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,
Will Deacon <will@kernel.org>, Marc Zyngier <maz@kernel.org>,
Michael Ellerman <mpe@ellerman.id.au>,
Petr Mladek <pmladek@suse.com>
Subject: [PATCH v3 01/22] hardirq/nmi: Allow nested nmi_enter()
Date: Wed, 19 Feb 2020 15:47:25 +0100 [thread overview]
Message-ID: <20200219150744.428764577@infradead.org> (raw)
In-Reply-To: 20200219144724.800607165@infradead.org
Since there are already a number of sites (ARM64, PowerPC) that
effectively nest nmi_enter(), lets make the primitive support this
before adding even more.
Cc: Will Deacon <will@kernel.org>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Petr Mladek <pmladek@suse.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
arch/arm64/include/asm/hardirq.h | 4 ++--
arch/arm64/kernel/sdei.c | 14 ++------------
arch/arm64/kernel/traps.c | 8 ++------
arch/powerpc/kernel/traps.c | 19 +++++--------------
include/linux/hardirq.h | 2 +-
include/linux/preempt.h | 4 ++--
kernel/printk/printk_safe.c | 6 ++++--
7 files changed, 18 insertions(+), 39 deletions(-)
--- a/arch/arm64/include/asm/hardirq.h
+++ b/arch/arm64/include/asm/hardirq.h
@@ -38,7 +38,7 @@ DECLARE_PER_CPU(struct nmi_ctx, nmi_cont
#define arch_nmi_enter() \
do { \
- if (is_kernel_in_hyp_mode()) { \
+ if (is_kernel_in_hyp_mode() && !in_nmi()) { \
struct nmi_ctx *nmi_ctx = this_cpu_ptr(&nmi_contexts); \
nmi_ctx->hcr = read_sysreg(hcr_el2); \
if (!(nmi_ctx->hcr & HCR_TGE)) { \
@@ -50,7 +50,7 @@ DECLARE_PER_CPU(struct nmi_ctx, nmi_cont
#define arch_nmi_exit() \
do { \
- if (is_kernel_in_hyp_mode()) { \
+ if (is_kernel_in_hyp_mode() && !in_nmi()) { \
struct nmi_ctx *nmi_ctx = this_cpu_ptr(&nmi_contexts); \
if (!(nmi_ctx->hcr & HCR_TGE)) \
write_sysreg(nmi_ctx->hcr, hcr_el2); \
--- a/arch/arm64/kernel/sdei.c
+++ b/arch/arm64/kernel/sdei.c
@@ -251,22 +251,12 @@ asmlinkage __kprobes notrace unsigned lo
__sdei_handler(struct pt_regs *regs, struct sdei_registered_event *arg)
{
unsigned long ret;
- bool do_nmi_exit = false;
- /*
- * nmi_enter() deals with printk() re-entrance and use of RCU when
- * RCU believed this CPU was idle. Because critical events can
- * interrupt normal events, we may already be in_nmi().
- */
- if (!in_nmi()) {
- nmi_enter();
- do_nmi_exit = true;
- }
+ nmi_enter();
ret = _sdei_handler(regs, arg);
- if (do_nmi_exit)
- nmi_exit();
+ nmi_exit();
return ret;
}
--- a/arch/arm64/kernel/traps.c
+++ b/arch/arm64/kernel/traps.c
@@ -906,17 +906,13 @@ bool arm64_is_fatal_ras_serror(struct pt
asmlinkage void do_serror(struct pt_regs *regs, unsigned int esr)
{
- const bool was_in_nmi = in_nmi();
-
- if (!was_in_nmi)
- nmi_enter();
+ nmi_enter();
/* non-RAS errors are not containable */
if (!arm64_is_ras_serror(esr) || arm64_is_fatal_ras_serror(regs, esr))
arm64_serror_panic(regs, esr);
- if (!was_in_nmi)
- nmi_exit();
+ nmi_exit();
}
asmlinkage void enter_from_user_mode(void)
--- a/arch/powerpc/kernel/traps.c
+++ b/arch/powerpc/kernel/traps.c
@@ -441,15 +441,9 @@ void hv_nmi_check_nonrecoverable(struct
void system_reset_exception(struct pt_regs *regs)
{
unsigned long hsrr0, hsrr1;
- bool nested = in_nmi();
bool saved_hsrrs = false;
- /*
- * Avoid crashes in case of nested NMI exceptions. Recoverability
- * is determined by RI and in_nmi
- */
- if (!nested)
- nmi_enter();
+ nmi_enter();
/*
* System reset can interrupt code where HSRRs are live and MSR[RI]=1.
