From: Dave Hansen Date: Mon, 14 Apr 2025 17:32:38 +0000 (-0700) Subject: x86/mm: Simplify PAE PGD sharing macros X-Git-Tag: v6.16-rc1~195^2~26^2~5 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=45fb940563f80b8138f465f18d71c2d3e4a0724e;p=thirdparty%2Fkernel%2Flinux.git x86/mm: Simplify PAE PGD sharing macros There are a few too many levels of abstraction here. First, just expand the PREALLOCATED_PMDS macro in place to make it clear that it is only conditional on PTI. Second, MAX_PREALLOCATED_PMDS is only used in one spot for an on-stack allocation. It has a *maximum* value of 4. Do not bother with the macro MAX() magic. Just set it to 4. Signed-off-by: Dave Hansen Link: https://lore.kernel.org/all/20250414173238.6E3CDA56%40davehans-spike.ostc.intel.com --- diff --git a/arch/x86/mm/pgtable.c b/arch/x86/mm/pgtable.c index f1c58860b9261..027e1d32925c4 100644 --- a/arch/x86/mm/pgtable.c +++ b/arch/x86/mm/pgtable.c @@ -68,12 +68,6 @@ static inline void pgd_list_del(pgd_t *pgd) list_del(&ptdesc->pt_list); } -#define UNSHARED_PTRS_PER_PGD \ - (SHARED_KERNEL_PMD ? KERNEL_PGD_BOUNDARY : PTRS_PER_PGD) -#define MAX_UNSHARED_PTRS_PER_PGD \ - MAX_T(size_t, KERNEL_PGD_BOUNDARY, PTRS_PER_PGD) - - static void pgd_set_mm(pgd_t *pgd, struct mm_struct *mm) { virt_to_ptdesc(pgd)->pt_mm = mm; @@ -132,8 +126,9 @@ static void pgd_dtor(pgd_t *pgd) * not shared between pagetables (!SHARED_KERNEL_PMDS), we allocate * and initialize the kernel pmds here. */ -#define PREALLOCATED_PMDS UNSHARED_PTRS_PER_PGD -#define MAX_PREALLOCATED_PMDS MAX_UNSHARED_PTRS_PER_PGD +#define PREALLOCATED_PMDS (static_cpu_has(X86_FEATURE_PTI) ? \ + PTRS_PER_PGD : KERNEL_PGD_BOUNDARY) +#define MAX_PREALLOCATED_PMDS PTRS_PER_PGD /* * We allocate separate PMDs for the kernel part of the user page-table