Commit 9e5c33d7 authored by Mark Salter's avatar Mark Salter Committed by Linus Torvalds
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mm: create generic early_ioremap() support



This patch creates a generic implementation of early_ioremap() support
based on the existing x86 implementation.  early_ioremp() is useful for
early boot code which needs to temporarily map I/O or memory regions
before normal mapping functions such as ioremap() are available.

Some architectures have optional MMU.  In the no-MMU case, the remap
functions simply return the passed in physical address and the unmap
functions do nothing.
Signed-off-by: default avatarMark Salter <msalter@redhat.com>
Acked-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
Acked-by: default avatarH. Peter Anvin <hpa@zytor.com>
Cc: Borislav Petkov <borislav.petkov@amd.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 6b550f6f
#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);
#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_ */
......@@ -578,3 +578,6 @@ config PGTABLE_MAPPING
You can check speed with zsmalloc benchmark:
https://github.com/spartacus06/zsmapbench
config GENERIC_EARLY_IOREMAP
bool
......@@ -61,3 +61,4 @@ obj-$(CONFIG_CLEANCACHE) += cleancache.o
obj-$(CONFIG_MEMORY_ISOLATION) += page_isolation.o
obj-$(CONFIG_ZBUD) += zbud.o
obj-$(CONFIG_ZSMALLOC) += zsmalloc.o
obj-$(CONFIG_GENERIC_EARLY_IOREMAP) += early_ioremap.o
/*
* 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);
}
#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);
}
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