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Diffstat (limited to 'arch/x86/kernel/traps.c')
-rw-r--r--arch/x86/kernel/traps.c90
1 files changed, 30 insertions, 60 deletions
diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
index f5791927aa64..346eec73f7db 100644
--- a/arch/x86/kernel/traps.c
+++ b/arch/x86/kernel/traps.c
@@ -62,6 +62,7 @@
#include <asm/fpu/xstate.h>
#include <asm/trace/mpx.h>
#include <asm/mpx.h>
+#include <asm/vm86.h>
#ifdef CONFIG_X86_64
#include <asm/x86_init.h>
@@ -108,13 +109,10 @@ static inline void preempt_conditional_cli(struct pt_regs *regs)
preempt_count_dec();
}
-enum ctx_state ist_enter(struct pt_regs *regs)
+void ist_enter(struct pt_regs *regs)
{
- enum ctx_state prev_state;
-
if (user_mode(regs)) {
- /* Other than that, we're just an exception. */
- prev_state = exception_enter();
+ RCU_LOCKDEP_WARN(!rcu_is_watching(), "entry code didn't wake RCU");
} else {
/*
* We might have interrupted pretty much anything. In
@@ -123,32 +121,25 @@ enum ctx_state ist_enter(struct pt_regs *regs)
* but we need to notify RCU.
*/
rcu_nmi_enter();
- prev_state = CONTEXT_KERNEL; /* the value is irrelevant. */
}
/*
- * We are atomic because we're on the IST stack (or we're on x86_32,
- * in which case we still shouldn't schedule).
- *
- * This must be after exception_enter(), because exception_enter()
- * won't do anything if in_interrupt() returns true.
+ * We are atomic because we're on the IST stack; or we're on
+ * x86_32, in which case we still shouldn't schedule; or we're
+ * on x86_64 and entered from user mode, in which case we're
+ * still atomic unless ist_begin_non_atomic is called.
*/
preempt_count_add(HARDIRQ_OFFSET);
/* This code is a bit fragile. Test it. */
- rcu_lockdep_assert(rcu_is_watching(), "ist_enter didn't work");
-
- return prev_state;
+ RCU_LOCKDEP_WARN(!rcu_is_watching(), "ist_enter didn't work");
}
-void ist_exit(struct pt_regs *regs, enum ctx_state prev_state)
+void ist_exit(struct pt_regs *regs)
{
- /* Must be before exception_exit. */
preempt_count_sub(HARDIRQ_OFFSET);
- if (user_mode(regs))
- return exception_exit(prev_state);
- else
+ if (!user_mode(regs))
rcu_nmi_exit();
}
@@ -162,7 +153,7 @@ void ist_exit(struct pt_regs *regs, enum ctx_state prev_state)
* a double fault, it can be safe to schedule. ist_begin_non_atomic()
* begins a non-atomic section within an ist_enter()/ist_exit() region.
* Callers are responsible for enabling interrupts themselves inside
- * the non-atomic section, and callers must call is_end_non_atomic()
+ * the non-atomic section, and callers must call ist_end_non_atomic()
* before ist_exit().
*/
void ist_begin_non_atomic(struct pt_regs *regs)
@@ -289,17 +280,16 @@ NOKPROBE_SYMBOL(do_trap);
static void do_error_trap(struct pt_regs *regs, long error_code, char *str,
unsigned long trapnr, int signr)
{
- enum ctx_state prev_state = exception_enter();
siginfo_t info;
+ RCU_LOCKDEP_WARN(!rcu_is_watching(), "entry code didn't wake RCU");
+
if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, signr) !=
NOTIFY_STOP) {
conditional_sti(regs);
do_trap(trapnr, signr, str, regs, error_code,
fill_trap_info(regs, signr, trapnr, &info));
}
-
- exception_exit(prev_state);
}
#define DO_ERROR(trapnr, signr, str, name) \
@@ -351,7 +341,7 @@ dotraplinkage void do_double_fault(struct pt_regs *regs, long error_code)
}
#endif
- ist_enter(regs); /* Discard prev_state because we won't return. */
+ ist_enter(regs);
notify_die(DIE_TRAP, str, regs, error_code, X86_TRAP_DF, SIGSEGV);
tsk->thread.error_code = error_code;
@@ -371,14 +361,13 @@ dotraplinkage void do_double_fault(struct pt_regs *regs, long error_code)
dotraplinkage void do_bounds(struct pt_regs *regs, long error_code)
{
- enum ctx_state prev_state;
const struct bndcsr *bndcsr;
siginfo_t *info;
- prev_state = exception_enter();
+ RCU_LOCKDEP_WARN(!rcu_is_watching(), "entry code didn't wake RCU");
if (notify_die(DIE_TRAP, "bounds", regs, error_code,
X86_TRAP_BR, SIGSEGV) == NOTIFY_STOP)
- goto exit;
+ return;
conditional_sti(regs);
if (!user_mode(regs))
@@ -435,9 +424,8 @@ dotraplinkage void do_bounds(struct pt_regs *regs, long error_code)
die("bounds", regs, error_code);
}
-exit:
- exception_exit(prev_state);
return;
+
exit_trap:
/*
* This path out is for all the cases where we could not
@@ -447,35 +435,33 @@ exit_trap:
* time..
