| /* SPDX-License-Identifier: GPL-2.0 */ |
| /* |
| * |
| * Copyright (C) 1991, 1992 Linus Torvalds |
| * |
| * Enhanced CPU detection and feature setting code by Mike Jagdis |
| * and Martin Mares, November 1997. |
| */ |
| |
| .text |
| #include <linux/threads.h> |
| #include <linux/init.h> |
| #include <linux/linkage.h> |
| #include <asm/segment.h> |
| #include <asm/page_types.h> |
| #include <asm/pgtable_types.h> |
| #include <asm/cache.h> |
| #include <asm/thread_info.h> |
| #include <asm/asm-offsets.h> |
| #include <asm/setup.h> |
| #include <asm/processor-flags.h> |
| #include <asm/msr-index.h> |
| #include <asm/cpufeatures.h> |
| #include <asm/percpu.h> |
| #include <asm/nops.h> |
| #include <asm/nospec-branch.h> |
| #include <asm/bootparam.h> |
| #include <asm/export.h> |
| #include <asm/pgtable_32.h> |
| |
| /* Physical address */ |
| #define pa(X) ((X) - __PAGE_OFFSET) |
| |
| /* |
| * References to members of the new_cpu_data structure. |
| */ |
| |
| #define X86 new_cpu_data+CPUINFO_x86 |
| #define X86_VENDOR new_cpu_data+CPUINFO_x86_vendor |
| #define X86_MODEL new_cpu_data+CPUINFO_x86_model |
| #define X86_STEPPING new_cpu_data+CPUINFO_x86_stepping |
| #define X86_HARD_MATH new_cpu_data+CPUINFO_hard_math |
| #define X86_CPUID new_cpu_data+CPUINFO_cpuid_level |
| #define X86_CAPABILITY new_cpu_data+CPUINFO_x86_capability |
| #define X86_VENDOR_ID new_cpu_data+CPUINFO_x86_vendor_id |
| |
| |
| #define SIZEOF_PTREGS 17*4 |
| |
| /* |
| * Worst-case size of the kernel mapping we need to make: |
| * a relocatable kernel can live anywhere in lowmem, so we need to be able |
| * to map all of lowmem. |
| */ |
| KERNEL_PAGES = LOWMEM_PAGES |
| |
| INIT_MAP_SIZE = PAGE_TABLE_SIZE(KERNEL_PAGES) * PAGE_SIZE |
| RESERVE_BRK(pagetables, INIT_MAP_SIZE) |
| |
| /* |
| * 32-bit kernel entrypoint; only used by the boot CPU. On entry, |
| * %esi points to the real-mode code as a 32-bit pointer. |
| * CS and DS must be 4 GB flat segments, but we don't depend on |
| * any particular GDT layout, because we load our own as soon as we |
| * can. |
| */ |
| __HEAD |
| SYM_CODE_START(startup_32) |
| movl pa(initial_stack),%ecx |
| |
| /* |
| * Set segments to known values. |
| */ |
| lgdt pa(boot_gdt_descr) |
| movl $(__BOOT_DS),%eax |
| movl %eax,%ds |
| movl %eax,%es |
| movl %eax,%fs |
| movl %eax,%gs |
| movl %eax,%ss |
| leal -__PAGE_OFFSET(%ecx),%esp |
| |
| /* |
| * Clear BSS first so that there are no surprises... |
| */ |
| cld |
| xorl %eax,%eax |
| movl $pa(__bss_start),%edi |
| movl $pa(__bss_stop),%ecx |
| subl %edi,%ecx |
| shrl $2,%ecx |
| rep ; stosl |
| /* |
| * Copy bootup parameters out of the way. |
| * Note: %esi still has the pointer to the real-mode data. |
| * With the kexec as boot loader, parameter segment might be loaded beyond |
| * kernel image and might not even be addressable by early boot page tables. |
| * (kexec on panic case). Hence copy out the parameters before initializing |
| * page tables. |
| */ |
| movl $pa(boot_params),%edi |
| movl $(PARAM_SIZE/4),%ecx |
| cld |
| rep |
| movsl |
| movl pa(boot_params) + NEW_CL_POINTER,%esi |
| andl %esi,%esi |
| jz 1f # No command line |
| movl $pa(boot_command_line),%edi |
