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: Mark Salter <msalter@redhat.com> Acked-by: Catalin Marinas <catalin.marinas@arm.com> Acked-by: H. 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: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Mark Salter
Linus Torvalds
parent
6b550f6f20
commit
9e5c33d7ae
4 changed files with 291 additions and 0 deletions
42
include/asm-generic/early_ioremap.h
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42
include/asm-generic/early_ioremap.h
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@ -0,0 +1,42 @@
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#ifndef _ASM_EARLY_IOREMAP_H_
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#define _ASM_EARLY_IOREMAP_H_
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#include <linux/types.h>
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/*
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* early_ioremap() and early_iounmap() are for temporary early boot-time
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* mappings, before the real ioremap() is functional.
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*/
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extern void __iomem *early_ioremap(resource_size_t phys_addr,
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unsigned long size);
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extern void *early_memremap(resource_size_t phys_addr,
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unsigned long size);
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extern void early_iounmap(void __iomem *addr, unsigned long size);
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extern void early_memunmap(void *addr, unsigned long size);
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/*
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* Weak function called by early_ioremap_reset(). It does nothing, but
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* architectures may provide their own version to do any needed cleanups.
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*/
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extern void early_ioremap_shutdown(void);
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#if defined(CONFIG_GENERIC_EARLY_IOREMAP) && defined(CONFIG_MMU)
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/* Arch-specific initialization */
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extern void early_ioremap_init(void);
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/* Generic initialization called by architecture code */
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extern void early_ioremap_setup(void);
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/*
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* Called as last step in paging_init() so library can act
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* accordingly for subsequent map/unmap requests.
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*/
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extern void early_ioremap_reset(void);
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#else
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static inline void early_ioremap_init(void) { }
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static inline void early_ioremap_setup(void) { }
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static inline void early_ioremap_reset(void) { }
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#endif
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#endif /* _ASM_EARLY_IOREMAP_H_ */
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@ -578,3 +578,6 @@ config PGTABLE_MAPPING
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You can check speed with zsmalloc benchmark:
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https://github.com/spartacus06/zsmapbench
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config GENERIC_EARLY_IOREMAP
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bool
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@ -61,3 +61,4 @@ obj-$(CONFIG_CLEANCACHE) += cleancache.o
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obj-$(CONFIG_MEMORY_ISOLATION) += page_isolation.o
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obj-$(CONFIG_ZBUD) += zbud.o
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obj-$(CONFIG_ZSMALLOC) += zsmalloc.o
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obj-$(CONFIG_GENERIC_EARLY_IOREMAP) += early_ioremap.o
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245
mm/early_ioremap.c
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245
mm/early_ioremap.c
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/*
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* Provide common bits of early_ioremap() support for architectures needing
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* temporary mappings during boot before ioremap() is available.
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*
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* This is mostly a direct copy of the x86 early_ioremap implementation.
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*
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* (C) Copyright 1995 1996, 2014 Linus Torvalds
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*
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*/
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#include <linux/kernel.h>
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#include <linux/init.h>
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#include <linux/io.h>
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#include <linux/module.h>
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#include <linux/slab.h>
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#include <linux/mm.h>
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#include <linux/vmalloc.h>
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#include <asm/fixmap.h>
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#ifdef CONFIG_MMU
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static int early_ioremap_debug __initdata;
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static int __init early_ioremap_debug_setup(char *str)
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{
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early_ioremap_debug = 1;
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return 0;
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}
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early_param("early_ioremap_debug", early_ioremap_debug_setup);
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static int after_paging_init __initdata;
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void __init __weak early_ioremap_shutdown(void)
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{
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}
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void __init early_ioremap_reset(void)
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{
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early_ioremap_shutdown();
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after_paging_init = 1;
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}
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/*
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* Generally, ioremap() is available after paging_init() has been called.
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* Architectures wanting to allow early_ioremap after paging_init() can
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* define __late_set_fixmap and __late_clear_fixmap to do the right thing.
