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Diffstat (limited to 'arch/x86/kernel/unwind_orc.c')
-rw-r--r--arch/x86/kernel/unwind_orc.c113
1 files changed, 74 insertions, 39 deletions
diff --git a/arch/x86/kernel/unwind_orc.c b/arch/x86/kernel/unwind_orc.c
index e9cc182aa97e..5b0bd8581fe6 100644
--- a/arch/x86/kernel/unwind_orc.c
+++ b/arch/x86/kernel/unwind_orc.c
@@ -8,19 +8,21 @@
#include <asm/orc_lookup.h>
#define orc_warn(fmt, ...) \
- printk_deferred_once(KERN_WARNING pr_fmt("WARNING: " fmt), ##__VA_ARGS__)
+ printk_deferred_once(KERN_WARNING "WARNING: " fmt, ##__VA_ARGS__)
+
+#define orc_warn_current(args...) \
+({ \
+ if (state->task == current) \
+ orc_warn(args); \
+})
extern int __start_orc_unwind_ip[];
extern int __stop_orc_unwind_ip[];
extern struct orc_entry __start_orc_unwind[];
extern struct orc_entry __stop_orc_unwind[];
-static DEFINE_MUTEX(sort_mutex);
-int *cur_orc_ip_table = __start_orc_unwind_ip;
-struct orc_entry *cur_orc_table = __start_orc_unwind;
-
-unsigned int lookup_num_blocks;
-bool orc_init;
+static bool orc_init __ro_after_init;
+static unsigned int lookup_num_blocks __ro_after_init;
static inline unsigned long orc_ip(const int *ip)
{
@@ -142,9 +144,6 @@ static struct orc_entry *orc_find(unsigned long ip)
{
static struct orc_entry *orc;
- if (!orc_init)
- return NULL;
-
if (ip == 0)
return &null_orc_entry;
@@ -189,6 +188,10 @@ static struct orc_entry *orc_find(unsigned long ip)
#ifdef CONFIG_MODULES
+static DEFINE_MUTEX(sort_mutex);
+static int *cur_orc_ip_table = __start_orc_unwind_ip;
+static struct orc_entry *cur_orc_table = __start_orc_unwind;
+
static void orc_sort_swap(void *_a, void *_b, int size)
{
struct orc_entry *orc_a, *orc_b;
@@ -381,9 +384,38 @@ static bool deref_stack_iret_regs(struct unwind_state *state, unsigned long addr
return true;
}
+/*
+ * If state->regs is non-NULL, and points to a full pt_regs, just get the reg
+ * value from state->regs.
+ *
+ * Otherwise, if state->regs just points to IRET regs, and the previous frame
+ * had full regs, it's safe to get the value from the previous regs. This can
+ * happen when early/late IRQ entry code gets interrupted by an NMI.
+ */
+static bool get_reg(struct unwind_state *state, unsigned int reg_off,
+ unsigned long *val)
+{
+ unsigned int reg = reg_off/8;
+
+ if (!state->regs)
+ return false;
+
+ if (state->full_regs) {
+ *val = ((unsigned long *)state->regs)[reg];
+ return true;
+ }
+
+ if (state->prev_regs) {
+ *val = ((unsigned long *)state->prev_regs)[reg];
+ return true;
+ }
+
+ return false;
+}
+
bool unwind_next_frame(struct unwind_state *state)
{
- unsigned long ip_p, sp, orig_ip = state->ip, prev_sp = state->sp;
+ unsigned long ip_p, sp, tmp, orig_ip = state->ip, prev_sp = state->sp;
enum stack_type prev_type = state->stack_info.type;
struct orc_entry *orc;
bool indirect = false;
@@ -445,43 +477,39 @@ bool unwind_next_frame(struct unwind_state *state)
break;
case ORC_REG_R10:
- if (!state->regs || !state->full_regs) {
- orc_warn("missing regs for base reg R10 at ip %pB\n",
- (void *)state->ip);
+ if (!get_reg(state, offsetof(struct pt_regs, r10), &sp)) {
+ orc_warn_current("missing R10 value at %pB\n",
+ (void *)state->ip);
goto err;
}
- sp = state->regs->r10;
break;
case ORC_REG_R13:
- if (!state->regs || !state->full_regs) {
- orc_warn("missing regs for base reg R13 at ip %pB\n",
- (void *)state->ip);
