[patch V5 03/39] x86/boot/32: De-uglify the 2/3 level paging difference in mk_early_pgtbl_32()

From: Thomas Gleixner
Date: Tue Oct 17 2023 - 17:23:37 EST


Move the ifdeffery out of the function and use proper typedefs to make it
work for both 2 and 3 level paging.

No functional change.

Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
---
V5: New patch
---
arch/x86/kernel/head32.c | 38 +++++++++++++++++++++-----------------
1 file changed, 21 insertions(+), 17 deletions(-)

--- a/arch/x86/kernel/head32.c
+++ b/arch/x86/kernel/head32.c
@@ -71,39 +71,43 @@ asmlinkage __visible void __init __noret
*/
void __init mk_early_pgtbl_32(void);

+#ifdef CONFIG_X86_PAE
+typedef pmd_t pl2_t;
+#define pl2_base initial_pg_pmd
+#define SET_PL2(val) { .pmd = (val), }
+#else
+typedef pgd_t pl2_t;
+#define pl2_base initial_page_table
+#define SET_PL2(val) { .pgd = (val), }
+#endif
+
void __init __no_stack_protector mk_early_pgtbl_32(void)
{
- pte_t pte, *ptep;
- int i;
- unsigned long *ptr;
/* Enough space to fit pagetables for the low memory linear map */
const unsigned long limit = __pa_nodebug(_end) +
(PAGE_TABLE_SIZE(LOWMEM_PAGES) << PAGE_SHIFT);
-#ifdef CONFIG_X86_PAE
- pmd_t pl2, *pl2p = (pmd_t *)__pa_nodebug(initial_pg_pmd);
-#define SET_PL2(pl2, val) { (pl2).pmd = (val); }
-#else
- pgd_t pl2, *pl2p = (pgd_t *)__pa_nodebug(initial_page_table);
-#define SET_PL2(pl2, val) { (pl2).pgd = (val); }
-#endif
+ pte_t pte, *ptep = (pte_t *)__pa_nodebug(__brk_base);
+ pl2_t *pl2p = (pl2_t *)__pa_nodebug(pl2_base);
+ unsigned long *ptr;
+ int i;

- ptep = (pte_t *)__pa_nodebug(__brk_base);
pte.pte = PTE_IDENT_ATTR;

while ((pte.pte & PTE_PFN_MASK) < limit) {
+ pl2_t pl2 = SET_PL2((unsigned long)ptep | PDE_IDENT_ATTR);

- SET_PL2(pl2, (unsigned long)ptep | PDE_IDENT_ATTR);
*pl2p = pl2;
-#ifndef CONFIG_X86_PAE
- /* Kernel PDE entry */
- *(pl2p + ((PAGE_OFFSET >> PGDIR_SHIFT))) = pl2;
-#endif
+
+ if (!IS_ENABLED(CONFIG_X86_PAE)) {
+ /* Kernel PDE entry */
+ *(pl2p + ((PAGE_OFFSET >> PGDIR_SHIFT))) = pl2;
+ }
+
for (i = 0; i < PTRS_PER_PTE; i++) {
*ptep = pte;
pte.pte += PAGE_SIZE;
ptep++;
}
-
pl2p++;
}