cregit-Linux how code gets into the kernel

Release 4.8 mm/early_ioremap.c

Directory: mm
/*
 * 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>
#include <asm/early_ioremap.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; }

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early_param("early_ioremap_debug", early_ioremap_debug_setup); static int after_paging_init __initdata;
void __init __weak early_ioremap_shutdown(void) { }

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void __init early_ioremap_reset(void) { early_ioremap_shutdown(); after_paging_init = 1; }

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/* * 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(); }

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#endif #ifndef __late_clear_fixmap
static inline void __init __late_clear_fixmap(enum fixed_addresses idx) { BUG(); }

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#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); }

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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; }

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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 = offset_in_page(phys_addr); 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]; }

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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 = offset_in_page(virt_addr); 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; }

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/* 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); }

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/* 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); }

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#ifdef FIXMAP_PAGE_RO
void __init * early_memremap_ro(resource_size_t phys_addr, unsigned long size) { return (__force void *)__early_ioremap(phys_addr, size, FIXMAP_PAGE_RO); }

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#endif #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 = offset_in_page(src); 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; } }

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#else /* CONFIG_MMU */
void __init __iomem * early_ioremap(resource_size_t phys_addr, unsigned long size) { return (__force void __iomem *)phys_addr; }

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/* Remap memory */
void __init * early_memremap(resource_size_t phys_addr, unsigned long size) { return (void *)phys_addr; }

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void __init * early_memremap_ro(resource_size_t phys_addr, unsigned long size) { return (void *)phys_addr; }

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void __init early_iounmap(void __iomem *addr, unsigned long size) { }

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#endif /* CONFIG_MMU */
void __init early_memunmap(void *addr, unsigned long size) { early_iounmap((__force void __iomem *)addr, size); }

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Directory: mm
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