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x86/boot/32: Restructure mk_early_pgtbl_32()
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Prepare it for adding a temporary initrd mapping by splitting out the
actual map loop.

No functional change.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20231017211722.175910753@linutronix.de
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Thomas Gleixner authored and Borislav Petkov (AMD) committed Oct 18, 2023
1 parent a62f4ca commit 69ba866
Showing 1 changed file with 23 additions and 19 deletions.
42 changes: 23 additions & 19 deletions arch/x86/kernel/head32.c
Original file line number Diff line number Diff line change
Expand Up @@ -79,35 +79,40 @@ typedef pgd_t pl2_t;
#define SET_PL2(val) { .pgd = (val), }
#endif

void __init __no_stack_protector mk_early_pgtbl_32(void)
static __init __no_stack_protector pte_t init_map(pte_t pte, pte_t **ptep, pl2_t **pl2p,
const unsigned long limit)
{
/* 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);
pte_t pte, *ptep = (pte_t *)__pa_nodebug(__brk_base);
pl2_t *pl2p = (pl2_t *)__pa_nodebug(pl2_base);
unsigned long *ptr;
int i;

pte.pte = PTE_IDENT_ATTR;

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

*pl2p = pl2;
pl2_t pl2 = SET_PL2((unsigned long)*ptep | PDE_IDENT_ATTR);
int i;

**pl2p = pl2;
if (!IS_ENABLED(CONFIG_X86_PAE)) {
/* Kernel PDE entry */
*(pl2p + ((PAGE_OFFSET >> PGDIR_SHIFT))) = pl2;
*(*pl2p + ((PAGE_OFFSET >> PGDIR_SHIFT))) = pl2;
}

for (i = 0; i < PTRS_PER_PTE; i++) {
*ptep = pte;
**ptep = pte;
pte.pte += PAGE_SIZE;
ptep++;
(*ptep)++;
}
pl2p++;
(*pl2p)++;
}
return pte;
}

void __init __no_stack_protector mk_early_pgtbl_32(void)
{
/* 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);
pte_t pte, *ptep = (pte_t *)__pa_nodebug(__brk_base);
pl2_t *pl2p = (pl2_t *)__pa_nodebug(pl2_base);
unsigned long *ptr;

pte.pte = PTE_IDENT_ATTR;
pte = init_map(pte, &ptep, &pl2p, limit);

ptr = (unsigned long *)__pa_nodebug(&max_pfn_mapped);
/* Can't use pte_pfn() since it's a call with CONFIG_PARAVIRT */
Expand All @@ -116,4 +121,3 @@ void __init __no_stack_protector mk_early_pgtbl_32(void)
ptr = (unsigned long *)__pa_nodebug(&_brk_end);
*ptr = (unsigned long)ptep + PAGE_OFFSET;
}

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