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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 | #include <linux/module.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <asm/cputype.h>
#include <asm/idmap.h>
#include <asm/pgalloc.h>
#include <asm/pgtable.h>
#include <asm/sections.h>
#include <asm/system_info.h>
#include <asm/virt.h>
pgd_t *idmap_pgd;
#ifdef CONFIG_ARM_LPAE
static void idmap_add_pmd(pud_t *pud, unsigned long addr, unsigned long end,
unsigned long prot)
{
pmd_t *pmd;
unsigned long next;
if (pud_none_or_clear_bad(pud) || (pud_val(*pud) & L_PGD_SWAPPER)) {
pmd = pmd_alloc_one(&init_mm, addr);
if (!pmd) {
pr_warning("Failed to allocate identity pmd.\n");
return;
}
pud_populate(&init_mm, pud, pmd);
pmd += pmd_index(addr);
} else
pmd = pmd_offset(pud, addr);
do {
next = pmd_addr_end(addr, end);
*pmd = __pmd((addr & PMD_MASK) | prot);
flush_pmd_entry(pmd);
} while (pmd++, addr = next, addr != end);
}
#else /* !CONFIG_ARM_LPAE */
static void idmap_add_pmd(pud_t *pud, unsigned long addr, unsigned long end,
unsigned long prot)
{
pmd_t *pmd = pmd_offset(pud, addr);
addr = (addr & PMD_MASK) | prot;
pmd[0] = __pmd(addr);
addr += SECTION_SIZE;
pmd[1] = __pmd(addr);
flush_pmd_entry(pmd);
}
#endif /* CONFIG_ARM_LPAE */
static void idmap_add_pud(pgd_t *pgd, unsigned long addr, unsigned long end,
unsigned long prot)
{
pud_t *pud = pud_offset(pgd, addr);
unsigned long next;
do {
next = pud_addr_end(addr, end);
idmap_add_pmd(pud, addr, next, prot);
} while (pud++, addr = next, addr != end);
}
static void identity_mapping_add(pgd_t *pgd, const char *text_start,
const char *text_end, unsigned long prot)
{
unsigned long addr, end;
unsigned long next;
addr = virt_to_phys(text_start);
end = virt_to_phys(text_end);
prot |= PMD_TYPE_SECT | PMD_SECT_AP_WRITE | PMD_SECT_AF;
if (cpu_architecture() <= CPU_ARCH_ARMv5TEJ && !cpu_is_xscale())
prot |= PMD_BIT4;
pgd += pgd_index(addr);
do {
next = pgd_addr_end(addr, end);
idmap_add_pud(pgd, addr, next, prot);
} while (pgd++, addr = next, addr != end);
}
#if defined(CONFIG_ARM_VIRT_EXT) && defined(CONFIG_ARM_LPAE)
pgd_t *hyp_pgd;
extern char __hyp_idmap_text_start[], __hyp_idmap_text_end[];
static int __init init_static_idmap_hyp(void)
{
hyp_pgd = kzalloc(PTRS_PER_PGD * sizeof(pgd_t), GFP_KERNEL);
if (!hyp_pgd)
return -ENOMEM;
pr_info("Setting up static HYP identity map for 0x%p - 0x%p\n",
__hyp_idmap_text_start, __hyp_idmap_text_end);
identity_mapping_add(hyp_pgd, __hyp_idmap_text_start,
__hyp_idmap_text_end, PMD_SECT_AP1);
return 0;
}
#else
static int __init init_static_idmap_hyp(void)
{
return 0;
}
#endif
extern char __idmap_text_start[], __idmap_text_end[];
static int __init init_static_idmap(void)
{
int ret;
idmap_pgd = pgd_alloc(&init_mm);
if (!idmap_pgd)
return -ENOMEM;
pr_info("Setting up static identity map for 0x%p - 0x%p\n",
__idmap_text_start, __idmap_text_end);
identity_mapping_add(idmap_pgd, __idmap_text_start,
__idmap_text_end, 0);
ret = init_static_idmap_hyp();
/* Flush L1 for the hardware to see this page table content */
flush_cache_louis();
return ret;
}
early_initcall(init_static_idmap);
/*
* In order to soft-boot, we need to switch to a 1:1 mapping for the
* cpu_reset functions. This will then ensure that we have predictable
* results when turning off the mmu.
*/
void setup_mm_for_reboot(void)
{
/* Switch to the identity mapping. */
cpu_switch_mm(idmap_pgd, &init_mm);
local_flush_bp_all();
#ifdef CONFIG_CPU_HAS_ASID
/*
* We don't have a clean ASID for the identity mapping, which
* may clash with virtual addresses of the previous page tables
* and therefore potentially in the TLB.
*/
local_flush_tlb_all();
#endif
}
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