| movl $(COMMAND_LINE_SIZE/4),%ecx |
| rep |
| movsl |
| 1: |
| |
| #ifdef CONFIG_OLPC |
| /* save OFW's pgdir table for later use when calling into OFW */ |
| movl %cr3, %eax |
| movl %eax, pa(olpc_ofw_pgd) |
| #endif |
| |
| #ifdef CONFIG_MICROCODE |
| /* Early load ucode on BSP. */ |
| call load_ucode_bsp |
| #endif |
| |
| /* Create early pagetables. */ |
| call mk_early_pgtbl_32 |
| |
| /* Do early initialization of the fixmap area */ |
| movl $pa(initial_pg_fixmap)+PDE_IDENT_ATTR,%eax |
| #ifdef CONFIG_X86_PAE |
| #define KPMDS (((-__PAGE_OFFSET) >> 30) & 3) /* Number of kernel PMDs */ |
| movl %eax,pa(initial_pg_pmd+0x1000*KPMDS-8) |
| #else |
| movl %eax,pa(initial_page_table+0xffc) |
| #endif |
| |
| jmp .Ldefault_entry |
| SYM_CODE_END(startup_32) |
| |
| #ifdef CONFIG_HOTPLUG_CPU |
| /* |
| * Boot CPU0 entry point. It's called from play_dead(). Everything has been set |
| * up already except stack. We just set up stack here. Then call |
| * start_secondary(). |
| */ |
| SYM_FUNC_START(start_cpu0) |
| movl initial_stack, %ecx |
| movl %ecx, %esp |
| call *(initial_code) |
| 1: jmp 1b |
| SYM_FUNC_END(start_cpu0) |
| #endif |
| |
| /* |
| * Non-boot CPU entry point; entered from trampoline.S |
| * We can't lgdt here, because lgdt itself uses a data segment, but |
| * we know the trampoline has already loaded the boot_gdt for us. |
| * |
| * If cpu hotplug is not supported then this code can go in init section |
| * which will be freed later |
| */ |
| SYM_FUNC_START(startup_32_smp) |
| cld |
| movl $(__BOOT_DS),%eax |
| movl %eax,%ds |
| movl %eax,%es |
| movl %eax,%fs |
| movl %eax,%gs |
| movl pa(initial_stack),%ecx |
| movl %eax,%ss |
| leal -__PAGE_OFFSET(%ecx),%esp |
| |
| #ifdef CONFIG_MICROCODE |
| /* Early load ucode on AP. */ |
| call load_ucode_ap |
| #endif |
| |
| .Ldefault_entry: |
| movl $(CR0_STATE & ~X86_CR0_PG),%eax |
| movl %eax,%cr0 |
| |
| /* |
| * We want to start out with EFLAGS unambiguously cleared. Some BIOSes leave |
| * bits like NT set. This would confuse the debugger if this code is traced. So |
| * initialize them properly now before switching to protected mode. That means |
| * DF in particular (even though we have cleared it earlier after copying the |
| * command line) because GCC expects it. |
| */ |
| pushl $0 |
| popfl |
| |
| /* |
| * New page tables may be in 4Mbyte page mode and may be using the global pages. |
| * |
| * NOTE! If we are on a 486 we may have no cr4 at all! Specifically, cr4 exists |
| * if and only if CPUID exists and has flags other than the FPU flag set. |
| */ |
| movl $-1,pa(X86_CPUID) # preset CPUID level |
| movl $X86_EFLAGS_ID,%ecx |
| pushl %ecx |
| popfl # set EFLAGS=ID |
| pushfl |
| popl %eax # get EFLAGS |
| testl $X86_EFLAGS_ID,%eax # did EFLAGS.ID remained set? |
| jz .Lenable_paging # hw disallowed setting of ID bit |
| # which means no CPUID and no CR4 |
| |
| xorl %eax,%eax |
| cpuid |
| movl %eax,pa(X86_CPUID) # save largest std CPUID function |
| |
| movl $1,%eax |
| cpuid |
| andl $~1,%edx # Ignore CPUID.FPU |
| jz .Lenable_paging # No flags or only CPUID.FPU = no CR4 |
| |
| movl pa(mmu_cr4_features),%eax |
| movl %eax,%cr4 |
| |
