From: Peter Zijlstra <peterz@infradead.org>
To: linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org,
rostedt@goodmis.org
Cc: peterz@infradead.org, mingo@kernel.org, joel@joelfernandes.org,
gregkh@linuxfoundation.org, gustavo@embeddedor.com,
tglx@linutronix.de, paulmck@kernel.org, josh@joshtriplett.org,
mathieu.desnoyers@efficios.com, jiangshanlai@gmail.com,
luto@kernel.org, tony.luck@intel.com, frederic@kernel.org,
dan.carpenter@oracle.com, mhiramat@kernel.org
Subject: [PATCH v3 02/22] x86,mce: Delete ist_begin_non_atomic()
Date: Wed, 19 Feb 2020 15:47:26 +0100 [thread overview]
Message-ID: <20200219150744.488895196@infradead.org> (raw)
In-Reply-To: 20200219144724.800607165@infradead.org
It is an abomination; and in prepration of removing the whole
ist_enter() thing, it needs to go.
Convert #MC over to using task_work_add() instead; it will run the
same code slightly later, on the return to user path of the same
exception.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
arch/x86/include/asm/traps.h | 2 -
arch/x86/kernel/cpu/mce/core.c | 53 +++++++++++++++++++++++------------------
arch/x86/kernel/traps.c | 37 ----------------------------
include/linux/sched.h | 6 ++++
4 files changed, 36 insertions(+), 62 deletions(-)
--- a/arch/x86/include/asm/traps.h
+++ b/arch/x86/include/asm/traps.h
@@ -123,8 +123,6 @@ asmlinkage void smp_irq_move_cleanup_int
extern void ist_enter(struct pt_regs *regs);
extern void ist_exit(struct pt_regs *regs);
-extern void ist_begin_non_atomic(struct pt_regs *regs);
-extern void ist_end_non_atomic(void);
#ifdef CONFIG_VMAP_STACK
void __noreturn handle_stack_overflow(const char *message,
--- a/arch/x86/kernel/cpu/mce/core.c
+++ b/arch/x86/kernel/cpu/mce/core.c
@@ -42,6 +42,7 @@
#include <linux/export.h>
#include <linux/jump_label.h>
#include <linux/set_memory.h>
+#include <linux/task_work.h>
#include <asm/intel-family.h>
#include <asm/processor.h>
@@ -1084,23 +1085,6 @@ static void mce_clear_state(unsigned lon
}
}
-static int do_memory_failure(struct mce *m)
-{
- int flags = MF_ACTION_REQUIRED;
- int ret;
-
- pr_err("Uncorrected hardware memory error in user-access at %llx", m->addr);
- if (!(m->mcgstatus & MCG_STATUS_RIPV))
- flags |= MF_MUST_KILL;
- ret = memory_failure(m->addr >> PAGE_SHIFT, flags);
- if (ret)
- pr_err("Memory error not recovered");
- else
- set_mce_nospec(m->addr >> PAGE_SHIFT);
- return ret;
-}
-
-
/*
* Cases where we avoid rendezvous handler timeout:
* 1) If this CPU is offline.
@@ -1202,6 +1186,29 @@ static void __mc_scan_banks(struct mce *
*m = *final;
}
+static void mce_kill_me_now(struct callback_head *ch)
+{
+ force_sig(SIGBUS);
+}
+
+static void mce_kill_me_maybe(struct callback_head *cb)
+{
+ struct task_struct *p = container_of(cb, struct task_struct, mce_kill_me);
+ int flags = MF_ACTION_REQUIRED;
+
+ pr_err("Uncorrected hardware memory error in user-access at %llx", p->mce_addr);
+ if (!(p->mce_status & MCG_STATUS_RIPV))
+ flags |= MF_MUST_KILL;
+
+ if (!memory_failure(p->mce_addr >> PAGE_SHIFT, flags)) {
+ set_mce_nospec(p->mce_addr >> PAGE_SHIFT);
+ return;
+ }
+
+ pr_err("Memory error not recovered");
+ mce_kill_me_now(cb);
+}
+
/*
* The actual machine check handler. This only handles real
* exceptions when something got corrupted coming in through int 18.
@@ -1344,13 +1351,13 @@ void do_machine_check(struct pt_regs *re
/* Fault was in user mode and we need to take some action */
if ((m.cs & 3) == 3) {
- ist_begin_non_atomic(regs);
- local_irq_enable();
+ current->mce_addr = m.addr;
+ current->mce_status = m.mcgstatus;
+ current->mce_kill_me.func = mce_kill_me_maybe;
+ if (kill_it)
+ current->mce_kill_me.func = mce_kill_me_now;
- if (kill_it || do_memory_failure(&m))
- force_sig(SIGBUS);
- local_irq_disable();
- ist_end_non_atomic();
+ task_work_add(current, ¤t->mce_kill_me, true);
} else {
if (!fixup_exception(regs, X86_TRAP_MC, error_code, 0))
mce_panic("Failed kernel mode recovery", &m, msg);
--- a/arch/x86/kernel/traps.c
+++ b/arch/x86/kernel/traps.c
@@ -117,43 +117,6 @@ void ist_exit(struct pt_regs *regs)
rcu_nmi_exit();
}
-/**
- * ist_begin_non_atomic() - begin a non-atomic section in an IST exception
- * @regs: regs passed to the IST exception handler
- *
- * IST exception handlers normally cannot schedule. As a special
- * exception, if the exception interrupted userspace code (i.e.
