Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262092AbUCOBbi (ORCPT ); Sun, 14 Mar 2004 20:31:38 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262182AbUCOBbh (ORCPT ); Sun, 14 Mar 2004 20:31:37 -0500 Received: from pxy4allmi.all.mi.charter.com ([24.247.15.43]:15567 "EHLO proxy4.gha.chartermi.net") by vger.kernel.org with ESMTP id S262092AbUCOBbJ (ORCPT ); Sun, 14 Mar 2004 20:31:09 -0500 Message-ID: <405507A6.60706@quark.didntduck.org> Date: Sun, 14 Mar 2004 20:32:22 -0500 From: Brian Gerst User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.6) Gecko/20040116 X-Accept-Language: en-us, en MIME-Version: 1.0 To: Andrew Morton CC: linux-kernel@vger.kernel.org Subject: [PATCH] don't abuse empty_zero_page (x86) Content-Type: multipart/mixed; boundary="------------020207000809090806090107" X-Charter-MailScanner-Information: X-Charter-MailScanner: Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 7665 Lines: 213 This is a multi-part message in MIME format. --------------020207000809090806090107 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Don't abuse empty_zero_page as temporary storage for boot parameters and command line. This is a holdover from the days before discardable init sections. -- Brian Gerst --------------020207000809090806090107 Content-Type: text/plain; name="empty_zero_page-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="empty_zero_page-1" diff -urN linux-bk/arch/i386/boot/setup.S linux/arch/i386/boot/setup.S --- linux-bk/arch/i386/boot/setup.S 2004-03-12 14:00:43.000000000 -0500 +++ linux/arch/i386/boot/setup.S 2004-03-12 15:32:55.000000000 -0500 @@ -612,7 +612,7 @@ # int 13h ah=08h "Legacy Get Device Parameters" # # A buffer of size EDDMAXNR*(EDDEXTSIZE+EDDPARMSIZE) is reserved for our use -# in the empty_zero_page at EDDBUF. The first four bytes of which are +# in the boot_params at EDDBUF. The first four bytes of which are # used to store the device number, interface support map and version # results from fn41. The next four bytes are used to store the legacy # cylinders, heads, and sectors from fn08. The following 74 bytes are used to @@ -625,9 +625,9 @@ # the structure, and the fn41 and fn08 results are stored at offsets # from there. This removes the need to increment the pointer for # every store, and leaves it ready for the fn48 call. -# A second one-byte buffer, EDDNR, in the empty_zero_page stores +# A second one-byte buffer, EDDNR, in boot_params stores # the number of BIOS devices which exist, up to EDDMAXNR. -# In setup.c, copy_edd() stores both empty_zero_page buffers away +# In setup.c, copy_edd() stores both boot_params buffers away # for later use, as they would get overwritten otherwise. # This code is sensitive to the size of the structs in edd.h edd_start: diff -urN linux-bk/arch/i386/kernel/head.S linux/arch/i386/kernel/head.S --- linux-bk/arch/i386/kernel/head.S 2004-03-12 14:00:43.000000000 -0500 +++ linux/arch/i386/kernel/head.S 2004-03-12 16:58:20.000000000 -0500 @@ -18,12 +18,7 @@ #include #include #include - -#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 */ +#include /* * References to members of the new_cpu_data structure. @@ -195,22 +190,15 @@ call setup_idt /* - * Copy bootup parameters out of the way. First 2kB of - * _empty_zero_page is for boot parameters, second 2kB - * is for the command line. - * + * Copy bootup parameters out of the way. * Note: %esi still has the pointer to the real-mode data. */ - movl $empty_zero_page,%edi - movl $512,%ecx + movl $boot_params,%edi + movl $(PARAM_SIZE/4),%ecx cld rep movsl - xorl %eax,%eax - movl $512,%ecx - rep - stosl - movl empty_zero_page+NEW_CL_POINTER,%esi + movl boot_params+NEW_CL_POINTER,%esi andl %esi,%esi jnz 2f # New command line protocol cmpw $(OLD_CL_MAGIC),OLD_CL_MAGIC_ADDR @@ -218,8 +206,8 @@ movzwl OLD_CL_OFFSET,%esi addl $(OLD_CL_BASE_ADDR),%esi 2: - movl $empty_zero_page+2048,%edi - movl $512,%ecx + movl $saved_command_line,%edi + movl $(COMMAND_LINE_SIZE/4),%ecx rep movsl 1: diff -urN linux-bk/arch/i386/kernel/setup.c linux/arch/i386/kernel/setup.c --- linux-bk/arch/i386/kernel/setup.c 2004-03-12 14:00:43.000000000 -0500 +++ linux/arch/i386/kernel/setup.c 2004-03-12 15:38:38.000000000 -0500 @@ -130,6 +130,8 @@ static char command_line[COMMAND_LINE_SIZE]; char saved_command_line[COMMAND_LINE_SIZE]; +unsigned char __initdata boot_params[PARAM_SIZE]; + static struct resource code_resource = { "Kernel code", 0x100000, 0 }; static struct resource data_resource = { "Kernel data", 0, 0 }; @@ -456,7 +458,7 @@ #endif /** * copy_edd() - Copy the BIOS EDD information - * from empty_zero_page into a safe place. + * from boot_params into a safe place. * */ static inline void copy_edd(void) @@ -485,12 +487,11 @@ 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-bk/arch/i386/mm/init.c linux/arch/i386/mm/init.c --- linux-bk/arch/i386/mm/init.c 2004-02-15 00:41:30.000000000 -0500 +++ linux/arch/i386/mm/init.c 2004-03-12 15:41:51.000000000 -0500 @@ -474,9 +474,6 @@ 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-bk/Documentation/i386/zero-page.txt linux/Documentation/i386/zero-page.txt --- linux-bk/Documentation/i386/zero-page.txt 2004-03-12 14:00:43.000000000 -0500 +++ linux/Documentation/i386/zero-page.txt 2004-03-12 17:38:15.000000000 -0500 @@ -1,7 +1,7 @@ -Summary of empty_zero_page layout (kernel point of view) +Summary of boot_params layout (kernel point of view) ( collected by Hans Lermen and Martin Mares ) -The contents of empty_zero_page are used to pass parameters from the +The contents of boot_params are used to pass parameters from the 16-bit realmode code of the kernel to the 32-bit part. References/settings to it mainly are in: @@ -76,9 +76,3 @@ 0x2d0 - 0x600 E820MAP 0x600 - 0x7ff EDDBUF (setup.S) for disk signature read sector 0x600 - 0x7eb EDDBUF (setup.S) for edd data - -0x800 string, 2K max COMMAND_LINE, the kernel commandline as - copied using CL_OFFSET. - Note: this will be copied once more by setup.c - into a local buffer which is only 256 bytes long. - ( #define COMMAND_LINE_SIZE 256 ) diff -urN linux-bk/include/asm-i386/setup.h linux/include/asm-i386/setup.h --- linux-bk/include/asm-i386/setup.h 2004-02-18 01:37:26.000000000 -0500 +++ linux/include/asm-i386/setup.h 2004-03-12 15:44:17.000000000 -0500 @@ -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 */ --------------020207000809090806090107-- - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/