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 |   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

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Reply via email to