diff options
| author | Christoph Hellwig <[email protected]> | 2020-08-11 18:33:47 -0700 |
|---|---|---|
| committer | Linus Torvalds <[email protected]> | 2020-08-12 10:57:59 -0700 |
| commit | 3d13f313ce4c34c524ccc37986fe77172f601ff3 (patch) | |
| tree | fd71a87be80c03601ab0e3be425fe45da116b5ba /kernel | |
| parent | 428e2976a5bf7e7f5554286d7a5a33b8147b106a (diff) | |
uaccess: add force_uaccess_{begin,end} helpers
Add helpers to wrap the get_fs/set_fs magic for undoing any damange done
by set_fs(KERNEL_DS). There is no real functional benefit, but this
documents the intent of these calls better, and will allow stubbing the
functions out easily for kernels builds that do not allow address space
overrides in the future.
[[email protected]: drop two incorrect hunks, fix a commit log typo]
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Christoph Hellwig <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Acked-by: Linus Torvalds <[email protected]>
Acked-by: Mark Rutland <[email protected]>
Acked-by: Greentime Hu <[email protected]>
Acked-by: Geert Uytterhoeven <[email protected]>
Cc: Nick Hu <[email protected]>
Cc: Vincent Chen <[email protected]>
Cc: Paul Walmsley <[email protected]>
Cc: Palmer Dabbelt <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Linus Torvalds <[email protected]>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/events/callchain.c | 5 | ||||
| -rw-r--r-- | kernel/events/core.c | 5 | ||||
| -rw-r--r-- | kernel/kthread.c | 5 | ||||
| -rw-r--r-- | kernel/stacktrace.c | 5 |
4 files changed, 8 insertions, 12 deletions
diff --git a/kernel/events/callchain.c b/kernel/events/callchain.c index c6ce894e4ce9..58cbe357fb2b 100644 --- a/kernel/events/callchain.c +++ b/kernel/events/callchain.c @@ -217,10 +217,9 @@ get_perf_callchain(struct pt_regs *regs, u32 init_nr, bool kernel, bool user, if (add_mark) perf_callchain_store_context(&ctx, PERF_CONTEXT_USER); - fs = get_fs(); - set_fs(USER_DS); + fs = force_uaccess_begin(); perf_callchain_user(&ctx, regs); - set_fs(fs); + force_uaccess_end(fs); } } diff --git a/kernel/events/core.c b/kernel/events/core.c index d1f0a7e5b182..6961333ebad5 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -6453,10 +6453,9 @@ perf_output_sample_ustack(struct perf_output_handle *handle, u64 dump_size, /* Data. */ sp = perf_user_stack_pointer(regs); - fs = get_fs(); - set_fs(USER_DS); + fs = force_uaccess_begin(); rem = __output_copy_user(handle, (void *) sp, dump_size); - set_fs(fs); + force_uaccess_end(fs); dyn_size = dump_size - rem; perf_output_skip(handle, rem); diff --git a/kernel/kthread.c b/kernel/kthread.c index b2807e7be772..3edaa380dc7b 100644 --- a/kernel/kthread.c +++ b/kernel/kthread.c @@ -1258,8 +1258,7 @@ void kthread_use_mm(struct mm_struct *mm) if (active_mm != mm) mmdrop(active_mm); - to_kthread(tsk)->oldfs = get_fs(); - set_fs(USER_DS); + to_kthread(tsk)->oldfs = force_uaccess_begin(); } EXPORT_SYMBOL_GPL(kthread_use_mm); @@ -1274,7 +1273,7 @@ void kthread_unuse_mm(struct mm_struct *mm) WARN_ON_ONCE(!(tsk->flags & PF_KTHREAD)); WARN_ON_ONCE(!tsk->mm); - set_fs(to_kthread(tsk)->oldfs); + force_uaccess_end(to_kthread(tsk)->oldfs); task_lock(tsk); sync_mm_rss(mm); diff --git a/kernel/stacktrace.c b/kernel/stacktrace.c index 2af66e449aa6..946f44a9e86a 100644 --- a/kernel/stacktrace.c +++ b/kernel/stacktrace.c @@ -233,10 +233,9 @@ unsigned int stack_trace_save_user(unsigned long *store, unsigned int size) if (current->flags & PF_KTHREAD) return 0; - fs = get_fs(); - set_fs(USER_DS); + fs = force_uaccess_begin(); arch_stack_walk_user(consume_entry, &c, task_pt_regs(current)); - set_fs(fs); + force_uaccess_end(fs); return c.len; } |