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| author | Alex Smith <alex.smith@imgtec.com> | 2014-05-01 11:51:19 (GMT) |
|---|---|---|
| committer | Ralf Baechle <ralf@linux-mips.org> | 2014-05-28 08:54:41 (GMT) |
| commit | 57c7ea513f0e4b033ba602550992e2ca0e6b8d2c (patch) | |
| tree | 8bf4a477987a4fb671c099cea658b2a3a5ac3c63 /arch/mips/kernel | |
| parent | f02ffb199d3af57407a79075f3e0e6c0e8980b6c (diff) | |
| download | linux-57c7ea513f0e4b033ba602550992e2ca0e6b8d2c.tar.xz | |
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>
Diffstat (limited to 'arch/mips/kernel')
| -rw-r--r-- | arch/mips/kernel/ptrace.c | 14 |
1 files changed, 7 insertions, 7 deletions
diff --git a/arch/mips/kernel/ptrace.c b/arch/mips/kernel/ptrace.c index 71f85f4..f639ccd 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]; |