On Fri, Jan 19, 2018 at 10:09:41AM -0600, Eric W. Biederman wrote:
> Ram Pai <linuxram@xxxxxxxxxx> writes:
>
> > Currently the architecture specific code is expected to
> > display the protection keys in smap for a given vma.
> > This can lead to redundant code and possibly to divergent
> > formats in which the key gets displayed.
> >
> > This patch changes the implementation. It displays the
> > pkey only if the architecture support pkeys.
> >
> > x86 arch_show_smap() function is not needed anymore.
> > Delete it.
> >
> > Signed-off-by: Ram Pai <linuxram@xxxxxxxxxx>
> > ---
> > arch/x86/kernel/setup.c | 8 --------
> > fs/proc/task_mmu.c | 11 ++++++-----
> > 2 files changed, 6 insertions(+), 13 deletions(-)
> >
> > diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
> > index 8af2e8d..ddf945a 100644
> > --- a/arch/x86/kernel/setup.c
> > +++ b/arch/x86/kernel/setup.c
> > @@ -1326,11 +1326,3 @@ static int __init register_kernel_offset_dumper(void)
> > return 0;
> > }
> > __initcall(register_kernel_offset_dumper);
> > -
> > -void arch_show_smap(struct seq_file *m, struct vm_area_struct *vma)
> > -{
> > - if (!boot_cpu_has(X86_FEATURE_OSPKE))
> > - return;
> > -
> > - seq_printf(m, "ProtectionKey: %8u\n", vma_pkey(vma));
> > -}
> > diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
> > index 0edd4da..4b39a94 100644
> > --- a/fs/proc/task_mmu.c
> > +++ b/fs/proc/task_mmu.c
> > @@ -18,6 +18,7 @@
> > #include <linux/page_idle.h>
> > #include <linux/shmem_fs.h>
> > #include <linux/uaccess.h>
> > +#include <linux/pkeys.h>
> >
> > #include <asm/elf.h>
> > #include <asm/tlb.h>
> > @@ -728,10 +729,6 @@ static int smaps_hugetlb_range(pte_t *pte, unsigned long hmask,
> > }
> > #endif /* HUGETLB_PAGE */
> >
> > -void __weak arch_show_smap(struct seq_file *m, struct vm_area_struct *vma)
> > -{
> > -}
> > -
> > static int show_smap(struct seq_file *m, void *v, int is_pid)
> > {
> > struct proc_maps_private *priv = m->private;
> > @@ -851,9 +848,13 @@ static int show_smap(struct seq_file *m, void *v, int is_pid)
> > (unsigned long)(mss->pss >> (10 + PSS_SHIFT)));
> >
> > if (!rollup_mode) {
> > - arch_show_smap(m, vma);
> > +#ifdef CONFIG_ARCH_HAS_PKEYS
> > + if (arch_pkeys_enabled())
> > + seq_printf(m, "ProtectionKey: %8u\n", vma_pkey(vma));
> > +#endif
>
> Would it be worth it making vma_pkey a noop on architectures that don't
> support protection keys so that we don't need the #ifdef here?
You mean something like this?
#define vma_pkey(vma)
It will lead to compilation error.
I can make it
#define vma_pkey(vma) 0
and that will work and get rid of the #ifdef
RP
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