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Diffstat (limited to 'arch/x86/kernel/traps.c')
-rw-r--r--arch/x86/kernel/traps.c86
1 files changed, 60 insertions, 26 deletions
diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
index ecffca11f4e..772e2a846de 100644
--- a/arch/x86/kernel/traps.c
+++ b/arch/x86/kernel/traps.c
@@ -12,6 +12,7 @@
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+#include <linux/context_tracking.h>
#include <linux/interrupt.h>
#include <linux/kallsyms.h>
#include <linux/spinlock.h>
@@ -55,8 +56,7 @@
#include <asm/i387.h>
#include <asm/fpu-internal.h>
#include <asm/mce.h>
-#include <asm/context_tracking.h>
-
+#include <asm/fixmap.h>
#include <asm/mach_traps.h>
#ifdef CONFIG_X86_64
@@ -176,34 +176,38 @@ do_trap(int trapnr, int signr, char *str, struct pt_regs *regs,
#define DO_ERROR(trapnr, signr, str, name) \
dotraplinkage void do_##name(struct pt_regs *regs, long error_code) \
{ \
- exception_enter(regs); \
+ enum ctx_state prev_state; \
+ \
+ prev_state = exception_enter(); \
if (notify_die(DIE_TRAP, str, regs, error_code, \
trapnr, signr) == NOTIFY_STOP) { \
- exception_exit(regs); \
+ exception_exit(prev_state); \
return; \
} \
conditional_sti(regs); \
do_trap(trapnr, signr, str, regs, error_code, NULL); \
- exception_exit(regs); \
+ exception_exit(prev_state); \
}
#define DO_ERROR_INFO(trapnr, signr, str, name, sicode, siaddr) \
dotraplinkage void do_##name(struct pt_regs *regs, long error_code) \
{ \
siginfo_t info; \
+ enum ctx_state prev_state; \
+ \
info.si_signo = signr; \
info.si_errno = 0; \
info.si_code = sicode; \
info.si_addr = (void __user *)siaddr; \
- exception_enter(regs); \
+ prev_state = exception_enter(); \
if (notify_die(DIE_TRAP, str, regs, error_code, \
trapnr, signr) == NOTIFY_STOP) { \
- exception_exit(regs); \
+ exception_exit(prev_state); \
return; \
} \
conditional_sti(regs); \
do_trap(trapnr, signr, str, regs, error_code, &info); \
- exception_exit(regs); \
+ exception_exit(prev_state); \
}
DO_ERROR_INFO(X86_TRAP_DE, SIGFPE, "divide error", divide_error, FPE_INTDIV,
@@ -226,14 +230,16 @@ DO_ERROR_INFO(X86_TRAP_AC, SIGBUS, "alignment check", alignment_check,
/* Runs on IST stack */
dotraplinkage void do_stack_segment(struct pt_regs *regs, long error_code)
{
- exception_enter(regs);
+ enum ctx_state prev_state;
+
+ prev_state = exception_enter();
if (notify_die(DIE_TRAP, "stack segment", regs, error_code,
X86_TRAP_SS, SIGBUS) != NOTIFY_STOP) {
preempt_conditional_sti(regs);
do_trap(X86_TRAP_SS, SIGBUS, "stack segment", regs, error_code, NULL);
preempt_conditional_cli(regs);
}
- exception_exit(regs);
+ exception_exit(prev_state);
}
dotraplinkage void do_double_fault(struct pt_regs *regs, long error_code)
@@ -241,7 +247,7 @@ dotraplinkage void do_double_fault(struct pt_regs *regs, long error_code)
static const char str[] = "double fault";
struct task_struct *tsk = current;
- exception_enter(regs);
+ exception_enter();
/* Return not checked because double check cannot be ignored */
notify_die(DIE_TRAP, str, regs, error_code, X86_TRAP_DF, SIGSEGV);
@@ -261,8 +267,9 @@ dotraplinkage void __kprobes
do_general_protection(struct pt_regs *regs, long error_code)
{
struct task_struct *tsk;
+ enum ctx_state prev_state;
- exception_enter(regs);
+ prev_state = exception_enter();
conditional_sti(regs);
#ifdef CONFIG_X86_32
@@ -300,12 +307,14 @@ do_general_protection(struct pt_regs *regs, long error_code)
force_sig(SIGSEGV, tsk);
exit:
- exception_exit(regs);
+ exception_exit(prev_state);
}
/* May run on IST stack. */
dotraplinkage void __kprobes notrace do_int3(struct pt_regs *regs, long error_code)
{
+ enum ctx_state prev_state;
+
#ifdef CONFIG_DYNAMIC_FTRACE
/*
* ftrace must be first, everything else may cause a recursive crash.
