From 6655e0aaf768c39a62eea739c453b9db1e841cfb Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Mon, 18 Apr 2016 09:42:12 -0700 Subject: [PATCH] x86/boot: Rename "real_mode" to "boot_params" The non-compressed boot code uses the (much more obvious) name "boot_params" for the global pointer to the x86 boot parameters. The compressed kernel loader code, though, was using the legacy name "real_mode". There is no need to have a different name, and changing it improves readability. Suggested-by: Ingo Molnar Signed-off-by: Kees Cook Cc: Andrew Morton Cc: Andrey Ryabinin Cc: Andy Lutomirski Cc: Andy Lutomirski Cc: Baoquan He Cc: Borislav Petkov Cc: Borislav Petkov Cc: Brian Gerst Cc: Denys Vlasenko Cc: Dmitry Vyukov Cc: H. Peter Anvin Cc: H.J. Lu Cc: Josh Poimboeuf Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Yinghai Lu Link: http://lkml.kernel.org/r/1460997735-24785-4-git-send-email-keescook@chromium.org Signed-off-by: Ingo Molnar --- arch/x86/boot/compressed/cmdline.c | 4 ++-- arch/x86/boot/compressed/kaslr.c | 22 +++++++++++----------- arch/x86/boot/compressed/misc.c | 27 ++++++++++++++------------- arch/x86/boot/compressed/misc.h | 2 +- 4 files changed, 28 insertions(+), 27 deletions(-) diff --git a/arch/x86/boot/compressed/cmdline.c b/arch/x86/boot/compressed/cmdline.c index b68e3033e6b9..73ccf63b0f48 100644 --- a/arch/x86/boot/compressed/cmdline.c +++ b/arch/x86/boot/compressed/cmdline.c @@ -15,9 +15,9 @@ static inline char rdfs8(addr_t addr) #include "../cmdline.c" static unsigned long get_cmd_line_ptr(void) { - unsigned long cmd_line_ptr = real_mode->hdr.cmd_line_ptr; + unsigned long cmd_line_ptr = boot_params->hdr.cmd_line_ptr; - cmd_line_ptr |= (u64)real_mode->ext_cmd_line_ptr << 32; + cmd_line_ptr |= (u64)boot_params->ext_cmd_line_ptr << 32; return cmd_line_ptr; } diff --git a/arch/x86/boot/compressed/kaslr.c b/arch/x86/boot/compressed/kaslr.c index 622aa881c6ab..a51ec841c9b9 100644 --- a/arch/x86/boot/compressed/kaslr.c +++ b/arch/x86/boot/compressed/kaslr.c @@ -55,7 +55,7 @@ static unsigned long get_random_boot(void) unsigned long hash = 0; hash = rotate_xor(hash, build_str, sizeof(build_str)); - hash = rotate_xor(hash, real_mode, sizeof(*real_mode)); + hash = rotate_xor(hash, boot_params, sizeof(*boot_params)); return hash; } @@ -152,16 +152,16 @@ static void mem_avoid_init(unsigned long input, unsigned long input_size, mem_avoid[0].size = unsafe_len; /* Avoid initrd. */ - initrd_start = (u64)real_mode->ext_ramdisk_image << 32; - initrd_start |= real_mode->hdr.ramdisk_image; - initrd_size = (u64)real_mode->ext_ramdisk_size << 32; - initrd_size |= real_mode->hdr.ramdisk_size; + initrd_start = (u64)boot_params->ext_ramdisk_image << 32; + initrd_start |= boot_params->hdr.ramdisk_image; + initrd_size = (u64)boot_params->ext_ramdisk_size << 32; + initrd_size |= boot_params->hdr.ramdisk_size; mem_avoid[1].start = initrd_start; mem_avoid[1].size = initrd_size; /* Avoid kernel command line. */ - cmd_line = (u64)real_mode->ext_cmd_line_ptr << 32; - cmd_line |= real_mode->hdr.cmd_line_ptr; + cmd_line = (u64)boot_params->ext_cmd_line_ptr << 32; + cmd_line |= boot_params->hdr.cmd_line_ptr; /* Calculate size of cmd_line. */ ptr = (char *)(unsigned long)cmd_line; for (cmd_line_size = 0; ptr[cmd_line_size++]; ) @@ -190,7 +190,7 @@ static bool mem_avoid_overlap(struct mem_vector *img) } /* Avoid all entries in the setup_data linked list. */ - ptr = (struct setup_data *)(unsigned long)real_mode->hdr.setup_data; + ptr = (struct setup_data *)(unsigned long)boot_params->hdr.setup_data; while (ptr) { struct mem_vector avoid; @@ -288,8 +288,8 @@ static unsigned long find_random_addr(unsigned long minimum, minimum = ALIGN(minimum, CONFIG_PHYSICAL_ALIGN); /* Verify potential e820 positions, appending to slots list. */ - for (i = 0; i < real_mode->e820_entries; i++) { - process_e820_entry(&real_mode->e820_map[i], minimum, size); + for (i = 0; i < boot_params->e820_entries; i++) { + process_e820_entry(&boot_params->e820_map[i], minimum, size); } return slots_fetch_random(); @@ -315,7 +315,7 @@ unsigned char *choose_kernel_location(unsigned char *input, } #endif - real_mode->hdr.loadflags |= KASLR_FLAG; + boot_params->hdr.loadflags |= KASLR_FLAG; /* Record the various known unsafe memory ranges. */ mem_avoid_init((unsigned long)input, input_size, diff --git a/arch/x86/boot/compressed/misc.c b/arch/x86/boot/compressed/misc.c index f35ad9eb1bf1..462dfbf7467b 100644 --- a/arch/x86/boot/compressed/misc.c +++ b/arch/x86/boot/compressed/misc.c @@ -114,7 +114,7 @@ static void error(char *m); /* * This is set up by the setup-routine at boot-time */ -struct boot_params *real_mode; /* Pointer to real-mode data */ +struct boot_params *boot_params; memptr free_mem_ptr; memptr free_mem_end_ptr; @@ -184,12 +184,12 @@ void __putstr(const char *s) } } - if (real_mode->screen_info.orig_video_mode == 0 && + if (boot_params->screen_info.orig_video_mode == 0 && lines == 0 && cols == 0) return; - x = real_mode->screen_info.orig_x; - y = real_mode->screen_info.orig_y; + x = boot_params->screen_info.orig_x; + y = boot_params->screen_info.orig_y; while ((c = *s++) != '\0') { if (c == '\n') { @@ -210,8 +210,8 @@ void __putstr(const char *s) } } - real_mode->screen_info.orig_x = x; - real_mode->screen_info.orig_y = y; + boot_params->screen_info.orig_x = x; + boot_params->screen_info.orig_y = y; pos = (x + cols * y) * 2; /* Update cursor position */ outb(14, vidport); @@ -392,14 +392,15 @@ asmlinkage __visible void *decompress_kernel(void *rmode, memptr heap, { unsigned char *output_orig = output; - real_mode = rmode; + /* Retain x86 boot parameters pointer passed from startup_32/64. */ + boot_params = rmode; - /* Clear it for solely in-kernel use */ - real_mode->hdr.loadflags &= ~KASLR_FLAG; + /* Clear flags intended for solely in-kernel use. */ + boot_params->hdr.loadflags &= ~KASLR_FLAG; - sanitize_boot_params(real_mode); + sanitize_boot_params(boot_params); - if (real_mode->screen_info.orig_video_mode == 7) { + if (boot_params->screen_info.orig_video_mode == 7) { vidmem = (char *) 0xb0000; vidport = 0x3b4; } else { @@ -407,8 +408,8 @@ asmlinkage __visible void *decompress_kernel(void *rmode, memptr heap, vidport = 0x3d4; } - lines = real_mode->screen_info.orig_video_lines; - cols = real_mode->screen_info.orig_video_cols; + lines = boot_params->screen_info.orig_video_lines; + cols = boot_params->screen_info.orig_video_cols; console_init(); debug_putstr("early console in decompress_kernel\n"); diff --git a/arch/x86/boot/compressed/misc.h b/arch/x86/boot/compressed/misc.h index 22346d5a2fa0..1f750a516580 100644 --- a/arch/x86/boot/compressed/misc.h +++ b/arch/x86/boot/compressed/misc.h @@ -32,7 +32,7 @@ /* misc.c */ extern memptr free_mem_ptr; extern memptr free_mem_end_ptr; -extern struct boot_params *real_mode; /* Pointer to real-mode data */ +extern struct boot_params *boot_params; void __putstr(const char *s); void __puthex(unsigned long value); #define error_putstr(__x) __putstr(__x) -- 2.20.1