From: "tip-bot2 for Mark Rutland" <tip-bot2@linutronix.de>
To: linux-tip-commits@vger.kernel.org
Cc: Mark Rutland <mark.rutland@arm.com>,
Thomas Gleixner <tglx@linutronix.de>,
"Paul E. McKenney" <paulmck@kernel.org>,
x86@kernel.org, linux-kernel@vger.kernel.org
Subject: [tip: core/entry] x86: Snapshot thread flags
Date: Tue, 30 Nov 2021 23:08:46 -0000 [thread overview]
Message-ID: <163831372651.11128.8667725188143997608.tip-bot2@tip-bot2> (raw)
In-Reply-To: <20211129130653.2037928-12-mark.rutland@arm.com>
The following commit has been merged into the core/entry branch of tip:
Commit-ID: dca99fb643a2e9bc2e67a0f626b09d4f177f0f09
Gitweb: https://git.kernel.org/tip/dca99fb643a2e9bc2e67a0f626b09d4f177f0f09
Author: Mark Rutland <mark.rutland@arm.com>
AuthorDate: Mon, 29 Nov 2021 13:06:53
Committer: Thomas Gleixner <tglx@linutronix.de>
CommitterDate: Wed, 01 Dec 2021 00:06:43 +01:00
x86: Snapshot thread flags
Some thread flags can be set remotely, and so even when IRQs are disabled,
the flags can change under our feet. Generally this is unlikely to cause a
problem in practice, but it is somewhat unsound, and KCSAN will
legitimately warn that there is a data race.
To avoid such issues, a snapshot of the flags has to be taken prior to
using them. Some places already use READ_ONCE() for that, others do not.
Convert them all to the new flag accessor helpers.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Paul E. McKenney <paulmck@kernel.org>
Link: https://lore.kernel.org/r/20211129130653.2037928-12-mark.rutland@arm.com
---
arch/x86/kernel/process.c | 8 ++++----
arch/x86/kernel/process.h | 4 ++--
arch/x86/mm/tlb.c | 2 +-
3 files changed, 7 insertions(+), 7 deletions(-)
diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c
index 04143a6..5d48103 100644
--- a/arch/x86/kernel/process.c
+++ b/arch/x86/kernel/process.c
@@ -365,7 +365,7 @@ void arch_setup_new_exec(void)
clear_thread_flag(TIF_SSBD);
task_clear_spec_ssb_disable(current);
task_clear_spec_ssb_noexec(current);
- speculation_ctrl_update(task_thread_info(current)->flags);
+ speculation_ctrl_update(read_thread_flags());
}
}
@@ -617,7 +617,7 @@ static unsigned long speculation_ctrl_update_tif(struct task_struct *tsk)
clear_tsk_thread_flag(tsk, TIF_SPEC_IB);
}
/* Return the updated threadinfo flags*/
- return task_thread_info(tsk)->flags;
+ return read_task_thread_flags(tsk);
}
void speculation_ctrl_update(unsigned long tif)
@@ -653,8 +653,8 @@ void __switch_to_xtra(struct task_struct *prev_p, struct task_struct *next_p)
{
unsigned long tifp, tifn;
- tifn = READ_ONCE(task_thread_info(next_p)->flags);
- tifp = READ_ONCE(task_thread_info(prev_p)->flags);
+ tifn = read_task_thread_flags(next_p);
+ tifp = read_task_thread_flags(prev_p);
switch_to_bitmap(tifp);
diff --git a/arch/x86/kernel/process.h b/arch/x86/kernel/process.h
index 1d0797b..76b547b 100644
--- a/arch/x86/kernel/process.h
+++ b/arch/x86/kernel/process.h
@@ -13,8 +13,8 @@ void __switch_to_xtra(struct task_struct *prev_p, struct task_struct *next_p);
