[PATCH 1/7] x86, kgdb: early trap init for early debug

From: Jason Wessel
Date: Tue May 18 2010 - 21:44:23 EST


From: Jan Kiszka <jan.kiszka@xxxxxx>

Allow the x86 arch to have early exception processing for the purpose
of debugging via the kgdb.

Signed-off-by: Jan Kiszka <jan.kiszka@xxxxxx>
Signed-off-by: Jason Wessel <jason.wessel@xxxxxxxxxxxxx>
---
arch/x86/include/asm/processor.h | 2 ++
arch/x86/kernel/setup.c | 1 +
arch/x86/kernel/traps.c | 14 ++++++++++----
3 files changed, 13 insertions(+), 4 deletions(-)

diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
index b753ea5..543f48a 100644
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -793,6 +793,8 @@ static inline void wbinvd_halt(void)
extern void enable_sep_cpu(void);
extern int sysenter_setup(void);

+extern void early_trap_init(void);
+
/* Defined in head.S */
extern struct desc_ptr early_gdt_descr;

diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index c4851ef..e802989 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -725,6 +725,7 @@ void __init setup_arch(char **cmdline_p)
/* VMI may relocate the fixmap; do this before touching ioremap area */
vmi_init();

+ early_trap_init();
early_cpu_init();
early_ioremap_init();

diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
index 7296bd2..94b604b 100644
--- a/arch/x86/kernel/traps.c
+++ b/arch/x86/kernel/traps.c
@@ -885,6 +885,16 @@ dotraplinkage void do_iret_error(struct pt_regs *regs, long error_code)
}
#endif

+/* Set of traps needed for early debugging. */
+void __init early_trap_init(void)
+{
+ set_intr_gate_ist(1, &debug, DEBUG_STACK);
+ /* int3 can be called from all */
+ set_system_intr_gate_ist(3, &int3, DEBUG_STACK);
+ set_intr_gate(14, &page_fault);
+ load_idt(&idt_descr);
+}
+
void __init trap_init(void)
{
int i;
@@ -898,10 +908,7 @@ void __init trap_init(void)
#endif

set_intr_gate(0, &divide_error);
- set_intr_gate_ist(1, &debug, DEBUG_STACK);
set_intr_gate_ist(2, &nmi, NMI_STACK);
- /* int3 can be called from all */
- set_system_intr_gate_ist(3, &int3, DEBUG_STACK);
/* int4 can be called from all */
set_system_intr_gate(4, &overflow);
set_intr_gate(5, &bounds);
@@ -917,7 +924,6 @@ void __init trap_init(void)
set_intr_gate(11, &segment_not_present);
set_intr_gate_ist(12, &stack_segment, STACKFAULT_STACK);
set_intr_gate(13, &general_protection);
- set_intr_gate(14, &page_fault);
set_intr_gate(15, &spurious_interrupt_bug);
set_intr_gate(16, &coprocessor_error);
set_intr_gate(17, &alignment_check);
--
1.6.3.3

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