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authorFrederic Weisbecker <fweisbec@gmail.com>2009-11-27 04:55:53 +0100
committerIngo Molnar <mingo@elte.hu>2009-11-27 06:22:58 +0100
commit5fa10b28e57f94a90535cfeafe89dcee9f47d540 (patch)
tree951cf12a3b5b3a37546b4f6dd2994bebdac19dc0 /arch
parentb2e74a265ded1a185f762ebaab967e9e0d008dd8 (diff)
hw-breakpoints: Use struct perf_event_attr to define user breakpoints
In-kernel user breakpoints are created using functions in which we pass breakpoint parameters as individual variables: address, length and type. Although it fits well for x86, this just does not scale across archictectures that may support this api later as these may have more or different needs. Pass in a perf_event_attr structure instead because it is meant to evolve as much as possible into a generic hardware breakpoint parameter structure. Reported-by: K.Prasad <prasad@linux.vnet.ibm.com> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> LKML-Reference: <1259294154-5197-1-git-send-regression-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'arch')
-rw-r--r--arch/x86/kernel/ptrace.c74
1 files changed, 41 insertions, 33 deletions
diff --git a/arch/x86/kernel/ptrace.c b/arch/x86/kernel/ptrace.c
index 75e0cd847bd..2941b32ea66 100644
--- a/arch/x86/kernel/ptrace.c
+++ b/arch/x86/kernel/ptrace.c
@@ -593,6 +593,34 @@ static unsigned long ptrace_get_dr7(struct perf_event *bp[])
return dr7;
}
+static struct perf_event *
+ptrace_modify_breakpoint(struct perf_event *bp, int len, int type,
+ struct task_struct *tsk)
+{
+ int err;
+ int gen_len, gen_type;
+ DEFINE_BREAKPOINT_ATTR(attr);
+
+ /*
+ * We shoud 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 ERR_PTR(-EINVAL);
+
+ err = arch_bp_generic_fields(len, type, &gen_len, &gen_type);
+ if (err)
+ return ERR_PTR(err);
+
+ attr = bp->attr;
+ attr.bp_len = gen_len;
+ attr.bp_type = gen_type;
+ attr.disabled = 0;
+
+ return modify_user_hw_breakpoint(bp, &attr, bp->callback, tsk);
+}
+
/*
* Handle ptrace writes to debug register 7.
*/
@@ -603,7 +631,6 @@ static int ptrace_write_dr7(struct task_struct *tsk, unsigned long data)
int i, orig_ret = 0, rc = 0;
int enabled, second_pass = 0;
unsigned len, type;
- int gen_len, gen_type;
struct perf_event *bp;
data &= ~DR_CONTROL_RESERVED;
@@ -634,33 +661,12 @@ restore:
continue;
}
- /*
- * We shoud 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) {
- rc = -EINVAL;
- break;
- }
-
- rc = arch_bp_generic_fields(len, type, &gen_len, &gen_type);
- if (rc)
- break;
-
- /*
- * This is a temporary thing as bp is unregistered/registered
- * to simulate modification
- */
- bp = modify_user_hw_breakpoint(bp, bp->attr.bp_addr, gen_len,
- gen_type, bp->callback,
- tsk, true);
- thread->ptrace_bps[i] = NULL;
+ bp = ptrace_modify_breakpoint(bp, len, type, tsk);
/* Incorrect bp, or we have a bug in bp API */
if (IS_ERR(bp)) {
rc = PTR_ERR(bp);
- bp = NULL;
+ thread->ptrace_bps[i] = NULL;
break;
}
thread->ptrace_bps[i] = bp;
@@ -707,24 +713,26 @@ static int ptrace_set_breakpoint_addr(struct task_struct *tsk, int nr,
{
struct perf_event *bp;
struct thread_struct *t = &tsk->thread;
+ DEFINE_BREAKPOINT_ATTR(attr);
if (!t->ptrace_bps[nr]) {
/*
* Put stub len and type to register (reserve) an inactive but
* correct bp
*/
- bp = register_user_hw_breakpoint(addr, HW_BREAKPOINT_LEN_1,
- HW_BREAKPOINT_W,
- ptrace_triggered, tsk,
- false);
+ 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, tsk);
} else {
bp = t->ptrace_bps[nr];
t->ptrace_bps[nr] = NULL;
- bp = modify_user_hw_breakpoint(bp, addr, bp->attr.bp_len,
- bp->attr.bp_type,
- bp->callback,
- tsk,
- bp->attr.disabled);
+
+ attr = bp->attr;
+ attr.bp_addr = addr;
+ bp = modify_user_hw_breakpoint(bp, &attr, bp->callback, tsk);
}
/*
* CHECKME: the previous code returned -EIO if the addr wasn't a