2008-06-05 12:07:17

by tip-bot for Andreas Herrmann

Subject: [PATCH] x86: fix compile warning in io_apic_{32,64}.c

Commit 05f2d12c3563dea8c81b301f9f3cf7919af23b13
(x86: change GET_APIC_ID() from an inline function to an out-of-line function)

introduced a compile warning

arch/x86/kernel/io_apic_64.c: In function 'print_local_APIC':
arch/x86/kernel/io_apic_64.c:1152: warning: 'v' is used uninitialized in this function

in some debug code -- which is not enabled by default.
This patch reverts the code changes in print_local_APIC.

Signed-off-by: Andreas Herrmann <[email protected]>

--
diff --git a/arch/x86/kernel/io_apic_32.c b/arch/x86/kernel/io_apic_32.c
index a40d54f..9a3446f 100644
--- a/arch/x86/kernel/io_apic_32.c
+++ b/arch/x86/kernel/io_apic_32.c
@@ -1489,8 +1489,8 @@ void /*__init*/ print_local_APIC(void * dummy)

printk("\n" KERN_DEBUG "printing local APIC contents on CPU#%d/%d:\n",
smp_processor_id(), hard_smp_processor_id());
- printk(KERN_INFO "... APIC ID: %08x (%01x)\n", v,
- GET_APIC_ID(read_apic_id()));
+ v = apic_read(APIC_ID);
+ printk(KERN_INFO "... APIC ID: %08x (%01x)\n", v, GET_APIC_ID(v));
v = apic_read(APIC_LVR);
printk(KERN_INFO "... APIC VERSION: %08x\n", v);
ver = GET_APIC_VERSION(v);
diff --git a/arch/x86/kernel/io_apic_64.c b/arch/x86/kernel/io_apic_64.c
index ef1a8df..59ed52c 100644
--- a/arch/x86/kernel/io_apic_64.c
+++ b/arch/x86/kernel/io_apic_64.c
@@ -1077,7 +1077,8 @@ void __apicdebuginit print_local_APIC(void * dummy)

printk("\n" KERN_DEBUG "printing local APIC contents on CPU#%d/%d:\n",
smp_processor_id(), hard_smp_processor_id());
- printk(KERN_INFO "... APIC ID: %08x (%01x)\n", v, GET_APIC_ID(read_apic_id()));
+ v = apic_read(APIC_ID);
+ printk(KERN_INFO "... APIC ID: %08x (%01x)\n", v, GET_APIC_ID(v));
v = apic_read(APIC_LVR);
printk(KERN_INFO "... APIC VERSION: %08x\n", v);
ver = GET_APIC_VERSION(v);

2008-06-05 12:39:24

by tip-bot for Jack Steiner

Subject: Re: [PATCH] x86: fix compile warning in io_apic_{32,64}.c

On Thu, Jun 05, 2008 at 02:05:57PM +0200, Andreas Herrmann wrote:
> Commit 05f2d12c3563dea8c81b301f9f3cf7919af23b13
> (x86: change GET_APIC_ID() from an inline function to an out-of-line function)
>
> introduced a compile warning
>
> arch/x86/kernel/io_apic_64.c: In function 'print_local_APIC':
> arch/x86/kernel/io_apic_64.c:1152: warning: 'v' is used uninitialized in this function
>
> in some debug code -- which is not enabled by default.
> This patch reverts the code changes in print_local_APIC.
>
> Signed-off-by: Andreas Herrmann <[email protected]>
>
> --
> diff --git a/arch/x86/kernel/io_apic_32.c b/arch/x86/kernel/io_apic_32.c
> index a40d54f..9a3446f 100644
> --- a/arch/x86/kernel/io_apic_32.c
> +++ b/arch/x86/kernel/io_apic_32.c
> @@ -1489,8 +1489,8 @@ void /*__init*/ print_local_APIC(void * dummy)
>
> printk("\n" KERN_DEBUG "printing local APIC contents on CPU#%d/%d:\n",
> smp_processor_id(), hard_smp_processor_id());
> - printk(KERN_INFO "... APIC ID: %08x (%01x)\n", v,
> - GET_APIC_ID(read_apic_id()));
> + v = apic_read(APIC_ID);
> + printk(KERN_INFO "... APIC ID: %08x (%01x)\n", v, GET_APIC_ID(v));
> v = apic_read(APIC_LVR);
> printk(KERN_INFO "... APIC VERSION: %08x\n", v);
> ver = GET_APIC_VERSION(v);
> diff --git a/arch/x86/kernel/io_apic_64.c b/arch/x86/kernel/io_apic_64.c
> index ef1a8df..59ed52c 100644
> --- a/arch/x86/kernel/io_apic_64.c
> +++ b/arch/x86/kernel/io_apic_64.c
> @@ -1077,7 +1077,8 @@ void __apicdebuginit print_local_APIC(void * dummy)
>
> printk("\n" KERN_DEBUG "printing local APIC contents on CPU#%d/%d:\n",
> smp_processor_id(), hard_smp_processor_id());
> - printk(KERN_INFO "... APIC ID: %08x (%01x)\n", v, GET_APIC_ID(read_apic_id()));
> + v = apic_read(APIC_ID);

I don't think this work on UV systems. Because of processor limitations, not
all of the APICID bits are contained in the hardware APIC_ID register. See
read_apic_id() in arch/x86/kernel/genapic_64.c.

