Messages in this thread Patch in this message | | | Date | Fri, 31 Oct 2014 13:58:19 -0700 | From | Kees Cook <> | Subject | [PATCH v2] x86, boot: add hex output for debugging |
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This is useful for reporting various addresses or other values while debugging early boot. For example, when CONFIG_X86_VERBOSE_BOOTUP is set, this is now visible at boot time:
early console in setup code early console in decompress_kernel input_data: 0x0000000001e1526e input_len: 0x0000000000732236 output: 0x0000000001000000 output_len: 0x0000000001535640 run_size: 0x00000000021fb000 KASLR using RDTSC...
Signed-off-by: Kees Cook <keescook@chromium.org> --- Since this displays run_size, this patch depends on Junjie Mao's patch "x86, kaslr: Prevent .bss from overlaping initrd"
--- arch/x86/boot/compressed/misc.c | 24 ++++++++++++++++++++++++ arch/x86/boot/compressed/misc.h | 11 +++++++++++ 2 files changed, 35 insertions(+)
diff --git a/arch/x86/boot/compressed/misc.c b/arch/x86/boot/compressed/misc.c index 30dd59a9f0b4..2aefc8a63655 100644 --- a/arch/x86/boot/compressed/misc.c +++ b/arch/x86/boot/compressed/misc.c @@ -220,6 +220,23 @@ void __putstr(const char *s) outb(0xff & (pos >> 1), vidport+1); } +void __puthex(unsigned long value) +{ + char alpha[2] = "0"; + int bits; + + for (bits = sizeof(value) * 8 - 4; bits >= 0; bits -= 4) { + unsigned long digit = (value >> bits) & 0xf; + + if (digit < 0xA) + alpha[0] = '0' + digit; + else + alpha[0] = 'a' + (digit - 0xA); + + __putstr(alpha); + } +} + static void error(char *x) { error_putstr("\n\n"); @@ -382,6 +399,13 @@ asmlinkage __visible void *decompress_kernel(void *rmode, memptr heap, free_mem_ptr = heap; /* Heap */ free_mem_end_ptr = heap + BOOT_HEAP_SIZE; + /* Report initial kernel position details. */ + debug_putaddr(input_data); + debug_putaddr(input_len); + debug_putaddr(output); + debug_putaddr(output_len); + debug_putaddr(run_size); + /* * The memory hole needed for the kernel is the larger of either * the entire decompressed kernel plus relocation table, or the diff --git a/arch/x86/boot/compressed/misc.h b/arch/x86/boot/compressed/misc.h index 24e3e569a13c..70472ae98a73 100644 --- a/arch/x86/boot/compressed/misc.h +++ b/arch/x86/boot/compressed/misc.h @@ -34,16 +34,27 @@ extern memptr free_mem_ptr; extern memptr free_mem_end_ptr; extern struct boot_params *real_mode; /* Pointer to real-mode data */ void __putstr(const char *s); +void __puthex(unsigned long value); #define error_putstr(__x) __putstr(__x) +#define error_puthex(__x) __puthex(__x) #ifdef CONFIG_X86_VERBOSE_BOOTUP #define debug_putstr(__x) __putstr(__x) +#define debug_puthex(__x) __puthex(__x) +#define debug_putaddr(__x) { \ + debug_putstr(#__x ": 0x"); \ + debug_puthex((unsigned long)(__x)); \ + debug_putstr("\n"); \ + } #else static inline void debug_putstr(const char *s) { } +static inline void debug_puthex(const char *s) +{ } +#define debug_putaddr(x) /* */ #endif -- 1.9.1
-- Kees Cook Chrome OS Security
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