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| author | Christophe Leroy <christophe.leroy@c-s.fr> | 2018-11-28 20:21:10 +0300 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2018-12-19 10:56:32 +0300 |
| commit | 385e89d5b20f5a7c33fd7c1904da0e6a8e1b366f (patch) | |
| tree | 6bca1bde5792cd345deca9a6dea1f0b929f42e31 /arch/powerpc/mm/pgtable.c | |
| parent | badb9687cec50bdba59746532de1969d6d26f3a7 (diff) | |
| download | linux-385e89d5b20f5a7c33fd7c1904da0e6a8e1b366f.tar.xz | |
powerpc/mm: add exec protection on powerpc 603
The 603 doesn't have a HASH table, TLB misses are handled by
software. It is then possible to generate page fault when
_PAGE_EXEC is not set like in nohash/32.
There is one "reserved" PTE bit available, this patch uses
it for _PAGE_EXEC.
In order to support it, set_pte_filter() and
set_access_flags_filter() are made common, and the handling
is made dependent on MMU_FTR_HPTE_TABLE
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to 'arch/powerpc/mm/pgtable.c')
| -rw-r--r-- | arch/powerpc/mm/pgtable.c | 20 |
1 files changed, 11 insertions, 9 deletions
diff --git a/arch/powerpc/mm/pgtable.c b/arch/powerpc/mm/pgtable.c index 1e33dccbd176..d3d61d29b4f1 100644 --- a/arch/powerpc/mm/pgtable.c +++ b/arch/powerpc/mm/pgtable.c @@ -74,7 +74,7 @@ static struct page *maybe_pte_to_page(pte_t pte) * support falls into the same category. */ -static pte_t set_pte_filter(pte_t pte) +static pte_t set_pte_filter_hash(pte_t pte) { if (radix_enabled()) return pte; @@ -93,14 +93,12 @@ static pte_t set_pte_filter(pte_t pte) return pte; } -static pte_t set_access_flags_filter(pte_t pte, struct vm_area_struct *vma, - int dirty) -{ - return pte; -} - #else /* CONFIG_PPC_BOOK3S */ +static pte_t set_pte_filter_hash(pte_t pte) { return pte; } + +#endif /* CONFIG_PPC_BOOK3S */ + /* Embedded type MMU with HW exec support. This is a bit more complicated * as we don't have two bits to spare for _PAGE_EXEC and _PAGE_HWEXEC so * instead we "filter out" the exec permission for non clean pages. @@ -109,6 +107,9 @@ static pte_t set_pte_filter(pte_t pte) { struct page *pg; + if (mmu_has_feature(MMU_FTR_HPTE_TABLE)) + return set_pte_filter_hash(pte); + /* No exec permission in the first place, move on */ if (!pte_exec(pte) || !pte_looks_normal(pte)) return pte; @@ -138,6 +139,9 @@ static pte_t set_access_flags_filter(pte_t pte, struct vm_area_struct *vma, { struct page *pg; + if (mmu_has_feature(MMU_FTR_HPTE_TABLE)) + return pte; + /* So here, we only care about exec faults, as we use them * to recover lost _PAGE_EXEC and perform I$/D$ coherency * if necessary. Also if _PAGE_EXEC is already set, same deal, @@ -172,8 +176,6 @@ static pte_t set_access_flags_filter(pte_t pte, struct vm_area_struct *vma, return pte_mkexec(pte); } -#endif /* CONFIG_PPC_BOOK3S */ - /* * set_pte stores a linux PTE into the linux page table. */ |