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x86/mm: Simplify PAE PGD sharing macros

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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 <dave.hansen@linux.intel.com>
Link: https://lore.kernel.org/all/20250414173238.6E3CDA56%40davehans-spike.ostc.intel.com
This commit is contained in:
Dave Hansen 2025-04-14 10:32:38 -07:00
parent eb9c7f00f2
commit 45fb940563
1 changed files with 3 additions and 8 deletions
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11
arch/x86/mm/pgtable.c
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@ -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