x86/boot/32: Restructure mk_early_pgtbl_32()

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

diff --git a/arch/x86/kernel/head32.c b/arch/x86/kernel/head32.c
index 2b65998070264fa04ff736afa1e712b5ac6577dd..bdce6321fabd0dab8659c449b4c9172ba7a4f290 100644 (file)
--- a/arch/x86/kernel/head32.c
+++ b/arch/x86/kernel/head32.c
@@ -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 */
@@ -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;
 }
-