2007-12-30 03:48:51

by Yinghai Lu

[permalink] [raw]
Subject: [PATCH] x86_64: clear IO_APIC before enabing apic error vector. v2

please check if you can replace the one in the x86-mm

http://git.kernel.org/?p=linux/kernel/git/x86/linux-2.6-x86.git;a=commitdiff;h=ffcbdc220a1520d006a837f33589c7c19ffbeb76

the updated one avoid one link warning.

YH

[PATCH] x86_64: clear IO_APIC before enabing apic error vector. v2

some apic id lifting system: 4 socket quad core, 8 socket quad core will do apic id lifting for BSP.

but io-apic regs for ExtINT still use 0 as dest.

so when we enable apic error vector in BSP, we will get one APIC error.

CPU: L1 I Cache: 64K (64 bytes/line), D cache 64K (64 bytes/line)
CPU: L2 Cache: 512K (64 bytes/line)
CPU 0/4 -> Node 0
CPU: Physical Processor ID: 1
CPU: Processor Core ID: 0
SMP alternatives: switching to UP code
ACPI: Core revision 20070126
enabled ExtINT on CPU#0
ESR value after enabling vector: 00000000, after 0000000c
APIC error on CPU0: 0c(08)
ENABLING IO-APIC IRQs
Synchronizing Arb IDs.

So move enable_IO_APIC from setup_IO_APIC into setup_local_APIC and call it
before enabling apic error vector.

this is the updated verison that take enable_IO_APIC as extra call for
setup_local_APIC to avoid linking warning.

Signed-off-by: Yinghai Lu <[email protected]>

Index: linux-2.6/arch/x86/kernel/apic_64.c
===================================================================
--- linux-2.6.orig/arch/x86/kernel/apic_64.c
+++ linux-2.6/arch/x86/kernel/apic_64.c
@@ -418,7 +418,7 @@ void __init init_bsp_APIC(void)
apic_write(APIC_LVT1, value);
}

-void __cpuinit setup_local_APIC (void)
+void __cpuinit setup_local_APIC (void (*extra_call)(void))
{
unsigned int value, maxlvt;
int i, j;
@@ -517,6 +517,13 @@ void __cpuinit setup_local_APIC (void)
value = APIC_DM_NMI | APIC_LVT_MASKED;
apic_write(APIC_LVT1, value);

+ /*
+ * Now enable IO-APICs, actually call clear_IO_APIC
+ * We need clear_IO_APIC before enabling vector on BP
+ */
+ if (extra_call)
+ (*extra_call)();
+
{
unsigned oldvalue;
maxlvt = get_maxlvt();
@@ -1198,6 +1205,8 @@ int disable_apic;
*/
int __init APIC_init_uniprocessor (void)
{
+ void (*extra_call)(void) = NULL;
+
if (disable_apic) {
printk(KERN_INFO "Apic disabled\n");
return -1;
@@ -1213,7 +1222,10 @@ int __init APIC_init_uniprocessor (void)
phys_cpu_present_map = physid_mask_of_physid(boot_cpu_id);
apic_write(APIC_ID, SET_APIC_ID(boot_cpu_id));

- setup_local_APIC();
+ if (!skip_ioapic_setup && nr_ioapics)
+ extra_call = enable_IO_APIC;
+
+ setup_local_APIC(extra_call);

if (smp_found_config && !skip_ioapic_setup && nr_ioapics)
setup_IO_APIC();
Index: linux-2.6/arch/x86/kernel/io_apic_64.c
===================================================================
--- linux-2.6.orig/arch/x86/kernel/io_apic_64.c
+++ linux-2.6/arch/x86/kernel/io_apic_64.c
@@ -1171,7 +1171,7 @@ void __apicdebuginit print_PIC(void)

#endif /* 0 */

-static void __init enable_IO_APIC(void)
+void __init enable_IO_APIC(void)
{
union IO_APIC_reg_01 reg_01;
int i8259_apic, i8259_pin;
@@ -1790,7 +1790,10 @@ __setup("no_timer_check", notimercheck);

void __init setup_IO_APIC(void)
{
- enable_IO_APIC();
+
+ /*
+ * calling enable_IO_APIC() is moved to setup_local_APIC for BP
+ */

if (acpi_ioapic)
io_apic_irqs = ~0; /* all IRQs go through IOAPIC */
Index: linux-2.6/include/asm-x86/hw_irq_64.h
===================================================================
--- linux-2.6.orig/include/asm-x86/hw_irq_64.h
+++ linux-2.6/include/asm-x86/hw_irq_64.h
@@ -135,6 +135,7 @@ extern void init_8259A(int aeoi);
extern void send_IPI_self(int vector);
extern void init_VISWS_APIC_irqs(void);
extern void setup_IO_APIC(void);
+extern void enable_IO_APIC(void);
extern void disable_IO_APIC(void);
extern void print_IO_APIC(void);
extern int IO_APIC_get_PCI_irq_vector(int bus, int slot, int fn);
Index: linux-2.6/arch/x86/kernel/smpboot_64.c
===================================================================
--- linux-2.6.orig/arch/x86/kernel/smpboot_64.c
+++ linux-2.6/arch/x86/kernel/smpboot_64.c
@@ -211,7 +211,7 @@ void __cpuinit smp_callin(void)
*/