| testb $X86_CR4_PAE, %al # check if PAE is enabled |
| jz .Lenable_paging |
| |
| /* Check if extended functions are implemented */ |
| movl $0x80000000, %eax |
| cpuid |
| /* Value must be in the range 0x80000001 to 0x8000ffff */ |
| subl $0x80000001, %eax |
| cmpl $(0x8000ffff-0x80000001), %eax |
| ja .Lenable_paging |
| |
| /* Clear bogus XD_DISABLE bits */ |
| call verify_cpu |
| |
| mov $0x80000001, %eax |
| cpuid |
| /* Execute Disable bit supported? */ |
| btl $(X86_FEATURE_NX & 31), %edx |
| jnc .Lenable_paging |
| |
| /* Setup EFER (Extended Feature Enable Register) */ |
| movl $MSR_EFER, %ecx |
| rdmsr |
| |
| btsl $_EFER_NX, %eax |
| /* Make changes effective */ |
| wrmsr |
| |
| .Lenable_paging: |
| |
| /* |
| * Enable paging |
| */ |
| movl $pa(initial_page_table), %eax |
| movl %eax,%cr3 /* set the page table pointer.. */ |
| movl $CR0_STATE,%eax |
| movl %eax,%cr0 /* ..and set paging (PG) bit */ |
| ljmp $__BOOT_CS,$1f /* Clear prefetch and normalize %eip */ |
| 1: |
| /* Shift the stack pointer to a virtual address */ |
| addl $__PAGE_OFFSET, %esp |
| |
| /* |
| * start system 32-bit setup. We need to re-do some of the things done |
| * in 16-bit mode for the "real" operations. |
| */ |
| movl setup_once_ref,%eax |
| andl %eax,%eax |
| jz 1f # Did we do this already? |
| call *%eax |
| 1: |
| |
| /* |
| * Check if it is 486 |
| */ |
| movb $4,X86 # at least 486 |
| cmpl $-1,X86_CPUID |
| je .Lis486 |
| |
| /* get vendor info */ |
| xorl %eax,%eax # call CPUID with 0 -> return vendor ID |
| cpuid |
| movl %eax,X86_CPUID # save CPUID level |
| movl %ebx,X86_VENDOR_ID # lo 4 chars |
| movl %edx,X86_VENDOR_ID+4 # next 4 chars |
| movl %ecx,X86_VENDOR_ID+8 # last 4 chars |
| |
| orl %eax,%eax # do we have processor info as well? |
| je .Lis486 |
| |
| movl $1,%eax # Use the CPUID instruction to get CPU type |
| cpuid |
| movb %al,%cl # save reg for future use |
| andb $0x0f,%ah # mask processor family |
| movb %ah,X86 |
| andb $0xf0,%al # mask model |
| shrb $4,%al |
| movb %al,X86_MODEL |
| andb $0x0f,%cl # mask mask revision |
| movb %cl,X86_STEPPING |
| movl %edx,X86_CAPABILITY |
| |
| .Lis486: |
| movl $0x50022,%ecx # set AM, WP, NE and MP |
| movl %cr0,%eax |
| andl $0x80000011,%eax # Save PG,PE,ET |
| orl %ecx,%eax |
| movl %eax,%cr0 |
| |
| lgdt early_gdt_descr |
| ljmp $(__KERNEL_CS),$1f |
| 1: movl $(__KERNEL_DS),%eax # reload all the segment registers |
| movl %eax,%ss # after changing gdt. |
| |
| movl $(__USER_DS),%eax # DS/ES contains default USER segment |
| movl %eax,%ds |
| movl %eax,%es |
| |
| movl $(__KERNEL_PERCPU), %eax |
| movl %eax,%fs # set this cpu's percpu |
| |
| xorl %eax,%eax |
| movl %eax,%gs # clear possible garbage in %gs |
| |
| xorl %eax,%eax # Clear LDT |
| lldt %ax |
| |
| call *(initial_code) |
| 1: jmp 1b |
| SYM_FUNC_END(startup_32_smp) |
| |
| #include "verify_cpu.S" |
| |
| /* |
| * setup_once |
| * |
| * The setup work we only want to run on the BSP. |
| * |
| * Warning: %esi is live across this function. |
| */ |
| __INIT |
| setup_once: |
| andl $0,setup_once_ref /* Once is enough, thanks */ |
| RET |
| |
| SYM_FUNC_START(early_idt_handler_array) |
| # 36(%esp) %eflags |
