Le 09/03/2020 à 09:58, Ravi Bangoria a écrit :
ptrace_bps is already an array of size HBP_NUM_MAX. But we use
hardcoded index 0 while fetching/updating it. Convert such code
to loop over array.
Signed-off-by: Ravi Bangoria <ravi.bango...@linux.ibm.com>
---
arch/powerpc/kernel/hw_breakpoint.c | 7 +++++--
arch/powerpc/kernel/process.c | 6 +++++-
arch/powerpc/kernel/ptrace.c | 28 +++++++++++++++++++++-------
3 files changed, 31 insertions(+), 10 deletions(-)
diff --git a/arch/powerpc/kernel/hw_breakpoint.c
b/arch/powerpc/kernel/hw_breakpoint.c
index f4d48f87dcb8..b27aca623267 100644
--- a/arch/powerpc/kernel/hw_breakpoint.c
+++ b/arch/powerpc/kernel/hw_breakpoint.c
@@ -419,10 +419,13 @@ NOKPROBE_SYMBOL(hw_breakpoint_exceptions_notify);
*/
void flush_ptrace_hw_breakpoint(struct task_struct *tsk)
{
+ int i;
struct thread_struct *t = &tsk->thread;
- unregister_hw_breakpoint(t->ptrace_bps[0]);
- t->ptrace_bps[0] = NULL;
+ for (i = 0; i < nr_wp_slots(); i++) {
+ unregister_hw_breakpoint(t->ptrace_bps[i]);
+ t->ptrace_bps[i] = NULL;
+ }
}
void hw_breakpoint_pmu_read(struct perf_event *bp)
diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index 42ff62ef749c..b9ab740fcacf 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -1628,6 +1628,9 @@ int copy_thread_tls(unsigned long clone_flags, unsigned
long usp,
void (*f)(void);
unsigned long sp = (unsigned long)task_stack_page(p) + THREAD_SIZE;
struct thread_info *ti = task_thread_info(p);
+#ifdef CONFIG_HAVE_HW_BREAKPOINT
+ int i;
+#endif
Could we avoid all those #ifdefs ?
I think if we make p->thread.ptrace_bps[] exist all the time, with a
size of 0 when CONFIG_HAVE_HW_BREAKPOINT is not set, then we can drop a
lot of #ifdefs.
klp_init_thread_info(p);
@@ -1687,7 +1690,8 @@ int copy_thread_tls(unsigned long clone_flags, unsigned long usp,
p->thread.ksp_limit = (unsigned long)end_of_stack(p);
#endif
#ifdef CONFIG_HAVE_HW_BREAKPOINT
- p->thread.ptrace_bps[0] = NULL;
+ for (i = 0; i < nr_wp_slots(); i++)
+ p->thread.ptrace_bps[i] = NULL;
#endif
p->thread.fp_save_area = NULL;
diff --git a/arch/powerpc/kernel/ptrace.c b/arch/powerpc/kernel/ptrace.c
index f6d7955fc61e..e2651f86d56f 100644
--- a/arch/powerpc/kernel/ptrace.c
+++ b/arch/powerpc/kernel/ptrace.c
You'll have to rebase all this on the series
https://patchwork.ozlabs.org/project/linuxppc-dev/list/?series=161356
which is about to go into powerpc-next
@@ -2829,6 +2829,19 @@ static int set_dac_range(struct task_struct *child,
}
#endif /* CONFIG_PPC_ADV_DEBUG_DAC_RANGE */
+#ifdef CONFIG_HAVE_HW_BREAKPOINT
+static int empty_ptrace_bp(struct thread_struct *thread)
+{
+ int i;
+
+ for (i = 0; i < nr_wp_slots(); i++) {
+ if (!thread->ptrace_bps[i])
+ return i;
+ }
+ return -1;
+}
+#endif
What does this function do exactly ? I seems to do more than what its
name suggests.
+
#ifndef CONFIG_PPC_ADV_DEBUG_REGS
static int empty_hw_brk(struct thread_struct *thread)
{
@@ -2915,8 +2928,9 @@ static long ppc_set_hwdebug(struct task_struct *child,
len = 1;
else
return -EINVAL;
- bp = thread->ptrace_bps[0];
- if (bp)
+
+ i = empty_ptrace_bp(thread);
+ if (i < 0)
return -ENOSPC;
/* Create a new breakpoint request if one doesn't exist already */
@@ -2925,14 +2939,14 @@ static long ppc_set_hwdebug(struct task_struct *child,
attr.bp_len = len;
arch_bp_generic_fields(brk.type, &attr.bp_type);
- thread->ptrace_bps[0] = bp = register_user_hw_breakpoint(&attr,
+ thread->ptrace_bps[i] = bp = register_user_hw_breakpoint(&attr,
ptrace_triggered, NULL, child);
if (IS_ERR(bp)) {
- thread->ptrace_bps[0] = NULL;
+ thread->ptrace_bps[i] = NULL;
return PTR_ERR(bp);
}
- return 1;
+ return i + 1;
#endif /* CONFIG_HAVE_HW_BREAKPOINT */
if (bp_info->addr_mode != PPC_BREAKPOINT_MODE_EXACT)
@@ -2979,10 +2993,10 @@ static long ppc_del_hwdebug(struct task_struct *child,
long data)
return -EINVAL;
#ifdef CONFIG_HAVE_HW_BREAKPOINT
- bp = thread->ptrace_bps[0];
+ bp = thread->ptrace_bps[data - 1];
Is data checked somewhere to ensure it is not out of boundaries ? Or are
we sure it is always within ?
if (bp) {
unregister_hw_breakpoint(bp);
- thread->ptrace_bps[0] = NULL;
+ thread->ptrace_bps[data - 1] = NULL;
} else
ret = -ENOENT;
return ret;
Christophe