@@ -521,8 +515,7 @@ void system_reset_exception(struct pt_re
mtspr(SPRN_HSRR1, hsrr1);
}
- if (!nested)
- nmi_exit();
+ nmi_exit();
/* What should we do here? We could issue a shutdown or hard reset. */
}
@@ -823,9 +816,8 @@ int machine_check_generic(struct pt_regs
void machine_check_exception(struct pt_regs *regs)
{
int recover = 0;
- bool nested = in_nmi();
- if (!nested)
- nmi_enter();
+
+ nmi_enter();
__this_cpu_inc(irq_stat.mce_exceptions);
@@ -863,8 +855,7 @@ void machine_check_exception(struct pt_r
return;
bail:
- if (!nested)
- nmi_exit();
+ nmi_exit();
}
void SMIException(struct pt_regs *regs)
--- a/include/linux/hardirq.h
+++ b/include/linux/hardirq.h
@@ -71,7 +71,7 @@ extern void irq_exit(void);
printk_nmi_enter(); \
lockdep_off(); \
ftrace_nmi_enter(); \
- BUG_ON(in_nmi()); \
+ BUG_ON(in_nmi() == NMI_MASK); \
preempt_count_add(NMI_OFFSET + HARDIRQ_OFFSET); \
rcu_nmi_enter(); \
trace_hardirq_enter(); \
--- a/include/linux/preempt.h
+++ b/include/linux/preempt.h
@@ -26,13 +26,13 @@
* PREEMPT_MASK: 0x000000ff
* SOFTIRQ_MASK: 0x0000ff00
* HARDIRQ_MASK: 0x000f0000
- * NMI_MASK: 0x00100000
+ * NMI_MASK: 0x00f00000
* PREEMPT_NEED_RESCHED: 0x80000000
*/
#define PREEMPT_BITS 8
#define SOFTIRQ_BITS 8
#define HARDIRQ_BITS 4
-#define NMI_BITS 1
+#define NMI_BITS 4
#define PREEMPT_SHIFT 0
#define SOFTIRQ_SHIFT (PREEMPT_SHIFT + PREEMPT_BITS)
--- a/kernel/printk/printk_safe.c
+++ b/kernel/printk/printk_safe.c
@@ -296,12 +296,14 @@ static __printf(1, 0) int vprintk_nmi(co
void notrace printk_nmi_enter(void)
{
- this_cpu_or(printk_context, PRINTK_NMI_CONTEXT_MASK);
+ if (!in_nmi())
+ this_cpu_or(printk_context, PRINTK_NMI_CONTEXT_MASK);
}
void notrace printk_nmi_exit(void)
{
- this_cpu_and(printk_context, ~PRINTK_NMI_CONTEXT_MASK);
+ if (!in_nmi())
+ this_cpu_and(printk_context, ~PRINTK_NMI_CONTEXT_MASK);
}
/*
next prev parent reply other threads:[~2020-02-19 15:14 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 ` Peter Zijlstra [this message]
2020-02-19 15:31 ` [PATCH v3 01/22] hardirq/nmi: Allow nested nmi_enter() 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 ` [PATCH v3 02/22] x86,mce: Delete ist_begin_non_atomic() Peter Zijlstra
2020-02-19 17:13 ` 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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