powerpc/kasan: Refactor update of early shadow mappings

kasan_remap_early_shadow_ro() and kasan_unmap_early_shadow_vmalloc()
are both updating the early shadow mapping: the first one sets
the mapping read-only while the other clears the mapping.

Refactor and create kasan_update_early_region()

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/8c496c0828de2608c7c940c45525d177e91b6f1b.1589866984.git.christophe.leroy@csgroup.eu

diff --git a/arch/powerpc/mm/kasan/kasan_init_32.c b/arch/powerpc/mm/kasan/kasan_init_32.c
index 91e2ade..10481d9 100644 (file)
--- a/arch/powerpc/mm/kasan/kasan_init_32.c
+++ b/arch/powerpc/mm/kasan/kasan_init_32.c
@@ -79,45 +79,42 @@ static int __init kasan_init_region(void *start, size_t size)
        return 0;
 }
 
-static void __init kasan_remap_early_shadow_ro(void)
+static void __init
+kasan_update_early_region(unsigned long k_start, unsigned long k_end, pte_t pte)
 {
-       pgprot_t prot = kasan_prot_ro();
-       unsigned long k_start = KASAN_SHADOW_START;
-       unsigned long k_end = KASAN_SHADOW_END;
        unsigned long k_cur;
        phys_addr_t pa = __pa(kasan_early_shadow_page);
 
-       kasan_populate_pte(kasan_early_shadow_pte, prot);
-
-       for (k_cur = k_start & PAGE_MASK; k_cur != k_end; k_cur += PAGE_SIZE) {
+       for (k_cur = k_start; k_cur != k_end; k_cur += PAGE_SIZE) {
                pmd_t *pmd = pmd_ptr_k(k_cur);
                pte_t *ptep = pte_offset_kernel(pmd, k_cur);
 
                if ((pte_val(*ptep) & PTE_RPN_MASK) != pa)
                        continue;
 
-               __set_pte_at(&init_mm, k_cur, ptep, pfn_pte(PHYS_PFN(pa), prot), 0);
+               __set_pte_at(&init_mm, k_cur, ptep, pte, 0);
        }
-       flush_tlb_kernel_range(KASAN_SHADOW_START, KASAN_SHADOW_END);
+
+       flush_tlb_kernel_range(k_start, k_end);
 }
 
-static void __init kasan_unmap_early_shadow_vmalloc(void)
+static void __init kasan_remap_early_shadow_ro(void)
 {
-       unsigned long k_start = (unsigned long)kasan_mem_to_shadow((void *)VMALLOC_START);
-       unsigned long k_end = (unsigned long)kasan_mem_to_shadow((void *)VMALLOC_END);
-       unsigned long k_cur;
+       pgprot_t prot = kasan_prot_ro();
        phys_addr_t pa = __pa(kasan_early_shadow_page);
 
-       for (k_cur = k_start & PAGE_MASK; k_cur < k_end; k_cur += PAGE_SIZE) {
-               pmd_t *pmd = pmd_offset(pud_offset(pgd_offset_k(k_cur), k_cur), k_cur);
-               pte_t *ptep = pte_offset_kernel(pmd, k_cur);
+       kasan_populate_pte(kasan_early_shadow_pte, prot);
 
-               if ((pte_val(*ptep) & PTE_RPN_MASK) != pa)
-                       continue;
+       kasan_update_early_region(KASAN_SHADOW_START, KASAN_SHADOW_END,
+                                 pfn_pte(PHYS_PFN(pa), prot));
+}
 
-               __set_pte_at(&init_mm, k_cur, ptep, __pte(0), 0);
-       }
-       flush_tlb_kernel_range(k_start, k_end);
+static void __init kasan_unmap_early_shadow_vmalloc(void)
+{
+       unsigned long k_start = (unsigned long)kasan_mem_to_shadow((void *)VMALLOC_START);
+       unsigned long k_end = (unsigned long)kasan_mem_to_shadow((void *)VMALLOC_END);
+
+       kasan_update_early_region(k_start, k_end, __pte(0));
 }
 
 static void __init kasan_mmu_init(void)