From: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org, linux-api@vger.kernel.org,
Peter Zijlstra <peterz@infradead.org>,
"Paul E . McKenney" <paulmck@linux.vnet.ibm.com>,
Boqun Feng <boqun.feng@gmail.com>,
Andy Lutomirski <luto@amacapital.net>,
Dave Watson <davejwatson@fb.com>, Paul Turner <pjt@google.com>,
Andrew Morton <akpm@linux-foundation.org>,
Russell King <linux@arm.linux.org.uk>,
Ingo Molnar <mingo@redhat.com>, "H . Peter Anvin" <hpa@zytor.com>,
Andi Kleen <andi@firstfloor.org>, Chris Lameter <cl@linux.com>,
Ben Maurer <bmaurer@fb.com>, Steven Rostedt <rostedt@goodmis.org>,
Josh Triplett <josh@joshtriplett.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will.deacon@arm.com>,
Michael Kerrisk <mtk.manpages@gmail.com>,
Joel Fernandes <joelaf@google.com>,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
linux-arm-kernel@lists.infradead.org
Subject: [PATCH for 4.18 2/6] rseq: use get_user/put_user rather than __get_user/__put_user
Date: Mon, 9 Jul 2018 15:51:51 -0400 [thread overview]
Message-ID: <20180709195155.7654-3-mathieu.desnoyers@efficios.com> (raw)
In-Reply-To: <20180709195155.7654-1-mathieu.desnoyers@efficios.com>
__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>
CC: Thomas Gleixner <tglx@linutronix.de>
Cc: Joel Fernandes <joelaf@google.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dave Watson <davejwatson@fb.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: "H . Peter Anvin" <hpa@zytor.com>
Cc: Chris Lameter <cl@linux.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: "Paul E . McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Paul Turner <pjt@google.com>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Ben Maurer <bmaurer@fb.com>
Cc: linux-api@vger.kernel.org
CC: linux-arm-kernel@lists.infradead.org
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
---
kernel/rseq.c | 14 +++++++-------
1 file 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);
}
/*
--
2.11.0
next prev parent reply other threads:[~2018-07-09 19:53 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-07-09 19:51 [PATCH v2 for 4.18 0/6] Restartable Sequences updates Mathieu Desnoyers
2018-07-09 19:51 ` [PATCH for 4.18 1/6] rseq: use __u64 for rseq_cs fields, validate user inputs Mathieu Desnoyers
2018-07-10 20:21 ` [tip:core/urgent] rseq: Use " tip-bot for Mathieu Desnoyers
2018-07-09 19:51 ` Mathieu Desnoyers [this message]
2018-07-10 20:22 ` [tip:core/urgent] rseq: Use get_user/put_user rather than __get_user/__put_user tip-bot for Mathieu Desnoyers
2018-07-09 19:51 ` [PATCH for 4.18 3/6] rseq: uapi: update uapi comments Mathieu Desnoyers
2018-07-10 20:23 ` [tip:core/urgent] rseq: uapi: Update " tip-bot for Mathieu Desnoyers
2018-07-09 19:51 ` [PATCH for 4.18 4/6] rseq: uapi: declare rseq_cs field as union, update includes Mathieu Desnoyers
2018-07-10 20:23 ` [tip:core/urgent] rseq: uapi: Declare " tip-bot for Mathieu Desnoyers
2018-07-09 19:51 ` [PATCH for 4.18 5/6] rseq: remove unused types_32_64.h uapi header Mathieu Desnoyers
2018-07-10 20:24 ` [tip:core/urgent] rseq: Remove " tip-bot for Mathieu Desnoyers
2018-07-09 19:51 ` [PATCH for 4.18 6/6] rseq/selftests: cleanup: update comment above rseq_prepare_unload Mathieu Desnoyers
2018-07-10 20:24 ` [tip:core/urgent] rseq/selftests: cleanup: Update " tip-bot for Mathieu Desnoyers
-- strict thread matches above, loose matches on Subject: below --
2018-07-08 21:03 [PATCH for 4.18 0/6] Restartable Sequences updates Mathieu Desnoyers
2018-07-08 21:03 ` [PATCH for 4.18 2/6] rseq: use get_user/put_user rather than __get_user/__put_user Mathieu Desnoyers
2018-07-09 17:28 ` Mathieu Desnoyers
2018-07-09 18:04 ` Linus Torvalds
2018-07-09 18:19 ` Mathieu Desnoyers
2018-07-09 19:04 ` Linus Torvalds
2018-07-10 6:16 ` Michael Ellerman
2018-07-10 13:48 ` Mathieu Desnoyers
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