Commit 45fb9405 authored by Dave Hansen's avatar Dave Hansen
Browse files

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: default avatarDave Hansen <dave.hansen@linux.intel.com>
Link: https://lore.kernel.org/all/20250414173238.6E3CDA56%40davehans-spike.ostc.intel.com
parent eb9c7f00

arch/x86/mm/pgtable.c

+3 −8
Original line number Diff line number Diff line
@@ -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