2.6.4-rc1 remove x86 boot page tables

diff -uNrX linux-ignore-files linux-2.6.4-rc1/arch/i386/boot/tools/build.c linux-2.6.4-rc1.nobootpgtbl/arch/i386/boot/tools/build.c
@@ -150,10 +150,8 @@
 	sz = sb.st_size;
 	fprintf (stderr, "System is %d kB\n", sz/1024);
 	sys_size = (sz + 15) / 16;
-	/* 0x40000*16 = 4.0 MB, reasonable estimate for the current maximum */
-	if (sys_size > (is_big_kernel ? 0x40000 : DEF_SYSSIZE))
-		die("System is too big. Try using %smodules.",
-			is_big_kernel ? "" : "bzImage or ");
+	if (!is_big_kernel && sys_size > DEF_SYSSIZE)
+		die("System is too big. Try using bzImage or modules.");
 	while (sz > 0) {
 		int l, n;
 

diff -uNrX linux-ignore-files linux-2.6.4-rc1/arch/i386/mach-voyager/voyager_basic.c linux-2.6.4-rc1.nobootpgtbl/arch/i386/mach-voyager/voyager_basic.c
@@ -32,6 +32,8 @@
 #include <asm/tlbflush.h>
 #include <asm/arch_hooks.h>
 
+extern void * boot_ioremap(unsigned long, unsigned long);
+
 /*
  * Power off function, if any
  */

@@ -131,10 +133,9 @@
 	__u8 cmos[4];
 	ClickMap_t *map;
 	unsigned long map_addr;
-	unsigned long old;
 
 	if(region >= CLICK_ENTRIES) {
-		printk("Voyager: Illegal ClickMap region %d\n", region);
+		printk(KERN_WARNING "Voyager: Illegal ClickMap region %d\n", region);
 		return 0;
 	}
 

@@ -143,12 +144,13 @@
 
 	map_addr = *(unsigned long *)cmos;
 
-	/* steal page 0 for this */
-	old = pg0[0];
-	pg0[0] = ((map_addr & PAGE_MASK) | _PAGE_RW | _PAGE_PRESENT);
-	local_flush_tlb();
-	/* now clear everything out but page 0 */
-	map = (ClickMap_t *)(map_addr & (~PAGE_MASK));
+	/* map in the clickmap */
+	map = boot_ioremap(map_addr, sizeof(*map));
+	if (!map) {
+		printk(KERN_WARNING "Voyager: cannot map ClickMap\n");
+		return 0;
+	}
+		
 
 	/* zero length is the end of the clickmap */
 	if(map->Entry[region].Length != 0) {

@@ -156,10 +158,6 @@
 		*start = map->Entry[region].Address;
 		retval = 1;
 	}
-
-	/* replace the mapping */
-	pg0[0] = old;
-	local_flush_tlb();
 	return retval;
 }
 

100 lines not on this page · raw message

diff -uNrX linux-ignore-files linux-2.6.4-rc1/arch/i386/mm/init.c linux-2.6.4-rc1.nobootpgtbl/arch/i386/mm/init.c
@@ -288,6 +288,11 @@
 
 #ifdef CONFIG_X86_PAE
 	int i;
+	if (!cpu_has_pae)
+		panic("cannot execute a PAE-enabled kernel on a PAE-less CPU!");
+
+	set_in_cr4(X86_CR4_PAE);
+
 	/* Init entries of the first-level page table to the zero page */
 	for (i = 0; i < PTRS_PER_PGD; i++)
 		set_pgd(pgd_base + i, __pgd(__pa(empty_zero_page) | _PAGE_PRESENT));

@@ -316,16 +321,23 @@
 
 	permanent_kmaps_init(pgd_base);
 
-#ifdef CONFIG_X86_PAE
 	/*
-	 * Add low memory identity-mappings - SMP needs it when
-	 * starting up on an AP from real-mode. In the non-PAE
-	 * case we already have these mappings through head.S.
-	 * All user-space mappings are explicitly cleared after
+	 * Identity map the code between _text and _stext.  This
+	 * identity mapping needs to persist through SMP startup.
+	 *
+	 * The only real user is paging_start() which needs to
+	 * live on an identity mapped page to transition from physical
+	 * to virtual address mode.  paging_start() must be called
+	 * on each processor so this mapping needs to persist through
 	 * SMP startup.
+	 *
+	 * After SMP startup all user-space mappings are explicitly
+	 * cleared which removes the identity mapping.
+	 * 
+	 * Identity mapping the first pgd entry is overkill but it
+	 * is an extremely easy way to accomplish the needed mapping.
 	 */
 	pgd_base[0] = pgd_base[USER_PTRS_PER_PGD];
-#endif
 }
 
 void zap_low_mappings (void)

@@ -382,17 +394,7 @@
 {
 	pagetable_init();
 
-	load_cr3(swapper_pg_dir);
-
-#ifdef CONFIG_X86_PAE
-	/*
-	 * We will bail out later - printk doesn't work right now so
-	 * the user would just see a hanging kernel.
-	 */
-	if (cpu_has_pae)
-		set_in_cr4(X86_CR4_PAE);
-#endif
-	__flush_tlb_all();
+	paging_start();
 
 	kmap_init();
 	zone_sizes_init();