Dprintk("CALLIN, before setup_local_APIC().\n");
- setup_local_APIC();
+ setup_local_APIC(NULL);

/*
* Get our bogomips.
@@ -879,6 +879,8 @@ static void __init smp_cpu_index_default
*/
void __init smp_prepare_cpus(unsigned int max_cpus)
{
+ void (*extra_call)(void) = NULL;
+
nmi_watchdog_default();
smp_cpu_index_default();
current_cpu_data = boot_cpu_data;
@@ -896,7 +898,10 @@ void __init smp_prepare_cpus(unsigned in
/*
* Switch from PIC to APIC mode.
*/
- setup_local_APIC();
+ if (!skip_ioapic_setup && nr_ioapics)
+ extra_call = enable_IO_APIC;
+
+ setup_local_APIC(extra_call);

if (GET_APIC_ID(apic_read(APIC_ID)) != boot_cpu_id) {
panic("Boot APIC ID in local APIC unexpected (%d vs %d)",
Index: linux-2.6/include/asm-x86/apic_64.h
===================================================================
--- linux-2.6.orig/include/asm-x86/apic_64.h
+++ linux-2.6/include/asm-x86/apic_64.h
@@ -74,7 +74,7 @@ extern int verify_local_APIC (void);
extern void cache_APIC_registers (void);
extern void sync_Arb_IDs (void);
extern void init_bsp_APIC (void);
-extern void setup_local_APIC (void);
+extern void setup_local_APIC (void (*extra_call)(void));
extern void init_apic_mappings (void);
extern void smp_local_timer_interrupt (void);
extern void setup_boot_APIC_clock (void);


2007-12-30 14:55:25

by Ingo Molnar

[permalink] [raw]
Subject: Re: [PATCH] x86_64: clear IO_APIC before enabing apic error vector. v2


* Yinghai Lu <[email protected]> wrote:

> please check if you can replace the one in the x86-mm
>
> http://git.kernel.org/?p=linux/kernel/git/x86/linux-2.6-x86.git;a=commitdiff;h=ffcbdc220a1520d006a837f33589c7c19ffbeb76
>
> the updated one avoid one link warning.

please send delta patches instead - so that we can review the changes.

> this is the updated verison that take enable_IO_APIC as extra call for
> setup_local_APIC to avoid linking warning.

hm, what link warning did you get? Perhaps the following __cpuinit:

> -void __cpuinit setup_local_APIC (void)

does not mix well with an __init call:

> +void __init enable_IO_APIC(void)

and you hack it around by using a function pointer. Nasty and still
buggy. The proper solution would be to mark enable_IO_APIC as __cpuinit
too (or something like that).

Ingo

2007-12-30 20:48:58

by Yinghai Lu

[permalink] [raw]
Subject: Re: [PATCH] x86_64: clear IO_APIC before enabing apic error vector. v2

On Dec 30, 2007 6:51 AM, Ingo Molnar <[email protected]> wrote:
>
> * Yinghai Lu <[email protected]> wrote:
>
> > please check if you can replace the one in the x86-mm
> >
> > http://git.kernel.org/?p=linux/kernel/git/x86/linux-2.6-x86.git;a=commitdiff;h=ffcbdc220a1520d006a837f33589c7c19ffbeb76
> >
> > the updated one avoid one link warning.
>
> please send delta patches instead - so that we can review the changes.

will do that in another patch.

