6.11-stable review patch. If anyone has any objections, please let me know.
------------------
From: Huacai Chen chenhuacai@loongson.cn
commit a410656643ce4844ba9875aa4e87a7779308259b upstream.
Make KASAN work with 5-level page-tables, including: 1. Implement and use __pgd_none() and kasan_p4d_offset(). 2. As done in kasan_pmd_populate() and kasan_pte_populate(), restrict the loop conditions of kasan_p4d_populate() and kasan_pud_populate() to avoid unnecessary population.
Cc: stable@vger.kernel.org Signed-off-by: Huacai Chen chenhuacai@loongson.cn Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/loongarch/mm/kasan_init.c | 26 +++++++++++++++++++++++--- 1 file changed, 23 insertions(+), 3 deletions(-)
--- a/arch/loongarch/mm/kasan_init.c +++ b/arch/loongarch/mm/kasan_init.c @@ -13,6 +13,13 @@
static pgd_t kasan_pg_dir[PTRS_PER_PGD] __initdata __aligned(PAGE_SIZE);
+#ifdef __PAGETABLE_P4D_FOLDED +#define __pgd_none(early, pgd) (0) +#else +#define __pgd_none(early, pgd) (early ? (pgd_val(pgd) == 0) : \ +(__pa(pgd_val(pgd)) == (unsigned long)__pa(kasan_early_shadow_p4d))) +#endif + #ifdef __PAGETABLE_PUD_FOLDED #define __p4d_none(early, p4d) (0) #else @@ -147,6 +154,19 @@ static pud_t *__init kasan_pud_offset(p4 return pud_offset(p4dp, addr); }
+static p4d_t *__init kasan_p4d_offset(pgd_t *pgdp, unsigned long addr, int node, bool early) +{ + if (__pgd_none(early, pgdp_get(pgdp))) { + phys_addr_t p4d_phys = early ? + __pa_symbol(kasan_early_shadow_p4d) : kasan_alloc_zeroed_page(node); + if (!early) + memcpy(__va(p4d_phys), kasan_early_shadow_p4d, sizeof(kasan_early_shadow_p4d)); + pgd_populate(&init_mm, pgdp, (p4d_t *)__va(p4d_phys)); + } + + return p4d_offset(pgdp, addr); +} + static void __init kasan_pte_populate(pmd_t *pmdp, unsigned long addr, unsigned long end, int node, bool early) { @@ -183,19 +203,19 @@ static void __init kasan_pud_populate(p4 do { next = pud_addr_end(addr, end); kasan_pmd_populate(pudp, addr, next, node, early); - } while (pudp++, addr = next, addr != end); + } while (pudp++, addr = next, addr != end && __pud_none(early, READ_ONCE(*pudp))); }
static void __init kasan_p4d_populate(pgd_t *pgdp, unsigned long addr, unsigned long end, int node, bool early) { unsigned long next; - p4d_t *p4dp = p4d_offset(pgdp, addr); + p4d_t *p4dp = kasan_p4d_offset(pgdp, addr, node, early);
do { next = p4d_addr_end(addr, end); kasan_pud_populate(p4dp, addr, next, node, early); - } while (p4dp++, addr = next, addr != end); + } while (p4dp++, addr = next, addr != end && __p4d_none(early, READ_ONCE(*p4dp))); }
static void __init kasan_pgd_populate(unsigned long addr, unsigned long end,