@ int do_page_fault(struct pt_regs *regs, unsigned long address, NOKPROBE_SYMBOL(do_page_fault); #ifdef CONFIG_PPC_BOOK3S_64 -/* Same as do_page_fault but interrupt entry has already run in do_hash_fault */ -int hash__do_page_fault(struct pt_regs *regs, unsigned long address, - unsigned long error_code) +/* Same as do_page_fault but no interrupt entry */ +long hash__do_page_fault(struct pt_regs *regs) { - int err; + unsigned long address = regs->dar; + unsigned long error_code = regs->dsisr; + long err; err = __do_page_fault(regs, address, error_code); if (unlikely(err)) {
There is probably also something we can simplify around get_and_save_dar_dsisr_on_stack() macro in head_32.h, no need to reload DAR, at least for 8xx. Maybe as a followup patch later. Christophe