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Diffstat (limited to 'arch/x86/kernel/ptrace.c')
-rw-r--r--arch/x86/kernel/ptrace.c204
1 files changed, 85 insertions, 119 deletions
diff --git a/arch/x86/kernel/ptrace.c b/arch/x86/kernel/ptrace.c
index 29a8120e6fe..7461f50d5bb 100644
--- a/arch/x86/kernel/ptrace.c
+++ b/arch/x86/kernel/ptrace.c
@@ -601,30 +601,48 @@ static unsigned long ptrace_get_dr7(struct perf_event *bp[])
return dr7;
}
-static int
-ptrace_modify_breakpoint(struct perf_event *bp, int len, int type,
- struct task_struct *tsk, int disabled)
+static int ptrace_fill_bp_fields(struct perf_event_attr *attr,
+ int len, int type, bool disabled)
+{
+ int err, bp_len, bp_type;
+
+ err = arch_bp_generic_fields(len, type, &bp_len, &bp_type);
+ if (!err) {
+ attr->bp_len = bp_len;
+ attr->bp_type = bp_type;
+ attr->disabled = disabled;
+ }
+
+ return err;
+}
+
+static struct perf_event *
+ptrace_register_breakpoint(struct task_struct *tsk, int len, int type,
+ unsigned long addr, bool disabled)
{
- int err;
- int gen_len, gen_type;
struct perf_event_attr attr;
+ int err;
- /*
- * We should have at least an inactive breakpoint at this
- * slot. It means the user is writing dr7 without having
- * written the address register first
- */
- if (!bp)
- return -EINVAL;
+ ptrace_breakpoint_init(&attr);
+ attr.bp_addr = addr;
- err = arch_bp_generic_fields(len, type, &gen_len, &gen_type);
+ err = ptrace_fill_bp_fields(&attr, len, type, disabled);
if (err)
- return err;
+ return ERR_PTR(err);
+
+ return register_user_hw_breakpoint(&attr, ptrace_triggered,
+ NULL, tsk);
+}
- attr = bp->attr;
- attr.bp_len = gen_len;
- attr.bp_type = gen_type;
- attr.disabled = disabled;
+static int ptrace_modify_breakpoint(struct perf_event *bp, int len, int type,
+ int disabled)
+{
+ struct perf_event_attr attr = bp->attr;
+ int err;
+
+ err = ptrace_fill_bp_fields(&attr, len, type, disabled);
+ if (err)
+ return err;
return modify_user_hw_breakpoint(bp, &attr);
}
@@ -634,67 +652,50 @@ ptrace_modify_breakpoint(struct perf_event *bp, int len, int type,
*/
static int ptrace_write_dr7(struct task_struct *tsk, unsigned long data)
{
- struct thread_struct *thread = &(tsk->thread);
+ struct thread_struct *thread = &tsk->thread;
unsigned long old_dr7;
- int i, orig_ret = 0, rc = 0;
- int enabled, second_pass = 0;
- unsigned len, type;
- struct perf_event *bp;
-
- if (ptrace_get_breakpoints(tsk) < 0)
- return -ESRCH;
+ bool second_pass = false;
+ int i, rc, ret = 0;
data &= ~DR_CONTROL_RESERVED;
old_dr7 = ptrace_get_dr7(thread->ptrace_bps);
+
restore:
- /*
- * Loop through all the hardware breakpoints, making the
- * appropriate changes to each.
- */
+ rc = 0;
for (i = 0; i < HBP_NUM; i++) {
- enabled = decode_dr7(data, i, &len, &type);
- bp = thread->ptrace_bps[i];
-
- if (!enabled) {
- if (bp) {
- /*
- * Don't unregister the breakpoints right-away,
- * unless all register_user_hw_breakpoint()
- * requests have succeeded. This prevents
- * any window of opportunity for debug
- * register grabbing by other users.
- */
- if (!second_pass)
- continue;
-
- rc = ptrace_modify_breakpoint(bp, len, type,
- tsk, 1);
- if (rc)
- break;
+ unsigned len, type;
+ bool disabled = !decode_dr7(data, i, &len, &type);
+ struct perf_event *bp = thread->ptrace_bps[i];
+
+ if (!bp) {
+ if (disabled)
+ continue;
+
+ bp = ptrace_register_breakpoint(tsk,
+ len, type, 0, disabled);
+ if (IS_ERR(bp)) {
+ rc = PTR_ERR(bp);
+ break;
}
+
+ thread->ptrace_bps[i] = bp;
continue;
}
- rc = ptrace_modify_breakpoint(bp, len, type, tsk, 0);
+ rc = ptrace_modify_breakpoint(bp, len, type, disabled);
if (rc)
break;
}
- /*
- * Make a second pass to free the remaining unused breakpoints
- * or to restore the original breakpoints if an error occurred.
