Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933293AbbGGUW4 (ORCPT ); Tue, 7 Jul 2015 16:22:56 -0400 Received: from userp1040.oracle.com ([156.151.31.81]:16689 "EHLO userp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932586AbbGGUU6 (ORCPT ); Tue, 7 Jul 2015 16:20:58 -0400 From: Yinghai Lu To: Kees Cook , "H. Peter Anvin" , Baoquan He Cc: linux-kernel@vger.kernel.org, Yinghai Lu Subject: [PATCH 07/42] x86, boot: Move z_extract_offset calculation to header.S Date: Tue, 7 Jul 2015 13:19:53 -0700 Message-Id: <1436300428-21163-8-git-send-email-yinghai@kernel.org> X-Mailer: git-send-email 1.8.4.5 In-Reply-To: <1436300428-21163-1-git-send-email-yinghai@kernel.org> References: <1436300428-21163-1-git-send-email-yinghai@kernel.org> X-Source-IP: userv0022.oracle.com [156.151.31.74] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 5897 Lines: 150 Old extract_offset calculation is done without knowledge of decompressor size. so it guess one big size. We can move it to header.S, where we have exact decompressor size. We save 8 pages for init_size with this patch. before patch: kernel: [13e000000,13fa1dfff] input: [0x13f32d3b4-0x13fa01cc7], output: [0x13e000000-0x13f9ef81f], heap: [0x13fa0b680-0x13fa1367f] after patch: kernel: [13e000000,13fa15fff] input: [0x13f3253b4-0x13f9f9cc7], output: [0x13e000000-0x13f9ef81f], heap: [0x13fa03680-0x13fa0b67f] Signed-off-by: Yinghai Lu --- arch/x86/boot/Makefile | 2 +- arch/x86/boot/compressed/misc.c | 5 +---- arch/x86/boot/compressed/mkpiggy.c | 16 +--------------- arch/x86/boot/header.S | 29 +++++++++++++++++++++++++++++ 4 files changed, 32 insertions(+), 20 deletions(-) diff --git a/arch/x86/boot/Makefile b/arch/x86/boot/Makefile index 4d27e8b..e7196cf 100644 --- a/arch/x86/boot/Makefile +++ b/arch/x86/boot/Makefile @@ -77,7 +77,7 @@ $(obj)/vmlinux.bin: $(obj)/compressed/vmlinux FORCE SETUP_OBJS = $(addprefix $(obj)/,$(setup-y)) -sed-zoffset := -e 's/^\([0-9a-fA-F]*\) [ABCDGRSTVW] \(startup_32\|startup_64\|efi32_stub_entry\|efi64_stub_entry\|efi_pe_entry\|input_data\|_end\|z_.*\)$$/\#define ZO_\2 0x\1/p' +sed-zoffset := -e 's/^\([0-9a-fA-F]*\) [ABCDGRSTVW] \(startup_32\|startup_64\|efi32_stub_entry\|efi64_stub_entry\|efi_pe_entry\|input_data\|_end\|_ehead\|_text\|z_.*\)$$/\#define ZO_\2 0x\1/p' quiet_cmd_zoffset = ZOFFSET $@ cmd_zoffset = $(NM) $< | sed -n $(sed-zoffset) > $@ diff --git a/arch/x86/boot/compressed/misc.c b/arch/x86/boot/compressed/misc.c index 1c03098..db97bdf 100644 --- a/arch/x86/boot/compressed/misc.c +++ b/arch/x86/boot/compressed/misc.c @@ -84,13 +84,10 @@ * To avoid problems with the compressed data's meta information an extra 18 * bytes are needed. Leading to the formula: * - * extra_bytes = (uncompressed_size >> 12) + 32768 + 18 + decompressor_size. + * extra_bytes = (uncompressed_size >> 12) + 32768 + 18. * * Adding 8 bytes per 32K is a bit excessive but much easier to calculate. * Adding 32768 instead of 32767 just makes for round numbers. - * Adding the decompressor_size is necessary as it musht live after all - * of the data as well. Last I measured the decompressor is about 14K. - * 10K of actual data and 4K of bss. * */ diff --git a/arch/x86/boot/compressed/mkpiggy.c