static inline void switch_to_extra(struct task_struct *prev,
struct task_struct *next)
{
- unsigned long next_tif = task_thread_info(next)->flags;
- unsigned long prev_tif = task_thread_info(prev)->flags;
+ unsigned long next_tif = read_task_thread_flags(next);
+ unsigned long prev_tif = read_task_thread_flags(prev);
if (IS_ENABLED(CONFIG_SMP)) {
/*
diff --git a/arch/x86/mm/tlb.c b/arch/x86/mm/tlb.c
index 59ba296..92bb03b 100644
--- a/arch/x86/mm/tlb.c
+++ b/arch/x86/mm/tlb.c
@@ -361,7 +361,7 @@ static void l1d_flush_evaluate(unsigned long prev_mm, unsigned long next_mm,
static unsigned long mm_mangle_tif_spec_bits(struct task_struct *next)
{
- unsigned long next_tif = task_thread_info(next)->flags;
+ unsigned long next_tif = read_task_thread_flags(next);
unsigned long spec_bits = (next_tif >> TIF_SPEC_IB) & LAST_USER_MM_SPEC_MASK;
/*
next prev parent reply other threads:[~2021-11-30 23:09 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-29 13:06 [PATCH v8 00/11] thread_info: use helpers to snapshot thread flags Mark Rutland
2021-11-29 13:06 ` [PATCH v8 01/11] thread_info: add " Mark Rutland
2021-11-30 23:08 ` [tip: core/entry] thread_info: Add " tip-bot2 for Mark Rutland
2021-11-29 13:06 ` [PATCH v8 02/11] entry: " Mark Rutland
2021-11-30 23:08 ` [tip: core/entry] entry: Snapshot " tip-bot2 for Mark Rutland
2021-11-29 13:06 ` [PATCH v8 03/11] sched: snapshot " Mark Rutland
2021-11-30 23:08 ` [tip: core/entry] sched: Snapshot " tip-bot2 for Mark Rutland
2021-11-29 13:06 ` [PATCH v8 04/11] alpha: snapshot " Mark Rutland
2021-11-30 23:08 ` [tip: core/entry] alpha: Snapshot " tip-bot2 for Mark Rutland
2021-11-29 13:06 ` [PATCH v8 05/11] arm: snapshot " Mark Rutland
2021-11-30 23:08 ` [tip: core/entry] ARM: Snapshot " tip-bot2 for Mark Rutland
2021-11-29 13:06 ` [PATCH v8 06/11] arm64: snapshot " Mark Rutland
2021-11-30 23:08 ` [tip: core/entry] arm64: Snapshot " tip-bot2 for Mark Rutland
2021-11-29 13:06 ` [PATCH v8 07/11] microblaze: snapshot " Mark Rutland
2021-11-30 23:08 ` [tip: core/entry] microblaze: Snapshot " tip-bot2 for Mark Rutland
2021-11-29 13:06 ` [PATCH v8 08/11] openrisc: snapshot " Mark Rutland
2021-11-30 23:08 ` [tip: core/entry] openrisc: Snapshot " tip-bot2 for Mark Rutland
2021-11-29 13:06 ` [PATCH v8 09/11] powerpc: avoid discarding flags in system_call_exception() Mark Rutland
2021-11-30 23:08 ` [tip: core/entry] powerpc: Avoid " tip-bot2 for Mark Rutland
2021-11-29 13:06 ` [PATCH v8 10/11] powerpc: snapshot thread flags Mark Rutland
2021-11-30 23:08 ` [tip: core/entry] powerpc: Snapshot " tip-bot2 for Mark Rutland
2021-11-29 13:06 ` [PATCH v8 11/11] x86: snapshot " Mark Rutland
2021-11-30 23:08 ` tip-bot2 for Mark Rutland [this message]
-- strict thread matches above, loose matches on Subject: below --
2021-11-17 16:30 [PATCHv7 " Mark Rutland
2021-11-26 20:22 ` [tip: core/entry] x86: Snapshot " tip-bot2 for Mark Rutland
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