Subject: [PATCH 03/18] powerpc: bad_page_fault, do_break get registers from regs

From: Nicholas Piggin <[email-masked]>
Date: Fri, 6 Nov 2020 00:34:16 +1000

This also moves the 32s DABR match to C.

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 <[email-masked]>
---
 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);
 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@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;
-- 
2.23.0