[GIT PULL] IRQ changes for v3.13
From: Ingo Molnar
Date: Mon Nov 11 2013 - 09:17:57 EST
Linus,
Please pull the latest irq-core-for-linus git tree from:
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git irq-core-for-linus
# HEAD: 5702941eec32cfd7b8cf9e36a0936e48170011a4 irqchip: bcm2835: Convert to use IRQCHIP_DECLARE macro
The biggest change this cycle are the softirq/hardirq stack interaction
and nesting fixes, cleanups and reorganizations from Frederic. This is the
longer followup story to the softirq nesting fix that is already upstream:
ded797547548 irq: Force hardirq exit's softirq processing on its own stack
Thanks,
Ingo
------------------>
Axel Lin (1):
irqchip: bcm2835: Convert to use IRQCHIP_DECLARE macro
Frederic Weisbecker (7):
irq: Consolidate do_softirq() arch overriden implementations
irq: Optimize call to softirq on hardirq exit
irq: Improve a bit softirq debugging
irq: Justify the various softirq stack choices
irq: Optimize softirq stack selection in irq exit
x86: Tell about irq stack coverage
powerpc: Tell about irq stack coverage
Yanchuan Nian (1):
x86/irq: Correct comment about i8259 initialization
arch/Kconfig | 10 ++++++++
arch/arm/mach-bcm2835/bcm2835.c | 5 ++--
arch/metag/kernel/irq.c | 52 ++++++++++++++-----------------------
arch/parisc/kernel/irq.c | 17 ++----------
arch/powerpc/Kconfig | 1 +
arch/powerpc/kernel/irq.c | 17 +-----------
arch/s390/kernel/irq.c | 52 +++++++++++++++----------------------
arch/sh/kernel/irq.c | 57 +++++++++++++++--------------------------
arch/sparc/kernel/irq_64.c | 31 ++++++++--------------
arch/x86/Kconfig | 1 +
arch/x86/kernel/entry_64.S | 4 +--
arch/x86/kernel/i8259.c | 3 +--
arch/x86/kernel/irq_32.c | 30 ++++++----------------
arch/x86/kernel/irq_64.c | 21 ---------------
drivers/irqchip/irq-bcm2835.c | 22 ++++++++--------
include/linux/interrupt.h | 11 ++++++++
include/linux/irqchip/bcm2835.h | 29 ---------------------
kernel/softirq.c | 37 +++++++++++++++++---------
18 files changed, 145 insertions(+), 255 deletions(-)
delete mode 100644 include/linux/irqchip/bcm2835.h
diff --git a/arch/Kconfig b/arch/Kconfig
index af2cc6e..ad95133 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -390,6 +390,16 @@ config HAVE_UNDERSCORE_SYMBOL_PREFIX
Some architectures generate an _ in front of C symbols; things like
module loading and assembly files need to know about this.
+config HAVE_IRQ_EXIT_ON_IRQ_STACK
+ bool
+ help
+ Architecture doesn't only execute the irq handler on the irq stack
+ but also irq_exit(). This way we can process softirqs on this irq
+ stack instead of switching to a new one when we call __do_softirq()
+ in the end of an hardirq.
+ This spares a stack switch and improves cache usage on softirq
+ processing.
