linux/mm/early_ioremap.c
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

268 lines
5.9 KiB
C

/*
* Provide common bits of early_ioremap() support for architectures needing
* temporary mappings during boot before ioremap() is available.
*
* This is mostly a direct copy of the x86 early_ioremap implementation.
*
* (C) Copyright 1995 1996, 2014 Linus Torvalds
*
*/
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/mm.h>
#include <linux/vmalloc.h>
#include <asm/fixmap.h>
#ifdef CONFIG_MMU
static int early_ioremap_debug __initdata;
static int __init early_ioremap_debug_setup(char *str)
{
early_ioremap_debug = 1;
return 0;
}
early_param("early_ioremap_debug", early_ioremap_debug_setup);
static int after_paging_init __initdata;
void __init __weak early_ioremap_shutdown(void)
{
}
void __init early_ioremap_reset(void)
{
early_ioremap_shutdown();
after_paging_init = 1;
}
/*
* Generally, ioremap() is available after paging_init() has been called.
* Architectures wanting to allow early_ioremap after paging_init() can
* define __late_set_fixmap and __late_clear_fixmap to do the right thing.
*/
#ifndef __late_set_fixmap
static inline void __init __late_set_fixmap(enum fixed_addresses idx,
phys_addr_t phys, pgprot_t prot)
{
BUG();
}
#endif
#ifndef __late_clear_fixmap
static inline void __init __late_clear_fixmap(enum fixed_addresses idx)
{
BUG();
}
#endif
static void __iomem *prev_map[FIX_BTMAPS_SLOTS] __initdata;
static unsigned long prev_size[FIX_BTMAPS_SLOTS] __initdata;
static unsigned long slot_virt[FIX_BTMAPS_SLOTS] __initdata;
void __init early_ioremap_setup(void)
{
int i;
for (i = 0; i < FIX_BTMAPS_SLOTS; i++)
if (WARN_ON(prev_map[i]))
break;
for (i = 0; i < FIX_BTMAPS_SLOTS; i++)
slot_virt[i] = __fix_to_virt(FIX_BTMAP_BEGIN - NR_FIX_BTMAPS*i);
}
static int __init check_early_ioremap_leak(void)
{
int count = 0;
int i;
for (i = 0; i < FIX_BTMAPS_SLOTS; i++)
if (prev_map[i])
count++;
if (WARN(count, KERN_WARNING
"Debug warning: early ioremap leak of %d areas detected.\n"
"please boot with early_ioremap_debug and report the dmesg.\n",
count))
return 1;
return 0;
}
late_initcall(check_early_ioremap_leak);
static void __init __iomem *
__early_ioremap(resource_size_t phys_addr, unsigned long size, pgprot_t prot)
{
unsigned long offset;
resource_size_t last_addr;
unsigned int nrpages;
enum fixed_addresses idx;
int i, slot;
WARN_ON(system_state != SYSTEM_BOOTING);
slot = -1;
for (i = 0; i < FIX_BTMAPS_SLOTS; i++) {
if (!prev_map[i]) {
slot = i;
break;
}
}
if (WARN(slot < 0, "%s(%08llx, %08lx) not found slot\n",
__func__, (u64)phys_addr, size))
return NULL;
/* Don't allow wraparound or zero size */
last_addr = phys_addr + size - 1;
if (WARN_ON(!size || last_addr < phys_addr))
return NULL;
prev_size[slot] = size;
/*
* Mappings have to be page-aligned
*/
offset = phys_addr & ~PAGE_MASK;
phys_addr &= PAGE_MASK;
size = PAGE_ALIGN(last_addr + 1) - phys_addr;
/*
* Mappings have to fit in the FIX_BTMAP area.
*/
nrpages = size >> PAGE_SHIFT;
if (WARN_ON(nrpages > NR_FIX_BTMAPS))
return NULL;
/*
* Ok, go for it..
*/
idx = FIX_BTMAP_BEGIN - NR_FIX_BTMAPS*slot;
while (nrpages > 0) {
if (after_paging_init)
__late_set_fixmap(idx, phys_addr, prot);
else
__early_set_fixmap(idx, phys_addr, prot);
phys_addr += PAGE_SIZE;
--idx;
--nrpages;
}
WARN(early_ioremap_debug, "%s(%08llx, %08lx) [%d] => %08lx + %08lx\n",
__func__, (u64)phys_addr, size, slot, offset, slot_virt[slot]);
prev_map[slot] = (void __iomem *)(offset + slot_virt[slot]);
return prev_map[slot];
}
void __init early_iounmap(void __iomem *addr, unsigned long size)
{
unsigned long virt_addr;
unsigned long offset;
unsigned int nrpages;
enum fixed_addresses idx;
int i, slot;
slot = -1;
for (i = 0; i < FIX_BTMAPS_SLOTS; i++) {
if (prev_map[i] == addr) {
slot = i;
break;
}
}
if (WARN(slot < 0, "early_iounmap(%p, %08lx) not found slot\n",
addr, size))
return;
if (WARN(prev_size[slot] != size,
"early_iounmap(%p, %08lx) [%d] size not consistent %08lx\n",
addr, size, slot, prev_size[slot]))
return;
WARN(early_ioremap_debug, "early_iounmap(%p, %08lx) [%d]\n",
addr, size, slot);
virt_addr = (unsigned long)addr;
if (WARN_ON(virt_addr < fix_to_virt(FIX_BTMAP_BEGIN)))
return;
offset = virt_addr & ~PAGE_MASK;
nrpages = PAGE_ALIGN(offset + size) >> PAGE_SHIFT;
idx = FIX_BTMAP_BEGIN - NR_FIX_BTMAPS*slot;
while (nrpages > 0) {
if (after_paging_init)
__late_clear_fixmap(idx);
else
__early_set_fixmap(idx, 0, FIXMAP_PAGE_CLEAR);
--idx;
--nrpages;
}
prev_map[slot] = NULL;
}
/* Remap an IO device */
void __init __iomem *
early_ioremap(resource_size_t phys_addr, unsigned long size)
{
return __early_ioremap(phys_addr, size, FIXMAP_PAGE_IO);
}
/* Remap memory */
void __init *
early_memremap(resource_size_t phys_addr, unsigned long size)
{
return (__force void *)__early_ioremap(phys_addr, size,
FIXMAP_PAGE_NORMAL);
}
#define MAX_MAP_CHUNK (NR_FIX_BTMAPS << PAGE_SHIFT)
void __init copy_from_early_mem(void *dest, phys_addr_t src, unsigned long size)
{
unsigned long slop, clen;
char *p;
while (size) {
slop = src & ~PAGE_MASK;
clen = size;
if (clen > MAX_MAP_CHUNK - slop)
clen = MAX_MAP_CHUNK - slop;
p = early_memremap(src & PAGE_MASK, clen + slop);
memcpy(dest, p + slop, clen);
early_memunmap(p, clen + slop);
dest += clen;
src += clen;
size -= clen;
}
}
#else /* CONFIG_MMU */
void __init __iomem *
early_ioremap(resource_size_t phys_addr, unsigned long size)
{
return (__force void __iomem *)phys_addr;
}
/* Remap memory */
void __init *
early_memremap(resource_size_t phys_addr, unsigned long size)
{
return (void *)phys_addr;
}
void __init early_iounmap(void __iomem *addr, unsigned long size)
{
}
#endif /* CONFIG_MMU */
void __init early_memunmap(void *addr, unsigned long size)
{
early_iounmap((__force void __iomem *)addr, size);
}