| # 32(%esp) %cs |
| # 28(%esp) %eip |
| # 24(%rsp) error code |
| i = 0 |
| .rept NUM_EXCEPTION_VECTORS |
| .if ((EXCEPTION_ERRCODE_MASK >> i) & 1) == 0 |
| pushl $0 # Dummy error code, to make stack frame uniform |
| .endif |
| pushl $i # 20(%esp) Vector number |
| jmp early_idt_handler_common |
| i = i + 1 |
| .fill early_idt_handler_array + i*EARLY_IDT_HANDLER_SIZE - ., 1, 0xcc |
| .endr |
| SYM_FUNC_END(early_idt_handler_array) |
| |
| SYM_CODE_START_LOCAL(early_idt_handler_common) |
| /* |
| * The stack is the hardware frame, an error code or zero, and the |
| * vector number. |
| */ |
| cld |
| |
| incl %ss:early_recursion_flag |
| |
| /* The vector number is in pt_regs->gs */ |
| |
| cld |
| pushl %fs /* pt_regs->fs (__fsh varies by model) */ |
| pushl %es /* pt_regs->es (__esh varies by model) */ |
| pushl %ds /* pt_regs->ds (__dsh varies by model) */ |
| pushl %eax /* pt_regs->ax */ |
| pushl %ebp /* pt_regs->bp */ |
| pushl %edi /* pt_regs->di */ |
| pushl %esi /* pt_regs->si */ |
| pushl %edx /* pt_regs->dx */ |
| pushl %ecx /* pt_regs->cx */ |
| pushl %ebx /* pt_regs->bx */ |
| |
| /* Fix up DS and ES */ |
| movl $(__KERNEL_DS), %ecx |
| movl %ecx, %ds |
| movl %ecx, %es |
| |
| /* Load the vector number into EDX */ |
| movl PT_GS(%esp), %edx |
| |
| /* Load GS into pt_regs->gs (and maybe clobber __gsh) */ |
| movw %gs, PT_GS(%esp) |
| |
| movl %esp, %eax /* args are pt_regs (EAX), trapnr (EDX) */ |
| call early_fixup_exception |
| |
| popl %ebx /* pt_regs->bx */ |
| popl %ecx /* pt_regs->cx */ |
| popl %edx /* pt_regs->dx */ |
| popl %esi /* pt_regs->si */ |
| popl %edi /* pt_regs->di */ |
| popl %ebp /* pt_regs->bp */ |
| popl %eax /* pt_regs->ax */ |
| popl %ds /* pt_regs->ds (always ignores __dsh) */ |
| popl %es /* pt_regs->es (always ignores __esh) */ |
| popl %fs /* pt_regs->fs (always ignores __fsh) */ |
| popl %gs /* pt_regs->gs (always ignores __gsh) */ |
| decl %ss:early_recursion_flag |
| addl $4, %esp /* pop pt_regs->orig_ax */ |
| iret |
| SYM_CODE_END(early_idt_handler_common) |
| |
| /* This is the default interrupt "handler" :-) */ |
| SYM_FUNC_START(early_ignore_irq) |
| cld |
| #ifdef CONFIG_PRINTK |
| pushl %eax |
| pushl %ecx |
| pushl %edx |
| pushl %es |
| pushl %ds |
| movl $(__KERNEL_DS),%eax |
| movl %eax,%ds |
| movl %eax,%es |
| cmpl $2,early_recursion_flag |
| je hlt_loop |
| incl early_recursion_flag |
| pushl 16(%esp) |
| pushl 24(%esp) |
| pushl 32(%esp) |
| pushl 40(%esp) |
| pushl $int_msg |
| call _printk |
| |
| call dump_stack |
| |
| addl $(5*4),%esp |
| popl %ds |
| popl %es |
| popl %edx |
| popl %ecx |
| popl %eax |
| #endif |
| iret |
| |
| hlt_loop: |
| hlt |
| jmp hlt_loop |
| SYM_FUNC_END(early_ignore_irq) |
| |
| __INITDATA |
| .align 4 |
| SYM_DATA(early_recursion_flag, .long 0) |
| |
| __REFDATA |
| .align 4 |
| SYM_DATA(initial_code, .long i386_start_kernel) |
| SYM_DATA(setup_once_ref, .long setup_once) |
| |
| #ifdef CONFIG_PAGE_TABLE_ISOLATION |
| #define PGD_ALIGN (2 * PAGE_SIZE) |
| #define PTI_USER_PGD_FILL 1024 |
| #else |
| #define PGD_ALIGN (PAGE_SIZE) |
| #define PTI_USER_PGD_FILL 0 |
| #endif |
| /* |
| * BSS section |
| */ |
| __PAGE_ALIGNED_BSS |
