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authorAlex Smith <alex.smith@imgtec.com>2014-05-01 12:51:19 +0100
committerRalf Baechle <ralf@linux-mips.org>2014-05-28 10:54:41 +0200
commit57c7ea513f0e4b033ba602550992e2ca0e6b8d2c (patch)
tree8bf4a477987a4fb671c099cea658b2a3a5ac3c63
parentf02ffb199d3af57407a79075f3e0e6c0e8980b6c (diff)
downloadlinux-57c7ea513f0e4b033ba602550992e2ca0e6b8d2c.tar.gz
MIPS: ptrace: Avoid smp_processor_id() in preemptible code
ptrace_{get,set}_watch_regs access current_cpu_data to get the watch register count/masks, which calls smp_processor_id(). However they are run in preemptible context and therefore trigger warnings like so: [ 6340.092000] BUG: using smp_processor_id() in preemptible [00000000] code: gdb/367 [ 6340.092000] caller is ptrace_get_watch_regs+0x44/0x220 Since the watch register count/masks should be the same across all CPUs, use boot_cpu_data instead. Note that this may need to change in future should a heterogenous system be supported where the count/masks are not the same across all CPUs (the current code is also incorrect for this scenario - current_cpu_data here would not necessarily be correct for the CPU that the target task will execute on). Signed-off-by: Alex Smith <alex.smith@imgtec.com> Reviewed-by: Paul Burton <paul.burton@imgtec.com> Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/6879/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
-rw-r--r--arch/mips/kernel/ptrace.c14
1 files changed, 7 insertions, 7 deletions
diff --git a/arch/mips/kernel/ptrace.c b/arch/mips/kernel/ptrace.c
index 71f85f42703..f639ccd5060 100644
--- a/arch/mips/kernel/ptrace.c
+++ b/arch/mips/kernel/ptrace.c
@@ -163,7 +163,7 @@ int ptrace_get_watch_regs(struct task_struct *child,
enum pt_watch_style style;
int i;
- if (!cpu_has_watch || current_cpu_data.watch_reg_use_cnt == 0)
+ if (!cpu_has_watch || boot_cpu_data.watch_reg_use_cnt == 0)
return -EIO;
if (!access_ok(VERIFY_WRITE, addr, sizeof(struct pt_watch_regs)))
return -EIO;
@@ -177,14 +177,14 @@ int ptrace_get_watch_regs(struct task_struct *child,
#endif
__put_user(style, &addr->style);
- __put_user(current_cpu_data.watch_reg_use_cnt,
+ __put_user(boot_cpu_data.watch_reg_use_cnt,
&addr->WATCH_STYLE.num_valid);
- for (i = 0; i < current_cpu_data.watch_reg_use_cnt; i++) {
+ for (i = 0; i < boot_cpu_data.watch_reg_use_cnt; i++) {
__put_user(child->thread.watch.mips3264.watchlo[i],
&addr->WATCH_STYLE.watchlo[i]);
__put_user(child->thread.watch.mips3264.watchhi[i] & 0xfff,
&addr->WATCH_STYLE.watchhi[i]);
- __put_user(current_cpu_data.watch_reg_masks[i],
+ __put_user(boot_cpu_data.watch_reg_masks[i],
&addr->WATCH_STYLE.watch_masks[i]);
}
for (; i < 8; i++) {
@@ -204,12 +204,12 @@ int ptrace_set_watch_regs(struct task_struct *child,
unsigned long lt[NUM_WATCH_REGS];
u16 ht[NUM_WATCH_REGS];
- if (!cpu_has_watch || current_cpu_data.watch_reg_use_cnt == 0)
+ if (!cpu_has_watch || boot_cpu_data.watch_reg_use_cnt == 0)
return -EIO;
if (!access_ok(VERIFY_READ, addr, sizeof(struct pt_watch_regs)))
return -EIO;
/* Check the values. */
- for (i = 0; i < current_cpu_data.watch_reg_use_cnt; i++) {
+ for (i = 0; i < boot_cpu_data.watch_reg_use_cnt; i++) {
__get_user(lt[i], &addr->WATCH_STYLE.watchlo[i]);
#ifdef CONFIG_32BIT
if (lt[i] & __UA_LIMIT)
@@ -228,7 +228,7 @@ int ptrace_set_watch_regs(struct task_struct *child,
return -EINVAL;
}
/* Install them. */
- for (i = 0; i < current_cpu_data.watch_reg_use_cnt; i++) {
+ for (i = 0; i < boot_cpu_data.watch_reg_use_cnt; i++) {
if (lt[i] & 7)
watch_active = 1;
child->thread.watch.mips3264.watchlo[i] = lt[i];