- */
- if (!second_pass) {
- second_pass = 1;
- if (rc < 0) {
- orig_ret = rc;
- data = old_dr7;
- }
+
+ /* Restore if the first pass failed, second_pass shouldn't fail. */
+ if (rc && !WARN_ON(second_pass)) {
+ ret = rc;
+ data = old_dr7;
+ second_pass = true;
goto restore;
}
- ptrace_put_breakpoints(tsk);
-
- return ((orig_ret < 0) ? orig_ret : rc);
+ return ret;
}
/*
@@ -702,25 +703,17 @@ restore:
*/
static unsigned long ptrace_get_debugreg(struct task_struct *tsk, int n)
{
- struct thread_struct *thread = &(tsk->thread);
+ struct thread_struct *thread = &tsk->thread;
unsigned long val = 0;
if (n < HBP_NUM) {
- struct perf_event *bp;
+ struct perf_event *bp = thread->ptrace_bps[n];
- if (ptrace_get_breakpoints(tsk) < 0)
- return -ESRCH;
-
- bp = thread->ptrace_bps[n];
- if (!bp)
- val = 0;
- else
+ if (bp)
val = bp->hw.info.address;
-
- ptrace_put_breakpoints(tsk);
} else if (n == 6) {
val = thread->debugreg6;
- } else if (n == 7) {
+ } else if (n == 7) {
val = thread->ptrace_dr7;
}
return val;
@@ -729,29 +722,14 @@ static unsigned long ptrace_get_debugreg(struct task_struct *tsk, int n)
static int ptrace_set_breakpoint_addr(struct task_struct *tsk, int nr,
unsigned long addr)
{
- struct perf_event *bp;
struct thread_struct *t = &tsk->thread;
- struct perf_event_attr attr;
+ struct perf_event *bp = t->ptrace_bps[nr];
int err = 0;
- if (ptrace_get_breakpoints(tsk) < 0)
- return -ESRCH;
-
- if (!t->ptrace_bps[nr]) {
- ptrace_breakpoint_init(&attr);
- /*
- * Put stub len and type to register (reserve) an inactive but
- * correct bp
- */
- attr.bp_addr = addr;
- attr.bp_len = HW_BREAKPOINT_LEN_1;
- attr.bp_type = HW_BREAKPOINT_W;
- attr.disabled = 1;
-
- bp = register_user_hw_breakpoint(&attr, ptrace_triggered,
- NULL, tsk);
-
+ if (!bp) {
/*
+ * Put stub len and type to create an inactive but correct bp.
+ *
* CHECKME: the previous code returned -EIO if the addr wasn't
* a valid task virtual addr. The new one will return -EINVAL in
* this case.
@@ -760,22 +738,20 @@ static int ptrace_set_breakpoint_addr(struct task_struct *tsk, int nr,
* writing for the user. And anyway this is the previous
* behaviour.
*/
- if (IS_ERR(bp)) {
+ bp = ptrace_register_breakpoint(tsk,
+ X86_BREAKPOINT_LEN_1, X86_BREAKPOINT_WRITE,
+ addr, true);
+ if (IS_ERR(bp))
err = PTR_ERR(bp);
- goto put;
- }
-
- t->ptrace_bps[nr] = bp;
+ else
+ t->ptrace_bps[nr] = bp;
} else {
- bp = t->ptrace_bps[nr];
+ struct perf_event_attr attr = bp->attr;
- attr = bp->attr;
attr.bp_addr = addr;
err = modify_user_hw_breakpoint(bp, &attr);
}
-put:
- ptrace_put_breakpoints(tsk);
return err;
}
@@ -785,30 +761,20 @@ put:
static int ptrace_set_debugreg(struct task_struct *tsk, int n,
unsigned long val)
{
- struct thread_struct *thread = &(tsk->thread);
- int rc = 0;
-
+ struct thread_struct *thread = &tsk->thread;
/* There are no DR4 or DR5 registers */
- if (n == 4 || n == 5)
- return -EIO;
+ int rc = -EIO;
- if (n == 6) {
- thread->debugreg6 = val;
- goto ret_path;
- }
if (n < HBP_NUM) {
rc = ptrace_set_breakpoint_addr(tsk, n, val);
- if (rc)
- return rc;
- }
- /* All that's left is DR7 */
- if (n == 7) {
+ } else if (n == 6) {
+ thread->debugreg6 = val;
+ rc = 0;
+ } else if (n == 7) {
rc = ptrace_write_dr7(tsk, val);
if (!rc)
thread->ptrace_dr7 = val;
}
-
-ret_path:
return rc;
}
generated by cgit v1.2.3-70-g09d2 (git 2.46.0) at 2024-12-25 02:45:42 +0000