b/arch/x86/boot/compressed/mkpiggy.c index c03b009..c5148642 100644 --- a/arch/x86/boot/compressed/mkpiggy.c +++ b/arch/x86/boot/compressed/mkpiggy.c @@ -21,8 +21,7 @@ * ----------------------------------------------------------------------- */ /* - * Compute the desired load offset from a compressed program; outputs - * a small assembly wrapper with the appropriate symbols defined. + * outputs a small assembly wrapper with the appropriate symbols defined. */ #include @@ -35,7 +34,6 @@ int main(int argc, char *argv[]) { uint32_t olen; long ilen; - unsigned long offs; FILE *f = NULL; int retval = 1; @@ -65,23 +63,11 @@ int main(int argc, char *argv[]) ilen = ftell(f); olen = get_unaligned_le32(&olen); - /* - * Now we have the input (compressed) and output (uncompressed) - * sizes, compute the necessary decompression offset... - */ - - offs = (olen > ilen) ? olen - ilen : 0; - offs += olen >> 12; /* Add 8 bytes for each 32K block */ - offs += 64*1024 + 128; /* Add 64K + 128 bytes slack */ - offs = (offs+4095) & ~4095; /* Round to a 4K boundary */ - printf(".section \".rodata..compressed\",\"a\",@progbits\n"); printf(".globl z_input_len\n"); printf("z_input_len = %lu\n", ilen); printf(".globl z_output_len\n"); printf("z_output_len = %lu\n", (unsigned long)olen); - printf(".globl z_min_extract_offset\n"); - printf("z_min_extract_offset = 0x%lx\n", offs); printf(".globl input_data, input_data_end\n"); printf("input_data:\n"); diff --git a/arch/x86/boot/header.S b/arch/x86/boot/header.S index 9bfab22..99204e5 100644 --- a/arch/x86/boot/header.S +++ b/arch/x86/boot/header.S @@ -440,7 +440,36 @@ setup_data: .quad 0 # 64-bit physical pointer to pref_address: .quad LOAD_PHYSICAL_ADDR # preferred load addr +/* check arch/x86/boot/compressed/misc.c for the formula about extra_bytes. */ +#define ZO_z_extra_bytes ((ZO_z_output_len >> 12) + 32768 + 18) +#if ZO_z_output_len > ZO_z_input_len +#define ZO_z_extract_offset (ZO_z_output_len + ZO_z_extra_bytes - ZO_z_input_len) +#else +#define ZO_z_extract_offset ZO_z_extra_bytes +#endif + +/* + * extract_offset has to be bigger than ZO head section. + * otherwise during head code running to move ZO to end of buffer, + * will overwrite head code itself. + */ +#if (ZO__ehead - ZO_startup_32) > ZO_z_extract_offset +#define ZO_z_min_extract_offset ((ZO__ehead - ZO_startup_32 + 4095) & ~4095) +#else +#define ZO_z_min_extract_offset ((ZO_z_extract_offset + 4095) & ~4095) +#endif + #define ZO_INIT_SIZE (ZO__end - ZO_startup_32 + ZO_z_min_extract_offset) + +/* + * ZO__end - ZO_startup_32 is (ZO__ehead - ZO_startup_32) + ZO_z_input_len + (ZO__end - ZO__text) + * ZO_z_min_extract_offset >= (ZO_z_output_len + ZO_z_extra_bytes - ZO_z_input_len) + * then ZO_INIT_SIZE >= (ZO__ehead - ZO_startup_32) + ZO_z_input_len + (ZO__end - ZO__text) + (ZO_z_output_len + ZO_z_extra_bytes - ZO_z_input_len) + * so (ZO_INIT_SIZE - ZO_z_output_len) > (ZO__end - ZO__text) + * That means during decompressor running, output would not + * overwrite the decompressor itself. + */ + #define VO_INIT_SIZE (VO__end - VO__text) #if ZO_INIT_SIZE > VO_INIT_SIZE #define INIT_SIZE ZO_INIT_SIZE -- 1.8.4.5 -- 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/