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Commit 79063a7c authored by Kees Cook's avatar Kees Cook Committed by Ingo Molnar
Browse files

x86/boot: Add hex output for debugging 



This is useful for reporting various addresses or other values
while debugging early boot, for example, the recent kernel image
size vs kernel run size. 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: default avatarKees Cook <keescook@chromium.org>
Cc: Andrey Ryabinin <a.ryabinin@samsung.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@suse.de>
Cc: Jan Beulich <JBeulich@suse.com>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Joe Perches <joe@perches.com>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Junjie Mao <eternal.n08@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Link: http://lkml.kernel.org/r/20150706230620.GA17501@www.outflux.net


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent c7e9ad7d

arch/x86/boot/compressed/misc.c

+24 −0
Original line number Diff line number Diff line
@@ -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");
@@ -399,6 +416,13 @@ 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

arch/x86/boot/compressed/misc.h

+11 −0
Original line number Diff line number Diff line
@@ -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