>
> > this is the updated verison that take enable_IO_APIC as extra call for
> > setup_local_APIC to avoid linking warning.
>
> hm, what link warning did you get? Perhaps the following __cpuinit:

WARNING: vmlinux.o(.text+0x163d5): Section mismatch: reference to
.init.text:enable_IO_APIC (between 'setup_local_APIC' and
'apic_is_clustered_box')

>
> > -void __cpuinit setup_local_APIC (void)
>
> does not mix well with an __init call:
>
> > +void __init enable_IO_APIC(void)
>
> and you hack it around by using a function pointer. Nasty and still
> buggy. The proper solution would be to mark enable_IO_APIC as __cpuinit
> too (or something like that).

after change that to __cpuinit, i got

WARNING: vmlinux.o(.text+0x17f84): Section mismatch: reference to
.init.text: (between 'enable_IO_APIC' and 'ioapic_resume')
WARNING: vmlinux.o(.text+0x17f92): Section mismatch: reference to
.init.text: (between 'enable_IO_APIC' and 'ioapic_resume')

YH

2007-12-30 21:25:46

by Yinghai Lu

[permalink] [raw]
Subject: [PATCH] x86_64: fix section warning about enable_IO_APIC and setup_local_APIC

[PATCH] x86_64: fix section warning about enable_IO_APIC and setup_local_APIC

clear IO_APIC before enabing apic error vector cause link warning

use function call in setup_local_APIC to avoid that.

Signed-off-by: Yinghai Lu <[email protected]>

Index: linux-2.6/arch/x86/kernel/smpboot_64.c
===================================================================
--- linux-2.6.orig/arch/x86/kernel/smpboot_64.c
+++ linux-2.6/arch/x86/kernel/smpboot_64.c
@@ -211,7 +211,7 @@ void __cpuinit smp_callin(void)
*/

Dprintk("CALLIN, before setup_local_APIC().\n");
- setup_local_APIC();
+ setup_local_APIC(NULL);

/*
* Get our bogomips.
@@ -867,6 +867,8 @@ void __init smp_set_apicids(void)
*/
void __init smp_prepare_cpus(unsigned int max_cpus)
{
+ void (*extra_call)(void) = NULL;
+
nmi_watchdog_default();
current_cpu_data = boot_cpu_data;
current_thread_info()->cpu = 0; /* needed? */
@@ -883,7 +885,10 @@ void __init smp_prepare_cpus(unsigned in
/*
* Switch from PIC to APIC mode.
*/
- setup_local_APIC();
+ if (!skip_ioapic_setup && nr_ioapics)
+ extra_call = enable_IO_APIC;
+
+ setup_local_APIC(extra_call);

if (GET_APIC_ID(apic_read(APIC_ID)) != boot_cpu_id) {
panic("Boot APIC ID in local APIC unexpected (%d vs %d)",
Index: linux-2.6/include/asm-x86/apic_64.h
===================================================================
--- linux-2.6.orig/include/asm-x86/apic_64.h
+++ linux-2.6/include/asm-x86/apic_64.h
@@ -74,7 +74,7 @@ extern int verify_local_APIC (void);
extern void cache_APIC_registers (void);
extern void sync_Arb_IDs (void);
extern void init_bsp_APIC (void);
-extern void setup_local_APIC (void);
+extern void setup_local_APIC (void (*extra_call)(void));
extern void init_apic_mappings (void);
extern void smp_local_timer_interrupt (void);
extern void setup_boot_APIC_clock (void);
Index: linux-2.6/arch/x86/kernel/apic_64.c
===================================================================
--- linux-2.6.orig/arch/x86/kernel/apic_64.c
+++ linux-2.6/arch/x86/kernel/apic_64.c
@@ -418,7 +418,7 @@ void __init init_bsp_APIC(void)
apic_write(APIC_LVT1, value);
}

-void __cpuinit setup_local_APIC (void)
+void __cpuinit setup_local_APIC (void (*extra_call)(void))
{
unsigned int value, maxlvt;
int i, j;
@@ -521,9 +521,8 @@ void __cpuinit setup_local_APIC (void)
* Now enable IO-APICs, actually call clear_IO_APIC
* We need clear_IO_APIC before enabling vector on BP
*/
- if (!smp_processor_id())
- if (!skip_ioapic_setup && nr_ioapics)
- enable_IO_APIC();
+ if (extra_call)
+ (*extra_call)();

{
unsigned oldvalue;
@@ -1206,6 +1205,8 @@ int disable_apic;
*/
int __init APIC_init_uniprocessor (void)
{
+ void (*extra_call)(void) = NULL;
+
if (disable_apic) {
printk(KERN_INFO "Apic disabled\n");
return -1;
@@ -1221,7 +1222,10 @@ int __init APIC_init_uniprocessor (void)
phys_cpu_present_map = physid_mask_of_physid(boot_cpu_id);
apic_write(APIC_ID, SET_APIC_ID(boot_cpu_id));

- setup_local_APIC();
+ if (!skip_ioapic_setup && nr_ioapics)
+ extra_call = enable_IO_APIC;
+
+ setup_local_APIC(extra_call);

if (smp_found_config && !skip_ioapic_setup && nr_ioapics)
setup_IO_APIC();

2007-12-30 21:30:21

by Ingo Molnar

[permalink] [raw]
Subject: Re: [PATCH] x86_64: fix section warning about enable_IO_APIC and setup_local_APIC


* Yinghai Lu <[email protected]> wrote:

> [PATCH] x86_64: fix section warning about enable_IO_APIC and setup_local_APIC
>
> clear IO_APIC before enabing apic error vector cause link warning
>
> use function call in setup_local_APIC to avoid that.

as i said, this just works around the link warning - now we've traded
the link warning for a runtime crash.

