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Subject[PATCH 1/2] powerpc/mm: Add a helper to select PAGE_KERNEL_RO or PAGE_READONLY
Date
In a couple of places there is a need to select whether read-only
protection of shadow pages is performed with PAGE_KERNEL_RO or with
PAGE_READONLY.

Add a helper to avoid duplicating the choice.

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Cc: stable@vger.kernel.org

---
This small series applies on top of patch "powerpc/kasan: fix parallele
loading of modules" (https://patchwork.ozlabs.org/patch/1144757/).
Otherwise a manual merge has to be done (the modifications are
independant but close to each other in the file.)
---
arch/powerpc/mm/kasan/kasan_init_32.c | 21 +++++++++++++--------
1 file changed, 13 insertions(+), 8 deletions(-)

diff --git a/arch/powerpc/mm/kasan/kasan_init_32.c b/arch/powerpc/mm/kasan/kasan_init_32.c
index 802387b231ad..e8ab3cc5f6e4 100644
--- a/arch/powerpc/mm/kasan/kasan_init_32.c
+++ b/arch/powerpc/mm/kasan/kasan_init_32.c
@@ -12,6 +12,14 @@
#include <asm/code-patching.h>
#include <mm/mmu_decl.h>

+static pgprot_t kasan_prot_ro(void)
+{
+ if (early_mmu_has_feature(MMU_FTR_HPTE_TABLE))
+ return PAGE_READONLY;
+
+ return PAGE_KERNEL_RO;
+}
+
static void kasan_populate_pte(pte_t *ptep, pgprot_t prot)
{
unsigned long va = (unsigned long)kasan_early_shadow_page;
@@ -26,6 +34,7 @@ static int __ref kasan_init_shadow_page_tables(unsigned long k_start, unsigned l
{
pmd_t *pmd;
unsigned long k_cur, k_next;
+ pgprot_t prot = kasan_prot_ro();

pmd = pmd_offset(pud_offset(pgd_offset_k(k_start), k_start), k_start);

@@ -43,10 +52,7 @@ static int __ref kasan_init_shadow_page_tables(unsigned long k_start, unsigned l

if (!new)
return -ENOMEM;
- if (early_mmu_has_feature(MMU_FTR_HPTE_TABLE))
- kasan_populate_pte(new, PAGE_READONLY);
- else
- kasan_populate_pte(new, PAGE_KERNEL_RO);
+ kasan_populate_pte(new, prot);

smp_wmb(); /* See comment in __pte_alloc */

@@ -103,10 +109,9 @@ static int __ref kasan_init_region(void *start, size_t size)

static void __init kasan_remap_early_shadow_ro(void)
{
- if (early_mmu_has_feature(MMU_FTR_HPTE_TABLE))
- kasan_populate_pte(kasan_early_shadow_pte, PAGE_READONLY);
- else
- kasan_populate_pte(kasan_early_shadow_pte, PAGE_KERNEL_RO);
+ pgprot_t prot = kasan_prot_ro();
+
+ kasan_populate_pte(kasan_early_shadow_pte, prot);

flush_tlb_kernel_range(KASAN_SHADOW_START, KASAN_SHADOW_END);
}
--
2.13.3
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