[PATCH] x86: fix lguest used_vectors breakage

Ingo Molnar
2008-12-19T22:25:00Z

* Yinghai Lu <yinghai@kernel.org> wrote:

> Impact: fix and clean up

i tidied the changelog up - see it attached further below. Also Cc:-ed
Rusty as the motivation is to fix and standardize lguest's irq vector
allocation method.

One small detail, we'll need a -v2:

In file included from
/home/mingo/linux/linux/arch/x86/include/asm/elf.h:90,
from include/linux/elf.h:8,
from include/linux/module.h:15,
from include/linux/crypto.h:22,
from arch/x86/kernel/asm-offsets_32.c:8,
from arch/x86/kernel/asm-offsets.c:3:
/home/mingo/linux/linux/arch/x86/include/asm/desc.h:324: error: 'NR_VECTORS' undeclared here (not in a function)

config attached. Please pick up the changelog (and subject line) below
when you iterate the patch. Thanks,

Ingo

------------------>
>From 712403e560af439a61924cd18c8cd465aa2405bf Mon Sep 17 00:00:00 2001
From: Yinghai Lu <yinghai@kernel.org>
Date: Fri, 19 Dec 2008 03:37:52 -0800
Subject: [PATCH] x86: fix lguest used_vectors breakage

Impact: fix lguest, clean up

32-bit lguest used used_vectors to record vectors, but that model of
allocating vectors changed and got broken, after we changed vector
allocation to a per_cpu array.

Try enable that for 64bit, and the array is used for all vectors that
are not managed by vector_irq per_cpu array.

Also kill system_vectors[], that is now a duplication of the
used_vectors bitmap.

[ merged in cpus4096 due to io_apic.c cpumask changes. ]

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
arch/x86/include/asm/desc.h | 9 +++------
arch/x86/include/asm/irq.h | 1 +
arch/x86/kernel/apic.c | 2 --
arch/x86/kernel/io_apic.c | 9 +++------
arch/x86/kernel/irqinit_32.c | 16 +++++++++++++++-
arch/x86/kernel/irqinit_64.c | 13 +++++++++++++
arch/x86/kernel/traps.c | 12 +++++++-----
drivers/lguest/interrupts_and_traps.c | 13 +++++++++----
8 files changed, 51 insertions(+), 24 deletions(-)

diff --git a/arch/x86/include/asm/desc.h b/arch/x86/include/asm/desc.h
index e6b82b1..90c5eb2 100644
--- a/arch/x86/include/asm/desc.h
+++ b/arch/x86/include/asm/desc.h
@@ -320,16 +320,13 @@ static inline void set_intr_gate(unsigned int n, void *addr)
_set_gate(n, GATE_INTERRUPT, addr, 0, 0, __KERNEL_CS);
}

-#define SYS_VECTOR_FREE 0
-#define SYS_VECTOR_ALLOCED 1
-
extern int first_system_vector;
-extern char system_vectors[];
+extern DECLARE_BITMAP(used_vectors, NR_VECTORS);

static inline void alloc_system_vector(int vector)
{
- if (system_vectors[vector] == SYS_VECTOR_FREE) {
- system_vectors[vector] = SYS_VECTOR_ALLOCED;
+ if (!test_bit(vector, used_vectors)) {
+ set_bit(vector, used_vectors);
if (first_system_vector > vector)
first_system_vector = vector;
} else
diff --git a/arch/x86/include/asm/irq.h b/arch/x86/include/asm/irq.h
index 8766d30..4bb732e 100644
--- a/arch/x86/include/asm/irq.h
+++ b/arch/x86/include/asm/irq.h
@@ -46,5 +46,6 @@ extern void native_init_IRQ(void);

/* Interrupt vector management */
extern DECLARE_BITMAP(used_vectors, NR_VECTORS);
+extern int vector_used_by_percpu_irq(unsigned int vector);

#endif /* _ASM_X86_IRQ_H */
diff --git a/arch/x86/kernel/apic.c b/arch/x86/kernel/apic.c
index f7a32a3..b901927 100644
--- a/arch/x86/kernel/apic.c
+++ b/arch/x86/kernel/apic.c
@@ -118,8 +118,6 @@ EXPORT_SYMBOL_GPL(local_apic_timer_c2_ok);

int first_system_vector = 0xfe;

-char system_vectors[NR_VECTORS] = { [0 ... NR_VECTORS-1] = SYS_VECTOR_FREE};
-
/*
* Debug level, exported for io_apic.c
*/
diff --git a/arch/x86/kernel/io_apic.c b/arch/x86/kernel/io_apic.c
index 908c1d0..1cbf7c8 100644
--- a/arch/x86/kernel/io_apic.c
+++ b/arch/x86/kernel/io_apic.c
@@ -1326,13 +1326,10 @@ next:
}
if (unlikely(current_vector == vector))
continue;
-#ifdef CONFIG_X86_64
- if (vector == IA32_SYSCALL_VECTOR)
- goto next;
-#else
- if (vector == SYSCALL_VECTOR)
+
+ if (test_bit(vector, used_vectors))
goto next;
-#endif
+
for_each_cpu_and(new_cpu, tmp_mask, cpu_online_mask)
if (per_cpu(vector_irq, new_cpu)[vector] != -1)
goto next;
diff --git a/arch/x86/kernel/irqinit_32.c b/arch/x86/kernel/irqinit_32.c
index 6a92f47..61aa2a1 100644
--- a/arch/x86/kernel/irqinit_32.c
+++ b/arch/x86/kernel/irqinit_32.c
@@ -110,6 +110,18 @@ DEFINE_PER_CPU(vector_irq_t, vector_irq) = {
[IRQ15_VECTOR + 1 ... NR_VECTORS - 1] = -1
};

