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- /* 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)
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