+
#
# ABI hall of shame
#
diff --git a/arch/arm/mach-bcm2835/bcm2835.c b/arch/arm/mach-bcm2835/bcm2835.c
index 40686d7..a4abd85 100644
--- a/arch/arm/mach-bcm2835/bcm2835.c
+++ b/arch/arm/mach-bcm2835/bcm2835.c
@@ -14,7 +14,7 @@
#include <linux/delay.h>
#include <linux/init.h>
-#include <linux/irqchip/bcm2835.h>
+#include <linux/irqchip.h>
#include <linux/of_address.h>
#include <linux/of_platform.h>
#include <linux/clk/bcm2835.h>
@@ -131,8 +131,7 @@ static const char * const bcm2835_compat[] = {
DT_MACHINE_START(BCM2835, "BCM2835")
.map_io = bcm2835_map_io,
- .init_irq = bcm2835_init_irq,
- .handle_irq = bcm2835_handle_irq,
+ .init_irq = irqchip_init,
.init_machine = bcm2835_init,
.init_time = clocksource_of_init,
.restart = bcm2835_restart,
diff --git a/arch/metag/kernel/irq.c b/arch/metag/kernel/irq.c
index 2a2c9d5..3b4b7f6 100644
--- a/arch/metag/kernel/irq.c
+++ b/arch/metag/kernel/irq.c
@@ -159,44 +159,30 @@ void irq_ctx_exit(int cpu)
extern asmlinkage void __do_softirq(void);
-asmlinkage void do_softirq(void)
+void do_softirq_own_stack(void)
{
- unsigned long flags;
struct thread_info *curctx;
union irq_ctx *irqctx;
u32 *isp;
- if (in_interrupt())
- return;
-
- local_irq_save(flags);
-
- if (local_softirq_pending()) {
- curctx = current_thread_info();
- irqctx = softirq_ctx[smp_processor_id()];
- irqctx->tinfo.task = curctx->task;
-
- /* build the stack frame on the softirq stack */
- isp = (u32 *) ((char *)irqctx + sizeof(struct thread_info));
-
- asm volatile (
- "MOV D0.5,%0\n"
- "SWAP A0StP,D0.5\n"
- "CALLR D1RtP,___do_softirq\n"
- "MOV A0StP,D0.5\n"
- :
- : "r" (isp)
- : "memory", "cc", "D1Ar1", "D0Ar2", "D1Ar3", "D0Ar4",
- "D1Ar5", "D0Ar6", "D0Re0", "D1Re0", "D0.4", "D1RtP",
- "D0.5"
- );
- /*
- * Shouldn't happen, we returned above if in_interrupt():
- */
- WARN_ON_ONCE(softirq_count());
- }
-
- local_irq_restore(flags);
+ curctx = current_thread_info();
+ irqctx = softirq_ctx[smp_processor_id()];
+ irqctx->tinfo.task = curctx->task;
+
+ /* build the stack frame on the softirq stack */
+ isp = (u32 *) ((char *)irqctx + sizeof(struct thread_info));
+
+ asm volatile (
+ "MOV D0.5,%0\n"
+ "SWAP A0StP,D0.5\n"
+ "CALLR D1RtP,___do_softirq\n"
+ "MOV A0StP,D0.5\n"
+ :
+ : "r" (isp)
+ : "memory", "cc", "D1Ar1", "D0Ar2", "D1Ar3", "D0Ar4",
+ "D1Ar5", "D0Ar6", "D0Re0", "D1Re0", "D0.4", "D1RtP",
+ "D0.5"
+ );
}
#endif
diff --git a/arch/parisc/kernel/irq.c b/arch/parisc/kernel/irq.c
index 2e6443b..ef59276 100644
--- a/arch/parisc/kernel/irq.c
+++ b/arch/parisc/kernel/irq.c
@@ -499,22 +499,9 @@ static void execute_on_irq_stack(void *func, unsigned long param1)
*irq_stack_in_use = 1;
}
-asmlinkage void do_softirq(void)
+void do_softirq_own_stack(void)
{
- __u32 pending;
- unsigned long flags;
-
- if (in_interrupt())
- return;
-
- local_irq_save(flags);
-
- pending = local_softirq_pending();
-
- if (pending)
- execute_on_irq_stack(__do_softirq, 0);
-
- local_irq_restore(flags);
+ execute_on_irq_stack(__do_softirq, 0);
}
#endif /* CONFIG_IRQSTACKS */
