Re: [PATCH 03/10] x86: arch/x86/Kconfig.cpu unification

From: Brian Gerst
Date: Tue Nov 06 2007 - 02:10:59 EST


Adrian Bunk wrote:
> On Tue, Nov 06, 2007 at 03:46:30AM +0100, Sam Ravnborg wrote:
>> On Mon, Nov 05, 2007 at 07:53:39PM -0500, Brian Gerst wrote:
>>> Sam Ravnborg wrote:
>>>> Move all CPU definitions to Kconfig.cpu
>>> This patch causes build failure on x86_64:
>>>
>>> lib/rwsem.c: In function â__init_rwsemâ:
>>> lib/rwsem.c:24: error: âstruct rw_semaphoreâ has no member named âcountâ
>>> lib/rwsem.c:24: error: âRWSEM_UNLOCKED_VALUEâ undeclared (first use in
>>> this function)
>>> lib/rwsem.c:24: error: (Each undeclared identifier is reported only once
>>> lib/rwsem.c:24: error: for each function it appears in.)
>>> lib/rwsem.c: In function â__rwsem_do_wakeâ:
>>> lib/rwsem.c:64: error: implicit declaration of function
>>> ârwsem_atomic_updateâ
>>> lib/rwsem.c:64: error: âRWSEM_ACTIVE_BIASâ undeclared (first use in this
>>> function)
>>> lib/rwsem.c:66: error: âRWSEM_ACTIVE_MASKâ undeclared (first use in this
>>> function)
>>> lib/rwsem.c:115: error: âRWSEM_WAITING_BIASâ undeclared (first use in
>>> this function)
>>> lib/rwsem.c:120: error: implicit declaration of function ârwsem_atomic_addâ
>>> lib/rwsem.c: In function ârwsem_down_failed_commonâ:
>>> lib/rwsem.c:169: error: âRWSEM_ACTIVE_MASKâ undeclared (first use in
>>> this function)
>>> lib/rwsem.c: In function ârwsem_down_read_failedâ:
>>> lib/rwsem.c:197: error: âRWSEM_WAITING_BIASâ undeclared (first use in
>>> this function)
>>> lib/rwsem.c:197: error: âRWSEM_ACTIVE_BIASâ undeclared (first use in
>>> this function)
>>> lib/rwsem.c: In function ârwsem_down_write_failedâ:
>>> lib/rwsem.c:210: error: âRWSEM_ACTIVE_BIASâ undeclared (first use in
>>> this function)
>>>
>>> git bisect gives:
>>> 55432d383871d127685d78f94e0ad60307dcc0e9 is first bad commit
>>> commit 55432d383871d127685d78f94e0ad60307dcc0e9
>>> Author: Sam Ravnborg <sam@xxxxxxxxxxxx>
>>> Date: Thu Nov 1 21:54:39 2007 +0100
>>>
>>> x86: arch/x86/Kconfig.cpu unification
>> Seems that a default value fail to change value when we shift
>> from 32 to 64 bit. I have it reproduced here.
>> Will look at it tonight.
>
> The problem is that you source arch/x86/Kconfig.cpu from
> arch/x86/Kconfig.x86_64 but didn't give RWSEM_XCHGADD_ALGORITHM
> the required dependency on X86_32.
>
>> Sam
>
> cu
> Adrian
>

The quick fix is to move the RWSEM_XCHGADD_ALGORITHM and
RWSEM_XCHGADD_ALGORITHM defines from Kconfig.cpu to Kconfig.i386.

Looking at this closer, the 64-bit code has been using the generic
spinlock-based implementation, while the 32-bit code uses an optimized
version on all but true 386 cpus. The 64-bit code should be adapted to
use the optimized version at some point.
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