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Subject[PATCH 25/32] x86: Exception hooks for nohz cpusets
Date
Add necessary hooks to x86 exception for nohz cpusets
support. It includes traps, page fault, debug exceptions,
etc...

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Alessio Igor Bogani <abogani@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Avi Kivity <avi@redhat.com>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: Geoff Levand <geoff@infradead.org>
Cc: Gilad Ben Yossef <gilad@benyossef.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Max Krasnyansky <maxk@qualcomm.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephen Hemminger <shemminger@vyatta.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Sven-Thorsten Dietrich <thebigcorporation@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Zen Lin <zen@openhuawei.org>
---
arch/x86/Kconfig | 1 +
arch/x86/kernel/traps.c | 20 ++++++++++++++------
arch/x86/mm/fault.c | 13 +++++++++++--
3 files changed, 26 insertions(+), 8 deletions(-)
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 5bed94e..0d3116c 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -82,6 +82,7 @@ config X86
select CLKEVT_I8253
select ARCH_HAVE_NMI_SAFE_CMPXCHG
select GENERIC_IOMAP
+ select HAVE_CPUSETS_NO_HZ

config INSTRUCTION_DECODER
def_bool (KPROBES || PERF_EVENTS)
diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
index 4bbe04d..977d0b9 100644
--- a/arch/x86/kernel/traps.c
+++ b/arch/x86/kernel/traps.c
@@ -26,6 +26,7 @@
#include <linux/sched.h>
#include <linux/timer.h>
#include <linux/init.h>
+#include <linux/tick.h>
#include <linux/bug.h>
#include <linux/nmi.h>
#include <linux/mm.h>
@@ -301,15 +302,17 @@ gp_in_kernel:
/* May run on IST stack. */
dotraplinkage void __kprobes do_int3(struct pt_regs *regs, long error_code)
{
+ tick_nohz_enter_exception(regs);
+
#ifdef CONFIG_KGDB_LOW_LEVEL_TRAP
if (kgdb_ll_trap(DIE_INT3, "int3", regs, error_code, 3, SIGTRAP)
== NOTIFY_STOP)
- return;
+ goto exit;
#endif /* CONFIG_KGDB_LOW_LEVEL_TRAP */

if (notify_die(DIE_INT3, "int3", regs, error_code, 3, SIGTRAP)
== NOTIFY_STOP)
- return;
+ goto exit;

/*
* Let others (NMI) know that the debug stack is in use
@@ -320,6 +323,8 @@ dotraplinkage void __kprobes do_int3(struct pt_regs *regs, long error_code)
do_trap(3, SIGTRAP, "int3", regs, error_code, NULL);
preempt_conditional_cli(regs);
debug_stack_usage_dec();
+exit:
+ tick_nohz_exit_exception(regs);
}

#ifdef CONFIG_X86_64
@@ -380,6 +385,8 @@ dotraplinkage void __kprobes do_debug(struct pt_regs *regs, long error_code)
unsigned long dr6;
int si_code;

+ tick_nohz_enter_exception(regs);
+
get_debugreg(dr6, 6);

/* Filter out all the reserved bits which are preset to 1 */
@@ -395,7 +402,7 @@ dotraplinkage void __kprobes do_debug(struct pt_regs *regs, long error_code)

/* Catch kmemcheck conditions first of all! */
if ((dr6 & DR_STEP) && kmemcheck_trap(regs))
- return;
+ goto exit;

/* DR6 may or may not be cleared by the CPU */
set_debugreg(0, 6);
@@ -410,7 +417,7 @@ dotraplinkage void __kprobes do_debug(struct pt_regs *regs, long error_code)

if (notify_die(DIE_DEBUG, "debug", regs, PTR_ERR(&dr6), error_code,
SIGTRAP) == NOTIFY_STOP)
- return;
+ goto exit;

/*
* Let others (NMI) know that the debug stack is in use
@@ -426,7 +433,7 @@ dotraplinkage void __kprobes do_debug(struct pt_regs *regs, long error_code)
error_code, 1);
preempt_conditional_cli(regs);
debug_stack_usage_dec();
- return;
+ goto exit;
}

/*
@@ -447,7 +454,8 @@ dotraplinkage void __kprobes do_debug(struct pt_regs *regs, long error_code)
preempt_conditional_cli(regs);
debug_stack_usage_dec();

- return;
+exit:
+ tick_nohz_exit_exception(regs);
}

/*
diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
index f0b4caf..6c4c983 100644
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -13,6 +13,7 @@
#include <linux/perf_event.h> /* perf_sw_event */
#include <linux/hugetlb.h> /* hstate_index_to_shift */
#include <linux/prefetch.h> /* prefetchw */
+#include <linux/tick.h>

#include <asm/traps.h> /* dotraplinkage, ... */
#include <asm/pgalloc.h> /* pgd_*(), ... */
@@ -1000,8 +1001,8 @@ static int fault_in_kernel_space(unsigned long address)
* and the problem, and then passes it off to one of the appropriate
* routines.
*/
-dotraplinkage void __kprobes
-do_page_fault(struct pt_regs *regs, unsigned long error_code)
+static void __kprobes
+__do_page_fault(struct pt_regs *regs, unsigned long error_code)
{
struct vm_area_struct *vma;
struct task_struct *tsk;
@@ -1209,3 +1210,11 @@ good_area:

up_read(&mm->mmap_sem);
}
+
+dotraplinkage void __kprobes
+do_page_fault(struct pt_regs *regs, unsigned long error_code)
+{
+ tick_nohz_enter_exception(regs);
+ __do_page_fault(regs, error_code);
+ tick_nohz_exit_exception(regs);
+}
--
1.7.5.4


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