Re: [RFC PATCH v2 2/3] mm: make pXd_addr_end() functions page-table entry aware
From: Christophe Leroy <hidden>
Date: 2020-09-08 08:17:46
Also in:
linux-arch, linux-arm-kernel, linux-mm, linux-s390, linux-um, lkml, sparclinux
Le 08/09/2020 à 09:46, Alexander Gordeev a écrit :
quoted hunk ↗ jump to hunk
On Tue, Sep 08, 2020 at 07:14:38AM +0200, Christophe Leroy wrote:quoted
You forgot arch/powerpc/mm/book3s64/subpage_prot.c it seems.Yes, and also two more sources :/ arch/powerpc/mm/kasan/8xx.c arch/powerpc/mm/kasan/kasan_init_32.c But these two are not quite obvious wrt pgd_addr_end() used while traversing pmds. Could you please clarify a bit?diff --git a/arch/powerpc/mm/kasan/8xx.c b/arch/powerpc/mm/kasan/8xx.c index 2784224..89c5053 100644 --- a/arch/powerpc/mm/kasan/8xx.c +++ b/arch/powerpc/mm/kasan/8xx.c@@ -15,8 +15,8 @@ for (k_cur = k_start; k_cur != k_end; k_cur = k_next, pmd += 2, block += SZ_8M) { pte_basic_t *new; - k_next = pgd_addr_end(k_cur, k_end); - k_next = pgd_addr_end(k_next, k_end); + k_next = pmd_addr_end(k_cur, k_end); + k_next = pmd_addr_end(k_next, k_end);
No, I don't think so. On powerpc32 we have only two levels, so pgd and pmd are more or less the same. But pmd_addr_end() as defined in include/asm-generic/pgtable-nopmd.h is a no-op, so I don't think it will work. It is likely that this function should iterate on pgd, then you get pmd = pmd_offset(pud_offset(p4d_offset(pgd)));
quoted hunk ↗ jump to hunk
if ((void *)pmd_page_vaddr(*pmd) != kasan_early_shadow_pte) continue;diff --git a/arch/powerpc/mm/kasan/kasan_init_32.c b/arch/powerpc/mm/kasan/kasan_init_32.c index fb29404..3f7d6dc6 100644 --- a/arch/powerpc/mm/kasan/kasan_init_32.c +++ b/arch/powerpc/mm/kasan/kasan_init_32.c@@ -38,7 +38,7 @@ int __init kasan_init_shadow_page_tables(unsigned long k_start, unsigned long k_ for (k_cur = k_start; k_cur != k_end; k_cur = k_next, pmd++) { pte_t *new; - k_next = pgd_addr_end(k_cur, k_end); + k_next = pmd_addr_end(k_cur, k_end);
Same here I get, iterate on pgd then get pmd = pmd_offset(pud_offset(p4d_offset(pgd)));
quoted hunk ↗ jump to hunk
if ((void *)pmd_page_vaddr(*pmd) != kasan_early_shadow_pte) continue;@@ -196,7 +196,7 @@ void __init kasan_early_init(void) kasan_populate_pte(kasan_early_shadow_pte, PAGE_KERNEL); do { - next = pgd_addr_end(addr, end); + next = pmd_addr_end(addr, end); pmd_populate_kernel(&init_mm, pmd, kasan_early_shadow_pte); } while (pmd++, addr = next, addr != end);
Christophe