No functional changes, preparation.
Extract the "register breakpoint" code from ptrace_get_debugreg()
into the new/generic helper, ptrace_register_breakpoint(). It will
have more users.
The patch also adds another simple helper, ptrace_fill_bp_fields(),
to factor out the arch_bp_generic_fields() logic in register/modify.
Signed-off-by: Oleg Nesterov <o...@redhat.com>
Acked-by: Frederic Weisbecker <fweis...@gmail.com>
---
arch/x86/kernel/ptrace.c | 86 ++++++++++++++++++++++++++-------------------
1 files changed, 50 insertions(+), 36 deletions(-)
diff --git a/arch/x86/kernel/ptrace.c b/arch/x86/kernel/ptrace.c
index 98b0a2c..0526368 100644
--- a/arch/x86/kernel/ptrace.c
+++ b/arch/x86/kernel/ptrace.c
@@ -601,22 +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;
+
+ 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);
}
@@ -653,7 +679,7 @@ restore:
break;
}
- rc = ptrace_modify_breakpoint(bp, len, type, tsk, disabled);
+ rc = ptrace_modify_breakpoint(bp, len, type, disabled);
if (rc)
break;
}
@@ -693,26 +719,14 @@ 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 (!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.
@@ -721,20 +735,20 @@ 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 out;
- }
-
- 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);
}
-out:
+
return err;
}
--
1.5.5.1
--
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