+int vector_used_by_percpu_irq(unsigned int vector)
+{
+ int cpu;
+
+ for_each_online_cpu(cpu) {
+ if (per_cpu(vector_irq, cpu)[vector] != -1)
+ return 1;
+ }
+
+ return 0;
+}
+
/* Overridden in paravirt.c */
void init_IRQ(void) __attribute__((weak, alias("native_init_IRQ")));

@@ -146,10 +158,12 @@ void __init native_init_IRQ(void)
alloc_intr_gate(CALL_FUNCTION_VECTOR, call_function_interrupt);

/* IPI for single call function */
- set_intr_gate(CALL_FUNCTION_SINGLE_VECTOR, call_function_single_interrupt);
+ alloc_intr_gate(CALL_FUNCTION_SINGLE_VECTOR,
+ call_function_single_interrupt);

/* Low priority IPI to cleanup after moving an irq */
set_intr_gate(IRQ_MOVE_CLEANUP_VECTOR, irq_move_cleanup_interrupt);
+ set_bit(IRQ_MOVE_CLEANUP_VECTOR, used_vectors);
#endif

#ifdef CONFIG_X86_LOCAL_APIC
diff --git a/arch/x86/kernel/irqinit_64.c b/arch/x86/kernel/irqinit_64.c
index 40c1e62..1020919 100644
--- a/arch/x86/kernel/irqinit_64.c
+++ b/arch/x86/kernel/irqinit_64.c
@@ -135,6 +135,18 @@ DEFINE_PER_CPU(vector_irq_t, vector_irq) = {
[IRQ15_VECTOR + 1 ... NR_VECTORS - 1] = -1
};

+int vector_used_by_percpu_irq(unsigned int vector)
+{
+ int cpu;
+
+ for_each_online_cpu(cpu) {
+ if (per_cpu(vector_irq, cpu)[vector] != -1)
+ return 1;
+ }
+
+ return 0;
+}
+
void __init init_ISA_irqs(void)
{
int i;
@@ -187,6 +199,7 @@ static void __init smp_intr_init(void)

/* Low priority IPI to cleanup after moving an irq */
set_intr_gate(IRQ_MOVE_CLEANUP_VECTOR, irq_move_cleanup_interrupt);
+ set_bit(IRQ_MOVE_CLEANUP_VECTOR, used_vectors);
#endif
}

diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
index 04d242a..4a6dff3 100644
--- a/arch/x86/kernel/traps.c
+++ b/arch/x86/kernel/traps.c
@@ -72,9 +72,6 @@

#include "cpu/mcheck/mce.h"

-DECLARE_BITMAP(used_vectors, NR_VECTORS);
-EXPORT_SYMBOL_GPL(used_vectors);
-
asmlinkage int system_call(void);

/* Do we ignore FPU interrupts ? */
@@ -89,6 +86,9 @@ gate_desc idt_table[256]
__attribute__((__section__(".data.idt"))) = { { { { 0, 0 } } }, };
#endif

+DECLARE_BITMAP(used_vectors, NR_VECTORS);
+EXPORT_SYMBOL_GPL(used_vectors);
+
static int ignore_nmis;

static inline void conditional_sti(struct pt_regs *regs)
@@ -949,9 +949,7 @@ dotraplinkage void do_iret_error(struct pt_regs *regs, long error_code)

void __init trap_init(void)
{
-#ifdef CONFIG_X86_32
int i;
-#endif

#ifdef CONFIG_EISA
void __iomem *p = early_ioremap(0x0FFFD9, 4);
@@ -1008,11 +1006,15 @@ void __init trap_init(void)
}

set_system_trap_gate(SYSCALL_VECTOR, &system_call);
+#endif

/* Reserve all the builtin and the syscall vector: */
for (i = 0; i < FIRST_EXTERNAL_VECTOR; i++)
set_bit(i, used_vectors);

+#ifdef CONFIG_X86_64
+ set_bit(IA32_SYSCALL_VECTOR, used_vectors);
+#else
set_bit(SYSCALL_VECTOR, used_vectors);
#endif
/*
diff --git a/drivers/lguest/interrupts_and_traps.c b/drivers/lguest/interrupts_and_traps.c
index a103906..415fab0 100644
--- a/drivers/lguest/interrupts_and_traps.c
+++ b/drivers/lguest/interrupts_and_traps.c
@@ -222,11 +222,16 @@ bool check_syscall_vector(struct lguest *lg)
int init_interrupts(void)
{
/* 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) {
+ if (test_bit(syscall_vector, used_vectors) ||
+ vector_used_by_percpu_irq(syscall_vector)) {
+ printk(KERN_ERR "lg: couldn't reserve syscall %u\n",
+ syscall_vector);
+ return -EBUSY;
+ }
+ set_bit(syscall_vector, used_vectors);
}
+
return 0;
}