[PATCH v8 01/10] ARM: use _install_special_mapping for sigpage
Nathan_Lynch at mentor.com
Mon Aug 4 07:11:29 PDT 2014
On 08/04/2014 08:12 AM, Nathan Lynch wrote:
> On 08/04/2014 07:46 AM, Will Deacon wrote:
>> On Sat, Aug 02, 2014 at 07:16:38PM +0100, Nathan Lynch wrote:
>>> _install_special_mapping allows the VMA to be identifed in
>>> /proc/pid/maps without the use of arch_vma_name, providing a
>>> slight net reduction in object size:
>>> text data bss dec hex filename
>>> 2996 96 144 3236 ca4 arch/arm/kernel/process.o (before)
>>> 2956 104 144 3204 c84 arch/arm/kernel/process.o (after)
>>> Signed-off-by: Nathan Lynch <nathan_lynch at mentor.com>
>>> Reviewed-by: Kees Cook <keescook at chromium.org>
>>> arch/arm/kernel/process.c | 24 ++++++++++++++++--------
>>> 1 file changed, 16 insertions(+), 8 deletions(-)
>>> diff --git a/arch/arm/kernel/process.c b/arch/arm/kernel/process.c
>>> index 81ef686a91ca..46fbbb3701a0 100644
>>> --- a/arch/arm/kernel/process.c
>>> +++ b/arch/arm/kernel/process.c
>>> @@ -472,19 +472,23 @@ int in_gate_area_no_mm(unsigned long addr)
>>> const char *arch_vma_name(struct vm_area_struct *vma)
>>> - return is_gate_vma(vma) ? "[vectors]" :
>>> - (vma->vm_mm && vma->vm_start == vma->vm_mm->context.sigpage) ?
>>> - "[sigpage]" : NULL;
>>> + return is_gate_vma(vma) ? "[vectors]" : NULL;
>> Why do you need this function? I just removed it for arm64 and I think x86
>> has done the same.
> I think arch_vma_name is still needed for arm as long as the vectors
> page is not installed using _install_special_mapping.
Actually... if we give arm's gate_vma a vm_ops with a ->name() routine
that returns "[vectors]" we could get rid of arch_vma_name, I think.
This seems to be what x86_64 does.
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