diff options
| author | Tiejun Chen <tiejun.chen@windriver.com> | 2012-08-22 16:10:20 +0000 |
|---|---|---|
| committer | Benjamin Herrenschmidt <benh@kernel.crashing.org> | 2012-08-24 20:26:06 +1000 |
| commit | 5f630401f9e98bd062733b5bbef096dbf2158066 (patch) | |
| tree | 4d4d1d6fe382982119028473a14f9021d931684b | |
| parent | 949616cf2d3095d1bb6b3d155c1cc963abd98b5c (diff) | |
powerpc/kgdb: Restore current_thread_info properly
For powerpc BooKE and e200, singlestep is handled on the critical/dbg
exception stack. This causes current_thread_info() to fail for kgdb
internal, so previously We work around this issue by copying
the thread_info from the kernel stack before calling kgdb_handle_exception,
and copying it back afterwards.
But actually we don't do this properly. We should backup current_thread_info
then restore that when exit.
Signed-off-by: Tiejun Chen <tiejun.chen@windriver.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
| -rw-r--r-- | arch/powerpc/kernel/kgdb.c | 11 |
1 files changed, 9 insertions, 2 deletions
diff --git a/arch/powerpc/kernel/kgdb.c b/arch/powerpc/kernel/kgdb.c index 05adb69febf4..c470a40b29f5 100644 --- a/arch/powerpc/kernel/kgdb.c +++ b/arch/powerpc/kernel/kgdb.c @@ -25,6 +25,7 @@ #include <asm/processor.h> #include <asm/machdep.h> #include <asm/debug.h> +#include <linux/slab.h> /* * This table contains the mapping between PowerPC hardware trap types, and @@ -153,6 +154,8 @@ static int kgdb_handle_breakpoint(struct pt_regs *regs) static int kgdb_singlestep(struct pt_regs *regs) { struct thread_info *thread_info, *exception_thread_info; + struct thread_info *backup_current_thread_info = \ + (struct thread_info *)kmalloc(sizeof(struct thread_info), GFP_KERNEL); if (user_mode(regs)) return 0; @@ -170,13 +173,17 @@ static int kgdb_singlestep(struct pt_regs *regs) thread_info = (struct thread_info *)(regs->gpr[1] & ~(THREAD_SIZE-1)); exception_thread_info = current_thread_info(); - if (thread_info != exception_thread_info) + if (thread_info != exception_thread_info) { + /* Save the original current_thread_info. */ + memcpy(backup_current_thread_info, exception_thread_info, sizeof *thread_info); memcpy(exception_thread_info, thread_info, sizeof *thread_info); + } kgdb_handle_exception(0, SIGTRAP, 0, regs); if (thread_info != exception_thread_info) - memcpy(thread_info, exception_thread_info, sizeof *thread_info); + /* Restore current_thread_info lastly. */ + memcpy(exception_thread_info, backup_current_thread_info, sizeof *thread_info); return 1; } |