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x86 mm init cleanup

PATCH In review Brian Gerst 2 participants 3 messages Nov 18, 2000

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Brian Gerst

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#0 lore raw

PATCH 1/1 x86 mm init cleanup

Patch against test11. This patch moves the setting of %cr4 out of the loops and makes the code a bit more readable. Tested with standard pagetables, PSE, and PAE.

Signature · 1 line
						Brian Gerst
arch/i386/mm/init.c +29 -28
diff -urN linux-2.4.0t11p5/arch/i386/mm/init.c linux/arch/i386/mm/init.c
@@ -315,7 +315,7 @@
 
 static void __init pagetable_init (void)
 {
-	unsigned long vaddr, end;
+	unsigned long vaddr, end, __pe;
 	pgd_t *pgd, *pgd_base;
 	int i, j, k;
 	pmd_t *pmd;

@@ -334,11 +334,23 @@
 		__pgd_clear(pgd);
 	}
 #endif
-	i = __pgd_offset(PAGE_OFFSET);
+
+	__pe = _KERNPG_TABLE;
+	if (cpu_has_pse) {
+		set_in_cr4(X86_CR4_PSE);
+		__pe += _PAGE_PSE;
+		boot_cpu_data.wp_works_ok = 1;
+		if (cpu_has_pge) {
+			set_in_cr4(X86_CR4_PGE);
+			__pe += _PAGE_GLOBAL;
+		}
+	}
+
+	vaddr = PAGE_OFFSET;
+	i = __pgd_offset(vaddr);
 	pgd = pgd_base + i;
 
 	for (; i < PTRS_PER_PGD; pgd++, i++) {
-		vaddr = i*PGDIR_SIZE;
 		if (end && (vaddr >= end))
 			break;
 #if CONFIG_X86_PAE

@@ -350,35 +362,24 @@
 		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;
 			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(__pe + __pa(vaddr)));
+				vaddr += PMD_SIZE;
+			} else {
+				pte = (pte_t *) alloc_bootmem_low_pages(PAGE_SIZE);
+				set_pmd(pmd, __pmd(__pe + __pa(pte)));
+
+				if (pte != pte_offset(pmd, 0))
+					BUG();
+
+				for (k = 0; k < PTRS_PER_PTE; pte++, k++) {
+					if (end && (vaddr >= end))
+						break;
+					*pte = mk_pte_phys(__pa(vaddr), PAGE_KERNEL);
+					vaddr += PAGE_SIZE;
 				}
-				set_pmd(pmd, __pmd(__pe));
-				continue;
-			}
-
-			pte = (pte_t *) alloc_bootmem_low_pages(PAGE_SIZE);
-			set_pmd(pmd, __pmd(_KERNPG_TABLE + __pa(pte)));
-
-			if (pte != pte_offset(pmd, 0))
-				BUG();
-
-			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);
 			}
 		}
 	}
#1 lore raw
Quoted 5 lines · Brian Gerst

Patch against test11. This patch moves the setting of %cr4 out of the loops and makes the code a bit more readable. Tested with standard pagetables, PSE, and PAE.

Brian,

while you were there, so close to paging_init() why not also correct the wrong comment at the top of the function? It talks about 0-4M pagetables whereas we really setup (see head.S) 0-8M.

Regards,
Tigran

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author
#2 lore raw
Quoted 9 lines · Tigran Aivazian
Quoted 5 lines · Brian Gerst

Patch against test11. This patch moves the setting of %cr4 out of the loops and makes the code a bit more readable. Tested with standard pagetables, PSE, and PAE.

Quoted 8 lines

Brian,

while you were there, so close to paging_init() why not also correct the wrong comment at the top of the function? It talks about 0-4M pagetables whereas we really setup (see head.S) 0-8M.

Regards,
Tigran

Add this little patch then

Signature · 1 line
						Brian Gerst
arch/i386/mm/init.c +1 -1
diff -urN linux-2.4.0t11p7/arch/i386/mm/init.c linux/arch/i386/mm/init.c
@@ -437,7 +437,7 @@
 }
 
 /*
- * paging_init() sets up the page tables - note that the first 4MB are
+ * paging_init() sets up the page tables - note that the first 8MB are
  * already mapped by head.S.
  *
  * This routines also unmaps the page at virtual kernel address 0, so