Ingo

2007-12-30 21:53:46

by Yinghai Lu

[permalink] [raw]
Subject: Re: [PATCH] x86_64: fix section warning about enable_IO_APIC and setup_local_APIC

On Dec 30, 2007 1:29 PM, Ingo Molnar <[email protected]> wrote:
>
> * Yinghai Lu <[email protected]> wrote:
>
> > [PATCH] x86_64: fix section warning about enable_IO_APIC and setup_local_APIC
> >
> > clear IO_APIC before enabing apic error vector cause link warning
> >
> > use function call in setup_local_APIC to avoid that.
>
> as i said, this just works around the link warning - now we've traded
> the link warning for a runtime crash.

you got one runtime crash by this fix?

YH

2007-12-30 22:06:41

by Adrian Bunk

[permalink] [raw]
Subject: Re: [PATCH] x86_64: clear IO_APIC before enabing apic error vector. v2

On Sun, Dec 30, 2007 at 12:48:48PM -0800, Yinghai Lu wrote:
> On Dec 30, 2007 6:51 AM, Ingo Molnar <[email protected]> wrote:
> >
> > * Yinghai Lu <[email protected]> wrote:
> >
> > > please check if you can replace the one in the x86-mm
> > >
> > > http://git.kernel.org/?p=linux/kernel/git/x86/linux-2.6-x86.git;a=commitdiff;h=ffcbdc220a1520d006a837f33589c7c19ffbeb76
> > >
> > > the updated one avoid one link warning.
> >
> > please send delta patches instead - so that we can review the changes.
>
> will do that in another patch.
>
> >
> > > this is the updated verison that take enable_IO_APIC as extra call for
> > > setup_local_APIC to avoid linking warning.
> >
> > hm, what link warning did you get? Perhaps the following __cpuinit:
>
> WARNING: vmlinux.o(.text+0x163d5): Section mismatch: reference to
> .init.text:enable_IO_APIC (between 'setup_local_APIC' and
> 'apic_is_clustered_box')

So you are doing complicated things for silencing the warning (there is
an easier ways for achieving it), but the real bug that you will get an
Oops when calling enable_IO_APIC() after bootup since it already got
freed stays?

> > > -void __cpuinit setup_local_APIC (void)
> >
> > does not mix well with an __init call:
> >
> > > +void __init enable_IO_APIC(void)
> >
> > and you hack it around by using a function pointer. Nasty and still
> > buggy. The proper solution would be to mark enable_IO_APIC as __cpuinit
> > too (or something like that).
>
> after change that to __cpuinit, i got
>
> WARNING: vmlinux.o(.text+0x17f84): Section mismatch: reference to
> .init.text: (between 'enable_IO_APIC' and 'ioapic_resume')
> WARNING: vmlinux.o(.text+0x17f92): Section mismatch: reference to
> .init.text: (between 'enable_IO_APIC' and 'ioapic_resume')

find_isa_irq_{apic,pin} are called by enable_IO_APIC() and therefore
also have to be changed from __init to __cpuinit.

> YH

cu
Adrian

BTW: Is there a reason why your patch doesn't touch the 32bit code?

--

"Is there not promise of rain?" Ling Tan asked suddenly out
of the darkness. There had been need of rain for many days.
"Only a promise," Lao Er said.
Pearl S. Buck - Dragon Seed

2007-12-30 22:43:03

by Yinghai Lu

[permalink] [raw]
Subject: Re: [PATCH] x86_64: clear IO_APIC before enabing apic error vector. v2

