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| author | Mathieu Desnoyers <mathieu.desnoyers@efficios.com> | 2022-01-27 16:27:20 +0100 |
|---|---|---|
| committer | Peter Zijlstra <peterz@infradead.org> | 2022-02-02 13:11:34 +0100 |
| commit | bfdf4e6208051ed7165b2e92035b4bf11f43eb63 (patch) | |
| tree | 69822a3cb551575eb6702833efccc29d961bd25b /kernel/rseq.c | |
| parent | selftests/rseq: introduce own copy of rseq uapi header (diff) | |
| download | linux-bfdf4e6208051ed7165b2e92035b4bf11f43eb63.tar.xz linux-bfdf4e6208051ed7165b2e92035b4bf11f43eb63.zip | |
rseq: Remove broken uapi field layout on 32-bit little endian
The rseq rseq_cs.ptr.{ptr32,padding} uapi endianness handling is
entirely wrong on 32-bit little endian: a preprocessor logic mistake
wrongly uses the big endian field layout on 32-bit little endian
architectures.
Fortunately, those ptr32 accessors were never used within the kernel,
and only meant as a convenience for user-space.
Remove those and replace the whole rseq_cs union by a __u64 type, as
this is the only thing really needed to express the ABI. Document how
32-bit architectures are meant to interact with this field.
Fixes: ec9c82e03a74 ("rseq: uapi: Declare rseq_cs field as union, update includes")
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20220127152720.25898-1-mathieu.desnoyers@efficios.com
Diffstat (limited to 'kernel/rseq.c')
| -rw-r--r-- | kernel/rseq.c | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/kernel/rseq.c b/kernel/rseq.c index 6d45ac3dae7f..97ac20b4f738 100644 --- a/kernel/rseq.c +++ b/kernel/rseq.c @@ -128,10 +128,10 @@ static int rseq_get_rseq_cs(struct task_struct *t, struct rseq_cs *rseq_cs) int ret; #ifdef CONFIG_64BIT - if (get_user(ptr, &t->rseq->rseq_cs.ptr64)) + if (get_user(ptr, &t->rseq->rseq_cs)) return -EFAULT; #else - if (copy_from_user(&ptr, &t->rseq->rseq_cs.ptr64, sizeof(ptr))) + if (copy_from_user(&ptr, &t->rseq->rseq_cs, sizeof(ptr))) return -EFAULT; #endif if (!ptr) { @@ -217,9 +217,9 @@ static int clear_rseq_cs(struct task_struct *t) * Set rseq_cs to NULL. */ #ifdef CONFIG_64BIT - return put_user(0UL, &t->rseq->rseq_cs.ptr64); + return put_user(0UL, &t->rseq->rseq_cs); #else - if (clear_user(&t->rseq->rseq_cs.ptr64, sizeof(t->rseq->rseq_cs.ptr64))) + if (clear_user(&t->rseq->rseq_cs, sizeof(t->rseq->rseq_cs))) return -EFAULT; return 0; #endif |