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x86/boot/32: De-uglify the 2/3 level paging difference in mk_early_pgtbl_32()

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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.

  [ bp: Move mk_early_pgtbl_32() declaration into a header. ]

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20231017211722.111059491@linutronix.de
This commit is contained in:
Thomas Gleixner
2023-10-17 23:23:26 +02:00
committed by Borislav Petkov (AMD)
parent 1e2dd572d2
commit a62f4ca106
2 changed files with 21 additions and 18 deletions
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arch/x86/include/asm/setup.h
+1
View File
@@ -126,6 +126,7 @@ void clear_bss(void);
#ifdef __i386__
asmlinkage void __init __noreturn i386_start_kernel(void);
void __init mk_early_pgtbl_32(void);
#else
asmlinkage void __init __noreturn x86_64_start_kernel(char *real_mode);
arch/x86/kernel/head32.c
+20 -18
View File
@@ -69,41 +69,43 @@ asmlinkage __visible void __init __noreturn i386_start_kernel(void)
* to the first kernel PMD. Note the upper half of each PMD or PTE are
* always zero at this stage.
*/
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++;
}