*/
do_trap(X86_TRAP_BR, SIGSEGV, "bounds", regs, error_code, NULL);
- exception_exit(prev_state);
}
dotraplinkage void
do_general_protection(struct pt_regs *regs, long error_code)
{
struct task_struct *tsk;
- enum ctx_state prev_state;
- prev_state = exception_enter();
+ RCU_LOCKDEP_WARN(!rcu_is_watching(), "entry code didn't wake RCU");
conditional_sti(regs);
if (v8086_mode(regs)) {
local_irq_enable();
handle_vm86_fault((struct kernel_vm86_regs *) regs, error_code);
- goto exit;
+ return;
}
tsk = current;
if (!user_mode(regs)) {
if (fixup_exception(regs))
- goto exit;
+ return;
tsk->thread.error_code = error_code;
tsk->thread.trap_nr = X86_TRAP_GP;
if (notify_die(DIE_GPF, "general protection fault", regs, error_code,
X86_TRAP_GP, SIGSEGV) != NOTIFY_STOP)
die("general protection fault", regs, error_code);
- goto exit;
+ return;
}
tsk->thread.error_code = error_code;
@@ -491,16 +477,12 @@ do_general_protection(struct pt_regs *regs, long error_code)
}
force_sig_info(SIGSEGV, SEND_SIG_PRIV, tsk);
-exit:
- exception_exit(prev_state);
}
NOKPROBE_SYMBOL(do_general_protection);
/* May run on IST stack. */
dotraplinkage void 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.
@@ -513,7 +495,8 @@ dotraplinkage void notrace do_int3(struct pt_regs *regs, long error_code)
if (poke_int3_handler(regs))
return;
- prev_state = ist_enter(regs);
+ ist_enter(regs);
+ RCU_LOCKDEP_WARN(!rcu_is_watching(), "entry code didn't wake RCU");
#ifdef CONFIG_KGDB_LOW_LEVEL_TRAP
if (kgdb_ll_trap(DIE_INT3, "int3", regs, error_code, X86_TRAP_BP,
SIGTRAP) == NOTIFY_STOP)
@@ -539,7 +522,7 @@ dotraplinkage void notrace do_int3(struct pt_regs *regs, long error_code)
preempt_conditional_cli(regs);
debug_stack_usage_dec();
exit:
- ist_exit(regs, prev_state);
+ ist_exit(regs);
}
NOKPROBE_SYMBOL(do_int3);
@@ -615,12 +598,11 @@ NOKPROBE_SYMBOL(fixup_bad_iret);
dotraplinkage void 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;
- prev_state = ist_enter(regs);
+ ist_enter(regs);
get_debugreg(dr6, 6);
@@ -695,7 +677,7 @@ dotraplinkage void do_debug(struct pt_regs *regs, long error_code)
debug_stack_usage_dec();
exit:
- ist_exit(regs, prev_state);
+ ist_exit(regs);
}
NOKPROBE_SYMBOL(do_debug);
@@ -747,21 +729,15 @@ static void math_error(struct pt_regs *regs, int error_code, int trapnr)
dotraplinkage void do_coprocessor_error(struct pt_regs *regs, long error_code)
{
- enum ctx_state prev_state;
-
- prev_state = exception_enter();
+ RCU_LOCKDEP_WARN(!rcu_is_watching(), "entry code didn't wake RCU");
math_error(regs, error_code, X86_TRAP_MF);
- exception_exit(prev_state);
}
dotraplinkage void
do_simd_coprocessor_error(struct pt_regs *regs, long error_code)
{
- enum ctx_state prev_state;
-
- prev_state = exception_enter();
+ RCU_LOCKDEP_WARN(!rcu_is_watching(), "entry code didn't wake RCU");
math_error(regs, error_code, X86_TRAP_XF);
- exception_exit(prev_state);
}
dotraplinkage void
@@ -773,9 +749,7 @@ do_spurious_interrupt_bug(struct pt_regs *regs, long error_code)
dotraplinkage void
do_device_not_available(struct pt_regs *regs, long error_code)
{
- enum ctx_state prev_state;
-
- prev_state = exception_enter();
+ RCU_LOCKDEP_WARN(!rcu_is_watching(), "entry code didn't wake RCU");
BUG_ON(use_eager_fpu());
#ifdef CONFIG_MATH_EMULATION
@@ -786,7 +760,6 @@ do_device_not_available(struct pt_regs *regs, long error_code)
info.regs = regs;
math_emulate(&info);
- exception_exit(prev_state);
return;
}
#endif
@@ -794,7 +767,6 @@ do_device_not_available(struct pt_regs *regs, long error_code)
#ifdef CONFIG_X86_32
conditional_sti(regs);
#endif
- exception_exit(prev_state);
}
NOKPROBE_SYMBOL(do_device_not_available);
@@ -802,9 +774,8 @@ NOKPROBE_SYMBOL(do_device_not_available);
dotraplinkage void do_iret_error(struct pt_regs *regs, long error_code)
{
siginfo_t info;
- enum ctx_state prev_state;
- prev_state = exception_enter();
+ RCU_LOCKDEP_WARN(!rcu_is_watching(), "entry code didn't wake RCU");
local_irq_enable();
info.si_signo = SIGILL;
@@ -816,7 +787,6 @@ 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(prev_state);
}
#endif
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.