From 7543c1de84ed93c6769c9f20dced08a522af8912 Mon Sep 17 00:00:00 2001 From: Yinghai Lu Date: Thu, 12 Mar 2009 16:04:42 -0700 Subject: [PATCH] x86-32: compute initial mapping size more accurately Impact: simplification We only need to map the kernel in head_32.S, not the whole of lowmem. We use 512MB as a reasonable (but arbitrary) limit on the maximum size of the kernel image. Signed-off-by: Yinghai Lu Signed-off-by: Jeremy Fitzhardinge Signed-off-by: H. Peter Anvin --- arch/x86/include/asm/page_32_types.h | 5 +++++ arch/x86/kernel/head_32.S | 2 +- 2 files changed, 6 insertions(+), 1 deletion(-) diff --git a/arch/x86/include/asm/page_32_types.h b/arch/x86/include/asm/page_32_types.h index f1e4a79a6e41..0f915ae649a7 100644 --- a/arch/x86/include/asm/page_32_types.h +++ b/arch/x86/include/asm/page_32_types.h @@ -39,6 +39,11 @@ #define __VIRTUAL_MASK_SHIFT 32 #endif /* CONFIG_X86_PAE */ +/* + * Kernel image size is limited to 512 MB (see in arch/x86/kernel/head_32.S) + */ +#define KERNEL_IMAGE_SIZE (512 * 1024 * 1024) + #ifndef __ASSEMBLY__ /* diff --git a/arch/x86/kernel/head_32.S b/arch/x86/kernel/head_32.S index db6652710e98..3ce5456dfbe6 100644 --- a/arch/x86/kernel/head_32.S +++ b/arch/x86/kernel/head_32.S @@ -54,7 +54,7 @@ * * This should be a multiple of a page. */ -LOW_PAGES = 1<<(32-PAGE_SHIFT_asm) +LOW_PAGES = (KERNEL_IMAGE_SIZE + PAGE_SIZE_asm - 1)>>PAGE_SHIFT /* * To preserve the DMA pool in PAGEALLOC kernels, we'll allocate -- 2.34.1