diff options
| author | Jason Wessel <jason.wessel@windriver.com> | 2010-05-21 06:04:25 +0400 |
|---|---|---|
| committer | Jason Wessel <jason.wessel@windriver.com> | 2010-05-21 06:04:25 +0400 |
| commit | ba797b28131b1f1367b662936ea370239d603cff (patch) | |
| tree | 3939c2cf1ced75fc9a14339cf369a32c85c7f7fe | |
| parent | f503b5ae53cb557ac351a668fcac1baab1cef0db (diff) | |
| download | linux-ba797b28131b1f1367b662936ea370239d603cff.tar.xz | |
powerpc,kgdb: Introduce low level trap catching
The only way the debugger can handle a trap in inside rcu_lock,
notify_die, or atomic_notifier_call_chain without a recursive fault is
to allow the kernel debugger to handle the exception first in
program_check_exception().
The other change here is to make sure that kgdb_handle_exception() is
called with correct parameters when catching an oops, because kdb
needs to know if the entry was an oops, single step, or breakpoint
exception.
[benh@kernel.crashing.org: move debugger_bpt instead of #ifdef]
CC: Paul Mackerras <paulus@samba.org>
Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
| -rw-r--r-- | arch/powerpc/kernel/kgdb.c | 6 | ||||
| -rw-r--r-- | arch/powerpc/kernel/traps.c | 7 |
2 files changed, 9 insertions, 4 deletions
diff --git a/arch/powerpc/kernel/kgdb.c b/arch/powerpc/kernel/kgdb.c index c81e3de1306e..82a7b228c81a 100644 --- a/arch/powerpc/kernel/kgdb.c +++ b/arch/powerpc/kernel/kgdb.c @@ -20,6 +20,7 @@ #include <linux/smp.h> #include <linux/signal.h> #include <linux/ptrace.h> +#include <linux/kdebug.h> #include <asm/current.h> #include <asm/processor.h> #include <asm/machdep.h> @@ -115,7 +116,8 @@ void kgdb_roundup_cpus(unsigned long flags) /* KGDB functions to use existing PowerPC64 hooks. */ static int kgdb_debugger(struct pt_regs *regs) { - return kgdb_handle_exception(0, computeSignal(TRAP(regs)), 0, regs); + return !kgdb_handle_exception(1, computeSignal(TRAP(regs)), + DIE_OOPS, regs); } static int kgdb_handle_breakpoint(struct pt_regs *regs) @@ -123,7 +125,7 @@ static int kgdb_handle_breakpoint(struct pt_regs *regs) if (user_mode(regs)) return 0; - if (kgdb_handle_exception(0, SIGTRAP, 0, regs) != 0) + if (kgdb_handle_exception(1, SIGTRAP, 0, regs) != 0) return 0; if (*(u32 *) (regs->nip) == *(u32 *) (&arch_kgdb_ops.gdb_bpt_instr)) diff --git a/arch/powerpc/kernel/traps.c b/arch/powerpc/kernel/traps.c index 29d128eb6c43..b6859aade9c2 100644 --- a/arch/powerpc/kernel/traps.c +++ b/arch/powerpc/kernel/traps.c @@ -815,12 +815,15 @@ void __kprobes program_check_exception(struct pt_regs *regs) return; } if (reason & REASON_TRAP) { + /* Debugger is first in line to stop recursive faults in + * rcu_lock, notify_die, or atomic_notifier_call_chain */ + if (debugger_bpt(regs)) + return; + /* trap exception */ if (notify_die(DIE_BPT, "breakpoint", regs, 5, 5, SIGTRAP) == NOTIFY_STOP) return; - if (debugger_bpt(regs)) - return; if (!(regs->msr & MSR_PR) && /* not user-mode */ report_bug(regs->nip, regs) == BUG_TRAP_TYPE_WARN) { |