On 12/21/2012 02:41 AM, Kumar Gala wrote:
On Dec 20, 2012, at 3:08 AM, Tiejun Chen wrote:
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.c...@windriver.com>
---
arch/powerpc/kernel/kgdb.c | 10 ++++++++++
1 file changed, 10 insertions(+)
diff --git a/arch/powerpc/kernel/kgdb.c b/arch/powerpc/kernel/kgdb.c
index c470a40..516b44b 100644
--- a/arch/powerpc/kernel/kgdb.c
+++ b/arch/powerpc/kernel/kgdb.c
@@ -426,8 +426,18 @@ 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
+#ifdef CONFIG_PPC_BOOK3E
Should this really be CONFIG_PPC64 or CONFIG_PPC_BOOK3E_64?
Yes, I think CONFIG_PPC_BOOK3E_64 is better currently. Because I didn't validate
this on power arch since I have no a real machine :)
+ /* 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 =
+ mfspr(SPRN_DBCR0) | DBCR0_IC | DBCR0_IDM;
+ mtspr(SPRN_DBCR0, current->thread.dbcr0);
+#else
mtspr(SPRN_DBCR0,
mfspr(SPRN_DBCR0) | DBCR0_IC | DBCR0_IDM);
+#endif
Can we code this so we don't need the #else?
I guess you're saying something like this:
---
diff --git a/arch/powerpc/kernel/kgdb.c b/arch/powerpc/kernel/kgdb.c
index c470a40..b2df42a 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
Tiejun
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