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Subject[PATCH] x86 mm/init.c
This patch cleans up pagetable_init by
- pulling the setting of %cr4 out of the loops, only set them once.
- improve readability of the loops.
- change PAGE_KERNEL and friends to variables to avoid checking
cpu_has_pge all the time.

All pageing modes (PAE/PSE) have been tested.

--

Brian Gerst
diff -urN linux-2.5.9/arch/i386/kernel/i386_ksyms.c linux/arch/i386/kernel/i386_ksyms.c
--- linux-2.5.9/arch/i386/kernel/i386_ksyms.c Sun Apr 14 23:48:18 2002
+++ linux/arch/i386/kernel/i386_ksyms.c Tue Apr 23 22:31:25 2002
@@ -174,3 +174,7 @@

extern int is_sony_vaio_laptop;
EXPORT_SYMBOL(is_sony_vaio_laptop);
+
+EXPORT_SYMBOL(PAGE_KERNEL);
+EXPORT_SYMBOL(PAGE_KERNEL_RO);
+EXPORT_SYMBOL(PAGE_KERNEL_NOCACHE);
diff -urN linux-2.5.9/arch/i386/mm/init.c linux/arch/i386/mm/init.c
--- linux-2.5.9/arch/i386/mm/init.c Sun Apr 14 23:48:18 2002
+++ linux/arch/i386/mm/init.c Tue Apr 23 21:29:39 2002
@@ -180,32 +180,43 @@
}
}

+pgprot_t PAGE_KERNEL = __pgprot(__PAGE_KERNEL);
+pgprot_t PAGE_KERNEL_RO = __pgprot(__PAGE_KERNEL_RO);
+pgprot_t PAGE_KERNEL_NOCACHE = __pgprot(__PAGE_KERNEL_NOCACHE);
+
static void __init pagetable_init (void)
{
- unsigned long vaddr, end;
+ unsigned long vaddr, pfn, prot;
pgd_t *pgd, *pgd_base;
int i, j, k;
pmd_t *pmd;
pte_t *pte, *pte_base;

- /*
- * This can be zero as well - no problem, in that case we exit
- * the loops anyway due to the PTRS_PER_* conditions.
- */
- end = (unsigned long)__va(max_low_pfn*PAGE_SIZE);
-
pgd_base = swapper_pg_dir;
#if CONFIG_X86_PAE
for (i = 0; i < PTRS_PER_PGD; i++)
set_pgd(pgd_base + i, __pgd(1 + __pa(empty_zero_page)));
#endif
+
+ prot = _KERNPG_TABLE;
+ if (cpu_has_pse) {
+ set_in_cr4(X86_CR4_PSE);
+ prot |= _PAGE_PSE;
+ boot_cpu_data.wp_works_ok = 1;
+ }
+ if (cpu_has_pge) {
+ set_in_cr4(X86_CR4_PGE);
+ prot |= _PAGE_GLOBAL;
+ PAGE_KERNEL.pgprot |= _PAGE_GLOBAL;
+ PAGE_KERNEL_RO.pgprot |= _PAGE_GLOBAL;
+ PAGE_KERNEL_NOCACHE.pgprot |= _PAGE_GLOBAL;
+ }
+
+ pfn = 0;
i = __pgd_offset(PAGE_OFFSET);
pgd = pgd_base + i;

- for (; i < PTRS_PER_PGD; pgd++, i++) {
- vaddr = i*PGDIR_SIZE;
- if (end && (vaddr >= end))
- break;
+ for (; i < PTRS_PER_PGD && pfn < max_low_pfn; pgd++, i++) {
#if CONFIG_X86_PAE
pmd = (pmd_t *) alloc_bootmem_low_pages(PAGE_SIZE);
set_pgd(pgd, __pgd(__pa(pmd) + 0x1));
@@ -214,37 +225,21 @@
#endif
if (pmd != pmd_offset(pgd, 0))
BUG();
- for (j = 0; j < PTRS_PER_PMD; pmd++, j++) {
- vaddr = i*PGDIR_SIZE + j*PMD_SIZE;
- if (end && (vaddr >= end))
- break;
+ for (j = 0; j < PTRS_PER_PMD && pfn < max_low_pfn; pmd++, j++) {
if (cpu_has_pse) {
- unsigned long __pe;
-
- set_in_cr4(X86_CR4_PSE);
- boot_cpu_data.wp_works_ok = 1;
- __pe = _KERNPG_TABLE + _PAGE_PSE + __pa(vaddr);
- /* Make it "global" too if supported */
- if (cpu_has_pge) {
- set_in_cr4(X86_CR4_PGE);
- __pe += _PAGE_GLOBAL;
+ set_pmd(pmd, __pmd(prot + (pfn << PAGE_SHIFT)));
+ pfn += PMD_SIZE >> PAGE_SHIFT;
+ } else {
+ pte_base = pte = (pte_t *) alloc_bootmem_low_pages(PAGE_SIZE);
+
+ for (k = 0; k < PTRS_PER_PTE && pfn < max_low_pfn; pte++, k++) {
+ *pte = __mk_pte(pfn, PAGE_KERNEL);
+ pfn++;
}
- set_pmd(pmd, __pmd(__pe));
- continue;
+ set_pmd(pmd, __pmd(prot + __pa(pte_base)));
+ if (pte_base != pte_offset_kernel(pmd, 0))
+ BUG();
}
-
- pte_base = pte = (pte_t *) alloc_bootmem_low_pages(PAGE_SIZE);
-
- for (k = 0; k < PTRS_PER_PTE; pte++, k++) {
- vaddr = i*PGDIR_SIZE + j*PMD_SIZE + k*PAGE_SIZE;
- if (end && (vaddr >= end))
- break;
- *pte = mk_pte_phys(__pa(vaddr), PAGE_KERNEL);
- }
- set_pmd(pmd, __pmd(_KERNPG_TABLE + __pa(pte_base)));
- if (pte_base != pte_offset_kernel(pmd, 0))
- BUG();
-
}
}

diff -urN linux-2.5.9/include/asm-i386/pgtable.h linux/include/asm-i386/pgtable.h
--- linux-2.5.9/include/asm-i386/pgtable.h Mon Apr 22 19:35:31 2002
+++ linux/include/asm-i386/pgtable.h Tue Apr 23 22:25:48 2002
@@ -139,20 +139,7 @@
#define __PAGE_KERNEL_RO \
(_PAGE_PRESENT | _PAGE_DIRTY | _PAGE_ACCESSED)

-# define MAKE_GLOBAL(x) \
- ({ \
- pgprot_t __ret; \
- \
- if (cpu_has_pge) \
- __ret = __pgprot((x) | _PAGE_GLOBAL); \
- else \
- __ret = __pgprot(x); \
- __ret; \
- })
-
-#define PAGE_KERNEL MAKE_GLOBAL(__PAGE_KERNEL)
-#define PAGE_KERNEL_RO MAKE_GLOBAL(__PAGE_KERNEL_RO)
-#define PAGE_KERNEL_NOCACHE MAKE_GLOBAL(__PAGE_KERNEL_NOCACHE)
+extern pgprot_t PAGE_KERNEL, PAGE_KERNEL_RO, PAGE_KERNEL_NOCACHE;

/*
* The i386 can't do page protection for execute, and considers that
\
 
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