@@ -315,7 +324,7 @@ dotraplinkage void __kprobes notrace do_int3(struct pt_regs *regs, long error_co
ftrace_int3_handler(regs))
return;
#endif
- exception_enter(regs);
+ prev_state = exception_enter();
#ifdef CONFIG_KGDB_LOW_LEVEL_TRAP
if (kgdb_ll_trap(DIE_INT3, "int3", regs, error_code, X86_TRAP_BP,
SIGTRAP) == NOTIFY_STOP)
@@ -336,7 +345,7 @@ dotraplinkage void __kprobes notrace do_int3(struct pt_regs *regs, long error_co
preempt_conditional_cli(regs);
debug_stack_usage_dec();
exit:
- exception_exit(regs);
+ exception_exit(prev_state);
}
#ifdef CONFIG_X86_64
@@ -393,11 +402,12 @@ asmlinkage __kprobes struct pt_regs *sync_regs(struct pt_regs *eregs)
dotraplinkage void __kprobes do_debug(struct pt_regs *regs, long error_code)
{
struct task_struct *tsk = current;
+ enum ctx_state prev_state;
int user_icebp = 0;
unsigned long dr6;
int si_code;
- exception_enter(regs);
+ prev_state = exception_enter();
get_debugreg(dr6, 6);
@@ -467,7 +477,7 @@ dotraplinkage void __kprobes do_debug(struct pt_regs *regs, long error_code)
debug_stack_usage_dec();
exit:
- exception_exit(regs);
+ exception_exit(prev_state);
}
/*
@@ -561,17 +571,21 @@ void math_error(struct pt_regs *regs, int error_code, int trapnr)
dotraplinkage void do_coprocessor_error(struct pt_regs *regs, long error_code)
{
- exception_enter(regs);
+ enum ctx_state prev_state;
+
+ prev_state = exception_enter();
math_error(regs, error_code, X86_TRAP_MF);
- exception_exit(regs);
+ exception_exit(prev_state);
}
dotraplinkage void
do_simd_coprocessor_error(struct pt_regs *regs, long error_code)
{
- exception_enter(regs);
+ enum ctx_state prev_state;
+
+ prev_state = exception_enter();
math_error(regs, error_code, X86_TRAP_XF);
- exception_exit(regs);
+ exception_exit(prev_state);
}
dotraplinkage void
@@ -639,7 +653,9 @@ EXPORT_SYMBOL_GPL(math_state_restore);
dotraplinkage void __kprobes
do_device_not_available(struct pt_regs *regs, long error_code)
{
- exception_enter(regs);
+ enum ctx_state prev_state;
+
+ prev_state = exception_enter();
BUG_ON(use_eager_fpu());
#ifdef CONFIG_MATH_EMULATION
@@ -650,7 +666,7 @@ do_device_not_available(struct pt_regs *regs, long error_code)
info.regs = regs;
math_emulate(&info);
- exception_exit(regs);
+ exception_exit(prev_state);
return;
}
#endif
@@ -658,15 +674,16 @@ do_device_not_available(struct pt_regs *regs, long error_code)
#ifdef CONFIG_X86_32
conditional_sti(regs);
#endif
- exception_exit(regs);
+ exception_exit(prev_state);
}
#ifdef CONFIG_X86_32
dotraplinkage void do_iret_error(struct pt_regs *regs, long error_code)
{
siginfo_t info;
+ enum ctx_state prev_state;
- exception_enter(regs);
+ prev_state = exception_enter();
local_irq_enable();
info.si_signo = SIGILL;
@@ -678,7 +695,7 @@ dotraplinkage void do_iret_error(struct pt_regs *regs, long error_code)
do_trap(X86_TRAP_IRET, SIGILL, "iret exception", regs, error_code,
&info);
}
- exception_exit(regs);
+ exception_exit(prev_state);
}
#endif
@@ -688,10 +705,19 @@ void __init early_trap_init(void)
set_intr_gate_ist(X86_TRAP_DB, &debug, DEBUG_STACK);
/* int3 can be called from all */
set_system_intr_gate_ist(X86_TRAP_BP, &int3, DEBUG_STACK);
+#ifdef CONFIG_X86_32
set_intr_gate(X86_TRAP_PF, &page_fault);
+#endif
load_idt(&idt_descr);
}
+void __init early_trap_pf_init(void)
+{
+#ifdef CONFIG_X86_64
+ set_intr_gate(X86_TRAP_PF, &page_fault);
+#endif
+}
+
void __init trap_init(void)
{
int i;
@@ -744,6 +770,14 @@ void __init trap_init(void)
#endif
/*
+ * Set the IDT descriptor to a fixed read-only location, so that the
+ * "sidt" instruction will not leak the location of the kernel, and
+ * to defend the IDT against arbitrary memory write vulnerabilities.
+ * It will be reloaded in cpu_init() */
+ __set_fixmap(FIX_RO_IDT, __pa_symbol(idt_table), PAGE_KERNEL_RO);
+ idt_descr.address = fix_to_virt(FIX_RO_IDT);
+
+ /*
* Should be a barrier for any external CPU state:
*/
cpu_init();
generated by cgit v1.2.3-70-g09d2 (git 2.51.2) at 2025-11-04 06:53:26 +0000