| .align PGD_ALIGN |
| #ifdef CONFIG_X86_PAE |
| .globl initial_pg_pmd |
| initial_pg_pmd: |
| .fill 1024*KPMDS,4,0 |
| #else |
| .globl initial_page_table |
| initial_page_table: |
| .fill 1024,4,0 |
| #endif |
| .align PGD_ALIGN |
| initial_pg_fixmap: |
| .fill 1024,4,0 |
| .globl swapper_pg_dir |
| .align PGD_ALIGN |
| swapper_pg_dir: |
| .fill 1024,4,0 |
| .fill PTI_USER_PGD_FILL,4,0 |
| .globl empty_zero_page |
| empty_zero_page: |
| .fill 4096,1,0 |
| EXPORT_SYMBOL(empty_zero_page) |
| |
| /* |
| * This starts the data section. |
| */ |
| #ifdef CONFIG_X86_PAE |
| __PAGE_ALIGNED_DATA |
| /* Page-aligned for the benefit of paravirt? */ |
| .align PGD_ALIGN |
| SYM_DATA_START(initial_page_table) |
| .long pa(initial_pg_pmd+PGD_IDENT_ATTR),0 /* low identity map */ |
| # if KPMDS == 3 |
| .long pa(initial_pg_pmd+PGD_IDENT_ATTR),0 |
| .long pa(initial_pg_pmd+PGD_IDENT_ATTR+0x1000),0 |
| .long pa(initial_pg_pmd+PGD_IDENT_ATTR+0x2000),0 |
| # elif KPMDS == 2 |
| .long 0,0 |
| .long pa(initial_pg_pmd+PGD_IDENT_ATTR),0 |
| .long pa(initial_pg_pmd+PGD_IDENT_ATTR+0x1000),0 |
| # elif KPMDS == 1 |
| .long 0,0 |
| .long 0,0 |
| .long pa(initial_pg_pmd+PGD_IDENT_ATTR),0 |
| # else |
| # error "Kernel PMDs should be 1, 2 or 3" |
| # endif |
| .align PAGE_SIZE /* needs to be page-sized too */ |
| |
| #ifdef CONFIG_PAGE_TABLE_ISOLATION |
| /* |
| * PTI needs another page so sync_initial_pagetable() works correctly |
| * and does not scribble over the data which is placed behind the |
| * actual initial_page_table. See clone_pgd_range(). |
| */ |
| .fill 1024, 4, 0 |
| #endif |
| |
| SYM_DATA_END(initial_page_table) |
| #endif |
| |
| .data |
| .balign 4 |
| /* |
| * The SIZEOF_PTREGS gap is a convention which helps the in-kernel unwinder |
| * reliably detect the end of the stack. |
| */ |
| SYM_DATA(initial_stack, |
| .long init_thread_union + THREAD_SIZE - |
| SIZEOF_PTREGS - TOP_OF_KERNEL_STACK_PADDING) |
| |
| __INITRODATA |
| int_msg: |
| .asciz "Unknown interrupt or fault at: %p %p %p\n" |
| |
| #include "../../x86/xen/xen-head.S" |
| |
| /* |
| * The IDT and GDT 'descriptors' are a strange 48-bit object |
| * only used by the lidt and lgdt instructions. They are not |
| * like usual segment descriptors - they consist of a 16-bit |
| * segment size, and 32-bit linear address value: |
| */ |
| |
| .data |
| ALIGN |
| # early boot GDT descriptor (must use 1:1 address mapping) |
| .word 0 # 32 bit align gdt_desc.address |
| SYM_DATA_START_LOCAL(boot_gdt_descr) |
| .word __BOOT_DS+7 |
| .long boot_gdt - __PAGE_OFFSET |
| SYM_DATA_END(boot_gdt_descr) |
| |
| # boot GDT descriptor (later on used by CPU#0): |
| .word 0 # 32 bit align gdt_desc.address |
| SYM_DATA_START(early_gdt_descr) |
| .word GDT_ENTRIES*8-1 |
| .long gdt_page /* Overwritten for secondary CPUs */ |
| SYM_DATA_END(early_gdt_descr) |
| |
| /* |
| * The boot_gdt must mirror the equivalent in setup.S and is |
| * used only for booting. |
| */ |
| .align L1_CACHE_BYTES |
| SYM_DATA_START(boot_gdt) |
| .fill GDT_ENTRY_BOOT_CS,8,0 |
| .quad 0x00cf9a000000ffff /* kernel 4GB code at 0x00000000 */ |
| .quad 0x00cf92000000ffff /* kernel 4GB data at 0x00000000 */ |
| SYM_DATA_END(boot_gdt) |