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 38f3b7e..b365d5c 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -138,6 +138,7 @@ config PPC
select OLD_SIGSUSPEND
select OLD_SIGACTION if PPC32
select HAVE_DEBUG_STACKOVERFLOW
+ select HAVE_IRQ_EXIT_ON_IRQ_STACK
config EARLY_PRINTK
bool
diff --git a/arch/powerpc/kernel/irq.c b/arch/powerpc/kernel/irq.c
index 57d286a..5c4adfc 100644
--- a/arch/powerpc/kernel/irq.c
+++ b/arch/powerpc/kernel/irq.c
@@ -593,7 +593,7 @@ void irq_ctx_init(void)
}
}
-static inline void do_softirq_onstack(void)
+void do_softirq_own_stack(void)
{
struct thread_info *curtp, *irqtp;
@@ -611,21 +611,6 @@ static inline void do_softirq_onstack(void)
set_bits(irqtp->flags, &curtp->flags);
}
-void do_softirq(void)
-{
- unsigned long flags;
-
- if (in_interrupt())
- return;
-
- local_irq_save(flags);
-
- if (local_softirq_pending())
- do_softirq_onstack();
-
- local_irq_restore(flags);
-}
-
irq_hw_number_t virq_to_hw(unsigned int virq)
{
struct irq_data *irq_data = irq_get_irq_data(virq);
diff --git a/arch/s390/kernel/irq.c b/arch/s390/kernel/irq.c
index 8ac2097..bb27a26 100644
--- a/arch/s390/kernel/irq.c
+++ b/arch/s390/kernel/irq.c
@@ -157,39 +157,29 @@ int arch_show_interrupts(struct seq_file *p, int prec)
/*
* Switch to the asynchronous interrupt stack for softirq execution.
*/
-asmlinkage void do_softirq(void)
+void do_softirq_own_stack(void)
{
- unsigned long flags, old, new;
-
- if (in_interrupt())
- return;
-
- local_irq_save(flags);
-
- if (local_softirq_pending()) {
- /* Get current stack pointer. */
- asm volatile("la %0,0(15)" : "=a" (old));
- /* Check against async. stack address range. */
- new = S390_lowcore.async_stack;
- if (((new - old) >> (PAGE_SHIFT + THREAD_ORDER)) != 0) {
- /* Need to switch to the async. stack. */
- new -= STACK_FRAME_OVERHEAD;
- ((struct stack_frame *) new)->back_chain = old;
-
- asm volatile(" la 15,0(%0)\n"
- " basr 14,%2\n"
- " la 15,0(%1)\n"
- : : "a" (new), "a" (old),
- "a" (__do_softirq)
- : "0", "1", "2", "3", "4", "5", "14",
- "cc", "memory" );
- } else {
- /* We are already on the async stack. */
- __do_softirq();
- }
+ unsigned long old, new;
+
+ /* Get current stack pointer. */
+ asm volatile("la %0,0(15)" : "=a" (old));
+ /* Check against async. stack address range. */
+ new = S390_lowcore.async_stack;
+ if (((new - old) >> (PAGE_SHIFT + THREAD_ORDER)) != 0) {
+ /* Need to switch to the async. stack. */
+ new -= STACK_FRAME_OVERHEAD;
+ ((struct stack_frame *) new)->back_chain = old;
+ asm volatile(" la 15,0(%0)\n"
+ " basr 14,%2\n"
+ " la 15,0(%1)\n"
+ : : "a" (new), "a" (old),
+ "a" (__do_softirq)
+ : "0", "1", "2", "3", "4", "5", "14",
+ "cc", "memory" );
+ } else {
+ /* We are already on the async stack. */
+ __do_softirq();
}
-
- local_irq_restore(flags);
}
/*
diff --git a/arch/sh/kernel/irq.c b/arch/sh/kernel/irq.c
index 063af10..0833736 100644
--- a/arch/sh/kernel/irq.c
+++ b/arch/sh/kernel/irq.c
@@ -149,47 +149,32 @@ void irq_ctx_exit(int cpu)
hardirq_ctx[cpu] = NULL;
}
-asmlinkage void do_softirq(void)
+void do_softirq_own_stack(void)