On Dec 30, 2007 2:06 PM, Adrian Bunk <[email protected]> wrote:
> On Sun, Dec 30, 2007 at 12:48:48PM -0800, Yinghai Lu wrote:
> > On Dec 30, 2007 6:51 AM, Ingo Molnar <[email protected]> wrote:
> > >
> > > * Yinghai Lu <[email protected]> wrote:
> > >
> > > > please check if you can replace the one in the x86-mm
> > > >
> > > > http://git.kernel.org/?p=linux/kernel/git/x86/linux-2.6-x86.git;a=commitdiff;h=ffcbdc220a1520d006a837f33589c7c19ffbeb76
> > > >
> > > > the updated one avoid one link warning.
> > >
> > > please send delta patches instead - so that we can review the changes.
> >
> > will do that in another patch.
> >
> > >
> > > > this is the updated verison that take enable_IO_APIC as extra call for
> > > > setup_local_APIC to avoid linking warning.
> > >
> > > hm, what link warning did you get? Perhaps the following __cpuinit:
> >
> > WARNING: vmlinux.o(.text+0x163d5): Section mismatch: reference to
> > .init.text:enable_IO_APIC (between 'setup_local_APIC' and
> > 'apic_is_clustered_box')
>
> So you are doing complicated things for silencing the warning (there is
> an easier ways for achieving it), but the real bug that you will get an
> Oops when calling enable_IO_APIC() after bootup since it already got
> freed stays?

the enable_IO_APIC is actually doing clear_IO_APIC. and it is only
called by BSP via setup_local_APIC
and it is not called again after bootup

YH

2007-12-30 23:24:17

by Adrian Bunk

[permalink] [raw]
Subject: Re: [PATCH] x86_64: clear IO_APIC before enabing apic error vector. v2

On Sun, Dec 30, 2007 at 02:42:41PM -0800, Yinghai Lu wrote:
> On Dec 30, 2007 2:06 PM, Adrian Bunk <[email protected]> wrote:
> > On Sun, Dec 30, 2007 at 12:48:48PM -0800, Yinghai Lu wrote:
> > > On Dec 30, 2007 6:51 AM, Ingo Molnar <[email protected]> wrote:
> > > >
> > > > * Yinghai Lu <[email protected]> wrote:
> > > >
> > > > > please check if you can replace the one in the x86-mm
> > > > >
> > > > > http://git.kernel.org/?p=linux/kernel/git/x86/linux-2.6-x86.git;a=commitdiff;h=ffcbdc220a1520d006a837f33589c7c19ffbeb76
> > > > >
> > > > > the updated one avoid one link warning.
> > > >
> > > > please send delta patches instead - so that we can review the changes.
> > >
> > > will do that in another patch.
> > >
> > > >
> > > > > this is the updated verison that take enable_IO_APIC as extra call for
> > > > > setup_local_APIC to avoid linking warning.
> > > >
> > > > hm, what link warning did you get? Perhaps the following __cpuinit:
> > >
> > > WARNING: vmlinux.o(.text+0x163d5): Section mismatch: reference to
> > > .init.text:enable_IO_APIC (between 'setup_local_APIC' and
> > > 'apic_is_clustered_box')
> >
> > So you are doing complicated things for silencing the warning (there is
> > an easier ways for achieving it), but the real bug that you will get an
> > Oops when calling enable_IO_APIC() after bootup since it already got
> > freed stays?
>
> the enable_IO_APIC is actually doing clear_IO_APIC. and it is only
> called by BSP via setup_local_APIC
> and it is not called again after bootup

OK, this was a bit hidden inside your pointer games.

Please send a patch that ignores the warning (and therefore doesn't do
these pointer games), and I'll fix the warning in a followup patch.

> YH

cu
Adrian

--

"Is there not promise of rain?" Ling Tan asked suddenly out
of the darkness. There had been need of rain for many days.
"Only a promise," Lao Er said.
Pearl S. Buck - Dragon Seed

2007-12-31 00:01:52

by Yinghai Lu

[permalink] [raw]
Subject: Re: [PATCH] x86_64: clear IO_APIC before enabing apic error vector. v2

