From: ebiederm@xmission.com (Eric W. Biederman)
To: Ram Pai <linuxram@us.ibm.com>
Cc: mpe@ellerman.id.au, mingo@redhat.com, akpm@linux-foundation.org,
corbet@lwn.net, arnd@arndb.de, linuxppc-dev@lists.ozlabs.org,
linux-mm@kvack.org, x86@kernel.org, linux-arch@vger.kernel.org,
linux-doc@vger.kernel.org, linux-kselftest@vger.kernel.org,
linux-kernel@vger.kernel.org, dave.hansen@intel.com,
benh@kernel.crashing.org, paulus@samba.org,
khandual@linux.vnet.ibm.com, aneesh.kumar@linux.vnet.ibm.com,
bsingharora@gmail.com, hbabu@us.ibm.com, mhocko@kernel.org,
bauerman@linux.vnet.ibm.com
Subject: Re: [PATCH v10 27/27] mm: display pkey in smaps if arch_pkeys_enabled() is true
Date: Fri, 19 Jan 2018 11:04:02 -0600 [thread overview]
Message-ID: <87efmldblp.fsf@xmission.com> (raw)
In-Reply-To: <20180119165050.GK5612@ram.oc3035372033.ibm.com> (Ram Pai's message of "Fri, 19 Jan 2018 08:50:50 -0800")
Ram Pai <linuxram@us.ibm.com> writes:
> On Fri, Jan 19, 2018 at 10:09:41AM -0600, Eric W. Biederman wrote:
>> Ram Pai <linuxram@us.ibm.com> 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@us.ibm.com>
>> > ---
>> > 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
Yes the second is what I was thinking.
I don't know if it is worth it but #ifdefs can be problematic as the
result in code not being compile tested.
Eric
next prev parent reply other threads:[~2018-01-19 17:05 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-01-19 1:50 [PATCH v10 00/27] powerpc, mm: Memory Protection Keys Ram Pai
2018-01-19 1:50 ` [PATCH v10 01/27] mm, powerpc, x86: define VM_PKEY_BITx bits if CONFIG_ARCH_HAS_PKEYS is enabled Ram Pai
2018-01-21 15:34 ` Aneesh Kumar K.V
2018-01-23 6:37 ` Ram Pai
2018-01-19 1:50 ` [PATCH v10 02/27] mm, powerpc, x86: introduce an additional vma bit for powerpc pkey Ram Pai
2018-01-19 1:50 ` [PATCH v10 03/27] powerpc: initial pkey plumbing Ram Pai
2018-01-22 3:34 ` [v10,03/27] " Michael Ellerman
2018-01-19 1:50 ` [PATCH v10 04/27] powerpc: track allocation status of all pkeys Ram Pai
2018-01-19 1:50 ` [PATCH v10 05/27] powerpc: helper function to read, write AMR, IAMR, UAMOR registers Ram Pai
2018-01-19 1:50 ` [PATCH v10 06/27] powerpc: helper functions to initialize AMR, IAMR and " Ram Pai
2018-01-19 1:50 ` [PATCH v10 07/27] powerpc: cleanup AMR, IAMR when a key is allocated or freed Ram Pai
2018-01-19 1:50 ` [PATCH v10 08/27] powerpc: implementation for arch_set_user_pkey_access() Ram Pai
2018-01-19 1:50 ` [PATCH v10 09/27] powerpc: ability to create execute-disabled pkeys Ram Pai
2018-01-19 1:50 ` [PATCH v10 10/27] powerpc: store and restore the pkey state across context switches Ram Pai
2018-01-19 1:50 ` [PATCH v10 11/27] powerpc: introduce execute-only pkey Ram Pai
2018-01-19 1:50 ` [PATCH v10 12/27] powerpc: ability to associate pkey to a vma Ram Pai
2018-01-19 1:50 ` [PATCH v10 13/27] powerpc: implementation for arch_override_mprotect_pkey() Ram Pai
2018-01-19 1:50 ` [PATCH v10 14/27] powerpc: map vma key-protection bits to pte key bits Ram Pai
2018-01-19 1:50 ` [PATCH v10 15/27] powerpc: Program HPTE key protection bits Ram Pai
2018-01-19 1:50 ` [PATCH v10 16/27] powerpc: helper to validate key-access permissions of a pte Ram Pai
2018-01-19 1:50 ` [PATCH v10 17/27] powerpc: check key protection for user page access Ram Pai
2018-01-19 1:50 ` [PATCH v10 18/27] powerpc: implementation for arch_vma_access_permitted() Ram Pai
2018-01-19 1:50 ` [PATCH v10 19/27] powerpc: Handle exceptions caused by pkey violation Ram Pai
2018-01-19 1:50 ` [PATCH v10 20/27] powerpc: introduce get_mm_addr_key() helper Ram Pai
2018-01-19 1:50 ` [PATCH v10 21/27] powerpc: Deliver SEGV signal on pkey violation Ram Pai
2018-01-19 1:50 ` [PATCH v10 22/27] powerpc/ptrace: Add memory protection key regset Ram Pai
2018-01-19 1:50 ` [PATCH v10 23/27] powerpc: Enable pkey subsystem Ram Pai
2018-01-19 1:50 ` [PATCH v10 24/27] powerpc: sys_pkey_alloc() and sys_pkey_free() system calls Ram Pai
2018-01-19 1:50 ` [PATCH v10 25/27] powerpc: sys_pkey_mprotect() system call Ram Pai
2018-01-19 1:50 ` [PATCH v10 26/27] mm, x86 : introduce arch_pkeys_enabled() Ram Pai
2018-01-19 1:50 ` [PATCH v10 27/27] mm: display pkey in smaps if arch_pkeys_enabled() is true Ram Pai
2018-01-19 16:09 ` Eric W. Biederman
2018-01-19 16:50 ` Ram Pai
2018-01-19 17:04 ` Eric W. Biederman [this message]
2018-01-30 12:16 ` Michal Hocko
2018-01-30 16:28 ` Ram Pai
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