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| author |   Joerg Roedel <jroedel@suse.de> | 2018-07-18 11:41:05 +0200 |
|---|---|---|
| committer |   Thomas Gleixner <tglx@linutronix.de> | 2018-07-20 01:11:45 +0200 |
| commit | 1ac228a7c87f697d1d01eb6362a6b5246705b0dd (patch) | |
| tree | b883b01197ef55265df29797aca55f31aad18722 /arch/x86/mm | |
| parent | x86/mm/pti: Make pti_clone_kernel_text() compile on 32 bit (diff) | |
| download | linux-dev-1ac228a7c87f697d1d01eb6362a6b5246705b0dd.tar.xz linux-dev-1ac228a7c87f697d1d01eb6362a6b5246705b0dd.zip | |
x86/mm/pti: Keep permissions when cloning kernel text in pti_clone_kernel_text()
Mapping the kernel text area to user-space makes only sense if it has the
same permissions as in the kernel page-table. If permissions are different
this will cause a TLB reload when using the kernel page-table, which is as
good as not mapping it at all.
On 64-bit kernels this patch makes no difference, as the whole range cloned
by pti_clone_kernel_text() is mapped RO anyway. On 32 bit there are
writeable mappings in the range, so just keep the permissions as they are.
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Pavel Machek <pavel@ucw.cz>
Cc: "H . Peter Anvin" <hpa@zytor.com>
Cc: linux-mm@kvack.org
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: David Laight <David.Laight@aculab.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Eduardo Valentin <eduval@amazon.com>
Cc: Greg KH <gregkh@linuxfoundation.org>
Cc: Will Deacon <will.deacon@arm.com>
Cc: aliguori@amazon.com
Cc: daniel.gruss@iaik.tugraz.at
Cc: hughd@google.com
Cc: keescook@google.com
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Waiman Long <llong@redhat.com>
Cc: "David H . Gutteridge" <dhgutteridge@sympatico.ca>
Cc: joro@8bytes.org
Link: https://lkml.kernel.org/r/1531906876-13451-29-git-send-email-joro@8bytes.org
Diffstat (limited to 'arch/x86/mm')
| -rw-r--r-- | arch/x86/mm/pti.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/x86/mm/pti.c b/arch/x86/mm/pti.c index 453d23760941..e41ee93c430d 100644 --- a/arch/x86/mm/pti.c +++ b/arch/x86/mm/pti.c @@ -482,7 +482,7 @@ void pti_clone_kernel_text(void) * pti_set_kernel_image_nonglobal() did to clear the * global bit. */ - pti_clone_pmds(start, end, _PAGE_RW); + pti_clone_pmds(start, end, 0); } /* |