On Dec 30, 2007 3:23 PM, Adrian Bunk <[email protected]> wrote:
>
> On Sun, Dec 30, 2007 at 02:42:41PM -0800, Yinghai Lu wrote:
> > On Dec 30, 2007 2:06 PM, Adrian Bunk <[email protected]> wrote:
> > > On Sun, Dec 30, 2007 at 12:48:48PM -0800, Yinghai Lu wrote:
> > > > On Dec 30, 2007 6:51 AM, Ingo Molnar <[email protected]> wrote:
> > > > >
> > > > > * Yinghai Lu <[email protected]> wrote:
> > > > >
> > > > > > please check if you can replace the one in the x86-mm
> > > > > >
> > > > > > http://git.kernel.org/?p=linux/kernel/git/x86/linux-2.6-x86.git;a=commitdiff;h=ffcbdc220a1520d006a837f33589c7c19ffbeb76
> > > > > >
> > > > > > the updated one avoid one link warning.
> > > > >
> > > > > please send delta patches instead - so that we can review the changes.
> > > >
> > > > will do that in another patch.
> > > >
> > > > >
> > > > > > this is the updated verison that take enable_IO_APIC as extra call for
> > > > > > setup_local_APIC to avoid linking warning.
> > > > >
> > > > > hm, what link warning did you get? Perhaps the following __cpuinit:
> > > >
> > > > WARNING: vmlinux.o(.text+0x163d5): Section mismatch: reference to
> > > > .init.text:enable_IO_APIC (between 'setup_local_APIC' and
> > > > 'apic_is_clustered_box')
> > >
> > > So you are doing complicated things for silencing the warning (there is
> > > an easier ways for achieving it), but the real bug that you will get an
> > > Oops when calling enable_IO_APIC() after bootup since it already got
> > > freed stays?
> >
> > the enable_IO_APIC is actually doing clear_IO_APIC. and it is only
> > called by BSP via setup_local_APIC
> > and it is not called again after bootup
>
> OK, this was a bit hidden inside your pointer games.
>
> Please send a patch that ignores the warning (and therefore doesn't do
> these pointer games), and I'll fix the warning in a followup patch.

the old one is in x86-mm tree

http://git.kernel.org/?p=linux/kernel/git/x86/linux-2.6-x86.git;a=commitdiff;h=ffcbdc220a1520d006a837f33589c7c19ffbeb76

function call delta
http://lkml.org/lkml/2007/12/30/211

thanks

YH

2007-12-31 00:29:05

by Adrian Bunk

[permalink] [raw]
Subject: Re: [PATCH] x86_64: clear IO_APIC before enabing apic error vector. v2

On Sun, Dec 30, 2007 at 04:01:39PM -0800, Yinghai Lu wrote:
> On Dec 30, 2007 3:23 PM, Adrian Bunk <[email protected]> wrote:
> >
> > On Sun, Dec 30, 2007 at 02:42:41PM -0800, Yinghai Lu wrote:
> > > On Dec 30, 2007 2:06 PM, Adrian Bunk <[email protected]> wrote:
> > > > On Sun, Dec 30, 2007 at 12:48:48PM -0800, Yinghai Lu wrote:
> > > > > On Dec 30, 2007 6:51 AM, Ingo Molnar <[email protected]> wrote:
> > > > > >
> > > > > > * Yinghai Lu <[email protected]> wrote:
> > > > > >
> > > > > > > please check if you can replace the one in the x86-mm
> > > > > > >
> > > > > > > http://git.kernel.org/?p=linux/kernel/git/x86/linux-2.6-x86.git;a=commitdiff;h=ffcbdc220a1520d006a837f33589c7c19ffbeb76
> > > > > > >
> > > > > > > the updated one avoid one link warning.
> > > > > >
> > > > > > please send delta patches instead - so that we can review the changes.
> > > > >
> > > > > will do that in another patch.
> > > > >
> > > > > >
> > > > > > > this is the updated verison that take enable_IO_APIC as extra call for
> > > > > > > setup_local_APIC to avoid linking warning.
> > > > > >
> > > > > > hm, what link warning did you get? Perhaps the following __cpuinit:
> > > > >
> > > > > WARNING: vmlinux.o(.text+0x163d5): Section mismatch: reference to
> > > > > .init.text:enable_IO_APIC (between 'setup_local_APIC' and
> > > > > 'apic_is_clustered_box')
> > > >
> > > > So you are doing complicated things for silencing the warning (there is
> > > > an easier ways for achieving it), but the real bug that you will get an
> > > > Oops when calling enable_IO_APIC() after bootup since it already got
> > > > freed stays?
> > >
> > > the enable_IO_APIC is actually doing clear_IO_APIC. and it is only
> > > called by BSP via setup_local_APIC
> > > and it is not called again after bootup
> >
> > OK, this was a bit hidden inside your pointer games.
> >
> > Please send a patch that ignores the warning (and therefore doesn't do
> > these pointer games), and I'll fix the warning in a followup patch.
>
> the old one is in x86-mm tree
>
> http://git.kernel.org/?p=linux/kernel/git/x86/linux-2.6-x86.git;a=commitdiff;h=ffcbdc220a1520d006a837f33589c7c19ffbeb76
>...

Sorry for the dumb question, but what in

+ if (!smp_processor_id() && !skip_ioapic_setup && nr_ioapics)
+ enable_IO_APIC();

guarantees that this call doesn't happen when you hotplug CPU 0 ?

