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(I'm so sorry!) Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel os linux
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123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176// SPDX-License-Identifier: GPL-2.0-only/* * Fixmap manipulation code */
#include <linux/bug.h>#include <linux/init.h>#include <linux/kernel.h>#include <linux/libfdt.h>#include <linux/memory.h>#include <linux/mm.h>#include <linux/sizes.h>
#include <asm/fixmap.h>#include <asm/kernel-pgtable.h>#include <asm/pgalloc.h>#include <asm/tlbflush.h>
/* ensure that the fixmap region does not grow down into the PCI I/O region */static_assert(FIXADDR_TOT_START > PCI_IO_END);
#define NR_BM_PTE_TABLES \ SPAN_NR_ENTRIES(FIXADDR_TOT_START, FIXADDR_TOP, PMD_SHIFT)#define NR_BM_PMD_TABLES \ SPAN_NR_ENTRIES(FIXADDR_TOT_START, FIXADDR_TOP, PUD_SHIFT)
static_assert(NR_BM_PMD_TABLES == 1);
#define __BM_TABLE_IDX(addr, shift) \ (((addr) >> (shift)) - (FIXADDR_TOT_START >> (shift)))
#define BM_PTE_TABLE_IDX(addr) __BM_TABLE_IDX(addr, PMD_SHIFT)
static pte_t bm_pte[NR_BM_PTE_TABLES][PTRS_PER_PTE] __bss_pgtbl;static pmd_t bm_pmd[PTRS_PER_PMD] __bss_pgtbl __maybe_unused;static pud_t bm_pud[PTRS_PER_PUD] __bss_pgtbl __maybe_unused;
static inline pte_t *fixmap_pte(unsigned long addr){ return &bm_pte[BM_PTE_TABLE_IDX(addr)][pte_index(addr)];}
static void __init early_fixmap_init_pte(pmd_t *pmdp, unsigned long addr){ pmd_t pmd = READ_ONCE(*pmdp); pte_t *ptep;
if (pmd_none(pmd)) { ptep = bm_pte[BM_PTE_TABLE_IDX(addr)]; __pmd_populate(pmdp, __pa_symbol(ptep), PMD_TYPE_TABLE | PMD_TABLE_AF); }}
static void __init early_fixmap_init_pmd(pud_t *pudp, unsigned long addr, unsigned long end){ unsigned long next; pud_t pud = READ_ONCE(*pudp); pmd_t *pmdp;
if (pud_none(pud)) __pud_populate(pudp, __pa_symbol(bm_pmd), PUD_TYPE_TABLE | PUD_TABLE_AF);
pmdp = pmd_offset_kimg(pudp, addr); do { next = pmd_addr_end(addr, end); early_fixmap_init_pte(pmdp, addr); } while (pmdp++, addr = next, addr != end);}
static void __init early_fixmap_init_pud(p4d_t *p4dp, unsigned long addr, unsigned long end){ p4d_t p4d = READ_ONCE(*p4dp); pud_t *pudp;
if (CONFIG_PGTABLE_LEVELS > 3 && !p4d_none(p4d) && p4d_page_paddr(p4d) != __pa_symbol(bm_pud)) { /* * We only end up here if the kernel mapping and the fixmap * share the top level pgd entry, which should only happen on * 16k/4 levels configurations. */ BUG_ON(!IS_ENABLED(CONFIG_ARM64_16K_PAGES)); }
if (p4d_none(p4d)) __p4d_populate(p4dp, __pa_symbol(bm_pud), P4D_TYPE_TABLE | P4D_TABLE_AF);
pudp = pud_offset_kimg(p4dp, addr); early_fixmap_init_pmd(pudp, addr, end);}
/* * The p*d_populate functions call virt_to_phys implicitly so they can't be used * directly on kernel symbols (bm_p*d). This function is called too early to use * lm_alias so __p*d_populate functions must be used to populate with the * physical address from __pa_symbol. */void __init early_fixmap_init(void){ unsigned long addr = FIXADDR_TOT_START; unsigned long end = FIXADDR_TOP;
pgd_t *pgdp = pgd_offset_k(addr); p4d_t *p4dp = p4d_offset_kimg(pgdp, addr);
early_fixmap_init_pud(p4dp, addr, end);}
/* * Unusually, this is also called in IRQ context (ghes_iounmap_irq) so if we * ever need to use IPIs for TLB broadcasting, then we're in trouble here. */void __set_fixmap(enum fixed_addresses idx, phys_addr_t phys, pgprot_t flags){ unsigned long addr = __fix_to_virt(idx); pte_t *ptep;
BUG_ON(idx <= FIX_HOLE || idx >= __end_of_fixed_addresses);
ptep = fixmap_pte(addr);
if (pgprot_val(flags)) { __set_pte(ptep, pfn_pte(phys >> PAGE_SHIFT, flags)); } else { __pte_clear(&init_mm, addr, ptep); flush_tlb_kernel_range(addr, addr+PAGE_SIZE); }}
void *__init fixmap_remap_fdt(phys_addr_t dt_phys, int *size, pgprot_t prot){ const u64 dt_virt_base = __fix_to_virt(FIX_FDT); phys_addr_t dt_phys_base; int offset; void *dt_virt;
/* * Check whether the physical FDT address is set and meets the minimum * alignment requirement. Since we are relying on MIN_FDT_ALIGN to be * at least 8 bytes so that we can always access the magic and size * fields of the FDT header after mapping the first chunk, double check * here if that is indeed the case. */ BUILD_BUG_ON(MIN_FDT_ALIGN < 8); if (!dt_phys || dt_phys % MIN_FDT_ALIGN) return NULL;
dt_phys_base = round_down(dt_phys, PAGE_SIZE); offset = dt_phys % PAGE_SIZE; dt_virt = (void *)dt_virt_base + offset;
/* map the first chunk so we can read the size from the header */ create_mapping_noalloc(dt_phys_base, dt_virt_base, PAGE_SIZE, prot);
if (fdt_magic(dt_virt) != FDT_MAGIC) return NULL;
*size = fdt_totalsize(dt_virt); if (*size > MAX_FDT_SIZE) return NULL;
if (offset + *size > PAGE_SIZE) { create_mapping_noalloc(dt_phys_base, dt_virt_base, offset + *size, prot); }
return dt_virt;}