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Message-ID: <20080919200800.GD6528@sgi.com>
Date: Fri, 19 Sep 2008 15:08:00 -0500
From: Dean Nelson <dcn@....com>
To: Ingo Molnar <mingo@...e.hu>
Cc: "Eric W. Biederman" <ebiederm@...ssion.com>,
"H. Peter Anvin" <hpa@...or.com>, Jack Steiner <steiner@....com>,
Alan Mayer <ajm@....com>, jeremy@...p.org,
rusty@...tcorp.com.au, suresh.b.siddha@...el.com,
torvalds@...ux-foundation.org, linux-kernel@...r.kernel.org,
Thomas Gleixner <tglx@...utronix.de>,
Yinghai Lu <Yinghai.lu@....com>
Subject: [PATCH 3/3] switch non-standard SYSCALL_VECTOR allocation to use vector_irq v2
Replace the current use of used_vectors[] for the allocation of a non-standard
SYSCALL_VECTOR by also using the per_cpu variable vector_irq[].
Signed-off-by: Dean Nelson <dcn@....com>
---
arch/x86/kernel/traps_32.c | 16 ++++++++++------
drivers/lguest/interrupts_and_traps.c | 28 ++++++++++++++++++++++------
include/asm-x86/irq.h | 3 ---
3 files changed, 32 insertions(+), 15 deletions(-)
Index: linux/arch/x86/kernel/traps_32.c
===================================================================
--- linux.orig/arch/x86/kernel/traps_32.c 2008-09-19 11:01:10.000000000 -0500
+++ linux/arch/x86/kernel/traps_32.c 2008-09-19 12:35:32.000000000 -0500
@@ -63,9 +63,6 @@
#include "mach_traps.h"
-DECLARE_BITMAP(used_vectors, NR_VECTORS);
-EXPORT_SYMBOL_GPL(used_vectors);
-
asmlinkage int system_call(void);
/* Do we ignore FPU interrupts ? */
@@ -1185,6 +1182,8 @@ asmlinkage void math_emulate(long arg)
void __init trap_init(void)
{
int i;
+ int ret;
+ unsigned long flags;
#ifdef CONFIG_EISA
void __iomem *p = early_ioremap(0x0FFFD9, 4);
@@ -1232,10 +1231,15 @@ void __init trap_init(void)
set_system_gate(SYSCALL_VECTOR, &system_call);
/* Reserve all the builtin and the syscall vector: */
- for (i = 0; i < FIRST_EXTERNAL_VECTOR; i++)
- set_bit(i, used_vectors);
+ spin_lock_irqsave(&vector_lock, flags);
+ for (i = 0; i < FIRST_EXTERNAL_VECTOR; i++) {
+ ret = grab_irq_vector(NON_IRQ_DESC, i, &cpu_possible_map);
+ BUG_ON(ret != i);
+ }
- set_bit(SYSCALL_VECTOR, used_vectors);
+ ret = grab_irq_vector(NON_IRQ_DESC, SYSCALL_VECTOR, &cpu_possible_map);
+ BUG_ON(ret != SYSCALL_VECTOR);
+ spin_unlock_irqrestore(&vector_lock, flags);
/*
* Should be a barrier for any external CPU state:
Index: linux/include/asm-x86/irq.h
===================================================================
--- linux.orig/include/asm-x86/irq.h 2008-09-19 11:09:32.000000000 -0500
+++ linux/include/asm-x86/irq.h 2008-09-19 12:35:32.000000000 -0500
@@ -44,9 +44,6 @@ extern unsigned int do_IRQ(struct pt_reg
extern void init_IRQ(void);
extern void native_init_IRQ(void);
-/* Interrupt vector management */
-extern DECLARE_BITMAP(used_vectors, NR_VECTORS);
-
struct irq_desc;
extern int grab_irq_vector(struct irq_desc *desc, unsigned int vector,
cpumask_t *new_domain_mask);
Index: linux/drivers/lguest/interrupts_and_traps.c
===================================================================
--- linux.orig/drivers/lguest/interrupts_and_traps.c 2008-09-19 11:01:10.000000000 -0500
+++ linux/drivers/lguest/interrupts_and_traps.c 2008-09-19 12:41:02.000000000 -0500
@@ -221,19 +221,35 @@ bool check_syscall_vector(struct lguest
int init_interrupts(void)
{
+ unsigned long flags;
+ int ret;
+
/* If they want some strange system call vector, reserve it now */
- if (syscall_vector != SYSCALL_VECTOR
- && test_and_set_bit(syscall_vector, used_vectors)) {
- printk("lg: couldn't reserve syscall %u\n", syscall_vector);
- return -EBUSY;
+ if (syscall_vector != SYSCALL_VECTOR) {
+ spin_lock_irqsave(&vector_lock, flags);
+ ret = grab_irq_vector(NON_IRQ_DESC, syscall_vector,
+ &cpu_possible_map);
+ spin_unlock_irqrestore(&vector_lock, flags);
+ if (ret != syscall_vector) {
+ printk(KERN_WARNING "lg: couldn't reserve syscall %u\n",
+ syscall_vector);
+ return ret;
+ }
}
return 0;
}
void free_interrupts(void)
{
- if (syscall_vector != SYSCALL_VECTOR)
- clear_bit(syscall_vector, used_vectors);
+ int cpu;
+
+ if (syscall_vector != SYSCALL_VECTOR) {
+ for_each_possible_cpu(cpu) {
+ BUG_ON(per_cpu(vector_irq, cpu)[syscall_vector] !=
+ NON_IRQ_DESC);
+ per_cpu(vector_irq, cpu)[syscall_vector] = NULL;
+ }
+ }
}
/*H:220 Now we've got the routines to deliver interrupts, delivering traps like
--
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