Subject: [PATCH v3 03/19] powerpc: bad_page_fault, do_break get registers from regs

From: Nicholas Piggin <[email-masked]>
Date: Sun, 29 Nov 2020 00:40:58 +1000

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.

[32s DABR code from Christophe Leroy <[email-masked]>]
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             | 18 +-----------------
 arch/powerpc/kernel/exceptions-64e.S       |  3 +--
 arch/powerpc/kernel/exceptions-64s.S       |  3 +--
 arch/powerpc/kernel/head_8xx.S             |  5 ++---
 arch/powerpc/kernel/head_book3s_32.S       |  3 +++
 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                    | 10 +++++-----
 arch/powerpc/platforms/8xx/machine_check.c |  2 +-
 13 files changed, 23 insertions(+), 41 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..57b8e95ea2a0 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
@@ -668,23 +664,11 @@ 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)
 	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/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 690058043b17..77b730f515c4 100644
--- a/arch/powerpc/kernel/exceptions-64s.S
+++ b/arch/powerpc/kernel/exceptions-64s.S
@@ -2136,8 +2136,7 @@ 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 8acd365a2be6..71ad7ce28469 100644
--- a/arch/powerpc/kernel/head_8xx.S
+++ b/arch/powerpc/kernel/head_8xx.S
@@ -376,10 +376,9 @@ 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/head_book3s_32.S b/arch/powerpc/kernel/head_book3s_32.S
index 7addf67832f9..5875f8795d5b 100644
--- a/arch/powerpc/kernel/head_book3s_32.S
+++ b/arch/powerpc/kernel/head_book3s_32.S
@@ -689,7 +689,10 @@ handle_page_fault_tramp_1:
 #endif
 	/* fall through */
 handle_page_fault_tramp_2:
+	andis.	r0, r5, DSISR_DABRMATCH@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
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..e11989be8f1c 100644
--- a/arch/powerpc/mm/fault.c
+++ b/arch/powerpc/mm/fault.c
@@ -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