From: Andrew Morton <akpm@osdl.org>
To: Ashok Raj <ashok.raj@intel.com>
Cc: davej@redhat.com, ashok.raj@intel.com, len.brown@intel.com,
ak@suse.de, linux-kernel@vger.kernel.org,
linux-acpi@vger.kernel.org
Subject: Re: 2.6.16rc5 'found' an extra CPU.
Date: Thu, 2 Mar 2006 23:14:52 -0800 [thread overview]
Message-ID: <20060302231452.440a91c8.akpm@osdl.org> (raw)
In-Reply-To: <20060302112119.A13035@unix-os.sc.intel.com>
Ashok Raj <ashok.raj@intel.com> wrote:
>
> Local apic entries are only 8 bits, but it seemed to not be caught with
> u8 return value result in the check
>
> cpu_index >= NR_CPUS becomming always false.
>
> drivers/acpi/processor_core.c: In function `acpi_processor_get_info':
> drivers/acpi/processor_core.c:483: warning: comparison is always false due to limited range of data type
>
>
> Signed-off-by: Ashok Raj <ashok.raj@intel.com>
> -----------------------------------------------------
> drivers/acpi/processor_core.c | 8 ++++----
> 1 files changed, 4 insertions(+), 4 deletions(-)
>
> Index: linux-2.6.16-rc5-mm1/drivers/acpi/processor_core.c
> ===================================================================
> --- linux-2.6.16-rc5-mm1.orig/drivers/acpi/processor_core.c
> +++ linux-2.6.16-rc5-mm1/drivers/acpi/processor_core.c
> @@ -395,7 +395,7 @@ static int acpi_processor_remove_fs(stru
> #define ARCH_BAD_APICID (0xff)
> #endif
>
> -static u8 convert_acpiid_to_cpu(u8 acpi_id)
> +static int convert_acpiid_to_cpu(u8 acpi_id)
> {
> u16 apic_id;
> int i;
> @@ -421,7 +421,7 @@ static int acpi_processor_get_info(struc
> acpi_status status = 0;
> union acpi_object object = { 0 };
> struct acpi_buffer buffer = { sizeof(union acpi_object), &object };
> - u8 cpu_index;
> + int cpu_index;
> static int cpu0_initialized;
>
> ACPI_FUNCTION_TRACE("acpi_processor_get_info");
> @@ -466,7 +466,7 @@ static int acpi_processor_get_info(struc
> cpu_index = convert_acpiid_to_cpu(pr->acpi_id);
>
> /* Handle UP system running SMP kernel, with no LAPIC in MADT */
> - if (!cpu0_initialized && (cpu_index == 0xff) &&
> + if (!cpu0_initialized && (cpu_index == -1) &&
> (num_online_cpus() == 1)) {
> cpu_index = 0;
> }
> @@ -480,7 +480,7 @@ static int acpi_processor_get_info(struc
> * less than the max # of CPUs. They should be ignored _iff
> * they are physically not present.
> */
> - if (cpu_index >= NR_CPUS) {
> + if (cpu_index == -1) {
> if (ACPI_FAILURE
> (acpi_processor_hotadd_init(pr->handle, &pr->id))) {
> ACPI_ERROR((AE_INFO,
On a uniprocessor build this causes a crash in acpi_processor_start():
BUG_ON((pr->id >= NR_CPUS) || (pr->id < 0));
pr->id is 255.
I could bodge around this in various ways, but the semantics of cpu IDs in
there seem to be a bit opaque, and I suspect some more thought needs to go
into it all.
As well as uniprocessor testing ;)
next prev parent reply other threads:[~2006-03-03 7:16 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-03-02 5:49 Brown, Len
2006-03-02 9:33 ` Romano Giannetti
2006-03-02 15:53 ` Zwane Mwaikambo
2006-03-02 15:58 ` Romano Giannetti
2006-03-02 12:14 ` Andi Kleen
2006-03-02 16:30 ` Ashok Raj
2006-03-02 18:44 ` Dave Jones
2006-03-02 19:21 ` Ashok Raj
2006-03-03 7:14 ` Andrew Morton [this message]
2006-03-03 17:41 ` Ashok Raj
-- strict thread matches above, loose matches on Subject: below --
2006-03-02 19:37 Brown, Len
2006-03-02 19:26 Brown, Len
2006-03-02 19:31 ` Dave Jones
2006-03-02 19:33 ` Andi Kleen
2006-03-02 19:18 Brown, Len
2006-03-02 19:16 Brown, Len
2006-03-02 17:34 Brown, Len
2006-03-02 17:30 Brown, Len
2006-03-02 0:55 Chuck Ebbert
2006-03-02 1:09 ` Dave Jones
2006-03-05 0:42 ` Andrew Morton
2006-03-05 2:26 ` Dave Jones
2006-03-01 23:01 Moore, Robert
2006-03-01 22:46 Dave Jones
2006-03-01 23:03 ` Dave Jones
2006-03-02 0:55 ` Andi Kleen
2006-03-02 1:19 ` Dave Jones
2006-03-02 1:38 ` Andi Kleen
2006-03-02 3:13 ` Dave Jones
2006-03-02 3:24 ` Andi Kleen
2006-03-02 3:45 ` Dave Jones
2006-03-02 3:52 ` Ashok Raj
2006-03-02 4:11 ` Dave Jones
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