linux/include/asm-generic/early_ioremap.h
Mark Salter 6b0f68e32e mm: add utility for early copy from unmapped ram
When booting an arm64 kernel w/initrd using UEFI/grub, use of mem= will
likely cut off part or all of the initrd.  This leaves it outside the
kernel linear map which leads to failure when unpacking.  The x86 code
has a similar need to relocate an initrd outside of mapped memory in
some cases.

The current x86 code uses early_memremap() to copy the original initrd
from unmapped to mapped RAM.  This patchset creates a generic
copy_from_early_mem() utility based on that x86 code and has arm64 and
x86 share it in their respective initrd relocation code.

This patch (of 3):

In some early boot circumstances, it may be necessary to copy from RAM
outside the kernel linear mapping to mapped RAM.  The need to relocate
an initrd is one example in the x86 code.  This patch creates a helper
function based on current x86 code.

Signed-off-by: Mark Salter <msalter@redhat.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-09-08 15:35:28 -07:00

48 lines
1.4 KiB
C

#ifndef _ASM_EARLY_IOREMAP_H_
#define _ASM_EARLY_IOREMAP_H_
#include <linux/types.h>
/*
* early_ioremap() and early_iounmap() are for temporary early boot-time
* mappings, before the real ioremap() is functional.
*/
extern void __iomem *early_ioremap(resource_size_t phys_addr,
unsigned long size);
extern void *early_memremap(resource_size_t phys_addr,
unsigned long size);
extern void early_iounmap(void __iomem *addr, unsigned long size);
extern void early_memunmap(void *addr, unsigned long size);
/*
* Weak function called by early_ioremap_reset(). It does nothing, but
* architectures may provide their own version to do any needed cleanups.
*/
extern void early_ioremap_shutdown(void);
#if defined(CONFIG_GENERIC_EARLY_IOREMAP) && defined(CONFIG_MMU)
/* Arch-specific initialization */
extern void early_ioremap_init(void);
/* Generic initialization called by architecture code */
extern void early_ioremap_setup(void);
/*
* Called as last step in paging_init() so library can act
* accordingly for subsequent map/unmap requests.
*/
extern void early_ioremap_reset(void);
/*
* Early copy from unmapped memory to kernel mapped memory.
*/
extern void copy_from_early_mem(void *dest, phys_addr_t src,
unsigned long size);
#else
static inline void early_ioremap_init(void) { }
static inline void early_ioremap_setup(void) { }
static inline void early_ioremap_reset(void) { }
#endif
#endif /* _ASM_EARLY_IOREMAP_H_ */