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

Konstantin Khlebnikov
2012-03-27T05:58:43Z

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.

>
>> 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.

>
> Regards,
>
> Guan Xuetao
>
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