// SPDX-License-Identifier: GPL-2.0 /* * prepare to run common code * * Copyright (C) 2000 Andrea Arcangeli <andrea@suse.de> SuSE */ #define DISABLE_BRANCH_PROFILING /* cpu_feature_enabled() cannot be used this early */ #define USE_EARLY_PGTABLE_L5 #include <linux/init.h> #include <linux/linkage.h> #include <linux/types.h> #include <linux/kernel.h> #include <linux/string.h> #include <linux/percpu.h> #include <linux/start_kernel.h> #include <linux/io.h> #include <linux/memblock.h> #include <linux/mem_encrypt.h> #include <linux/pgtable.h> #include <asm/processor.h> #include <asm/proto.h> #include <asm/smp.h> #include <asm/setup.h> #include <asm/desc.h> #include <asm/tlbflush.h> #include <asm/sections.h> #include <asm/kdebug.h> #include <asm/e820/api.h> #include <asm/bios_ebda.h> #include <asm/bootparam_utils.h> #include <asm/microcode.h> #include <asm/kasan.h> #include <asm/fixmap.h> /* * Manage page tables very early on. */ extern pmd_t early_dynamic_pgts[EARLY_DYNAMIC_PAGE_TABLES][PTRS_PER_PMD]; static unsigned int __initdata next_early_pgt; pmdval_t early_pmd_flags = __PAGE_KERNEL_LARGE & ~(_PAGE_GLOBAL | _PAGE_NX); #ifdef CONFIG_X86_5LEVEL unsigned int __pgtable_l5_enabled __ro_after_init; unsigned int pgdir_shift __ro_after_init = 39; EXPORT_SYMBOL(pgdir_shift); unsigned int ptrs_per_p4d __ro_after_init = 1; EXPORT_SYMBOL(ptrs_per_p4d); #endif #ifdef CONFIG_DYNAMIC_MEMORY_LAYOUT unsigned long page_offset_base __ro_after_init = __PAGE_OFFSET_BASE_L4; EXPORT_SYMBOL(page_offset_base); unsigned long vmalloc_base __ro_after_init = __VMALLOC_BASE_L4; EXPORT_SYMBOL(vmalloc_base); unsigned long vmemmap_base __ro_after_init = __VMEMMAP_BASE_L4; EXPORT_SYMBOL(vmemmap_base); #endif #define __head __section(.head.text) static void __head *fixup_pointer(void *ptr, unsigned long physaddr) { return ptr - (void *)_text + (void *)physaddr; } static unsigned long __head *fixup_long(void *ptr, unsigned long physaddr) { return fixup_pointer(ptr, physaddr); } #ifdef CONFIG_X86_5LEVEL static unsigned int __head *fixup_int(void *ptr, unsigned long physaddr) { return fixup_pointer(ptr, physaddr); } static bool __head check_la57_support(unsigned long physaddr) { /* * 5-level paging is detected and enabled at kernel decomression * stage. Only check if it has been enabled there. */ if (!(native_read_cr4() & X86_CR4_LA57)) return false; *fixup_int(&__pgtable_l5_enabled, physaddr) = 1; *fixup_int(&pgdir_shift, physaddr) = 48; *fixup_int(&ptrs_per_p4d, physaddr) = 512; *fixup_long(&page_offset_base, physaddr) = __PAGE_OFFSET_BASE_L5; *fixup_long(&vmalloc_base, physaddr) = __VMALLOC_BASE_L5; *fixup_long(&vmemmap_base, physaddr) = __VMEMMAP_BASE_L5; return true; } #else static bool __head check_la57_support(unsigned long physaddr) { return false; } #endif /* Code in __startup_64() can be relocated during execution, but the compiler * doesn't have to generate PC-relative relocations when accessing globals from * that function. Clang actually does not generate them, which leads to * boot-time crashes. To work around this problem, every global pointer must * be adjusted using fixup_pointer(). */ unsigned long __head __startup_64(unsigned long physaddr, struct boot_params *bp) { unsigned long vaddr, vaddr_end; unsigned long load_delta, *p; unsigned long pgtable_flags; pgdval_t *pgd; p4dval_t *p4d; pudval_t *pud; pmdval_t *pmd, pmd_entry; pteval_t *mask_ptr; bool la57; int i; unsigned int *next_pgt_ptr; la57 = check_la57_support(physaddr); /* Is the address too large? */ if (physaddr >> MAX_PHYSMEM_BITS) for (;;); /* * Compute the delta between the address I am compiled to run at * and the address I am actually running at. */ load_delta = physaddr - (unsigned long)(_text - __START_KERNEL_map); /* Is the address not 2M aligned? */ if (load_delta & ~PMD_PAGE_MASK) for (;;); /* Activate Secure Memory Encryption (SME) if supported and enabled */ sme_enable(bp); /* Include the SME encryption mask in the fixup value */ load_delta += sme_get_me_mask(); /* Fixup the physical addresses in the page table */ pgd = fixup_pointer(&early_top_pgt, physaddr); p = pgd + pgd_index(__START_KERNEL_map); if (la57) *p = (unsigned long)level4_kernel_pgt; else *p = (unsigned long)level3_kernel_pgt; *p += _PAGE_TABLE_NOENC - __START_KERNEL_map + load_delta; if (la57) { p4d = fixup_pointer(&level4_kernel_pgt, physaddr); p4d[511] += load_delta; } pud = fixup_pointer(&level3_kernel_pgt, physaddr); pud[510] += load_delta; pud[511] += load_delta; pmd = fixup_pointer(level2_fixmap_pgt, physaddr); for (i = FIXMAP_PMD_TOP; i > FIXMAP_PMD_TOP - FIXMAP_PMD_NUM; i--) pmd[i] += load_delta; /* * Set up the identity mapping for the switchover. These * entries should *NOT* have the global bit set! This also * creates a bunch of nonsense entries but that is fine -- * it avoids problems around wraparound. */ next_pgt_ptr = fixup_pointer(&next_early_pgt, physaddr); pud = fixup_pointer(early_dynamic_pgts[(*next_pgt_ptr)++], physaddr); pmd = fixup_pointer(early_dynamic_pgts[(*next_pgt_ptr)++], physaddr); pgtable_flags = _KERNPG_TABLE_NOENC + sme_get_me_mask(); if (la57) { p4d = fixup_pointer(early_dynamic_pgts[(*next_pgt_ptr)++], physaddr); i = (physaddr >> PGDIR_SHIFT) % PTRS_PER_PGD; pgd[i + 0] = (pgdval_t)p4d + pgtable_flags; pgd[i + 1] = (pgdval_t)p4d + pgtable_flags; i = physaddr >> P4D_SHIFT; p4d[(i + 0) % PTRS_PER_P4D] = (pgdval_t)pud + pgtable_flags; p4d[(i + 1) % PTRS_PER_P4D] = (pgdval_t)pud + pgtable_flags; } else { i = (physaddr >> PGDIR_SHIFT) % PTRS_PER_PGD; pgd[i + 0] = (pgdval_t)pud + pgtable_flags; pgd[i + 1] = (pgdval_t)pud + pgtable_flags; } i = physaddr >> PUD_SHIFT; pud[(i + 0) % PTRS_PER_PUD] = (pudval_t)pmd + pgtable_flags; pud[(i + 1) % PTRS_PER_PUD] = (pudval_t)pmd + pgtable_flags; pmd_entry = __PAGE_KERNEL_LARGE_EXEC & ~_PAGE_GLOBAL; /* Filter out unsupported __PAGE_KERNEL_* bits: */ mask_ptr = fixup_pointer(&__supported_pte_mask, physaddr); pmd_entry &= *mask_ptr; pmd_entry += sme_get_me_mask(); pmd_entry += physaddr; for (i = 0; i < DIV_ROUND_UP(_end - _text, PMD_SIZE); i++) { int idx = i + (physaddr >> PMD_SHIFT); pmd[idx % PTRS_PER_PMD] = pmd_entry + i * PMD_SIZE; } /* * Fixup the kernel text+data virtual addresses. Note that * we might write invalid pmds, when the kernel is relocated * cleanup_highmap() fixes this up along with the mappings * beyond _end. * * Only the region occupied by the kernel image has so far * been checked against the table of usable memory regions * provided by the firmware, so invalidate pages outside that * region. A page table entry that maps to a reserved area of * memory would allow processor speculation into that area, * and on some hardware (particularly the UV platform) even * speculative access to some reserved