linux/arch/x86/include/asm/setup.h
Jiri Kosina 4545c89880 x86: introduce kaslr_offset()
Offset that has been chosen for kaslr during kernel decompression can be
easily computed as a difference between _text and __START_KERNEL. We are
already making use of this in dump_kernel_offset() notifier and in
arch_crash_save_vmcoreinfo().

Introduce kaslr_offset() that makes this computation instead of hard-coding
it, so that other kernel code (such as live patching) can make use of it.
Also convert existing users to make use of it.

This patch is equivalent transofrmation without any effects on the resulting
code:

	$ diff -u vmlinux.old.asm vmlinux.new.asm
	--- vmlinux.old.asm     2015-04-28 17:55:19.520983368 +0200
	+++ vmlinux.new.asm     2015-04-28 17:55:24.141206072 +0200
	@@ -1,5 +1,5 @@

	-vmlinux.old:     file format elf64-x86-64
	+vmlinux.new:     file format elf64-x86-64

	Disassembly of section .text:
	$

Acked-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2015-04-29 16:51:33 +02:00

137 lines
3.3 KiB
C

#ifndef _ASM_X86_SETUP_H
#define _ASM_X86_SETUP_H
#include <uapi/asm/setup.h>
#define COMMAND_LINE_SIZE 2048
#include <linux/linkage.h>
#ifdef __i386__
#include <linux/pfn.h>
/*
* Reserved space for vmalloc and iomap - defined in asm/page.h
*/
#define MAXMEM_PFN PFN_DOWN(MAXMEM)
#define MAX_NONPAE_PFN (1 << 20)
#endif /* __i386__ */
#define PARAM_SIZE 4096 /* sizeof(struct boot_params) */
#define OLD_CL_MAGIC 0xA33F
#define OLD_CL_ADDRESS 0x020 /* Relative to real mode data */
#define NEW_CL_POINTER 0x228 /* Relative to real mode data */
#ifndef __ASSEMBLY__
#include <asm/bootparam.h>
#include <asm/x86_init.h>
extern u64 relocated_ramdisk;
/* Interrupt control for vSMPowered x86_64 systems */
#ifdef CONFIG_X86_64
void vsmp_init(void);
#else
static inline void vsmp_init(void) { }
#endif
void setup_bios_corruption_check(void);
extern unsigned long saved_video_mode;
extern void reserve_standard_io_resources(void);
extern void i386_reserve_resources(void);
extern void setup_default_timer_irq(void);
#ifdef CONFIG_X86_INTEL_MID
extern void x86_intel_mid_early_setup(void);
#else
static inline void x86_intel_mid_early_setup(void) { }
#endif
#ifdef CONFIG_X86_INTEL_CE
extern void x86_ce4100_early_setup(void);
#else
static inline void x86_ce4100_early_setup(void) { }
#endif
#ifndef _SETUP
#include <asm/espfix.h>
/*
* This is set up by the setup-routine at boot-time
*/
extern struct boot_params boot_params;
extern char _text[];
static inline bool kaslr_enabled(void)
{
return !!(boot_params.hdr.loadflags & KASLR_FLAG);
}
static inline unsigned long kaslr_offset(void)
{
return (unsigned long)&_text - __START_KERNEL;
}
/*
* Do NOT EVER look at the BIOS memory size location.
* It does not work on many machines.
*/
#define LOWMEMSIZE() (0x9f000)
/* exceedingly early brk-like allocator */
extern unsigned long _brk_end;
void *extend_brk(size_t size, size_t align);
/*
* Reserve space in the brk section. The name must be unique within
* the file, and somewhat descriptive. The size is in bytes. Must be
* used at file scope.
*
* (This uses a temp function to wrap the asm so we can pass it the
* size parameter; otherwise we wouldn't be able to. We can't use a
* "section" attribute on a normal variable because it always ends up
* being @progbits, which ends up allocating space in the vmlinux
* executable.)
*/
#define RESERVE_BRK(name,sz) \
static void __section(.discard.text) __used notrace \
__brk_reservation_fn_##name##__(void) { \
asm volatile ( \
".pushsection .brk_reservation,\"aw\",@nobits;" \
".brk." #name ":" \
" 1:.skip %c0;" \
" .size .brk." #name ", . - 1b;" \
" .popsection" \
: : "i" (sz)); \
}
/* Helper for reserving space for arrays of things */
#define RESERVE_BRK_ARRAY(type, name, entries) \
type *name; \
RESERVE_BRK(name, sizeof(type) * entries)
extern void probe_roms(void);
#ifdef __i386__
asmlinkage void __init i386_start_kernel(void);
#else
asmlinkage void __init x86_64_start_kernel(char *real_mode);
asmlinkage void __init x86_64_start_reservations(char *real_mode_data);
#endif /* __i386__ */
#endif /* _SETUP */
#else
#define RESERVE_BRK(name,sz) \
.pushsection .brk_reservation,"aw",@nobits; \
.brk.name: \
1: .skip sz; \
.size .brk.name,.-1b; \
.popsection
#endif /* __ASSEMBLY__ */
#endif /* _ASM_X86_SETUP_H */