+ if (!get_reg(state, offsetof(struct pt_regs, r13), &sp)) {
+ orc_warn_current("missing R13 value at %pB\n",
+ (void *)state->ip);
goto err;
}
- sp = state->regs->r13;
break;
case ORC_REG_DI:
- if (!state->regs || !state->full_regs) {
- orc_warn("missing regs for base reg DI at ip %pB\n",
- (void *)state->ip);
+ if (!get_reg(state, offsetof(struct pt_regs, di), &sp)) {
+ orc_warn_current("missing RDI value at %pB\n",
+ (void *)state->ip);
goto err;
}
- sp = state->regs->di;
break;
case ORC_REG_DX:
- if (!state->regs || !state->full_regs) {
- orc_warn("missing regs for base reg DX at ip %pB\n",
- (void *)state->ip);
+ if (!get_reg(state, offsetof(struct pt_regs, dx), &sp)) {
+ orc_warn_current("missing DX value at %pB\n",
+ (void *)state->ip);
goto err;
}
- sp = state->regs->dx;
break;
default:
- orc_warn("unknown SP base reg %d for ip %pB\n",
+ orc_warn("unknown SP base reg %d at %pB\n",
orc->sp_reg, (void *)state->ip);
goto err;
}
@@ -504,44 +532,48 @@ bool unwind_next_frame(struct unwind_state *state)
state->sp = sp;
state->regs = NULL;
+ state->prev_regs = NULL;
state->signal = false;
break;
case ORC_TYPE_REGS:
if (!deref_stack_regs(state, sp, &state->ip, &state->sp)) {
- orc_warn("can't dereference registers at %p for ip %pB\n",
- (void *)sp, (void *)orig_ip);
+ orc_warn_current("can't access registers at %pB\n",
+ (void *)orig_ip);
goto err;
}
state->regs = (struct pt_regs *)sp;
+ state->prev_regs = NULL;
state->full_regs = true;
state->signal = true;
break;
case ORC_TYPE_REGS_IRET:
if (!deref_stack_iret_regs(state, sp, &state->ip, &state->sp)) {
- orc_warn("can't dereference iret registers at %p for ip %pB\n",
- (void *)sp, (void *)orig_ip);
+ orc_warn_current("can't access iret registers at %pB\n",
+ (void *)orig_ip);
goto err;
}
+ if (state->full_regs)
+ state->prev_regs = state->regs;
state->regs = (void *)sp - IRET_FRAME_OFFSET;
state->full_regs = false;
state->signal = true;
break;
default:
- orc_warn("unknown .orc_unwind entry type %d for ip %pB\n",
+ orc_warn("unknown .orc_unwind entry type %d at %pB\n",
orc->type, (void *)orig_ip);
- break;
+ goto err;
}
/* Find BP: */
switch (orc->bp_reg) {
case ORC_REG_UNDEFINED:
- if (state->regs && state->full_regs)
- state->bp = state->regs->bp;
+ if (get_reg(state, offsetof(struct pt_regs, bp), &tmp))
+ state->bp = tmp;
break;
case ORC_REG_PREV_SP:
@@ -564,8 +596,8 @@ bool unwind_next_frame(struct unwind_state *state)
if (state->stack_info.type == prev_type &&
on_stack(&state->stack_info, (void *)state->sp, sizeof(long)) &&
state->sp <= prev_sp) {
- orc_warn("stack going in the wrong direction? ip=%pB\n",
- (void *)orig_ip);
+ orc_warn_current("stack going in the wrong direction? at %pB\n",
+ (void *)orig_ip);
goto err;
}
@@ -585,6 +617,9 @@ EXPORT_SYMBOL_GPL(unwind_next_frame);
void __unwind_start(struct unwind_state *state, struct task_struct *task,
struct pt_regs *regs, unsigned long *first_frame)
{
+ if (!orc_init)
+ goto done;
+
memset(state, 0, sizeof(*state));
state->task = task;
@@ -651,7 +686,7 @@ void __unwind_start(struct unwind_state *state, struct task_struct *task,
/* Otherwise, skip ahead to the user-specified starting frame: */
while (!unwind_done(state) &&
(!on_stack(&state->stack_info, first_frame, sizeof(long)) ||
- state->sp <= (unsigned long)first_frame))
+ state->sp < (unsigned long)first_frame))
unwind_next_frame(state);
return;