diff options
| author | Dave Hansen <dave.hansen@linux.intel.com> | 2025-04-14 10:32:41 -0700 |
|---|---|---|
| committer | Dave Hansen <dave.hansen@linux.intel.com> | 2025-04-17 10:39:25 -0700 |
| commit | 454e65b4fb38ddeea62472649ef16b5e8d285015 (patch) | |
| tree | aca58932d2ae1f4d84b1b0c64ebd189dd9342581 | |
| parent | 82f120010f3b86c2f9c1279452c1ecab7bc117d2 (diff) | |
x86/mm: Preallocate all PAE page tables
Finally, move away from having PAE kernels share any PMDs across
processes.
This was already the default on PTI kernels which are the common
case.
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Link: https://lore.kernel.org/all/20250414173241.1288CAB4%40davehans-spike.ostc.intel.com
| -rw-r--r-- | arch/x86/mm/pgtable.c | 12 |
1 files changed, 3 insertions, 9 deletions
diff --git a/arch/x86/mm/pgtable.c b/arch/x86/mm/pgtable.c index ca07db510d26..f4fa8fabf326 100644 --- a/arch/x86/mm/pgtable.c +++ b/arch/x86/mm/pgtable.c @@ -80,16 +80,11 @@ struct mm_struct *pgd_page_get_mm(struct page *page) static void pgd_ctor(struct mm_struct *mm, pgd_t *pgd) { - /* If the pgd points to a shared pagetable level (either the - ptes in non-PAE, or shared PMD in PAE), then just copy the - references from swapper_pg_dir. */ - if (CONFIG_PGTABLE_LEVELS == 2 || - (CONFIG_PGTABLE_LEVELS == 3 && SHARED_KERNEL_PMD) || - CONFIG_PGTABLE_LEVELS >= 4) { + /* PAE preallocates all its PMDs. No cloning needed. */ + if (!IS_ENABLED(CONFIG_X86_PAE)) clone_pgd_range(pgd + KERNEL_PGD_BOUNDARY, swapper_pg_dir + KERNEL_PGD_BOUNDARY, KERNEL_PGD_PTRS); - } /* List used to sync kernel mapping updates */ pgd_set_mm(pgd, mm); @@ -122,8 +117,7 @@ static void pgd_dtor(pgd_t *pgd) * all 4 top-level entries are used almost immediately in a * new process's life, we just pre-populate them here. */ -#define PREALLOCATED_PMDS (static_cpu_has(X86_FEATURE_PTI) ? \ - PTRS_PER_PGD : KERNEL_PGD_BOUNDARY) +#define PREALLOCATED_PMDS PTRS_PER_PGD #define MAX_PREALLOCATED_PMDS PTRS_PER_PGD /* |