linux/arch/arm/kernel/armksyms.c
Russell King dc21af99fa ARM: P2V: introduce phys_to_virt/virt_to_phys runtime patching
This idea came from Nicolas, Eric Miao produced an initial version,
which was then rewritten into this.

Patch the physical to virtual translations at runtime.  As we modify
the code, this makes it incompatible with XIP kernels, but allows us
to achieve this with minimal loss of performance.

As many translations are of the form:

	physical = virtual + (PHYS_OFFSET - PAGE_OFFSET)
	virtual = physical - (PHYS_OFFSET - PAGE_OFFSET)

we generate an 'add' instruction for __virt_to_phys(), and a 'sub'
instruction for __phys_to_virt().  We calculate at run time (PHYS_OFFSET
- PAGE_OFFSET) by comparing the address prior to MMU initialization with
where it should be once the MMU has been initialized, and place this
constant into the above add/sub instructions.

Once we have (PHYS_OFFSET - PAGE_OFFSET), we can calculate the real
PHYS_OFFSET as PAGE_OFFSET is a build-time constant, and save this for
the C-mode PHYS_OFFSET variable definition to use.

At present, we are unable to support Realview with Sparsemem enabled
as this uses a complex mapping function, and MSM as this requires a
constant which will not fit in our math instruction.

Add a module version magic string for this feature to prevent
incompatible modules being loaded.

Tested-by: Tony Lindgren <tony@atomide.com>
Reviewed-by: Nicolas Pitre <nicolas.pitre@linaro.org>
Tested-by: Nicolas Pitre <nicolas.pitre@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2011-02-17 23:27:32 +00:00