- * user_mode(regs) would return true) and the exception was not
- * a double fault, it can be safe to schedule. ist_begin_non_atomic()
- * begins a non-atomic section within an ist_enter()/ist_exit() region.
- * Callers are responsible for enabling interrupts themselves inside
- * the non-atomic section, and callers must call ist_end_non_atomic()
- * before ist_exit().
- */
-void ist_begin_non_atomic(struct pt_regs *regs)
-{
- BUG_ON(!user_mode(regs));
-
- /*
- * Sanity check: we need to be on the normal thread stack. This
- * will catch asm bugs and any attempt to use ist_preempt_enable
- * from double_fault.
- */
- BUG_ON(!on_thread_stack());
-
- preempt_enable_no_resched();
-}
-
-/**
- * ist_end_non_atomic() - begin a non-atomic section in an IST exception
- *
- * Ends a non-atomic section started with ist_begin_non_atomic().
- */
-void ist_end_non_atomic(void)
-{
- preempt_disable();
-}
-
int is_valid_bugaddr(unsigned long addr)
{
unsigned short ud;
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1285,6 +1285,12 @@ struct task_struct {
unsigned long prev_lowest_stack;
#endif
+#ifdef CONFIG_X86_MCE
+ u64 mce_addr;
+ u64 mce_status;
+ struct callback_head mce_kill_me;
+#endif
+
/*
* New fields for task_struct should be added above here, so that
* they are included in the randomized portion of task_struct.
next prev parent reply other threads:[~2020-02-19 15:15 UTC|newest]
Thread overview: 99+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-19 14:47 [PATCH v3 00/22] tracing vs world Peter Zijlstra
2020-02-19 14:47 ` [PATCH v3 01/22] hardirq/nmi: Allow nested nmi_enter() Peter Zijlstra
2020-02-19 15:31 ` Steven Rostedt
2020-02-19 16:56 ` Borislav Petkov
2020-02-19 17:07 ` Peter Zijlstra
2020-02-20 8:41 ` Will Deacon
2020-02-20 9:19 ` Marc Zyngier
2020-02-20 13:18 ` Petr Mladek
2020-02-19 14:47 ` Peter Zijlstra [this message]
2020-02-19 17:13 ` [PATCH v3 02/22] x86,mce: Delete ist_begin_non_atomic() Borislav Petkov
2020-02-19 17:21 ` Andy Lutomirski
2020-02-19 17:33 ` Peter Zijlstra
2020-02-19 22:12 ` Andy Lutomirski
2020-02-19 22:33 ` Luck, Tony
2020-02-19 22:48 ` Andy Lutomirski
2020-02-20 7:39 ` Peter Zijlstra
2020-02-19 17:42 ` Borislav Petkov
2020-02-19 17:46 ` Peter Zijlstra
2020-02-19 14:47 ` [PATCH v3 03/22] x86: Replace ist_enter() with nmi_enter() Peter Zijlstra
2020-02-20 10:54 ` Borislav Petkov
2020-02-20 12:11 ` Peter Zijlstra
2020-02-19 14:47 ` [PATCH v3 04/22] x86/doublefault: Make memmove() notrace/NOKPROBE Peter Zijlstra
2020-02-19 15:36 ` Steven Rostedt
2020-02-19 15:40 ` Peter Zijlstra
2020-02-19 15:55 ` Steven Rostedt
2020-02-19 15:57 ` Peter Zijlstra
2020-02-19 16:04 ` Peter Zijlstra
2020-02-19 16:12 ` Steven Rostedt
2020-02-19 16:27 ` Paul E. McKenney
2020-02-19 16:34 ` Peter Zijlstra
2020-02-19 16:46 ` Paul E. McKenney
2020-02-19 17:05 ` Steven Rostedt
2020-02-20 12:17 ` Borislav Petkov
2020-02-20 12:37 ` Peter Zijlstra
2020-02-19 15:47 ` Steven Rostedt
2020-02-19 14:47 ` [PATCH v3 05/22] rcu: Make RCU IRQ enter/exit functions rely on in_nmi() Peter Zijlstra
2020-02-19 16:31 ` Paul E. McKenney
2020-02-19 16:37 ` Peter Zijlstra
2020-02-19 16:45 ` Paul E. McKenney
2020-02-19 17:03 ` Peter Zijlstra
2020-02-19 17:42 ` Paul E. McKenney
