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>
asmlinkage void debug(void);
asmlinkage void nmi(void);
asmlinkage void int3(void);
asmlinkage void debug(void);
asmlinkage void nmi(void);
asmlinkage void int3(void);
+asmlinkage void xen_debug(void);
+asmlinkage void xen_int3(void);
+asmlinkage void xen_stack_segment(void);
asmlinkage void overflow(void);
asmlinkage void bounds(void);
asmlinkage void invalid_op(void);
asmlinkage void overflow(void);
asmlinkage void bounds(void);
asmlinkage void invalid_op(void);
paranoidzeroentry_ist debug do_debug DEBUG_STACK
paranoidzeroentry_ist int3 do_int3 DEBUG_STACK
paranoiderrorentry stack_segment do_stack_segment
paranoidzeroentry_ist debug do_debug DEBUG_STACK
paranoidzeroentry_ist int3 do_int3 DEBUG_STACK
paranoiderrorentry stack_segment do_stack_segment
+#ifdef CONFIG_XEN
+zeroentry xen_debug do_debug
+zeroentry xen_int3 do_int3
+errorentry xen_stack_segment do_stack_segment
+#endif
errorentry general_protection do_general_protection
errorentry page_fault do_page_fault
#ifdef CONFIG_X86_MCE
errorentry general_protection do_general_protection
errorentry page_fault do_page_fault
#ifdef CONFIG_X86_MCE
#include <linux/delay.h>
#include <linux/start_kernel.h>
#include <linux/sched.h>
#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>
#include <linux/bootmem.h>
#include <linux/module.h>
#include <linux/mm.h>
#include <asm/processor.h>
#include <asm/proto.h>
#include <asm/msr-index.h>
#include <asm/processor.h>
#include <asm/proto.h>
#include <asm/msr-index.h>
#include <asm/setup.h>
#include <asm/desc.h>
#include <asm/pgtable.h>
#include <asm/setup.h>
#include <asm/desc.h>
#include <asm/pgtable.h>
static int cvt_gate_to_trap(int vector, const gate_desc *val,
struct trap_info *info)
{
static int cvt_gate_to_trap(int vector, const gate_desc *val,
struct trap_info *info)
{
if (val->type != GATE_TRAP && val->type != GATE_INTERRUPT)
return 0;
info->vector = vector;
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 */
info->cs = gate_segment(*val);
info->flags = val->dpl;
/* interrupt gates clear IF */