177 lines
4.2 KiB
C

/*
* linux/arch/arm/kernel/armksyms.c
*
* Copyright (C) 2000 Russell King
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/module.h>
#include <linux/sched.h>
#include <linux/string.h>
#include <linux/cryptohash.h>
#include <linux/delay.h>
#include <linux/in6.h>
#include <linux/syscalls.h>
#include <linux/uaccess.h>
#include <linux/io.h>
#include <asm/checksum.h>
#include <asm/system.h>
#include <asm/ftrace.h>
/*
* libgcc functions - functions that are used internally by the
* compiler... (prototypes are not correct though, but that
* doesn't really matter since they're not versioned).
*/
extern void __ashldi3(void);
extern void __ashrdi3(void);
extern void __divsi3(void);
extern void __lshrdi3(void);
extern void __modsi3(void);
extern void __muldi3(void);
extern void __ucmpdi2(void);
extern void __udivsi3(void);
extern void __umodsi3(void);
extern void __do_div64(void);
extern void __aeabi_idiv(void);
extern void __aeabi_idivmod(void);
extern void __aeabi_lasr(void);
extern void __aeabi_llsl(void);
extern void __aeabi_llsr(void);
extern void __aeabi_lmul(void);
extern void __aeabi_uidiv(void);
extern void __aeabi_uidivmod(void);
extern void __aeabi_ulcmp(void);
extern void fpundefinstr(void);
EXPORT_SYMBOL(__backtrace);
/* platform dependent support */
EXPORT_SYMBOL(__udelay);
EXPORT_SYMBOL(__const_udelay);
/* networking */
EXPORT_SYMBOL(csum_partial);
EXPORT_SYMBOL(csum_partial_copy_from_user);
EXPORT_SYMBOL(csum_partial_copy_nocheck);
EXPORT_SYMBOL(__csum_ipv6_magic);
/* io */
#ifndef __raw_readsb
EXPORT_SYMBOL(__raw_readsb);
#endif
#ifndef __raw_readsw
EXPORT_SYMBOL(__raw_readsw);
#endif
#ifndef __raw_readsl
EXPORT_SYMBOL(__raw_readsl);
#endif
#ifndef __raw_writesb
EXPORT_SYMBOL(__raw_writesb);
#endif
#ifndef __raw_writesw
EXPORT_SYMBOL(__raw_writesw);
#endif
#ifndef __raw_writesl
EXPORT_SYMBOL(__raw_writesl);
#endif
/* string / mem functions */
EXPORT_SYMBOL(strchr);
EXPORT_SYMBOL(strrchr);
EXPORT_SYMBOL(memset);
EXPORT_SYMBOL(memcpy);
EXPORT_SYMBOL(memmove);
EXPORT_SYMBOL(memchr);
EXPORT_SYMBOL(__memzero);
/* user mem (segment) */
EXPORT_SYMBOL(__strnlen_user);
EXPORT_SYMBOL(__strncpy_from_user);
#ifdef CONFIG_MMU
EXPORT_SYMBOL(copy_page);
EXPORT_SYMBOL(__copy_from_user);
EXPORT_SYMBOL(__copy_to_user);
EXPORT_SYMBOL(__clear_user);
EXPORT_SYMBOL(__get_user_1);
EXPORT_SYMBOL(__get_user_2);
EXPORT_SYMBOL(__get_user_4);
EXPORT_SYMBOL(__put_user_1);
EXPORT_SYMBOL(__put_user_2);
EXPORT_SYMBOL(__put_user_4);
EXPORT_SYMBOL(__put_user_8);
#endif
/* crypto hash */
EXPORT_SYMBOL(sha_transform);
/* gcc lib functions */
EXPORT_SYMBOL(__ashldi3);
EXPORT_SYMBOL(__ashrdi3);
EXPORT_SYMBOL(__divsi3);
EXPORT_SYMBOL(__lshrdi3);
EXPORT_SYMBOL(__modsi3);
EXPORT_SYMBOL(__muldi3);
EXPORT_SYMBOL(__ucmpdi2);
EXPORT_SYMBOL(__udivsi3);
EXPORT_SYMBOL(__umodsi3);
EXPORT_SYMBOL(__do_div64);
#ifdef CONFIG_AEABI
EXPORT_SYMBOL(__aeabi_idiv);
EXPORT_SYMBOL(__aeabi_idivmod);
EXPORT_SYMBOL(__aeabi_lasr);
EXPORT_SYMBOL(__aeabi_llsl);
EXPORT_SYMBOL(__aeabi_llsr);
EXPORT_SYMBOL(__aeabi_lmul);
EXPORT_SYMBOL(__aeabi_uidiv);
EXPORT_SYMBOL(__aeabi_uidivmod);
EXPORT_SYMBOL(__aeabi_ulcmp);
#endif
/* bitops */
EXPORT_SYMBOL(_set_bit_le);
EXPORT_SYMBOL(_test_and_set_bit_le);
EXPORT_SYMBOL(_clear_bit_le);
EXPORT_SYMBOL(_test_and_clear_bit_le);
EXPORT_SYMBOL(_change_bit_le);
EXPORT_SYMBOL(_test_and_change_bit_le);
EXPORT_SYMBOL(_find_first_zero_bit_le);
EXPORT_SYMBOL(_find_next_zero_bit_le);
EXPORT_SYMBOL(_find_first_bit_le);
EXPORT_SYMBOL(_find_next_bit_le);
#ifdef __ARMEB__
EXPORT_SYMBOL(_set_bit_be);
EXPORT_SYMBOL(_test_and_set_bit_be);
EXPORT_SYMBOL(_clear_bit_be);
EXPORT_SYMBOL(_test_and_clear_bit_be);
EXPORT_SYMBOL(_change_bit_be);
EXPORT_SYMBOL(_test_and_change_bit_be);
EXPORT_SYMBOL(_find_first_zero_bit_be);
EXPORT_SYMBOL(_find_next_zero_bit_be);
EXPORT_SYMBOL(_find_first_bit_be);
EXPORT_SYMBOL(_find_next_bit_be);
#endif
#ifdef CONFIG_FUNCTION_TRACER
#ifdef CONFIG_OLD_MCOUNT
EXPORT_SYMBOL(mcount);
#endif
EXPORT_SYMBOL(__gnu_mcount_nc);
#endif
#ifdef CONFIG_ARM_PATCH_PHYS_VIRT
EXPORT_SYMBOL(__pv_phys_offset);
#endif