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authorAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>2016-11-24 15:09:54 +0530
committerMichael Ellerman <mpe@ellerman.id.au>2016-11-25 14:18:25 +1100
commit984d7a1ec67ce3a46324fa4bcb4c745bbc266cf2 (patch)
treeb195670447b52622a4f3b9679db3e6ec189d4054
parenta1ff57416af9a7971a801d553cd53edd8afb28d6 (diff)
downloadlinux-984d7a1ec67ce3a46324fa4bcb4c745bbc266cf2.tar.bz2
powerpc/mm: Fixup kernel read only mapping
With commit e58e87adc8bf9 ("powerpc/mm: Update _PAGE_KERNEL_RO") we started using the ppp value 0b110 to map kernel readonly. But that facility was only added as part of ISA 2.04. For earlier ISA version only supported ppp bit value for readonly mapping is 0b011. (This implies both user and kernel get mapped using the same ppp bit value for readonly mapping.). Update the code such that for earlier architecture version we use ppp value 0b011 for readonly mapping. We don't differentiate between power5+ and power5 here and apply the new ppp bits only from power6 (ISA 2.05). This keep the changes minimal. This fixes issue with PS3 spu usage reported at https://lkml.kernel.org/r/rep.1421449714.geoff@infradead.org Fixes: e58e87adc8bf9 ("powerpc/mm: Update _PAGE_KERNEL_RO") Cc: stable@vger.kernel.org # v4.7+ Tested-by: Geoff Levand <geoff@infradead.org> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
-rw-r--r--arch/powerpc/include/asm/mmu.h14
-rw-r--r--arch/powerpc/mm/hash_utils_64.c8
2 files changed, 16 insertions, 6 deletions
diff --git a/arch/powerpc/include/asm/mmu.h b/arch/powerpc/include/asm/mmu.h
index e88368354e49..e311c25751a4 100644
--- a/arch/powerpc/include/asm/mmu.h
+++ b/arch/powerpc/include/asm/mmu.h
@@ -29,6 +29,12 @@
*/
/*
+ * Kernel read only support.
+ * We added the ppp value 0b110 in ISA 2.04.
+ */
+#define MMU_FTR_KERNEL_RO ASM_CONST(0x00004000)
+
+/*
* We need to clear top 16bits of va (from the remaining 64 bits )in
* tlbie* instructions
*/
@@ -103,10 +109,10 @@
#define MMU_FTRS_POWER4 MMU_FTRS_DEFAULT_HPTE_ARCH_V2
#define MMU_FTRS_PPC970 MMU_FTRS_POWER4 | MMU_FTR_TLBIE_CROP_VA
#define MMU_FTRS_POWER5 MMU_FTRS_POWER4 | MMU_FTR_LOCKLESS_TLBIE
-#define MMU_FTRS_POWER6 MMU_FTRS_POWER4 | MMU_FTR_LOCKLESS_TLBIE
-#define MMU_FTRS_POWER7 MMU_FTRS_POWER4 | MMU_FTR_LOCKLESS_TLBIE
-#define MMU_FTRS_POWER8 MMU_FTRS_POWER4 | MMU_FTR_LOCKLESS_TLBIE
-#define MMU_FTRS_POWER9 MMU_FTRS_POWER4 | MMU_FTR_LOCKLESS_TLBIE
+#define MMU_FTRS_POWER6 MMU_FTRS_POWER4 | MMU_FTR_LOCKLESS_TLBIE | MMU_FTR_KERNEL_RO
+#define MMU_FTRS_POWER7 MMU_FTRS_POWER4 | MMU_FTR_LOCKLESS_TLBIE | MMU_FTR_KERNEL_RO
+#define MMU_FTRS_POWER8 MMU_FTRS_POWER4 | MMU_FTR_LOCKLESS_TLBIE | MMU_FTR_KERNEL_RO
+#define MMU_FTRS_POWER9 MMU_FTRS_POWER4 | MMU_FTR_LOCKLESS_TLBIE | MMU_FTR_KERNEL_RO
#define MMU_FTRS_CELL MMU_FTRS_DEFAULT_HPTE_ARCH_V2 | \
MMU_FTR_CI_LARGE_PAGE
#define MMU_FTRS_PA6T MMU_FTRS_DEFAULT_HPTE_ARCH_V2 | \
diff --git a/arch/powerpc/mm/hash_utils_64.c b/arch/powerpc/mm/hash_utils_64.c
index 5503078090cd..78dabf065ba9 100644
--- a/arch/powerpc/mm/hash_utils_64.c
+++ b/arch/powerpc/mm/hash_utils_64.c
@@ -193,8 +193,12 @@ unsigned long htab_convert_pte_flags(unsigned long pteflags)
/*
* Kernel read only mapped with ppp bits 0b110
*/
- if (!(pteflags & _PAGE_WRITE))
- rflags |= (HPTE_R_PP0 | 0x2);
+ if (!(pteflags & _PAGE_WRITE)) {
+ if (mmu_has_feature(MMU_FTR_KERNEL_RO))
+ rflags |= (HPTE_R_PP0 | 0x2);
+ else
+ rflags |= 0x3;
+ }
} else {
if (pteflags & _PAGE_RWX)
rflags |= 0x2;