{
- unsigned long flags;
struct thread_info *curctx;
union irq_ctx *irqctx;
u32 *isp;
- if (in_interrupt())
- return;
-
- local_irq_save(flags);
-
- if (local_softirq_pending()) {
- curctx = current_thread_info();
- irqctx = softirq_ctx[smp_processor_id()];
- irqctx->tinfo.task = curctx->task;
- irqctx->tinfo.previous_sp = current_stack_pointer;
-
- /* build the stack frame on the softirq stack */
- isp = (u32 *)((char *)irqctx + sizeof(*irqctx));
-
- __asm__ __volatile__ (
- "mov r15, r9 \n"
- "jsr @%0 \n"
- /* switch to the softirq stack */
- " mov %1, r15 \n"
- /* restore the thread stack */
- "mov r9, r15 \n"
- : /* no outputs */
- : "r" (__do_softirq), "r" (isp)
- : "memory", "r0", "r1", "r2", "r3", "r4",
- "r5", "r6", "r7", "r8", "r9", "r15", "t", "pr"
- );
-
- /*
- * Shouldn't happen, we returned above if in_interrupt():
- */
- WARN_ON_ONCE(softirq_count());
- }
-
- local_irq_restore(flags);
+ curctx = current_thread_info();
+ irqctx = softirq_ctx[smp_processor_id()];
+ irqctx->tinfo.task = curctx->task;
+ irqctx->tinfo.previous_sp = current_stack_pointer;
+
+ /* build the stack frame on the softirq stack */
+ isp = (u32 *)((char *)irqctx + sizeof(*irqctx));
+
+ __asm__ __volatile__ (
+ "mov r15, r9 \n"
+ "jsr @%0 \n"
+ /* switch to the softirq stack */
+ " mov %1, r15 \n"
+ /* restore the thread stack */
+ "mov r9, r15 \n"
+ : /* no outputs */
+ : "r" (__do_softirq), "r" (isp)
+ : "memory", "r0", "r1", "r2", "r3", "r4",
+ "r5", "r6", "r7", "r8", "r9", "r15", "t", "pr"
+ );
}
#else
static inline void handle_one_irq(unsigned int irq)
diff --git a/arch/sparc/kernel/irq_64.c b/arch/sparc/kernel/irq_64.c
index d4840ce..666193f 100644
--- a/arch/sparc/kernel/irq_64.c
+++ b/arch/sparc/kernel/irq_64.c
@@ -698,30 +698,19 @@ void __irq_entry handler_irq(int pil, struct pt_regs *regs)
set_irq_regs(old_regs);
}
-void do_softirq(void)
+void do_softirq_own_stack(void)
{
- unsigned long flags;
-
- if (in_interrupt())
- return;
-
- local_irq_save(flags);
+ void *orig_sp, *sp = softirq_stack[smp_processor_id()];
- if (local_softirq_pending()) {
- void *orig_sp, *sp = softirq_stack[smp_processor_id()];
-
- sp += THREAD_SIZE - 192 - STACK_BIAS;
-
- __asm__ __volatile__("mov %%sp, %0\n\t"
- "mov %1, %%sp"
- : "=&r" (orig_sp)
- : "r" (sp));
- __do_softirq();
- __asm__ __volatile__("mov %0, %%sp"
- : : "r" (orig_sp));
- }
+ sp += THREAD_SIZE - 192 - STACK_BIAS;
- local_irq_restore(flags);
+ __asm__ __volatile__("mov %%sp, %0\n\t"
+ "mov %1, %%sp"
+ : "=&r" (orig_sp)
+ : "r" (sp));
+ __do_softirq();
+ __asm__ __volatile__("mov %0, %%sp"
+ : : "r" (orig_sp));
}
#ifdef CONFIG_HOTPLUG_CPU
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index ee2fb9d..99eb1cc 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -123,6 +123,7 @@ config X86
select COMPAT_OLD_SIGACTION if IA32_EMULATION
select RTC_LIB
select HAVE_DEBUG_STACKOVERFLOW
+ select HAVE_IRQ_EXIT_ON_IRQ_STACK if X86_64
config INSTRUCTION_DECODER
def_bool y
diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S
index b077f4c..083da7c 100644
