[PATCH] x86_64: Move int 3 handler to debug stack and allow to increase it.
This
- switches the INT3 handler to run on an IST stack (to cope with
breakpoints set by a kernel debugger on places where the kernel's
%gs base hasn't been set up, yet); the IST stack used is shared with
the INT1 handler's
[AK: this also allows setting a kprobe on the interrupt/exception entry
points]
- allows nesting of INT1/INT3 handlers so that one can, with a kernel
debugger, debug (at least) the user-mode portions of the INT1/INT3
handling; the nesting isn't actively enabled here since a kernel-
debugger-free kernel doesn't need it
Signed-Off-By: Jan Beulich <jbeulich@novell.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/include/asm-x86_64/pda.h b/include/asm-x86_64/pda.h
index 8733ccf..431a909 100644
--- a/include/asm-x86_64/pda.h
+++ b/include/asm-x86_64/pda.h
@@ -5,6 +5,7 @@
#include <linux/stddef.h>
#include <linux/types.h>
#include <linux/cache.h>
+#include <asm/page.h>
/* Per processor datastructure. %gs points to it while the kernel runs */
struct x8664_pda {
@@ -12,6 +13,9 @@
unsigned long data_offset; /* Per cpu data offset from linker address */
unsigned long kernelstack; /* top of kernel stack for current */
unsigned long oldrsp; /* user rsp for system call */
+#if DEBUG_STKSZ > EXCEPTION_STKSZ
+ unsigned long debugstack; /* #DB/#BP stack. */
+#endif
int irqcount; /* Irq nesting counter. Starts with -1 */
int cpunumber; /* Logical CPU number */
char *irqstackptr; /* top of irqstack */
@@ -23,10 +27,6 @@
unsigned apic_timer_irqs;
} ____cacheline_aligned_in_smp;
-
-#define IRQSTACK_ORDER 2
-#define IRQSTACKSIZE (PAGE_SIZE << IRQSTACK_ORDER)
-
extern struct x8664_pda cpu_pda[];
/*