> thanks
>
> YH

cu
Adrian

--

"Is there not promise of rain?" Ling Tan asked suddenly out
of the darkness. There had been need of rain for many days.
"Only a promise," Lao Er said.
Pearl S. Buck - Dragon Seed

2007-12-31 00:56:55

by Yinghai Lu

[permalink] [raw]
Subject: Re: [PATCH] x86_64: clear IO_APIC before enabing apic error vector. v2

On Dec 30, 2007 4:28 PM, Adrian Bunk <[email protected]> wrote:
>
> On Sun, Dec 30, 2007 at 04:01:39PM -0800, Yinghai Lu wrote:
> > On Dec 30, 2007 3:23 PM, Adrian Bunk <[email protected]> wrote:
> > >
> > > On Sun, Dec 30, 2007 at 02:42:41PM -0800, Yinghai Lu wrote:
> > > > On Dec 30, 2007 2:06 PM, Adrian Bunk <[email protected]> wrote:
> > > > > On Sun, Dec 30, 2007 at 12:48:48PM -0800, Yinghai Lu wrote:
> > > > > > On Dec 30, 2007 6:51 AM, Ingo Molnar <[email protected]> wrote:
> > > > > > >
> > > > > > > * Yinghai Lu <[email protected]> wrote:
> > > > > > >
> > > > > > > > please check if you can replace the one in the x86-mm
> > > > > > > >
> > > > > > > > http://git.kernel.org/?p=linux/kernel/git/x86/linux-2.6-x86.git;a=commitdiff;h=ffcbdc220a1520d006a837f33589c7c19ffbeb76
> > > > > > > >
> > > > > > > > the updated one avoid one link warning.
> > > > > > >
> > > > > > > please send delta patches instead - so that we can review the changes.
> > > > > >
> > > > > > will do that in another patch.
> > > > > >
> > > > > > >
> > > > > > > > this is the updated verison that take enable_IO_APIC as extra call for
> > > > > > > > setup_local_APIC to avoid linking warning.
> > > > > > >
> > > > > > > hm, what link warning did you get? Perhaps the following __cpuinit:
> > > > > >
> > > > > > WARNING: vmlinux.o(.text+0x163d5): Section mismatch: reference to
> > > > > > .init.text:enable_IO_APIC (between 'setup_local_APIC' and
> > > > > > 'apic_is_clustered_box')
> > > > >
> > > > > So you are doing complicated things for silencing the warning (there is
> > > > > an easier ways for achieving it), but the real bug that you will get an
> > > > > Oops when calling enable_IO_APIC() after bootup since it already got
> > > > > freed stays?
> > > >
> > > > the enable_IO_APIC is actually doing clear_IO_APIC. and it is only
> > > > called by BSP via setup_local_APIC
> > > > and it is not called again after bootup
> > >
> > > OK, this was a bit hidden inside your pointer games.
> > >
> > > Please send a patch that ignores the warning (and therefore doesn't do
> > > these pointer games), and I'll fix the warning in a followup patch.
> >
> > the old one is in x86-mm tree
> >
> > http://git.kernel.org/?p=linux/kernel/git/x86/linux-2.6-x86.git;a=commitdiff;h=ffcbdc220a1520d006a837f33589c7c19ffbeb76
> >...
>
> Sorry for the dumb question, but what in
>
> + if (!smp_processor_id() && !skip_ioapic_setup && nr_ioapics)
> + enable_IO_APIC();
>
> guarantees that this call doesn't happen when you hotplug CPU 0 ?

so we can hotplug cpu0 or the bsp?

YH

2007-12-31 01:04:00

by Yinghai Lu

[permalink] [raw]
Subject: Re: [PATCH] x86_64: clear IO_APIC before enabing apic error vector. v2