--- a/arch/x86/kernel/entry_64.S
+++ b/arch/x86/kernel/entry_64.S
@@ -1342,7 +1342,7 @@ bad_gs:
.previous
/* Call softirq on interrupt stack. Interrupts are off. */
-ENTRY(call_softirq)
+ENTRY(do_softirq_own_stack)
CFI_STARTPROC
pushq_cfi %rbp
CFI_REL_OFFSET rbp,0
@@ -1359,7 +1359,7 @@ ENTRY(call_softirq)
decl PER_CPU_VAR(irq_count)
ret
CFI_ENDPROC
-END(call_softirq)
+END(do_softirq_own_stack)
#ifdef CONFIG_XEN
zeroentry xen_hypervisor_callback xen_do_hypervisor_callback
diff --git a/arch/x86/kernel/i8259.c b/arch/x86/kernel/i8259.c
index 9a5c460..2e977b5 100644
--- a/arch/x86/kernel/i8259.c
+++ b/arch/x86/kernel/i8259.c
@@ -312,8 +312,7 @@ static void init_8259A(int auto_eoi)
*/
outb_pic(0x11, PIC_MASTER_CMD); /* ICW1: select 8259A-1 init */
- /* ICW2: 8259A-1 IR0-7 mapped to 0x30-0x37 on x86-64,
- to 0x20-0x27 on i386 */
+ /* ICW2: 8259A-1 IR0-7 mapped to 0x30-0x37 */
outb_pic(IRQ0_VECTOR, PIC_MASTER_IMR);
/* 8259A-1 (the master) has a slave on IR2 */
diff --git a/arch/x86/kernel/irq_32.c b/arch/x86/kernel/irq_32.c
index 4186755..8a5bb01 100644
--- a/arch/x86/kernel/irq_32.c
+++ b/arch/x86/kernel/irq_32.c
@@ -149,35 +149,21 @@ void irq_ctx_init(int cpu)
cpu, per_cpu(hardirq_ctx, cpu), per_cpu(softirq_ctx, cpu));
}
-asmlinkage void do_softirq(void)
+void do_softirq_own_stack(void)
{
- unsigned long flags;
struct thread_info *curctx;
union irq_ctx *irqctx;
u32 *isp;
- if (in_interrupt())
- return;
-
- local_irq_save(flags);
-
- if (local_softirq_pending()) {
- curctx = current_thread_info();
- irqctx = __this_cpu_read(softirq_ctx);
- irqctx->tinfo.task = curctx->task;
- irqctx->tinfo.previous_esp = current_stack_pointer;
-
- /* build the stack frame on the softirq stack */
- isp = (u32 *) ((char *)irqctx + sizeof(*irqctx));
+ curctx = current_thread_info();
+ irqctx = __this_cpu_read(softirq_ctx);
+ irqctx->tinfo.task = curctx->task;
+ irqctx->tinfo.previous_esp = current_stack_pointer;
- call_on_stack(__do_softirq, isp);
- /*
- * Shouldn't happen, we returned above if in_interrupt():
- */
- WARN_ON_ONCE(softirq_count());
- }
+ /* build the stack frame on the softirq stack */
+ isp = (u32 *) ((char *)irqctx + sizeof(*irqctx));
- local_irq_restore(flags);
+ call_on_stack(__do_softirq, isp);
}
bool handle_irq(unsigned irq, struct pt_regs *regs)
diff --git a/arch/x86/kernel/irq_64.c b/arch/x86/kernel/irq_64.c
index d04d3ec..4d1c746 100644
--- a/arch/x86/kernel/irq_64.c
+++ b/arch/x86/kernel/irq_64.c
@@ -87,24 +87,3 @@ bool handle_irq(unsigned irq, struct pt_regs *regs)
generic_handle_irq_desc(irq, desc);
return true;
}
-
-
-extern void call_softirq(void);
-
-asmlinkage void do_softirq(void)
-{
- __u32 pending;
- unsigned long flags;
-
- if (in_interrupt())
- return;
-
- local_irq_save(flags);
- pending = local_softirq_pending();
- /* Switch to interrupt stack */
- if (pending) {
- call_softirq();
- WARN_ON_ONCE(softirq_count());
- }
- local_irq_restore(flags);
-}
diff --git a/drivers/irqchip/irq-bcm2835.c b/drivers/irqchip/irq-bcm2835.c
index 16c78f1..1693b8e 100644
