From ccf3fe02e35f4abca2589f99022cc25084bbd8ae Mon Sep 17 00:00:00 2001 From: Jeremy Fitzhardinge Date: Fri, 27 Feb 2009 13:27:38 -0800 Subject: [PATCH] x86-32: use brk segment for allocating initial kernel pagetable Impact: use new interface instead of previous ad hoc implementation Rather than having special purpose init_pg_table_start/end variables to delimit the kernel pagetable built by head_32.S, just use the brk mechanism to extend the bss for the new pagetable. This patch removes init_pg_table_start/end and pg0, defines __brk_base (which is page-aligned and immediately follows _end), initializes the brk region to start there, and uses it for the 32-bit pagetable. Signed-off-by: Jeremy Fitzhardinge Signed-off-by: H. Peter Anvin --- arch/x86/include/asm/pgtable_32.h | 3 --- arch/x86/include/asm/setup.h | 3 --- arch/x86/kernel/head32.c | 3 --- arch/x86/kernel/head_32.S | 14 +++++++------- arch/x86/kernel/setup.c | 6 ------ arch/x86/kernel/vmlinux_32.lds.S | 4 ---- arch/x86/lguest/boot.c | 8 -------- 7 files changed, 7 insertions(+), 34 deletions(-) diff --git a/arch/x86/include/asm/pgtable_32.h b/arch/x86/include/asm/pgtable_32.h index 97612fc7632f..31bd120cf2a2 100644 --- a/arch/x86/include/asm/pgtable_32.h +++ b/arch/x86/include/asm/pgtable_32.h @@ -42,9 +42,6 @@ extern void set_pmd_pfn(unsigned long, unsigned long, pgprot_t); */ #undef TEST_ACCESS_OK -/* The boot page tables (all created as a single array) */ -extern unsigned long pg0[]; - #ifdef CONFIG_X86_PAE # include #else diff --git a/arch/x86/include/asm/setup.h b/arch/x86/include/asm/setup.h index 45454f3fa121..366d36639940 100644 --- a/arch/x86/include/asm/setup.h +++ b/arch/x86/include/asm/setup.h @@ -109,9 +109,6 @@ void *extend_brk(size_t size, size_t align); void __init i386_start_kernel(void); extern void probe_roms(void); -extern unsigned long init_pg_tables_start; -extern unsigned long init_pg_tables_end; - #else void __init x86_64_start_kernel(char *real_mode); void __init x86_64_start_reservations(char *real_mode_data); diff --git a/arch/x86/kernel/head32.c b/arch/x86/kernel/head32.c index 29f1095b0849..3f8579f8d42c 100644 --- a/arch/x86/kernel/head32.c +++ b/arch/x86/kernel/head32.c @@ -29,9 +29,6 @@ void __init i386_start_kernel(void) reserve_early(ramdisk_image, ramdisk_end, "RAMDISK"); } #endif - reserve_early(init_pg_tables_start, init_pg_tables_end, - "INIT_PG_TABLE"); - reserve_ebda_region(); /* diff --git a/arch/x86/kernel/head_32.S b/arch/x86/kernel/head_32.S index c32ca19d591a..db6652710e98 100644 --- a/arch/x86/kernel/head_32.S +++ b/arch/x86/kernel/head_32.S @@ -167,7 +167,7 @@ num_subarch_entries = (. - subarch_entries) / 4 /* * Initialize page tables. This creates a PDE and a set of page * tables, which are located immediately beyond _end. The variable - * init_pg_tables_end is set up to point to the first "safe" location. + * _brk_end is set up to point to the first "safe" location. * Mappings are created both at virtual address 0 (identity mapping) * and PAGE_OFFSET for up to _end+sizeof(page tables)+INIT_MAP_BEYOND_END. * @@ -190,8 +190,7 @@ default_entry: xorl %ebx,%ebx /* %ebx is kept at zero */ - movl $pa(pg0), %edi - movl %edi, pa(init_pg_tables_start) + movl $pa(__brk_base), %edi movl $pa(swapper_pg_pmd), %edx movl $PTE_IDENT_ATTR, %eax 10: @@ -216,7 +215,8 @@ default_entry: cmpl %ebp,%eax jb 10b 1: - movl %edi,pa(init_pg_tables_end) + addl $__PAGE_OFFSET, %edi + movl %edi, pa(_brk_end) shrl $12, %eax movl %eax, pa(max_pfn_mapped) @@ -227,8 +227,7 @@ default_entry: page_pde_offset = (__PAGE_OFFSET >> 20); - movl $pa(pg0), %edi - movl %edi, pa(init_pg_tables_start) + movl $pa(__brk_base), %edi movl $pa(swapper_pg_dir), %edx movl $PTE_IDENT_ATTR, %eax 10: @@ -249,7 +248,8 @@ page_pde_offset = (__PAGE_OFFSET >> 20); leal (INIT_MAP_BEYOND_END+PTE_IDENT_ATTR)(%edi),%ebp cmpl %ebp,%eax jb 10b - movl %edi,pa(init_pg_tables_end) + addl $__PAGE_OFFSET, %edi + movl %edi, pa(_brk_end) shrl $12, %eax movl %eax, pa(max_pfn_mapped) diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c index b8329029c150..3ac2aa7b9eaf 100644 --- a/arch/x86/kernel/setup.c +++ b/arch/x86/kernel/setup.c @@ -161,12 +161,6 @@ static struct resource bss_resource = { #ifdef CONFIG_X86_32 -/* This value is set up by the early boot code to point to the value - immediately after the boot time page tables. It contains a *physical* - address, and must not be in the .bss segment! */ -unsigned long init_pg_tables_start __initdata = ~0UL; -unsigned long init_pg_tables_end __initdata = ~0UL; - static struct resource video_ram_resource = { .name = "Video RAM area", .start = 0xa0000, diff --git a/arch/x86/kernel/vmlinux_32.lds.S b/arch/x86/kernel/vmlinux_32.lds.S index 27e44aa21585..1063fbe93c73 100644 --- a/arch/x86/kernel/vmlinux_32.lds.S +++ b/arch/x86/kernel/vmlinux_32.lds.S @@ -196,10 +196,6 @@ SECTIONS __brk_limit = . ; _end = . ; - - /* This is where the kernel creates the early boot page tables */ - . = ALIGN(PAGE_SIZE); - pg0 = . ; } /* Sections to be discarded */ diff --git a/arch/x86/lguest/boot.c b/arch/x86/lguest/boot.c index 9fe4ddaa8f6f..90e44a10e68a 100644 --- a/arch/x86/lguest/boot.c +++ b/arch/x86/lguest/boot.c @@ -1058,14 +1058,6 @@ __init void lguest_init(void) * lguest_init() where the rest of the fairly chaotic boot setup * occurs. */ - /* The native boot code sets up initial page tables immediately after - * the kernel itself, and sets init_pg_tables_end so they're not - * clobbered. The Launcher places our initial pagetables somewhere at - * the top of our physical memory, so we don't need extra space: set - * init_pg_tables_end to the end of the kernel. */ - init_pg_tables_start = __pa(pg0); - init_pg_tables_end = __pa(pg0); - /* As described in head_32.S, we map the first 128M of memory. */ max_pfn_mapped = (128*1024*1024) >> PAGE_SHIFT;