powerpc: remove arguments from fault handler functions

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>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210130130852.2952424-7-npiggin@gmail.com

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,

arch/powerpc/include/asm/book3s/64/mmu-hash.h

@@ -456,7 +456,7 @@ static inline unsigned long hpt_hash(unsigned long vpn,
 
 long hpte_insert_repeating(unsigned long hash, unsigned long vpn, unsigned long pa,
 			   unsigned long rlags, unsigned long vflags, int psize, int ssize);
-int do_hash_fault(struct pt_regs *regs, unsigned long ea, unsigned long dsisr);
+long do_hash_fault(struct pt_regs *regs);
 extern int __hash_page_4K(unsigned long ea, unsigned long access,
 			  unsigned long vsid, pte_t *ptep, unsigned long trap,
 			  unsigned long flags, int ssize, int subpage_prot);

arch/powerpc/include/asm/bug.h

@@ -111,7 +111,7 @@
 #ifndef __ASSEMBLY__
 
 struct pt_regs;
-extern int do_page_fault(struct pt_regs *, unsigned long, unsigned long);
+long do_page_fault(struct pt_regs *);
 extern void bad_page_fault(struct pt_regs *, unsigned long, int);
 void __bad_page_fault(struct pt_regs *regs, unsigned long address, int sig);
 extern void _exception(int, struct pt_regs *, int, unsigned long);

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_fault

arch/powerpc/kernel/exceptions-64s.S

@@ -1438,10 +1438,9 @@ 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)
+	ld	r4,_DSISR(r1)
 	addi	r3,r1,STACK_FRAME_OVERHEAD
-	andis.	r0,r5,DSISR_DABRMATCH@h
+	andis.	r0,r4,DSISR_DABRMATCH@h
 	bne-	1f
 BEGIN_MMU_FTR_SECTION
 	bl	do_hash_fault
@@ -1504,10 +1503,9 @@ 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
@@ -1519,8 +1517,6 @@ 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
@@ -1555,8 +1551,6 @@ 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
@@ -1602,10 +1596,9 @@ 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
@@ -1617,8 +1610,6 @@ 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

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 */
 	EXC_XFER_LITE(0x400, handle_page_fault)
 
 /* 0x0500 - External Interrupt Exception */

arch/powerpc/kernel/head_8xx.S

@@ -312,14 +312,14 @@ DataStoreTLBMiss:
 	. = 0x1300
 InstructionTLBError:
 	EXCEPTION_PROLOG
-	mr	r4,r12
 	andis.	r5,r9,DSISR_SRR1_MATCH_32S@h /* Filter relevant SRR1 bits */
 	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)
 	EXC_XFER_LITE(0x400, handle_page_fault)
 
 /* This is the data TLB error on the MPC8xx.  This could be due to

arch/powerpc/kernel/head_book3s_32.S

@@ -362,9 +362,9 @@ BEGIN_MMU_FTR_SECTION
 END_MMU_FTR_SECTION_IFSET(MMU_FTR_HPTE_TABLE)
 #endif
 #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)
 	EXC_XFER_LITE(0x400, handle_page_fault)
 
 /* External interrupt */
@@ -686,7 +686,6 @@ 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:

arch/powerpc/kernel/head_booke.h

@@ -476,9 +476,7 @@ 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 */		      \
 	EXC_XFER_LITE(0x0400, handle_page_fault)
 
 #define ALIGNMENT_EXCEPTION						      \

arch/powerpc/mm/book3s64/hash_utils.c

@@ -1512,13 +1512,15 @@ 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_KEYFAULT)))
 		goto page_fault;
@@ -1582,7 +1584,7 @@ int do_hash_fault(struct pt_regs *regs, unsigned long ea, unsigned long dsisr)
 
 	} else if (err) {
 page_fault:
-		err = do_page_fault(regs, ea, dsisr);
+		err = do_page_fault(regs);
 	}
 
 	return err;

arch/powerpc/mm/book3s64/slb.c

@@ -813,8 +813,9 @@ 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 */
@@ -865,13 +866,15 @@ 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 {

arch/powerpc/mm/fault.c

@@ -542,12 +542,11 @@ 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)
 {
 	const struct exception_table_entry *entry;
 	enum ctx_state prev_state = exception_enter();
-	int rc = __do_page_fault(regs, address, error_code);
+	int rc = __do_page_fault(regs, regs->dar, regs->dsisr);
 	exception_exit(prev_state);
 	if (likely(!rc))
 		return 0;