areas is caught as an * error, causing the BIOS to halt the system. */ pmd = fixup_pointer(level2_kernel_pgt, physaddr); /* invalidate pages before the kernel image */ for (i = 0; i < pmd_index((unsigned long)_text); i++) pmd[i] &= ~_PAGE_PRESENT; /* fixup pages that are part of the kernel image */ for (; i <= pmd_index((unsigned long)_end); i++) if (pmd[i] & _PAGE_PRESENT) pmd[i] += load_delta; /* invalidate pages after the kernel image */ for (; i < PTRS_PER_PMD; i++) pmd[i] &= ~_PAGE_PRESENT; /* * Fixup phys_base - remove the memory encryption mask to obtain * the true physical address. */ *fixup_long(&phys_base, physaddr) += load_delta - sme_get_me_mask(); /* Encrypt the kernel and related (if SME is active) */ sme_encrypt_kernel(bp); /* * Clear the memory encryption mask from the .bss..decrypted section. * The bss section will be memset to zero later in the initialization so * there is no need to zero it after changing the memory encryption * attribute. */ if (mem_encrypt_active()) { vaddr = (unsigned long)__start_bss_decrypted; vaddr_end = (unsigned long)__end_bss_decrypted; for (; vaddr < vaddr_end; vaddr += PMD_SIZE) { i = pmd_index(vaddr); pmd[i] -= sme_get_me_mask(); } } /* * Return the SME encryption mask (if SME is active) to be used as a * modifier for the initial pgdir entry programmed into CR3. */ return sme_get_me_mask(); } unsigned long __startup_secondary_64(void) { /* * Return the SME encryption mask (if SME is active) to be used as a * modifier for the initial pgdir entry programmed into CR3. */ return sme_get_me_mask(); } /* Wipe all early page tables except for the kernel symbol map */ static void __init reset_early_page_tables(void) { memset(early_top_pgt, 0, sizeof(pgd_t)*(PTRS_PER_PGD-1)); next_early_pgt = 0; write_cr3(__sme_pa_nodebug(early_top_pgt)); } /* Create a new PMD entry */ int __init __early_make_pgtable(unsigned long address, pmdval_t pmd) { unsigned long physaddr = address - __PAGE_OFFSET; pgdval_t pgd, *pgd_p; p4dval_t p4d, *p4d_p; pudval_t pud, *pud_p; pmdval_t *pmd_p; /* Invalid address or early pgt is done ? */ if (physaddr >= MAXMEM || read_cr3_pa() != __pa_nodebug(early_top_pgt)) return -1; again: pgd_p = &early_top_pgt[pgd_index(address)].pgd; pgd = *pgd_p; /* * The use of __START_KERNEL_map rather than __PAGE_OFFSET here is * critical -- __PAGE_OFFSET would point us back into the dynamic * range and we might end up looping forever... */ if (!pgtable_l5_enabled()) p4d_p = pgd_p; else if (pgd) p4d_p = (p4dval_t *)((pgd & PTE_PFN_MASK) + __START_KERNEL_map - phys_base); else { if (next_early_pgt >= EARLY_DYNAMIC_PAGE_TABLES) { reset_early_page_tables(); goto again; } p4d_p = (p4dval_t *)early_dynamic_pgts[next_early_pgt++]; memset(p4d_p, 0, sizeof(*p4d_p) * PTRS_PER_P4D); *pgd_p = (pgdval_t)p4d_p - __START_KERNEL_map + phys_base + _KERNPG_TABLE; } p4d_p += p4d_index(address); p4d = *p4d_p; if (p4d) pud_p = (pudval_t *)((p4d & PTE_PFN_MASK) + __START_KERNEL_map - phys_base); else { if (next_early_pgt >= EARLY_DYNAMIC_PAGE_TABLES) { reset_early_page_tables(); goto again; } pud_p = (pudval_t *)early_dynamic_pgts[next_early_pgt++]; memset(pud_p, 0, sizeof(*pud_p) * PTRS_PER_PUD); *p4d_p = (p4dval_t)pud_p - __START_KERNEL_map + phys_base + _KERNPG_TABLE; } pud_p += pud_index(address); pud = *pud_p; if (pud) pmd_p = (pmdval_t *)((pud & PTE_PFN_MASK) + __START_KERNEL_map - phys_base); else { if (next_early_pgt >= EARLY_DYNAMIC_PAGE_TABLES) { reset_early_page_tables(); goto again; } pmd_p = (pmdval_t *)early_dynamic_pgts[next_early_pgt++]; memset(pmd_p, 0, sizeof(*pmd_p) * PTRS_PER_PMD); *pud_p = (pudval_t)pmd_p - __START_KERNEL_map + phys_base + _KERNPG_TABLE; } pmd_p[pmd_index(address)] = pmd; return 0; } int __init early_make_pgtable(unsigned long address) { unsigned long physaddr = address - __PAGE_OFFSET; pmdval_t pmd; pmd = (physaddr & PMD_MASK) + early_pmd_flags; return __early_make_pgtable(address, pmd); } /* Don't add a printk in there. printk relies on the PDA which is not initialized yet. */ static void __init clear_bss(void) { memset(__bss_start, 0, (unsigned long) __bss_stop - (unsigned long) __bss_start); } static unsigned long get_cmd_line_ptr(void) { unsigned long cmd_line_ptr = boot_params.hdr.cmd_line_ptr; cmd_line_ptr |= (u64)boot_params.ext_cmd_line_ptr << 32; return cmd_line_ptr; } static void __init copy_bootdata(char *real_mode_data) { char * command_line; unsigned long cmd_line_ptr; /* * If SME is active, this will create decrypted mappings of the * boot data in advance of the copy operations. */ sme_map_bootdata(real_mode_data); memcpy(&boot_params, real_mode_data, sizeof(boot_params)); sanitize_boot_params(&boot_params); cmd_line_ptr = get_cmd_line_ptr(); if (cmd_line_ptr) { command_line = __va(cmd_line_ptr); memcpy(boot_command_line, command_line, COMMAND_LINE_SIZE); } /* * The old boot data is no longer needed and won't be reserved, * freeing up that memory for use by the system. If SME is active, * we need to remove the mappings that were created so that the * memory doesn't remain mapped as decrypted. */ sme_unmap_bootdata(real_mode_data); } asmlinkage __visible void __init x86_64_start_kernel(char * real_mode_data) { /* * Build-time sanity checks on the kernel image and module * area mappings. (these are purely build-time and produce no code) */ BUILD_BUG_ON(MODULES_VADDR < __START_KERNEL_map); BUILD_BUG_ON(MODULES_VADDR - __START_KERNEL_map < KERNEL_IMAGE_SIZE); BUILD_BUG_ON(MODULES_LEN + KERNEL_IMAGE_SIZE > 2*PUD_SIZE); BUILD_BUG_ON((__START_KERNEL_map & ~PMD_MASK) != 0); BUILD_BUG_ON((MODULES_VADDR & ~PMD_MASK) != 0); BUILD_BUG_ON(!(MODULES_VADDR > __START_KERNEL)); MAYBE_BUILD_BUG_ON(!(((MODULES_END - 1) & PGDIR_MASK) == (__START_KERNEL & PGDIR_MASK))); BUILD_BUG_ON(__fix_to_virt(__end_of_fixed_addresses) <= MODULES_END); cr4_init_shadow(); /* Kill off the identity-map trampoline */ reset_early_page_tables(); clear_bss(); clear_page(init_top_pgt); /* * SME support may update early_pmd_flags to include the memory * encryption mask, so it needs to be called before anything * that may generate a page fault. */ sme_early_init(); kasan_early_init(); idt_setup_early_handler(); copy_bootdata(__va(real_mode_data)); /* * Load microcode early on BSP. */ load_ucode_bsp(); /* set init_top_pgt kernel high mapping*/ init_top_pgt[511] = early_top_pgt[511]; x86_64_start_reservations(real_mode_data); } void __init x86_64_start_reservations(char *real_mode_data) { /* version is always not zero if it is copied */ if (!boot_params.hdr.version) copy_bootdata(__va(real_mode_data)); x86_early_init_platform_quirks(); switch (boot_params.hdr.hardware_subarch) { case X86_SUBARCH_INTEL_MID: x86_intel_mid_early_setup(); break; default: break; } start_kernel(); }