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authorSimon Glass <sjg@chromium.org>2011-08-16 23:44:26 +0100
committerRussell King <rmk+kernel@arm.linux.org.uk>2011-10-17 09:13:41 +0100
commit87e040b6456fd3416a1f6831c1eedaef5c0a94ff (patch)
tree6a532e73b33c60d0f8b57d0954a055de4a243120 /arch/arm/kernel
parenta675002c797815ec5df4a89748d8cab83158b11d (diff)
ARM: 7017/1: Use generic BUG() handler
ARM uses its own BUG() handler which makes its output slightly different from other archtectures. One of the problems is that the ARM implementation doesn't report the function with the BUG() in it, but always reports the PC being in __bug(). The generic implementation doesn't have this problem. Currently we get something like: kernel BUG at fs/proc/breakme.c:35! Unable to handle kernel NULL pointer dereference at virtual address 00000000 ... PC is at __bug+0x20/0x2c With this patch it displays: kernel BUG at fs/proc/breakme.c:35! Internal error: Oops - undefined instruction: 0 [#1] PREEMPT SMP ... PC is at write_breakme+0xd0/0x1b4 This implementation uses an undefined instruction to implement BUG, and sets up a bug table containing the relevant information. Many versions of gcc do not support %c properly for ARM (inserting a # when they shouldn't) so we work around this using distasteful macro magic. v1: Initial version to replace existing ARM BUG() implementation with something more similar to other architectures. v2: Add Thumb support, remove backtrace whitespace output changes. Change to use macros instead of requiring the asm %d flag to work (thanks to Dave Martin <dave.martin@linaro.org>) v3: Remove old BUG() implementation in favor of this one. Remove the Backtrace: message (will submit this separately). Use ARM_EXIT_KEEP() so that some architectures can dump exit text at link time thanks to Stephen Boyd <sboyd@codeaurora.org> (although since we always define GENERIC_BUG this might be academic.) Rebase to linux-2.6.git master. v4: Allow BUGS in modules (these were not reported correctly in v3) (thanks to Stephen Boyd <sboyd@codeaurora.org> for suggesting that.) Remove __bug() as this is no longer needed. v5: Add %progbits as the section flags. Signed-off-by: Simon Glass <sjg@chromium.org> Reviewed-by: Stephen Boyd <sboyd@codeaurora.org> Tested-by: Stephen Boyd <sboyd@codeaurora.org> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Diffstat (limited to 'arch/arm/kernel')
-rw-r--r--arch/arm/kernel/traps.c31
-rw-r--r--arch/arm/kernel/vmlinux.lds.S3
2 files changed, 23 insertions, 11 deletions
diff --git a/arch/arm/kernel/traps.c b/arch/arm/kernel/traps.c
index bc9f9da782cb..74969248c375 100644
--- a/arch/arm/kernel/traps.c
+++ b/arch/arm/kernel/traps.c
@@ -21,6 +21,7 @@
#include <linux/kdebug.h>
#include <linux/module.h>
#include <linux/kexec.h>
+#include <linux/bug.h>
#include <linux/delay.h>
#include <linux/init.h>
#include <linux/sched.h>
@@ -270,6 +271,8 @@ void die(const char *str, struct pt_regs *regs, int err)
spin_lock_irq(&die_lock);
console_verbose();
bust_spinlocks(1);
+ if (!user_mode(regs))
+ report_bug(regs->ARM_pc, regs);
ret = __die(str, err, thread, regs);
if (regs && kexec_should_crash(thread->task))
@@ -301,6 +304,24 @@ void arm_notify_die(const char *str, struct pt_regs *regs,
}
}
+#ifdef CONFIG_GENERIC_BUG
+
+int is_valid_bugaddr(unsigned long pc)
+{
+#ifdef CONFIG_THUMB2_KERNEL
+ unsigned short bkpt;
+#else
+ unsigned long bkpt;
+#endif
+
+ if (probe_kernel_address((unsigned *)pc, bkpt))
+ return 0;
+
+ return bkpt == BUG_INSTR_VALUE;
+}
+
+#endif
+
static LIST_HEAD(undef_hook);
static DEFINE_SPINLOCK(undef_lock);
@@ -706,16 +727,6 @@ baddataabort(int code, unsigned long instr, struct pt_regs *regs)
arm_notify_die("unknown data abort code", regs, &info, instr, 0);
}
-void __attribute__((noreturn)) __bug(const char *file, int line)
-{
- printk(KERN_CRIT"kernel BUG at %s:%d!\n", file, line);
- *(int *)0 = 0;
-
- /* Avoid "noreturn function does return" */
- for (;;);
-}
-EXPORT_SYMBOL(__bug);
-
void __readwrite_bug(const char *fn)
{
printk("%s called, but not implemented\n", fn);
diff --git a/arch/arm/kernel/vmlinux.lds.S b/arch/arm/kernel/vmlinux.lds.S
index bf977f8514f6..7b2541efd9f8 100644
--- a/arch/arm/kernel/vmlinux.lds.S
+++ b/arch/arm/kernel/vmlinux.lds.S
@@ -21,7 +21,8 @@
#define ARM_CPU_KEEP(x)
#endif
-#if defined(CONFIG_SMP_ON_UP) && !defined(CONFIG_DEBUG_SPINLOCK)
+#if (defined(CONFIG_SMP_ON_UP) && !defined(CONFIG_DEBUG_SPINLOCK)) || \
+ defined(CONFIG_GENERIC_BUG)
#define ARM_EXIT_KEEP(x) x
#else
#define ARM_EXIT_KEEP(x)