diff options
| author | Mark Rutland <mark.rutland@arm.com> | 2021-11-29 16:06:52 +0300 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2021-12-01 02:06:44 +0300 |
| commit | 985faa78687de6e583cfd8b8094d87dcb80c33a6 (patch) | |
| tree | c0b6f83c475b2410eba14d3dbd7738296a8c4098 /arch/powerpc | |
| parent | 08b0af5b2affbe7419853e8dd1330e4b3fe27125 (diff) | |
| download | linux-985faa78687de6e583cfd8b8094d87dcb80c33a6.tar.xz | |
powerpc: 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>
Acked-by: Paul E. McKenney <paulmck@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Paul Mackerras <paulus@samba.org>
Link: https://lore.kernel.org/r/20211129130653.2037928-11-mark.rutland@arm.com
Diffstat (limited to 'arch/powerpc')
| -rw-r--r-- | arch/powerpc/kernel/interrupt.c | 13 | ||||
| -rw-r--r-- | arch/powerpc/kernel/ptrace/ptrace.c | 3 |
2 files changed, 7 insertions, 9 deletions
diff --git a/arch/powerpc/kernel/interrupt.c b/arch/powerpc/kernel/interrupt.c index df048e331cbf..563ebfcd16e2 100644 --- a/arch/powerpc/kernel/interrupt.c +++ b/arch/powerpc/kernel/interrupt.c @@ -181,7 +181,7 @@ notrace long system_call_exception(long r3, long r4, long r5, local_irq_enable(); - if (unlikely(current_thread_info()->flags & _TIF_SYSCALL_DOTRACE)) { + if (unlikely(read_thread_flags() & _TIF_SYSCALL_DOTRACE)) { if (unlikely(trap_is_unsupported_scv(regs))) { /* Unsupported scv vector */ _exception(SIGILL, regs, ILL_ILLOPC, regs->nip); @@ -343,7 +343,7 @@ interrupt_exit_user_prepare_main(unsigned long ret, struct pt_regs *regs) unsigned long ti_flags; again: - ti_flags = READ_ONCE(current_thread_info()->flags); + ti_flags = read_thread_flags(); while (unlikely(ti_flags & (_TIF_USER_WORK_MASK & ~_TIF_RESTORE_TM))) { local_irq_enable(); if (ti_flags & _TIF_NEED_RESCHED) { @@ -359,7 +359,7 @@ again: do_notify_resume(regs, ti_flags); } local_irq_disable(); - ti_flags = READ_ONCE(current_thread_info()->flags); + ti_flags = read_thread_flags(); } if (IS_ENABLED(CONFIG_PPC_BOOK3S_64) && IS_ENABLED(CONFIG_PPC_FPU)) { @@ -437,7 +437,7 @@ notrace unsigned long syscall_exit_prepare(unsigned long r3, /* Check whether the syscall is issued inside a restartable sequence */ rseq_syscall(regs); - ti_flags = current_thread_info()->flags; + ti_flags = read_thread_flags(); if (unlikely(r3 >= (unsigned long)-MAX_ERRNO) && is_not_scv) { if (likely(!(ti_flags & (_TIF_NOERROR | _TIF_RESTOREALL)))) { @@ -532,8 +532,7 @@ notrace unsigned long interrupt_exit_kernel_prepare(struct pt_regs *regs) unsigned long flags; unsigned long ret = 0; unsigned long kuap; - bool stack_store = current_thread_info()->flags & - _TIF_EMULATE_STACK_STORE; + bool stack_store = read_thread_flags() & _TIF_EMULATE_STACK_STORE; if (regs_is_unrecoverable(regs)) unrecoverable_exception(regs); @@ -554,7 +553,7 @@ notrace unsigned long interrupt_exit_kernel_prepare(struct pt_regs *regs) again: if (IS_ENABLED(CONFIG_PREEMPT)) { /* Return to preemptible kernel context */ - if (unlikely(current_thread_info()->flags & _TIF_NEED_RESCHED)) { + if (unlikely(read_thread_flags() & _TIF_NEED_RESCHED)) { if (preempt_count() == 0) preempt_schedule_irq(); } diff --git a/arch/powerpc/kernel/ptrace/ptrace.c b/arch/powerpc/kernel/ptrace/ptrace.c index 7c7093c17c45..c43f77e2ac31 100644 --- a/arch/powerpc/kernel/ptrace/ptrace.c +++ b/arch/powerpc/kernel/ptrace/ptrace.c @@ -260,8 +260,7 @@ long do_syscall_trace_enter(struct pt_regs *regs) { u32 flags; - flags = READ_ONCE(current_thread_info()->flags) & - (_TIF_SYSCALL_EMU | _TIF_SYSCALL_TRACE); + flags = read_thread_flags() & (_TIF_SYSCALL_EMU | _TIF_SYSCALL_TRACE); if (flags) { int rc = tracehook_report_syscall_entry(regs); |