I have not seen the compiler warning. What tree/options cause the error???


> + printk(KERN_INFO "... APIC ID: %08x (%01x)\n", v, GET_APIC_ID(v));
> v = apic_read(APIC_LVR);
> printk(KERN_INFO "... APIC VERSION: %08x\n", v);
> ver = GET_APIC_VERSION(v);
>
>
>

--- jack

2008-06-05 14:35:49

by tip-bot for Andreas Herrmann

Subject: Re: [PATCH] x86: fix compile warning in io_apic_{32,64}.c

On Thu, Jun 05, 2008 at 02:39:10PM +0200, Jack Steiner wrote:
> I have not seen the compiler warning. What tree/options cause the error???

Sure. It's currently dead code. I use it from time to time for debugging.
At least you have to do something like

diff --git a/arch/x86/kernel/io_apic_64.c b/arch/x86/kernel/io_apic_64.c
index ef1a8df..ddfdabd 100644
--- a/arch/x86/kernel/io_apic_64.c
+++ b/arch/x86/kernel/io_apic_64.c
@@ -1045,7 +1045,6 @@ void __apicdebuginit print_IO_APIC(void)
return;
}

-#if 0

static __apicdebuginit void print_APIC_bitfield (int base)
{
@@ -1181,7 +1180,6 @@ void __apicdebuginit print_PIC(void)
printk(KERN_DEBUG "... PIC ELCR: %04x\n", v);
}

-#endif /* 0 */

void __init enable_IO_APIC(void)
{


to compile it.

> I don't think this work on UV systems. Because of processor limitations, not
> all of the APICID bits are contained in the hardware APIC_ID register. See
> read_apic_id() in arch/x86/kernel/genapic_64.c.

I am not that familar with UV. So can't really comment on that.
But then it seems that the proper adaption for print_local_APIC to avoid the warning is
---
[PATCH] x86: fix compile warning in io_apic_{32,64}.c

Commit 05f2d12c3563dea8c81b301f9f3cf7919af23b13
(x86: change GET_APIC_ID() from an inline function to an out-of-line function)
introduced a compile warning:

arch/x86/kernel/io_apic_64.c: In function 'print_local_APIC':
arch/x86/kernel/io_apic_64.c:1152: warning: 'v' is used uninitialized in this function

in some debug code -- which is disabled by default.

Signed-off-by: Andreas Herrmann <[email protected]>
--
diff --git a/arch/x86/kernel/io_apic_32.c b/arch/x86/kernel/io_apic_32.c
index a40d54f..4fbf656 100644
--- a/arch/x86/kernel/io_apic_32.c
+++ b/arch/x86/kernel/io_apic_32.c
@@ -1489,6 +1489,7 @@ void /*__init*/ print_local_APIC(void * dummy)

printk("\n" KERN_DEBUG "printing local APIC contents on CPU#%d/%d:\n",
smp_processor_id(), hard_smp_processor_id());
+ v = apic_read(APIC_ID);
printk(KERN_INFO "... APIC ID: %08x (%01x)\n", v,
GET_APIC_ID(read_apic_id()));
v = apic_read(APIC_LVR);
diff --git a/arch/x86/kernel/io_apic_64.c b/arch/x86/kernel/io_apic_64.c
index ef1a8df..c7c6b00 100644
--- a/arch/x86/kernel/io_apic_64.c
+++ b/arch/x86/kernel/io_apic_64.c
@@ -1077,6 +1077,7 @@ void __apicdebuginit print_local_APIC(void * dummy)

printk("\n" KERN_DEBUG "printing local APIC contents on CPU#%d/%d:\n",
smp_processor_id(), hard_smp_processor_id());
+ v = apic_read(APIC_ID);
printk(KERN_INFO "... APIC ID: %08x (%01x)\n", v, GET_APIC_ID(read_apic_id()));
v = apic_read(APIC_LVR);
printk(KERN_INFO "... APIC VERSION: %08x\n", v);

2008-06-10 10:21:57

by Ingo Molnar

Subject: Re: [PATCH] x86: fix compile warning in io_apic_{32,64}.c

* Andreas Herrmann <[email protected]> wrote:

> Commit 05f2d12c3563dea8c81b301f9f3cf7919af23b13
> (x86: change GET_APIC_ID() from an inline function to an out-of-line function)
>
> introduced a compile warning
>
> arch/x86/kernel/io_apic_64.c: In function 'print_local_APIC':
> arch/x86/kernel/io_apic_64.c:1152: warning: 'v' is used uninitialized in this function
>
> in some debug code -- which is not enabled by default.
> This patch reverts the code changes in print_local_APIC.

applied to tip/x86/cleanups - thanks Andreas.

Ingo