[PATCH v2 03/13] mm/debug_vm_pgtable/ppc64: Avoid setting top bits in radom value
From: Aneesh Kumar K.V <hidden>
Date: 2020-08-19 13:02:29
Also in:
linux-mm
Subsystem:
memory management, the rest · Maintainers:
Andrew Morton, Linus Torvalds
ppc64 use bit 62 to indicate a pte entry (_PAGE_PTE). Avoid setting that bit in random value. Signed-off-by: Aneesh Kumar K.V <redacted> --- mm/debug_vm_pgtable.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-)
diff --git a/mm/debug_vm_pgtable.c b/mm/debug_vm_pgtable.c
index 086309fb9b6f..57259e2dbd17 100644
--- a/mm/debug_vm_pgtable.c
+++ b/mm/debug_vm_pgtable.c@@ -44,10 +44,13 @@ * entry type. But these bits might affect the ability to clear entries with * pxx_clear() because of how dynamic page table folding works on s390. So * while loading up the entries do not change the lower 4 bits. It does not - * have affect any other platform. + * have affect any other platform. Also avoid the 62nd bit on ppc64 that is + * used to mark a pte entry. */ -#define S390_MASK_BITS 4 -#define RANDOM_ORVALUE GENMASK(BITS_PER_LONG - 1, S390_MASK_BITS) +#define S390_SKIP_MASK GENMASK(3, 0) +#define PPC64_SKIP_MASK GENMASK(62, 62) +#define ARCH_SKIP_MASK (S390_SKIP_MASK | PPC64_SKIP_MASK) +#define RANDOM_ORVALUE (GENMASK(BITS_PER_LONG - 1, 0) & ~ARCH_SKIP_MASK) #define RANDOM_NZVALUE GENMASK(7, 0) static void __init pte_basic_tests(unsigned long pfn, pgprot_t prot)
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2.26.2