From 70f12567ac9aca9c2f242ae060d7de245904889e Mon Sep 17 00:00:00 2001
From: Mike Frysinger <vapier@gentoo.org>
Date: Sun, 7 Jun 2009 17:18:25 -0400
Subject: Blackfin: add support for GENERIC_BUG

Signed-off-by: Mike Frysinger <vapier@gentoo.org>
---
 arch/blackfin/Kconfig              |  4 +++
 arch/blackfin/include/asm/bug.h    | 57 ++++++++++++++++++++++++++++++++++----
 arch/blackfin/kernel/traps.c       | 30 ++++++++++++++++++++
 arch/blackfin/kernel/vmlinux.lds.S | 16 +++++++++--
 4 files changed, 99 insertions(+), 8 deletions(-)

diff --git a/arch/blackfin/Kconfig b/arch/blackfin/Kconfig
index c56fd3eb7c10..74cdcf39b41c 100644
--- a/arch/blackfin/Kconfig
+++ b/arch/blackfin/Kconfig
@@ -28,6 +28,10 @@ config BLACKFIN
 	select HAVE_OPROFILE
 	select ARCH_WANT_OPTIONAL_GPIOLIB
 
+config GENERIC_BUG
+	def_bool y
+	depends on BUG
+
 config ZONE_DMA
 	bool
 	default y
diff --git a/arch/blackfin/include/asm/bug.h b/arch/blackfin/include/asm/bug.h
index 6d3e11b1fc57..655e49540e41 100644
--- a/arch/blackfin/include/asm/bug.h
+++ b/arch/blackfin/include/asm/bug.h
@@ -2,13 +2,58 @@
 #define _BLACKFIN_BUG_H
 
 #ifdef CONFIG_BUG
-#define HAVE_ARCH_BUG
 
-#define BUG() do { \
-	dump_bfin_trace_buffer(); \
-	printk(KERN_EMERG "BUG: failure at %s:%d/%s()!\n", __FILE__, __LINE__, __func__); \
-	panic("BUG!"); \
-} while (0)
+#define BFIN_BUG_OPCODE	0xefcd
+
+#ifdef CONFIG_DEBUG_BUGVERBOSE
+
+#define _BUG_OR_WARN(flags)						\
+	asm volatile(							\
+		"1:	.hword	%0\n"					\
+		"	.section __bug_table,\"a\",@progbits\n"		\
+		"2:	.long	1b\n"					\
+		"	.long	%1\n"					\
+		"	.short	%2\n"					\
+		"	.short	%3\n"					\
+		"	.org	2b + %4\n"				\
+		"	.previous"					\
+		:							\
+		: "i"(BFIN_BUG_OPCODE), "i"(__FILE__),			\
+		  "i"(__LINE__), "i"(flags),				\
+		  "i"(sizeof(struct bug_entry)))
+
+#else
+
+#define _BUG_OR_WARN(flags)						\
+	asm volatile(							\
+		"1:	.hword	%0\n"					\
+		"	.section __bug_table,\"a\",@progbits\n"		\
+		"2:	.long	1b\n"					\
+		"	.short	%1\n"					\
+		"	.org	2b + %2\n"				\
+		"	.previous"					\
+		:							\
+		: "i"(BFIN_BUG_OPCODE), "i"(flags),			\
+		  "i"(sizeof(struct bug_entry)))
+
+#endif /* CONFIG_DEBUG_BUGVERBOSE */
+
+#define BUG()								\
+	do {								\
+		_BUG_OR_WARN(0);					\
+		for (;;);						\
+	} while (0)
+
+#define WARN_ON(condition)							\
+	({								\
+		int __ret_warn_on = !!(condition);			\
+		if (unlikely(__ret_warn_on))				\
+			_BUG_OR_WARN(BUGFLAG_WARNING);			\
+		unlikely(__ret_warn_on);				\
+	})
+
+#define HAVE_ARCH_BUG
+#define HAVE_ARCH_WARN_ON
 
 #endif
 
diff --git a/arch/blackfin/kernel/traps.c b/arch/blackfin/kernel/traps.c
index aa76dfb0226e..2405f193224e 100644
--- a/arch/blackfin/kernel/traps.c
+++ b/arch/blackfin/kernel/traps.c
@@ -27,6 +27,7 @@
  * 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  */
 
+#include <linux/bug.h>
 #include <linux/uaccess.h>
 #include <linux/interrupt.h>
 #include <linux/module.h>
@@ -381,6 +382,23 @@ asmlinkage void trap_c(struct pt_regs *fp)
 	/* 0x20 - Reserved, Caught by default */
 	/* 0x21 - Undefined Instruction, handled here */
 	case VEC_UNDEF_I:
+#ifdef CONFIG_BUG
+		if (kernel_mode_regs(fp)) {
+			switch (report_bug(fp->pc, fp)) {
+			case BUG_TRAP_TYPE_NONE:
+				break;
+			case BUG_TRAP_TYPE_WARN:
+				dump_bfin_trace_buffer();
+				fp->pc += 2;
+				goto traps_done;
+			case BUG_TRAP_TYPE_BUG:
+				/* call to panic() will dump trace, and it is
+				 * off at this point, so it won't be clobbered
+				 */
+				panic("BUG()");
+			}
+		}
+#endif
 		info.si_code = ILL_ILLOPC;
 		sig = SIGILL;
 		verbose_printk(KERN_NOTICE EXC_0x21(KERN_NOTICE));
@@ -792,6 +810,18 @@ void dump_bfin_trace_buffer(void)
 }
 EXPORT_SYMBOL(dump_bfin_trace_buffer);
 
+#ifdef CONFIG_BUG
+int is_valid_bugaddr(unsigned long addr)
+{
+	unsigned short opcode;
+
+	if (!get_instruction(&opcode, (unsigned short *)addr))
+		return 0;
+
+	return opcode == BFIN_BUG_OPCODE;
+}
+#endif
+
 /*
  * Checks to see if the address pointed to is either a
  * 16-bit CALL instruction, or a 32-bit CALL instruction
diff --git a/arch/blackfin/kernel/vmlinux.lds.S b/arch/blackfin/kernel/vmlinux.lds.S
index 8b67167cb4f4..119fbdb46475 100644
--- a/arch/blackfin/kernel/vmlinux.lds.S
+++ b/arch/blackfin/kernel/vmlinux.lds.S
@@ -166,6 +166,20 @@ SECTIONS
 	}
 	PERCPU(4)
 	SECURITY_INIT
+
+	/* we have to discard exit text and such at runtime, not link time, to
+	 * handle embedded cross-section references (alt instructions, bug
+	 * table, eh_frame, etc...)
+	 */
+	.exit.text :
+	{
+		EXIT_TEXT
+	}
+	.exit.data :
+	{
+		EXIT_DATA
+	}
+
 	.init.ramfs :
 	{
 		. = ALIGN(4);
@@ -264,8 +278,6 @@ SECTIONS
 
 	/DISCARD/ :
 	{
-		EXIT_TEXT
-		EXIT_DATA
 		*(.exitcall.exit)
 	}
 }
-- 
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