--- a/drivers/irqchip/irq-bcm2835.c
+++ b/drivers/irqchip/irq-bcm2835.c
@@ -49,9 +49,11 @@
#include <linux/of_address.h>
#include <linux/of_irq.h>
#include <linux/irqdomain.h>
-#include <linux/irqchip/bcm2835.h>
#include <asm/exception.h>
+#include <asm/mach/irq.h>
+
+#include "irqchip.h"
/* Put the bank and irq (32 bits) into the hwirq */
#define MAKE_HWIRQ(b, n) ((b << 5) | (n))
@@ -93,6 +95,8 @@ struct armctrl_ic {
};
static struct armctrl_ic intc __read_mostly;
+static asmlinkage void __exception_irq_entry bcm2835_handle_irq(
+ struct pt_regs *regs);
static void armctrl_mask_irq(struct irq_data *d)
{
@@ -164,17 +168,9 @@ static int __init armctrl_of_init(struct device_node *node,
set_irq_flags(irq, IRQF_VALID | IRQF_PROBE);
}
}
- return 0;
-}
-
-static struct of_device_id irq_of_match[] __initconst = {
- { .compatible = "brcm,bcm2835-armctrl-ic", .data = armctrl_of_init },
- { }
-};
-void __init bcm2835_init_irq(void)
-{
- of_irq_init(irq_of_match);
+ set_handle_irq(bcm2835_handle_irq);
+ return 0;
}
/*
@@ -200,7 +196,7 @@ static void armctrl_handle_shortcut(int bank, struct pt_regs *regs,
handle_IRQ(irq_linear_revmap(intc.domain, irq), regs);
}
-asmlinkage void __exception_irq_entry bcm2835_handle_irq(
+static asmlinkage void __exception_irq_entry bcm2835_handle_irq(
struct pt_regs *regs)
{
u32 stat, irq;
@@ -222,3 +218,5 @@ asmlinkage void __exception_irq_entry bcm2835_handle_irq(
}
}
}
+
+IRQCHIP_DECLARE(bcm2835_armctrl_ic, "brcm,bcm2835-armctrl-ic", armctrl_of_init);
diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h
index 5e865b5..c9e831d 100644
--- a/include/linux/interrupt.h
+++ b/include/linux/interrupt.h
@@ -19,6 +19,7 @@
#include <linux/atomic.h>
#include <asm/ptrace.h>
+#include <asm/irq.h>
/*
* These correspond to the IORESOURCE_IRQ_* defines in
@@ -374,6 +375,16 @@ struct softirq_action
asmlinkage void do_softirq(void);
asmlinkage void __do_softirq(void);
+
+#ifdef __ARCH_HAS_DO_SOFTIRQ
+void do_softirq_own_stack(void);
+#else
+static inline void do_softirq_own_stack(void)
+{
+ __do_softirq();
+}
+#endif
+
extern void open_softirq(int nr, void (*action)(struct softirq_action *));
extern void softirq_init(void);
extern void __raise_softirq_irqoff(unsigned int nr);
diff --git a/include/linux/irqchip/bcm2835.h b/include/linux/irqchip/bcm2835.h
deleted file mode 100644
index 48a859b..0000000
--- a/include/linux/irqchip/bcm2835.h
+++ /dev/null
@@ -1,29 +0,0 @@
-/*
- * Copyright (C) 2010 Broadcom
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
- */
-
-#ifndef __LINUX_IRQCHIP_BCM2835_H_
-#define __LINUX_IRQCHIP_BCM2835_H_
-
-#include <asm/exception.h>
-
-extern void bcm2835_init_irq(void);
-
-extern asmlinkage void __exception_irq_entry bcm2835_handle_irq(
- struct pt_regs *regs);
-
-#endif
diff --git a/kernel/softirq.c b/kernel/softirq.c
index d7d498d..dacd0ab 100644
--- a/kernel/softirq.c
+++ b/kernel/softirq.c
@@ -29,7 +29,6 @@
#define CREATE_TRACE_POINTS
#include <trace/events/irq.h>
-#include <asm/irq.h>
/*
- No shared variables, all the data are CPU local.
