[v2][PATCH 3/6] book3e/kgdb: update thread's dbcr0

Tiejun Chen
2013-01-21T07:45:02Z

gdb always need to generate a single step properly to invoke
a kgdb state. But with lazy interrupt, book3e can't always
trigger a debug exception with a single step since the current
is blocked for handling those pending exception, then we miss
that expected dbcr configuration at last to generate a debug
exception.

So here we also update thread's dbcr0 to make sure the current
can go back with that missed dbcr0 configuration.

Signed-off-by: Tiejun Chen <tiejun.chen@windriver.com>
---
arch/powerpc/kernel/kgdb.c | 13 ++++++++++---
1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/arch/powerpc/kernel/kgdb.c b/arch/powerpc/kernel/kgdb.c
index 8747447..eb30a40 100644
--- a/arch/powerpc/kernel/kgdb.c
+++ b/arch/powerpc/kernel/kgdb.c
@@ -409,7 +409,7 @@ int kgdb_arch_handle_exception(int vector, int signo, int err_code,
struct pt_regs *linux_regs)
{
char *ptr = &remcom_in_buffer[1];
- unsigned long addr;
+ unsigned long addr, dbcr0;

switch (remcom_in_buffer[0]) {
/*
@@ -426,8 +426,15 @@ int kgdb_arch_handle_exception(int vector, int signo, int err_code,
/* set the trace bit if we're stepping */
if (remcom_in_buffer[0] == 's') {
#ifdef CONFIG_PPC_ADV_DEBUG_REGS
- mtspr(SPRN_DBCR0,
- mfspr(SPRN_DBCR0) | DBCR0_IC | DBCR0_IDM);
+ dbcr0 = mfspr(SPRN_DBCR0) | DBCR0_IC | DBCR0_IDM;
+ mtspr(SPRN_DBCR0, dbcr0);
+#ifdef CONFIG_PPC_BOOK3E_64
+ /* With lazy interrut we have to update thread dbcr0 here
+ * to make sure we can set debug properly at last to invoke
+ * kgdb again to work well.
+ */
+ current->thread.dbcr0 = dbcr0;
+#endif
linux_regs->msr |= MSR_DE;
#else
linux_regs->msr |= MSR_SE;
--
1.7.9.5