@@ -508,10 +510,6 @@
 		(unsigned long) (totalhigh_pages << (PAGE_SHIFT-10))
 	       );
 
-#ifdef CONFIG_X86_PAE
-	if (!cpu_has_pae)
-		panic("cannot execute a PAE-enabled kernel on a PAE-less CPU!");
-#endif
 	if (boot_cpu_data.wp_works_ok < 0)
 		test_wp_bit();
 

diff -uNrX linux-ignore-files linux-2.6.4-rc1/include/asm-i386/pgtable.h linux-2.6.4-rc1.nobootpgtbl/include/asm-i386/pgtable.h
@@ -42,6 +42,7 @@
 void pgd_dtor(void *, kmem_cache_t *, unsigned long);
 void pgtable_cache_init(void);
 void paging_init(void);
+void paging_start(void);
 
 #endif /* !__ASSEMBLY__ */
 

diff -uNrX linux-ignore-files linux-2.6.4-rc1/include/asm-i386/segment.h linux-2.6.4-rc1.nobootpgtbl/include/asm-i386/segment.h
@@ -88,6 +88,11 @@
 #define GDT_ENTRY_BOOT_DS		(GDT_ENTRY_BOOT_CS + 1)
 #define __BOOT_DS	(GDT_ENTRY_BOOT_DS * 8)
 
+/* Additional GDT entries for ..... */
+#define GDT_ENTRY_VIRT_CS		4
+#define __VIRT_CS	(GDT_ENTRY_VIRT_CS * 8)
+#define GDT_ENTRY_VIRT_DS		(GDT_ENTRY_VIRT_CS + 1)
+#define __VIRT_DS	(GDT_ENTRY_VIRT_DS * 8)
 /*
  * The interrupt descriptor table has room for 256 idt's,
  * the global descriptor table is dependent on the number

diff -urN linux-bootseg/arch/i386/kernel/setup.c linux/arch/i386/kernel/setup.c
@@ -126,6 +126,8 @@
 static char command_line[COMMAND_LINE_SIZE];
        char saved_command_line[COMMAND_LINE_SIZE];
 
+unsigned char __initdata boot_params[PARAM_SIZE] = { 0, };
+
 static struct resource code_resource = { "Kernel code", 0x100000, 0 };
 static struct resource data_resource = { "Kernel data", 0, 0 };
 

@@ -452,7 +454,7 @@
 #endif
 /**
  * copy_edd() - Copy the BIOS EDD information
- *              from empty_zero_page into a safe place.
+ *              from boot_param into a safe place.
  *
  */
 static inline void copy_edd(void)

@@ -481,12 +483,11 @@
 
 static void __init parse_cmdline_early (char ** cmdline_p)
 {
-	char c = ' ', *to = command_line, *from = COMMAND_LINE;
+	char c = ' ', *to = command_line, *from = saved_command_line;
 	int len = 0;
 	int userdef = 0;
 
 	/* Save unparsed command line copy for /proc/cmdline */
-	memcpy(saved_command_line, COMMAND_LINE, COMMAND_LINE_SIZE);
 	saved_command_line[COMMAND_LINE_SIZE-1] = '\0';
 
 	for (;;) {

diff -urN linux-bootseg/arch/i386/mm/init.c linux/arch/i386/mm/init.c
@@ -476,9 +476,6 @@
 	high_memory = (void *) __va(max_low_pfn * PAGE_SIZE);
 #endif
 
-	/* clear the zero-page */
-	memset(empty_zero_page, 0, PAGE_SIZE);
-
 	/* this will put all low memory onto the freelists */
 	totalram_pages += __free_all_bootmem();
 

diff -urN linux-bootseg/include/asm-i386/setup.h linux/include/asm-i386/setup.h
@@ -16,10 +16,22 @@
 #define MAXMEM_PFN	PFN_DOWN(MAXMEM)
 #define MAX_NONPAE_PFN	(1 << 20)
 
+#define PARAM_SIZE 2048
+#define COMMAND_LINE_SIZE 256
+
+#define OLD_CL_MAGIC_ADDR	0x90020
+#define OLD_CL_MAGIC		0xA33F
+#define OLD_CL_BASE_ADDR	0x90000
+#define OLD_CL_OFFSET		0x90022
+#define NEW_CL_POINTER		0x228	/* Relative to real mode data */
+
+#ifndef __ASSEMBLY__
 /*
  * This is set up by the setup-routine at boot-time
  */
-#define PARAM	((unsigned char *)empty_zero_page)
+extern unsigned char boot_params[PARAM_SIZE];
+
+#define PARAM	(boot_params)
 #define SCREEN_INFO (*(struct screen_info *) (PARAM+0))
 #define EXT_MEM_K (*(unsigned short *) (PARAM+2))
 #define ALT_MEM_K (*(unsigned long *) (PARAM+0x1e0))

@@ -47,7 +59,7 @@
 #define DISK80_SIGNATURE (*(unsigned int*) (PARAM+DISK80_SIG_BUFFER))
 #define EDD_NR     (*(unsigned char *) (PARAM+EDDNR))
 #define EDD_BUF     ((struct edd_info *) (PARAM+EDDBUF))
-#define COMMAND_LINE ((char *) (PARAM+2048))
-#define COMMAND_LINE_SIZE 256
+
+#endif /* __ASSEMBLY__ */
 
 #endif /* _i386_SETUP_H */