On Dec 30, 2007 4:28 PM, Adrian Bunk <[email protected]> wrote:
>
> On Sun, Dec 30, 2007 at 04:01:39PM -0800, Yinghai Lu wrote:
> > On Dec 30, 2007 3:23 PM, Adrian Bunk <[email protected]> wrote:
> > >
> > > On Sun, Dec 30, 2007 at 02:42:41PM -0800, Yinghai Lu wrote:
> > > > On Dec 30, 2007 2:06 PM, Adrian Bunk <[email protected]> wrote:
> > > > > On Sun, Dec 30, 2007 at 12:48:48PM -0800, Yinghai Lu wrote:
> > > > > > On Dec 30, 2007 6:51 AM, Ingo Molnar <[email protected]> wrote:
> > > > > > >
> > > > > > > * Yinghai Lu <[email protected]> wrote:
> > > > > > >
> > > > > > > > please check if you can replace the one in the x86-mm
> > > > > > > >
> > > > > > > > http://git.kernel.org/?p=linux/kernel/git/x86/linux-2.6-x86.git;a=commitdiff;h=ffcbdc220a1520d006a837f33589c7c19ffbeb76
> > > > > > > >
> > > > > > > > the updated one avoid one link warning.
> > > > > > >
> > > > > > > please send delta patches instead - so that we can review the changes.
> > > > > >
> > > > > > will do that in another patch.
> > > > > >
> > > > > > >
> > > > > > > > this is the updated verison that take enable_IO_APIC as extra call for
> > > > > > > > setup_local_APIC to avoid linking warning.
> > > > > > >
> > > > > > > hm, what link warning did you get? Perhaps the following __cpuinit:
> > > > > >
> > > > > > WARNING: vmlinux.o(.text+0x163d5): Section mismatch: reference to
> > > > > > .init.text:enable_IO_APIC (between 'setup_local_APIC' and
> > > > > > 'apic_is_clustered_box')
> > > > >
> > > > > So you are doing complicated things for silencing the warning (there is
> > > > > an easier ways for achieving it), but the real bug that you will get an
> > > > > Oops when calling enable_IO_APIC() after bootup since it already got
> > > > > freed stays?
> > > >
> > > > the enable_IO_APIC is actually doing clear_IO_APIC. and it is only
> > > > called by BSP via setup_local_APIC
> > > > and it is not called again after bootup
> > >
> > > OK, this was a bit hidden inside your pointer games.
> > >
> > > Please send a patch that ignores the warning (and therefore doesn't do
> > > these pointer games), and I'll fix the warning in a followup patch.
> >
> > the old one is in x86-mm tree
> >
> > http://git.kernel.org/?p=linux/kernel/git/x86/linux-2.6-x86.git;a=commitdiff;h=ffcbdc220a1520d006a837f33589c7c19ffbeb76
> >...
>
> Sorry for the dumb question, but what in
>
> + if (!smp_processor_id() && !skip_ioapic_setup && nr_ioapics)
> + enable_IO_APIC();
>
> guarantees that this call doesn't happen when you hotplug CPU 0 ?
>

if CPU 0 (BSP) can be hotplug, it will be restarted via smp_callin.
and the delta function call patch will use setup_local_APIC(NULL),
then it will be safe.

YH

2008-01-01 23:17:38

by Adrian Bunk

[permalink] [raw]
Subject: Re: [PATCH] x86_64: clear IO_APIC before enabing apic error vector. v2

On Sun, Dec 30, 2007 at 04:56:35PM -0800, Yinghai Lu wrote:
> On Dec 30, 2007 4:28 PM, Adrian Bunk <[email protected]> wrote:
>...
> > Sorry for the dumb question, but what in
> >
> > + if (!smp_processor_id() && !skip_ioapic_setup && nr_ioapics)
> > + enable_IO_APIC();
> >
> > guarantees that this call doesn't happen when you hotplug CPU 0 ?
>
> so we can hotplug cpu0 or the bsp?

Honestly I don't know the amd64 architecture well enough for telling
whether the hardware allows it or not.

> YH

cu
Adrian

--

"Is there not promise of rain?" Ling Tan asked suddenly out
of the darkness. There had been need of rain for many days.
"Only a promise," Lao Er said.
Pearl S. Buck - Dragon Seed

2008-01-01 23:18:55

by Adrian Bunk

[permalink] [raw]
Subject: Re: [PATCH] x86_64: clear IO_APIC before enabing apic error vector. v2

On Sun, Dec 30, 2007 at 05:03:50PM -0800, Yinghai Lu wrote:
> On Dec 30, 2007 4:28 PM, Adrian Bunk <[email protected]> wrote:
> >
> > On Sun, Dec 30, 2007 at 04:01:39PM -0800, Yinghai Lu wrote:
>...
> > > the old one is in x86-mm tree
> > >
> > > http://git.kernel.org/?p=linux/kernel/git/x86/linux-2.6-x86.git;a=commitdiff;h=ffcbdc220a1520d006a837f33589c7c19ffbeb76
> > >...
> >
> > Sorry for the dumb question, but what in
> >
> > + if (!smp_processor_id() && !skip_ioapic_setup && nr_ioapics)
> > + enable_IO_APIC();
> >
> > guarantees that this call doesn't happen when you hotplug CPU 0 ?
> >
>
> if CPU 0 (BSP) can be hotplug, it will be restarted via smp_callin.
> and the delta function call patch will use setup_local_APIC(NULL),
> then it will be safe.

We are talking about the version without the pointer games.

> YH

cu
Adrian

--

"Is there not promise of rain?" Ling Tan asked suddenly out
of the darkness. There had been need of rain for many days.
"Only a promise," Lao Er said.
Pearl S. Buck - Dragon Seed