Thread (9 messages) 9 messages, 2 authors, 2012-12-21

Re: [v1][PATCH 3/6] book3e/kgdb: update thread's dbcr0

From: Kumar Gala <hidden>
Date: 2012-12-20 18:42:09
Also in: lkml

On Dec 20, 2012, at 3:08 AM, Tiejun Chen wrote:
quoted hunk ↗ jump to hunk
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.
=20
So here we also update thread's dbcr0 to make sure the current
can go back with that missed dbcr0 configuration.
=20
Signed-off-by: Tiejun Chen <redacted>
---
arch/powerpc/kernel/kgdb.c |   10 ++++++++++
1 file changed, 10 insertions(+)
=20
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] =3D=3D 's') {
#ifdef CONFIG_PPC_ADV_DEBUG_REGS
+#ifdef CONFIG_PPC_BOOK3E
Should this really be CONFIG_PPC64 or 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 =3D
+				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?
			linux_regs->msr |=3D MSR_DE;
#else
			linux_regs->msr |=3D MSR_SE;
--=20
1.7.9.5
=20
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