diff options
Diffstat (limited to 'arch/x86/kernel/head64.c')
| -rw-r--r-- | arch/x86/kernel/head64.c | 344 |
1 files changed, 14 insertions, 330 deletions
diff --git a/arch/x86/kernel/head64.c b/arch/x86/kernel/head64.c index dc0956067944..533fcf5636fc 100644 --- a/arch/x86/kernel/head64.c +++ b/arch/x86/kernel/head64.c @@ -5,8 +5,6 @@ * 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 @@ -22,6 +20,8 @@ #include <linux/cc_platform.h> #include <linux/pgtable.h> +#include <asm/asm.h> +#include <asm/page_64.h> #include <asm/processor.h> #include <asm/proto.h> #include <asm/smp.h> @@ -47,276 +47,22 @@ * 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; +unsigned int __initdata next_early_pgt; +SYM_PIC_ALIAS(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 - -/* - * GDT used on the boot CPU before switching to virtual addresses. - */ -static struct desc_struct startup_gdt[GDT_ENTRIES] __initdata = { - [GDT_ENTRY_KERNEL32_CS] = GDT_ENTRY_INIT(DESC_CODE32, 0, 0xfffff), - [GDT_ENTRY_KERNEL_CS] = GDT_ENTRY_INIT(DESC_CODE64, 0, 0xfffff), - [GDT_ENTRY_KERNEL_DS] = GDT_ENTRY_INIT(DESC_DATA64, 0, 0xfffff), -}; - -/* - * Address needs to be set at runtime because it references the startup_gdt - * while the kernel still uses a direct mapping. - */ -static struct desc_ptr startup_gdt_descr __initdata = { - .size = sizeof(startup_gdt)-1, - .address = 0, -}; - -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 decompression - * 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 - -static unsigned long __head sme_postprocess_startup(struct boot_params *bp, pmdval_t *pmd) -{ - unsigned long vaddr, vaddr_end; - int i; - - /* 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 (sme_get_me_mask()) { - vaddr = (unsigned long)__start_bss_decrypted; - vaddr_end = (unsigned long)__end_bss_decrypted; - - for (; vaddr < vaddr_end; vaddr += PMD_SIZE) { - /* - * On SNP, transition the page to shared in the RMP table so that - * it is consistent with the page table attribute change. - * - * __start_bss_decrypted has a virtual address in the high range - * mapping (kernel .text). PVALIDATE, by way of - * early_snp_set_memory_shared(), requires a valid virtual - * address but the kernel is currently running off of the identity - * mapping so use __pa() to get a *currently* valid virtual address. - */ - early_snp_set_memory_shared(__pa(vaddr), __pa(vaddr), PTRS_PER_PMD); - - 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(); -} - -/* 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 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_MASK) - for (;;); - - /* 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(); - - return sme_postprocess_startup(bp, pmd); -} /* Wipe all early page tables except for the kernel symbol map */ static void __init reset_early_page_tables(void) @@ -491,6 +237,12 @@ asmlinkage __visible void __init __noreturn x86_64_start_kernel(char * real_mode /* Kill off the identity-map trampoline */ reset_early_page_tables(); + if (pgtable_l5_enabled()) { + page_offset_base = __PAGE_OFFSET_BASE_L5; + vmalloc_base = __VMALLOC_BASE_L5; + vmemmap_base = __VMEMMAP_BASE_L5; + } + clear_bss(); /* @@ -555,82 +307,14 @@ void __init __noreturn x86_64_start_reservations(char *real_mode_data) start_kernel(); } -/* - * Data structures and code used for IDT setup in head_64.S. The bringup-IDT is - * used until the idt_table takes over. On the boot CPU this happens in - * x86_64_start_kernel(), on secondary CPUs in start_secondary(). In both cases - * this happens in the functions called from head_64.S. - * - * The idt_table can't be used that early because all the code modifying it is - * in idt.c and can be instrumented by tracing or KASAN, which both don't work - * during early CPU bringup. Also the idt_table has the runtime vectors - * configured which require certain CPU state to be setup already (like TSS), - * which also hasn't happened yet in early CPU bringup. - */ -static gate_desc bringup_idt_table[NUM_EXCEPTION_VECTORS] __page_aligned_data; - -static struct desc_ptr bringup_idt_descr = { - .size = (NUM_EXCEPTION_VECTORS * sizeof(gate_desc)) - 1, - .address = 0, /* Set at runtime */ -}; - -static void set_bringup_idt_handler(gate_desc *idt, int n, void *handler) -{ -#ifdef CONFIG_AMD_MEM_ENCRYPT - struct idt_data data; - gate_desc desc; - - init_idt_data(&data, n, handler); - idt_init_desc(&desc, &data); - native_write_idt_entry(idt, n, &desc); -#endif -} - -/* This runs while still in the direct mapping */ -static void __head startup_64_load_idt(unsigned long physbase) -{ - struct desc_ptr *desc = fixup_pointer(&bringup_idt_descr, physbase); - gate_desc *idt = fixup_pointer(bringup_idt_table, physbase); - - - if (IS_ENABLED(CONFIG_AMD_MEM_ENCRYPT)) { - void *handler; - - /* VMM Communication Exception */ - handler = fixup_pointer(vc_no_ghcb, physbase); - set_bringup_idt_handler(idt, X86_TRAP_VC, handler); - } - - desc->address = (unsigned long)idt; - native_load_idt(desc); -} - -/* This is used when running on kernel addresses */ void early_setup_idt(void) { - /* VMM Communication Exception */ + void *handler = NULL; + if (IS_ENABLED(CONFIG_AMD_MEM_ENCRYPT)) { setup_ghcb(); - set_bringup_idt_handler(bringup_idt_table, X86_TRAP_VC, vc_boot_ghcb); + handler = vc_boot_ghcb; } - bringup_idt_descr.address = (unsigned long)bringup_idt_table; - native_load_idt(&bringup_idt_descr); -} - -/* - * Setup boot CPU state needed before kernel switches to virtual addresses. - */ -void __head startup_64_setup_env(unsigned long physbase) -{ - /* Load GDT */ - startup_gdt_descr.address = (unsigned long)fixup_pointer(startup_gdt, physbase); - native_load_gdt(&startup_gdt_descr); - - /* New GDT is live - reload data segment registers */ - asm volatile("movl %%eax, %%ds\n" - "movl %%eax, %%ss\n" - "movl %%eax, %%es\n" : : "a"(__KERNEL_DS) : "memory"); - - startup_64_load_idt(physbase); + startup_64_load_idt(handler); } |