| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-ID: <4B424305.7050803@kernel.org>
Date: Mon, 04 Jan 2010 11:35:33 -0800
From: Yinghai Lu <yinghai@...nel.org>
To: "Eric W. Biederman" <ebiederm@...ssion.com>
CC: "H. Peter Anvin" <hpa@...or.com>,
Jesse Brandeburg <jesse.brandeburg@...il.com>,
Ingo Molnar <mingo@...e.hu>,
Thomas Gleixner <tglx@...utronix.de>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
Andrew Morton <akpm@...ux-foundation.org>,
NetDEV list <netdev@...r.kernel.org>,
Jesse Brandeburg <jesse.brandeburg@...el.com>
Subject: Re: Subject: [PATCH 1/2] x86: get back 15 vectors
On 01/04/2010 11:09 AM, Eric W. Biederman wrote:
> "H. Peter Anvin" <hpa@...or.com> writes:
>
>> On 01/04/2010 08:18 AM, Eric W. Biederman wrote:
>>> Yinghai Lu <yinghai@...nel.org> writes:
>>>
>>> This patch is wrong.
>>>
>>>> between FIRST_EXTERNAL_VECTOR (0x20) and FIRST_DEVICE_VECTOR (0x41)
>>>>
>>>> for 0x20 and 0x2f, we are safe be used_vectors will prevent it to use used one.
>>>
>>> We can not use any of 0x20 - 0x2f for ioapic irqs. We need the entire
>>> priority level to ensure that the irq move cleanup ipi is of a lower
>>> priority.
>>>
>>
>> Almost makes one want to abuse 0x1f for that. Although 0x00..0x1f are
>> reserved for exceptions, the APICs range down to 0x10, and well, when
>> 0x1f ends up actually getting used as an exception vector that we
>> support, then we can trivially change that. In the meantime it would
>> actually make use of an otherwise-unusable APIC priority level.
>
> An optimization like that (with a big fat comment) seems reasonable
> to me.
so we can use [0x10, 0x1f]
sth like this?
Subject: [PATCH 1/2] x86: get back 16 vectors
-v2: according to hpa that we could start from 0x10
according to Eric, we should hold 16 vectors for IRQ MOVE
Signed-off-by: Yinghai Lu <yinghai@...nel.org>
---
arch/x86/include/asm/irq_vectors.h | 3 ++-
arch/x86/kernel/apic/io_apic.c | 5 +++--
arch/x86/kernel/irqinit.c | 11 +++++++++--
3 files changed, 14 insertions(+), 5 deletions(-)
Index: linux-2.6/arch/x86/kernel/apic/io_apic.c
===================================================================
--- linux-2.6.orig/arch/x86/kernel/apic/io_apic.c
+++ linux-2.6/arch/x86/kernel/apic/io_apic.c
@@ -1162,7 +1162,8 @@ __assign_irq_vector(int irq, struct irq_
* Also, we've got to be careful not to trash gate
* 0x80, because int 0x80 is hm, kind of importantish. ;)
*/
- static int current_vector = FIRST_DEVICE_VECTOR, current_offset = 0;
+ static int current_vector = 0;
+ static int current_offset = 0;
unsigned int old_vector;
int cpu, err;
cpumask_var_t tmp_mask;
@@ -1198,7 +1199,7 @@ next:
if (vector >= first_system_vector) {
/* If out of vectors on large boxen, must share them. */
offset = (offset + 1) % 8;
- vector = FIRST_DEVICE_VECTOR + offset;
+ vector = 0 + offset;
}
if (unlikely(current_vector == vector))
continue;
Index: linux-2.6/arch/x86/include/asm/irq_vectors.h
===================================================================
--- linux-2.6.orig/arch/x86/include/asm/irq_vectors.h
+++ linux-2.6/arch/x86/include/asm/irq_vectors.h
@@ -30,8 +30,9 @@
/*
* IDT vectors usable for external interrupt sources start
* at 0x20:
+ * hpa said we can start from 0x10
*/
-#define FIRST_EXTERNAL_VECTOR 0x20
+#define FIRST_EXTERNAL_VECTOR 0x10
#ifdef CONFIG_X86_32
# define SYSCALL_VECTOR 0x80
Index: linux-2.6/arch/x86/kernel/irqinit.c
===================================================================
--- linux-2.6.orig/arch/x86/kernel/irqinit.c
+++ linux-2.6/arch/x86/kernel/irqinit.c
@@ -149,6 +149,8 @@ static void __init smp_intr_init(void)
{
#ifdef CONFIG_SMP
#if defined(CONFIG_X86_64) || defined(CONFIG_X86_LOCAL_APIC)
+ int i;
+
/*
* The reschedule interrupt is a CPU-to-CPU reschedule-helper
* IPI, driven by wakeup.
@@ -174,7 +176,9 @@ 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);
+ /* Eric said: Need to hold entire priority */
+ for (i = IRQ_MOVE_CLEANUP_VECTOR; i < IRQ_MOVE_CLEANUP_VECTOR+0x10; i++)
+ set_bit(i, used_vectors);
/* IPI used for rebooting/stopping */
alloc_intr_gate(REBOOT_VECTOR, reboot_interrupt);
@@ -222,6 +226,9 @@ void __init native_init_IRQ(void)
/* Execute any quirks before the call gates are initialised: */
x86_init.irqs.pre_vector_init();
+ for (i = 0; i < 0x10; i++)
+ set_bit(i, used_vectors);
+
apic_intr_init();
/*
@@ -229,7 +236,7 @@ void __init native_init_IRQ(void)
* us. (some of these will be overridden and become
* 'special' SMP interrupts)
*/
- for (i = FIRST_EXTERNAL_VECTOR; i < NR_VECTORS; i++) {
+ for (i = 0; i < NR_VECTORS; i++) {
/* IA32_SYSCALL_VECTOR could be used in trap_init already. */
if (!test_bit(i, used_vectors))
set_intr_gate(i, interrupt[i-FIRST_EXTERNAL_VECTOR]);
--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Powered by blists - more mailing lists