2020-02-19 17:16 ` [PATCH] rcu/kprobes: Comment why rcu_nmi_enter() is marked NOKPROBE Steven Rostedt
2020-02-19 17:18 ` Joel Fernandes
2020-02-19 17:41 ` Paul E. McKenney
2020-02-20 5:54 ` Masami Hiramatsu
2020-02-19 14:47 ` [PATCH v3 06/22] rcu: Rename rcu_irq_{enter,exit}_irqson() Peter Zijlstra
2020-02-19 16:38 ` Paul E. McKenney
2020-02-19 14:47 ` [PATCH v3 07/22] rcu: Mark rcu_dynticks_curr_cpu_in_eqs() inline Peter Zijlstra
2020-02-19 16:39 ` Paul E. McKenney
2020-02-19 17:19 ` Steven Rostedt
2020-02-19 14:47 ` [PATCH v3 08/22] rcu,tracing: Create trace_rcu_{enter,exit}() Peter Zijlstra
2020-02-19 15:49 ` Steven Rostedt
2020-02-19 15:58 ` Peter Zijlstra
2020-02-19 16:15 ` Steven Rostedt
2020-02-19 16:35 ` Peter Zijlstra
2020-02-19 16:44 ` Paul E. McKenney
2020-02-20 10:34 ` Peter Zijlstra
2020-02-20 13:58 ` Paul E. McKenney
2020-02-19 14:47 ` [PATCH v3 09/22] sched,rcu,tracing: Avoid tracing before in_nmi() is correct Peter Zijlstra
2020-02-19 15:50 ` Steven Rostedt
2020-02-19 15:50 ` Steven Rostedt
2020-02-19 14:47 ` [PATCH v3 10/22] x86,tracing: Add comments to do_nmi() Peter Zijlstra
2020-02-19 15:51 ` Steven Rostedt
2020-02-19 14:47 ` [PATCH v3 11/22] perf,tracing: Prepare the perf-trace interface for RCU changes Peter Zijlstra
2020-02-19 14:47 ` [PATCH v3 12/22] tracing: Employ trace_rcu_{enter,exit}() Peter Zijlstra
2020-02-19 15:52 ` Steven Rostedt
2020-02-19 14:47 ` [PATCH v3 13/22] tracing: Remove regular RCU context for _rcuidle tracepoints (again) Peter Zijlstra
2020-02-19 15:53 ` Steven Rostedt
2020-02-19 16:43 ` Paul E. McKenney
2020-02-19 16:47 ` Peter Zijlstra
2020-02-19 17:05 ` Peter Zijlstra
2020-02-19 17:21 ` Steven Rostedt
2020-02-19 17:40 ` Paul E. McKenney
2020-02-19 18:00 ` Steven Rostedt
2020-02-19 19:05 ` Paul E. McKenney
2020-02-19 14:47 ` [PATCH v3 14/22] perf,tracing: Allow function tracing when !RCU Peter Zijlstra
2020-02-19 14:47 ` [PATCH v3 15/22] x86/int3: Ensure that poke_int3_handler() is not traced Peter Zijlstra
2020-02-19 14:47 ` [PATCH v3 16/22] locking/atomics, kcsan: Add KCSAN instrumentation Peter Zijlstra
2020-02-19 15:46 ` Steven Rostedt
2020-02-19 16:03 ` Peter Zijlstra
2020-02-19 16:50 ` Paul E. McKenney
2020-02-19 16:54 ` Peter Zijlstra
2020-02-19 17:36 ` Paul E. McKenney
2020-02-19 14:47 ` [PATCH v3 17/22] asm-generic/atomic: Use __always_inline for pure wrappers Peter Zijlstra
2020-02-19 14:47 ` [PATCH v3 18/22] asm-generic/atomic: Use __always_inline for fallback wrappers Peter Zijlstra
2020-02-19 16:55 ` Paul E. McKenney
2020-02-19 17:06 ` Peter Zijlstra
2020-02-19 17:35 ` Paul E. McKenney
2020-02-19 14:47 ` [PATCH v3 19/22] compiler: Simple READ/WRITE_ONCE() implementations Peter Zijlstra
2020-02-19 14:47 ` [PATCH v3 20/22] locking/atomics: Flip fallbacks and instrumentation Peter Zijlstra
2020-02-19 14:47 ` [PATCH v3 21/22] x86/int3: Avoid atomic instrumentation Peter Zijlstra
2020-02-19 14:47 ` [PATCH v3 22/22] x86/int3: Ensure that poke_int3_handler() is not sanitized Peter Zijlstra
2020-02-19 16:06 ` Dmitry Vyukov
2020-02-19 16:30 ` Peter Zijlstra
2020-02-19 16:51 ` Peter Zijlstra
2020-02-19 17:20 ` Peter Zijlstra
2020-02-20 10:37 ` Dmitry Vyukov
2020-02-20 12:06 ` Peter Zijlstra
2020-02-20 16:22 ` Dmitry Vyukov
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