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authorJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>2009-03-29 19:56:29 -0700
committerJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>2009-05-08 15:51:03 -0700
commit6cac5a924668a56c7ccefc345805f1fe0536a90e (patch)
tree0e15fe317a21ac40244cbf38cdeaa36f4c9837fd /arch/x86/xen
parent6b2e8523df148c15ea5abf13075026fb8bdb3f86 (diff)
xen/x86-64: fix breakpoints and hardware watchpoints
Native x86-64 uses the IST mechanism to run int3 and debug traps on an alternative stack. Xen does not do this, and so the frames were being misinterpreted by the ptrace code. This change special-cases these two exceptions by using Xen variants which run on the normal kernel stack properly. Impact: avoid crash or bad data when IST trap is invoked under Xen Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Diffstat (limited to 'arch/x86/xen')
-rw-r--r--arch/x86/xen/enlighten.c19
1 files changed, 18 insertions, 1 deletions
diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c
index 12a3159333bc..7566e13c0cac 100644
--- a/arch/x86/xen/enlighten.c
+++ b/arch/x86/xen/enlighten.c
@@ -20,6 +20,7 @@
#include <linux/delay.h>
#include <linux/start_kernel.h>
#include <linux/sched.h>
+#include <linux/kprobes.h>
#include <linux/bootmem.h>
#include <linux/module.h>
#include <linux/mm.h>
@@ -44,6 +45,7 @@
#include <asm/processor.h>
#include <asm/proto.h>
#include <asm/msr-index.h>
+#include <asm/traps.h>
#include <asm/setup.h>
#include <asm/desc.h>
#include <asm/pgtable.h>
@@ -428,11 +430,26 @@ static void xen_write_ldt_entry(struct desc_struct *dt, int entrynum,
static int cvt_gate_to_trap(int vector, const gate_desc *val,
struct trap_info *info)
{
+ unsigned long addr;
+
if (val->type != GATE_TRAP && val->type != GATE_INTERRUPT)
return 0;
info->vector = vector;
- info->address = gate_offset(*val);
+
+ addr = gate_offset(*val);
+#ifdef CONFIG_X86_64
+ if (addr == (unsigned long)debug)
+ addr = (unsigned long)xen_debug;
+ else if (addr == (unsigned long)int3)
+ addr = (unsigned long)xen_int3;
+ else if (addr == (unsigned long)stack_segment)
+ addr = (unsigned long)xen_stack_segment;
+ else
+ WARN_ON(val->ist != 0);
+#endif /* CONFIG_X86_64 */
+ info->address = addr;
+
info->cs = gate_segment(*val);
info->flags = val->dpl;
/* interrupt gates clear IF */