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| author | Mathieu Desnoyers <mathieu.desnoyers@efficios.com> | 2018-07-09 15:51:51 -0400 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2018-07-10 22:18:52 +0200 |
| commit | 8f28177014925f968baf45fc833c25848faf8c1c (patch) | |
| tree | 505cfc5235f2ab4778a3244f454135a87f5dfba4 /kernel/rseq.c | |
| parent | e96d71359e9bbea846a2111e4469a03a055dfa6f (diff) | |
| download | lwn-8f28177014925f968baf45fc833c25848faf8c1c.tar.gz lwn-8f28177014925f968baf45fc833c25848faf8c1c.zip | |
rseq: Use get_user/put_user rather than __get_user/__put_user
__get_user()/__put_user() is used to read values for address ranges that
were already checked with access_ok() on rseq registration.
It has been recognized that __get_user/__put_user are optimizing the
wrong thing. Replace them by get_user/put_user across rseq instead.
If those end up showing up in benchmarks, the proper approach would be to
use user_access_begin() / unsafe_{get,put}_user() / user_access_end()
anyway.
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-api@vger.kernel.org
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: "Paul E . McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Dave Watson <davejwatson@fb.com>
Cc: Paul Turner <pjt@google.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: "H . Peter Anvin" <hpa@zytor.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Chris Lameter <cl@linux.com>
Cc: Ben Maurer <bmaurer@fb.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: Joel Fernandes <joelaf@google.com>
Cc: linux-arm-kernel@lists.infradead.org
Link: https://lkml.kernel.org/r/20180709195155.7654-3-mathieu.desnoyers@efficios.com
Diffstat (limited to 'kernel/rseq.c')
| -rw-r--r-- | kernel/rseq.c | 14 |
1 files changed, 7 insertions, 7 deletions
diff --git a/kernel/rseq.c b/kernel/rseq.c index 16b38c5342f9..2c8463acb50d 100644 --- a/kernel/rseq.c +++ b/kernel/rseq.c @@ -85,9 +85,9 @@ static int rseq_update_cpu_id(struct task_struct *t) { u32 cpu_id = raw_smp_processor_id(); - if (__put_user(cpu_id, &t->rseq->cpu_id_start)) + if (put_user(cpu_id, &t->rseq->cpu_id_start)) return -EFAULT; - if (__put_user(cpu_id, &t->rseq->cpu_id)) + if (put_user(cpu_id, &t->rseq->cpu_id)) return -EFAULT; trace_rseq_update(t); return 0; @@ -100,14 +100,14 @@ static int rseq_reset_rseq_cpu_id(struct task_struct *t) /* * Reset cpu_id_start to its initial state (0). */ - if (__put_user(cpu_id_start, &t->rseq->cpu_id_start)) + if (put_user(cpu_id_start, &t->rseq->cpu_id_start)) return -EFAULT; /* * Reset cpu_id to RSEQ_CPU_ID_UNINITIALIZED, so any user coming * in after unregistration can figure out that rseq needs to be * registered again. */ - if (__put_user(cpu_id, &t->rseq->cpu_id)) + if (put_user(cpu_id, &t->rseq->cpu_id)) return -EFAULT; return 0; } @@ -120,7 +120,7 @@ static int rseq_get_rseq_cs(struct task_struct *t, struct rseq_cs *rseq_cs) u32 sig; int ret; - ret = __get_user(ptr, &t->rseq->rseq_cs); + ret = get_user(ptr, &t->rseq->rseq_cs); if (ret) return ret; if (!ptr) { @@ -163,7 +163,7 @@ static int rseq_need_restart(struct task_struct *t, u32 cs_flags) int ret; /* Get thread flags. */ - ret = __get_user(flags, &t->rseq->flags); + ret = get_user(flags, &t->rseq->flags); if (ret) return ret; @@ -203,7 +203,7 @@ static int clear_rseq_cs(struct task_struct *t) * * Set rseq_cs to NULL with single-copy atomicity. */ - return __put_user(0UL, &t->rseq->rseq_cs); + return put_user(0UL, &t->rseq->rseq_cs); } /* |