- If a softirq needs serialization, let it serialize itself
@@ -134,7 +133,6 @@ EXPORT_SYMBOL(local_bh_disable);
static void __local_bh_enable(unsigned int cnt)
{
- WARN_ON_ONCE(in_irq());
WARN_ON_ONCE(!irqs_disabled());
if (softirq_count() == cnt)
@@ -149,6 +147,7 @@ static void __local_bh_enable(unsigned int cnt)
*/
void _local_bh_enable(void)
{
+ WARN_ON_ONCE(in_irq());
__local_bh_enable(SOFTIRQ_DISABLE_OFFSET);
}
@@ -171,8 +170,13 @@ static inline void _local_bh_enable_ip(unsigned long ip)
*/
sub_preempt_count(SOFTIRQ_DISABLE_OFFSET - 1);
- if (unlikely(!in_interrupt() && local_softirq_pending()))
+ if (unlikely(!in_interrupt() && local_softirq_pending())) {
+ /*
+ * Run softirq if any pending. And do it in its own stack
+ * as we may be calling this deep in a task call stack already.
+ */
do_softirq();
+ }
dec_preempt_count();
#ifdef CONFIG_TRACE_IRQFLAGS
@@ -280,10 +284,11 @@ restart:
account_irq_exit_time(current);
__local_bh_enable(SOFTIRQ_OFFSET);
+ WARN_ON_ONCE(in_interrupt());
tsk_restore_flags(current, old_flags, PF_MEMALLOC);
}
-#ifndef __ARCH_HAS_DO_SOFTIRQ
+
asmlinkage void do_softirq(void)
{
@@ -298,13 +303,11 @@ asmlinkage void do_softirq(void)
pending = local_softirq_pending();
if (pending)
- __do_softirq();
+ do_softirq_own_stack();
local_irq_restore(flags);
}
-#endif
-
/*
* Enter an interrupt context.
*/
@@ -329,15 +332,21 @@ void irq_enter(void)
static inline void invoke_softirq(void)
{
if (!force_irqthreads) {
+#ifdef CONFIG_HAVE_IRQ_EXIT_ON_IRQ_STACK
/*
* We can safely execute softirq on the current stack if
* it is the irq stack, because it should be near empty
- * at this stage. But we have no way to know if the arch
- * calls irq_exit() on the irq stack. So call softirq
- * in its own stack to prevent from any overrun on top
- * of a potentially deep task stack.
+ * at this stage.
*/
- do_softirq();
+ __do_softirq();
+#else
+ /*
+ * Otherwise, irq_exit() is called on the task stack that can
+ * be potentially deep already. So call softirq in its own stack
+ * to prevent from any overrun.
+ */
+ do_softirq_own_stack();
+#endif
} else {
wakeup_softirqd();
}
@@ -771,6 +780,10 @@ static void run_ksoftirqd(unsigned int cpu)
{
local_irq_disable();
if (local_softirq_pending()) {
+ /*
+ * We can safely run softirq on inline stack, as we are not deep
+ * in the task stack here.
+ */
__do_softirq();
rcu_note_context_switch(cpu);
local_irq_enable();
--
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