Re: [PATCH 08/16] mm/unicore32: use vm_flags_t for vma flags

Guan Xuetao
2012-03-27T07:49:57Z

On 03/27/2012 01:58 PM, Konstantin Khlebnikov wrote:
> Guan Xuetao wrote:
>> On 03/21/2012 02:56 PM, Konstantin Khlebnikov wrote:
>>> The same magic like in arm: assembler code wants to test VM_EXEC,
>>> but for big-endian we should get upper word for this.
>>>
>>> Signed-off-by: Konstantin Khlebnikov<khlebnikov@openvz.org>
>>> Cc: Guan Xuetao<gxt@mprc.pku.edu.cn>
>>> ---
>>> arch/unicore32/kernel/asm-offsets.c | 6 +++++-
>>> arch/unicore32/mm/fault.c | 2 +-
>>> 2 files changed, 6 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/arch/unicore32/kernel/asm-offsets.c
>>> b/arch/unicore32/kernel/asm-offsets.c
>>> index ffcbe75..e3199b5 100644
>>> --- a/arch/unicore32/kernel/asm-offsets.c
>>> +++ b/arch/unicore32/kernel/asm-offsets.c
>>> @@ -87,9 +87,13 @@ int main(void)
>>> DEFINE(S_FRAME_SIZE, sizeof(struct pt_regs));
>>> BLANK();
>>> DEFINE(VMA_VM_MM, offsetof(struct vm_area_struct, vm_mm));
>>> +#if defined(CONFIG_CPU_BIG_ENDIAN)&& (NR_VMA_FLAGS> 32)
>>> + DEFINE(VMA_VM_FLAGS, offsetof(struct vm_area_struct,
>>> vm_flags) + 4);
>>> +#else
>> CONFIG_CPU_BIG/LITTLE_ENDIAN is defined only in some archs, and not
>> supported by unicore32.
>
> Ok, I'll drop this in v2
>
>>
>>> DEFINE(VMA_VM_FLAGS, offsetof(struct vm_area_struct,
>>> vm_flags));
>>> +#endif
>>> BLANK();
>>> - DEFINE(VM_EXEC, VM_EXEC);
>>> + DEFINE(VM_EXEC, (__force unsigned int)VM_EXEC);
>
>> Is this check useful for asm-offsets.h?
>
> this forced-typecast to make sparse happy, because we use here only
> (int) part of vma->vm_flags.
Perhaps, vm_flags_t, not unsigned int is more proper.

>
>>
>>> BLANK();
>>> DEFINE(PAGE_SZ, PAGE_SIZE);
>>> BLANK();
>>> diff --git a/arch/unicore32/mm/fault.c b/arch/unicore32/mm/fault.c
>>> index 283aa4b..9137996 100644
>>> --- a/arch/unicore32/mm/fault.c
>>> +++ b/arch/unicore32/mm/fault.c
>>> @@ -158,7 +158,7 @@ void do_bad_area(unsigned long addr, unsigned
>>> int fsr, struct pt_regs *regs)
>>> */
>>> static inline bool access_error(unsigned int fsr, struct
>>> vm_area_struct *vma)
>>> {
>>> - unsigned int mask = VM_READ | VM_WRITE | VM_EXEC;
>>> + vm_flags_t mask = VM_READ | VM_WRITE | VM_EXEC;
>>
>> I am confused for the type of vm_flags in vm_area_struct being
>> 'unsigned long', not vm_flags_t.
>
> Second patch in this patchset changes it.
> vm_flags_t will be unsigned long or or unsigned long long depending on
> vma flags count.
> But more likely it will be unsigned int, because I have another
> patchset in work,
> which currently drop four bits in vm_flags, so we can postpone its
> expansion.
I see. Thanks for your explanation.

Regards,
Guan Xuetao