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*/
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#ifndef __late_set_fixmap
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static inline void __init __late_set_fixmap(enum fixed_addresses idx,
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phys_addr_t phys, pgprot_t prot)
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{
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BUG();
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}
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#endif
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#ifndef __late_clear_fixmap
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static inline void __init __late_clear_fixmap(enum fixed_addresses idx)
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{
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BUG();
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}
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#endif
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static void __iomem *prev_map[FIX_BTMAPS_SLOTS] __initdata;
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static unsigned long prev_size[FIX_BTMAPS_SLOTS] __initdata;
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static unsigned long slot_virt[FIX_BTMAPS_SLOTS] __initdata;
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void __init early_ioremap_setup(void)
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{
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int i;
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for (i = 0; i < FIX_BTMAPS_SLOTS; i++)
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if (WARN_ON(prev_map[i]))
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break;
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for (i = 0; i < FIX_BTMAPS_SLOTS; i++)
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slot_virt[i] = __fix_to_virt(FIX_BTMAP_BEGIN - NR_FIX_BTMAPS*i);
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}
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static int __init check_early_ioremap_leak(void)
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{
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int count = 0;
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int i;
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for (i = 0; i < FIX_BTMAPS_SLOTS; i++)
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if (prev_map[i])
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count++;
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if (WARN(count, KERN_WARNING
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"Debug warning: early ioremap leak of %d areas detected.\n"
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"please boot with early_ioremap_debug and report the dmesg.\n",
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count))
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return 1;
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return 0;
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}
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late_initcall(check_early_ioremap_leak);
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static void __init __iomem *
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__early_ioremap(resource_size_t phys_addr, unsigned long size, pgprot_t prot)
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{
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unsigned long offset;
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resource_size_t last_addr;
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unsigned int nrpages;
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enum fixed_addresses idx;
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int i, slot;
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WARN_ON(system_state != SYSTEM_BOOTING);
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slot = -1;
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for (i = 0; i < FIX_BTMAPS_SLOTS; i++) {
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if (!prev_map[i]) {
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slot = i;
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break;
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}
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}
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if (WARN(slot < 0, "%s(%08llx, %08lx) not found slot\n",
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__func__, (u64)phys_addr, size))
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return NULL;
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/* Don't allow wraparound or zero size */
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last_addr = phys_addr + size - 1;
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if (WARN_ON(!size || last_addr < phys_addr))
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return NULL;
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prev_size[slot] = size;
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/*
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* Mappings have to be page-aligned
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*/
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offset = phys_addr & ~PAGE_MASK;
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phys_addr &= PAGE_MASK;
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size = PAGE_ALIGN(last_addr + 1) - phys_addr;
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/*
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* Mappings have to fit in the FIX_BTMAP area.
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*/
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nrpages = size >> PAGE_SHIFT;
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if (WARN_ON(nrpages > NR_FIX_BTMAPS))
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return NULL;
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/*
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* Ok, go for it..
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*/
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idx = FIX_BTMAP_BEGIN - NR_FIX_BTMAPS*slot;
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while (nrpages > 0) {
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if (after_paging_init)
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__late_set_fixmap(idx, phys_addr, prot);
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else
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__early_set_fixmap(idx, phys_addr, prot);
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phys_addr += PAGE_SIZE;
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--idx;
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--nrpages;
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}
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WARN(early_ioremap_debug, "%s(%08llx, %08lx) [%d] => %08lx + %08lx\n",
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__func__, (u64)phys_addr, size, slot, offset, slot_virt[slot]);
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prev_map[slot] = (void __iomem *)(offset + slot_virt[slot]);
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return prev_map[slot];
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}
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void __init early_iounmap(void __iomem *addr, unsigned long size)
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{
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unsigned long virt_addr;
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unsigned long offset;
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unsigned int nrpages;
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enum fixed_addresses idx;
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int i, slot;
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slot = -1;
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for (i = 0; i < FIX_BTMAPS_SLOTS; i++) {
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if (prev_map[i] == addr) {
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slot = i;
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break;
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}
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}
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if (WARN(slot < 0, "early_iounmap(%p, %08lx) not found slot\n",
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addr, size))
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return;
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if (WARN(prev_size[slot] != size,
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"early_iounmap(%p, %08lx) [%d] size not consistent %08lx\n",
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addr, size, slot, prev_size[slot]))
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return;
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WARN(early_ioremap_debug, "early_iounmap(%p, %08lx) [%d]\n",
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addr, size, slot);
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virt_addr = (unsigned long)addr;
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if (WARN_ON(virt_addr < fix_to_virt(FIX_BTMAP_BEGIN)))
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return;
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offset = virt_addr & ~PAGE_MASK;
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nrpages = PAGE_ALIGN(offset + size) >> PAGE_SHIFT;
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idx = FIX_BTMAP_BEGIN - NR_FIX_BTMAPS*slot;
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while (nrpages > 0) {
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if (after_paging_init)
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__late_clear_fixmap(idx);
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else
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__early_set_fixmap(idx, 0, FIXMAP_PAGE_CLEAR);
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--idx;
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--nrpages;
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}
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prev_map[slot] = NULL;
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}
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/* Remap an IO device */
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void __init __iomem *
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early_ioremap(resource_size_t phys_addr, unsigned long size)
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{
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return __early_ioremap(phys_addr, size, FIXMAP_PAGE_IO);
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}
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/* Remap memory */
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void __init *
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early_memremap(resource_size_t phys_addr, unsigned long size)
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{
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return (__force void *)__early_ioremap(phys_addr, size,
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FIXMAP_PAGE_NORMAL);
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}
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#else /* CONFIG_MMU */
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void __init __iomem *
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early_ioremap(resource_size_t phys_addr, unsigned long size)
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{
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return (__force void __iomem *)phys_addr;
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}
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/* Remap memory */
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void __init *
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early_memremap(resource_size_t phys_addr, unsigned long size)
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{
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return (void *)phys_addr;
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}
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void __init early_iounmap(void __iomem *addr, unsigned long size)
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{
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}
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#endif /* CONFIG_MMU */
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void __init early_memunmap(void *addr, unsigned long size)
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{
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early_iounmap((__force void __iomem *)addr, size);
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}
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