linux-kernel - [PATCH] kgdbts: unify/generalize gdb breakpoint adjustment

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Message-Id: <1243927050-30685-1-git-send-email-vapier@gentoo.org>
Date:	Tue,  2 Jun 2009 03:17:30 -0400
From:	Mike Frysinger <vapier@...too.org>
To:	Jason Wessel <jason.wessel@...driver.com>
Cc:	kgdb-bugreport@...ts.sourceforge.net, linux-kernel@...r.kernel.org
Subject: [PATCH] kgdbts: unify/generalize gdb breakpoint adjustment

The Blackfin arch, like the x86 arch, needs to adjust the PC manually
after a breakpoint is hit as normally this is handled by the remote gdb.
However, rather than starting another arch ifdef mess, create a common
GDB_ADJUSTS_BREAK_OFFSET define for any arch to opt-in via their kgdb.h.

Signed-off-by: Mike Frysinger <vapier@...too.org>
---
 arch/blackfin/include/asm/kgdb.h |    1 +
 arch/x86/include/asm/kgdb.h      |    1 +
 drivers/misc/kgdbts.c            |   14 ++++++--------
 3 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/arch/blackfin/include/asm/kgdb.h b/arch/blackfin/include/asm/kgdb.h
index c8b256d..8d5fe42 100644
--- a/arch/blackfin/include/asm/kgdb.h
+++ b/arch/blackfin/include/asm/kgdb.h
@@ -107,6 +107,7 @@ static inline void arch_kgdb_breakpoint(void)
 }
 #define BREAK_INSTR_SIZE	2
 #define CACHE_FLUSH_IS_SAFE	1
+#define GDB_ADJUSTS_BREAK_OFFSET
 #define HW_INST_WATCHPOINT_NUM	6
 #define HW_WATCHPOINT_NUM	8
 #define TYPE_INST_WATCHPOINT	0
diff --git a/arch/x86/include/asm/kgdb.h b/arch/x86/include/asm/kgdb.h
index e6c6c80..30671a8 100644
--- a/arch/x86/include/asm/kgdb.h
+++ b/arch/x86/include/asm/kgdb.h
@@ -75,5 +75,6 @@ static inline void arch_kgdb_breakpoint(void)
 }
 #define BREAK_INSTR_SIZE	1
 #define CACHE_FLUSH_IS_SAFE	1
+#define GDB_ADJUSTS_BREAK_OFFSET
 
 #endif /* _ASM_X86_KGDB_H */
diff --git a/drivers/misc/kgdbts.c b/drivers/misc/kgdbts.c
index e4ff50b..faff9cb 100644
--- a/drivers/misc/kgdbts.c
+++ b/drivers/misc/kgdbts.c
@@ -291,10 +291,10 @@ static int check_and_rewind_pc(char *put_str, char *arg)
 		 NUMREGBYTES);
 	gdb_regs_to_pt_regs(kgdbts_gdb_regs, &kgdbts_regs);
 	v2printk("Stopped at IP: %lx\n", instruction_pointer(&kgdbts_regs));
-#ifdef CONFIG_X86
-	/* On x86 a breakpoint stop requires it to be decremented */
-	if (addr + 1 == kgdbts_regs.ip)
-		offset = -1;
+#ifdef GDB_ADJUSTS_BREAK_OFFSET
+	/* On some arches, a breakpoint stop requires it to be decremented */
+	if (addr + BREAK_INSTR_SIZE == instruction_pointer(&kgdbts_regs))
+		offset = -BREAK_INSTR_SIZE;
 #endif
 	if (strcmp(arg, "silent") &&
 		instruction_pointer(&kgdbts_regs) + offset != addr) {
@@ -302,10 +302,8 @@ static int check_and_rewind_pc(char *put_str, char *arg)
 			   instruction_pointer(&kgdbts_regs) + offset, addr);
 		return 1;
 	}
-#ifdef CONFIG_X86
-	/* On x86 adjust the instruction pointer if needed */
-	kgdbts_regs.ip += offset;
-#endif
+	/* Readjust the instruction pointer if needed */
+	instruction_pointer(&kgdbts_regs) += offset;
 	return 0;
 }
 
-- 
1.6.3.1

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