blob: 99db769307ec30ccb0e182d6a97ff66a985a2fc7 [file] [log] [blame]
Russell King614dd052010-11-21 11:41:57 +00001#include <linux/kernel.h>
2
3#include <asm/cputype.h>
Will Deacon89038262011-09-30 11:43:29 +01004#include <asm/idmap.h>
Russell King614dd052010-11-21 11:41:57 +00005#include <asm/pgalloc.h>
6#include <asm/pgtable.h>
Will Deacon89038262011-09-30 11:43:29 +01007#include <asm/sections.h>
David Howells9f97da72012-03-28 18:30:01 +01008#include <asm/system_info.h>
Will Deacon89038262011-09-30 11:43:29 +01009
10pgd_t *idmap_pgd;
Russell King614dd052010-11-21 11:41:57 +000011
Catalin Marinasae2de1012011-11-22 17:30:32 +000012#ifdef CONFIG_ARM_LPAE
13static void idmap_add_pmd(pud_t *pud, unsigned long addr, unsigned long end,
14 unsigned long prot)
15{
16 pmd_t *pmd;
17 unsigned long next;
18
19 if (pud_none_or_clear_bad(pud) || (pud_val(*pud) & L_PGD_SWAPPER)) {
20 pmd = pmd_alloc_one(&init_mm, addr);
21 if (!pmd) {
22 pr_warning("Failed to allocate identity pmd.\n");
23 return;
24 }
25 pud_populate(&init_mm, pud, pmd);
26 pmd += pmd_index(addr);
27 } else
28 pmd = pmd_offset(pud, addr);
29
30 do {
31 next = pmd_addr_end(addr, end);
32 *pmd = __pmd((addr & PMD_MASK) | prot);
33 flush_pmd_entry(pmd);
34 } while (pmd++, addr = next, addr != end);
35}
36#else /* !CONFIG_ARM_LPAE */
Russell King516295e2010-11-21 16:27:49 +000037static void idmap_add_pmd(pud_t *pud, unsigned long addr, unsigned long end,
Russell Kingaf3813d2010-11-21 11:48:16 +000038 unsigned long prot)
39{
Russell King516295e2010-11-21 16:27:49 +000040 pmd_t *pmd = pmd_offset(pud, addr);
Russell Kingaf3813d2010-11-21 11:48:16 +000041
42 addr = (addr & PMD_MASK) | prot;
43 pmd[0] = __pmd(addr);
44 addr += SECTION_SIZE;
45 pmd[1] = __pmd(addr);
46 flush_pmd_entry(pmd);
47}
Catalin Marinasae2de1012011-11-22 17:30:32 +000048#endif /* CONFIG_ARM_LPAE */
Russell Kingaf3813d2010-11-21 11:48:16 +000049
Russell King516295e2010-11-21 16:27:49 +000050static void idmap_add_pud(pgd_t *pgd, unsigned long addr, unsigned long end,
51 unsigned long prot)
52{
53 pud_t *pud = pud_offset(pgd, addr);
54 unsigned long next;
55
56 do {
57 next = pud_addr_end(addr, end);
58 idmap_add_pmd(pud, addr, next, prot);
59 } while (pud++, addr = next, addr != end);
60}
61
Will Deacon4e8ee7d2011-11-23 12:26:25 +000062static void identity_mapping_add(pgd_t *pgd, unsigned long addr, unsigned long end)
Russell King614dd052010-11-21 11:41:57 +000063{
Russell Kingaf3813d2010-11-21 11:48:16 +000064 unsigned long prot, next;
Russell King614dd052010-11-21 11:41:57 +000065
Catalin Marinasae2de1012011-11-22 17:30:32 +000066 prot = PMD_TYPE_SECT | PMD_SECT_AP_WRITE | PMD_SECT_AF;
Russell King614dd052010-11-21 11:41:57 +000067 if (cpu_architecture() <= CPU_ARCH_ARMv5TEJ && !cpu_is_xscale())
68 prot |= PMD_BIT4;
69
Russell Kingaf3813d2010-11-21 11:48:16 +000070 pgd += pgd_index(addr);
71 do {
72 next = pgd_addr_end(addr, end);
Russell King516295e2010-11-21 16:27:49 +000073 idmap_add_pud(pgd, addr, next, prot);
Russell Kingaf3813d2010-11-21 11:48:16 +000074 } while (pgd++, addr = next, addr != end);
Russell King614dd052010-11-21 11:41:57 +000075}
76
Will Deacon89038262011-09-30 11:43:29 +010077extern char __idmap_text_start[], __idmap_text_end[];
78
79static int __init init_static_idmap(void)
80{
81 phys_addr_t idmap_start, idmap_end;
82
83 idmap_pgd = pgd_alloc(&init_mm);
84 if (!idmap_pgd)
85 return -ENOMEM;
86
87 /* Add an identity mapping for the physical address of the section. */
88 idmap_start = virt_to_phys((void *)__idmap_text_start);
89 idmap_end = virt_to_phys((void *)__idmap_text_end);
90
91 pr_info("Setting up static identity map for 0x%llx - 0x%llx\n",
92 (long long)idmap_start, (long long)idmap_end);
93 identity_mapping_add(idmap_pgd, idmap_start, idmap_end);
94
Nicolas Pitree4067852012-11-08 19:46:07 +010095 /* Flush L1 for the hardware to see this page table content */
96 flush_cache_louis();
97
Will Deacon89038262011-09-30 11:43:29 +010098 return 0;
99}
Will Deacon4e8ee7d2011-11-23 12:26:25 +0000100early_initcall(init_static_idmap);
Will Deacon89038262011-09-30 11:43:29 +0100101
Russell King614dd052010-11-21 11:41:57 +0000102/*
Will Deacon2c8951a2011-06-08 15:53:34 +0100103 * In order to soft-boot, we need to switch to a 1:1 mapping for the
104 * cpu_reset functions. This will then ensure that we have predictable
105 * results when turning off the mmu.
Russell King614dd052010-11-21 11:41:57 +0000106 */
Russell King5aafec12011-11-01 10:15:27 +0000107void setup_mm_for_reboot(void)
Russell King614dd052010-11-21 11:41:57 +0000108{
Will Deacon2c8951a2011-06-08 15:53:34 +0100109 /* Switch to the identity mapping. */
110 cpu_switch_mm(idmap_pgd, &init_mm);
111
Nicolas Pitree4067852012-11-08 19:46:07 +0100112#ifdef CONFIG_CPU_HAS_ASID
113 /*
114 * We don't have a clean ASID for the identity mapping, which
115 * may clash with virtual addresses of the previous page tables
116 * and therefore potentially in the TLB.
117 */
Russell King614dd052010-11-21 11:41:57 +0000118 local_flush_tlb_all();
Nicolas Pitree4067852012-11-08 19:46:07 +0100119#endif
Russell King614dd052010-11-21 11:41:57 +0000120}