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powerpc/mm: Use _PAGE_READ to indicate Read access

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This splits the _PAGE_RW bit into _PAGE_READ and _PAGE_WRITE. It also
removes the dependency on _PAGE_USER for implying read only. Few things
to note here is that, we have read implied with write and execute
permission. Hence we should always find _PAGE_READ set on hash pte
fault.

We still can't switch PROT_NONE to !(_PAGE_RWX). Auto numa depends on
marking a prot none pte _PAGE_WRITE. (For more details look at
b191f9b106 "mm: numa: preserve PTE write permissions across a NUMA
hinting fault")

Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Jeremy Kerr <jk@ozlabs.org>
Cc: Frederic Barrat <fbarrat@linux.vnet.ibm.com>
Acked-by: Ian Munsie <imunsie@au1.ibm.com>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This commit is contained in:
Aneesh Kumar K.V
2016-04-29 23:25:30 +10:00
committed by Michael Ellerman
parent ee3caed37d
commit c7d54842de
14 changed files with 49 additions and 37 deletions
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9
arch/powerpc/mm/hash_utils_64.c
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@@ -175,8 +175,9 @@ unsigned long htab_convert_pte_flags(unsigned long pteflags)
* or PP=0x3 for read-only (including writeable but clean pages).
*/
if (pteflags & _PAGE_USER) {
rflags |= 0x2;
if (!((pteflags & _PAGE_RW) && (pteflags & _PAGE_DIRTY)))
if (pteflags & _PAGE_RWX)
rflags |= 0x2;
if (!((pteflags & _PAGE_WRITE) && (pteflags & _PAGE_DIRTY)))
rflags |= 0x1;
}
/*
@@ -1209,7 +1210,7 @@ EXPORT_SYMBOL_GPL(hash_page);
int __hash_page(unsigned long ea, unsigned long msr, unsigned long trap,
unsigned long dsisr)
{
unsigned long access = _PAGE_PRESENT;
unsigned long access = _PAGE_PRESENT | _PAGE_READ;
unsigned long flags = 0;
struct mm_struct *mm = current->mm;
@@ -1220,7 +1221,7 @@ int __hash_page(unsigned long ea, unsigned long msr, unsigned long trap,
flags |= HPTE_NOHPTE_UPDATE;
if (dsisr & DSISR_ISSTORE)
access |= _PAGE_RW;
access |= _PAGE_WRITE;
/*
* We need to set the _PAGE_USER bit if MSR_PR is set or if we are
* accessing a userspace segment (even from the kernel). We assume