|  | /* | 
|  | * | 
|  | *  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/cpufeature.h> | 
|  | #include <asm/percpu.h> | 
|  | #include <asm/nops.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_MASK	new_cpu_data+CPUINFO_x86_mask | 
|  | #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 | 
|  |  | 
|  | /* | 
|  | * This is how much memory in addition to the memory covered up to | 
|  | * and including _end we need mapped initially. | 
|  | * We need: | 
|  | *     (KERNEL_IMAGE_SIZE/4096) / 1024 pages (worst case, non PAE) | 
|  | *     (KERNEL_IMAGE_SIZE/4096) / 512 + 4 pages (worst case for PAE) | 
|  | * | 
|  | * Modulo rounding, each megabyte assigned here requires a kilobyte of | 
|  | * memory, which is currently unreclaimed. | 
|  | * | 
|  | * This should be a multiple of a page. | 
|  | * | 
|  | * KERNEL_IMAGE_SIZE should be greater than pa(_end) | 
|  | * and small than max_low_pfn, otherwise will waste some page table entries | 
|  | */ | 
|  |  | 
|  | #if PTRS_PER_PMD > 1 | 
|  | #define PAGE_TABLE_SIZE(pages) (((pages) / PTRS_PER_PMD) + PTRS_PER_PGD) | 
|  | #else | 
|  | #define PAGE_TABLE_SIZE(pages) ((pages) / PTRS_PER_PGD) | 
|  | #endif | 
|  |  | 
|  | /* Number of possible pages in the lowmem region */ | 
|  | LOWMEM_PAGES = (((1<<32) - __PAGE_OFFSET) >> PAGE_SHIFT) | 
|  |  | 
|  | /* Enough space to fit pagetables for the low memory linear map */ | 
|  | MAPPING_BEYOND_END = PAGE_TABLE_SIZE(LOWMEM_PAGES) << PAGE_SHIFT | 
|  |  | 
|  | /* | 
|  | * 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 | 
|  | ENTRY(startup_32) | 
|  | movl pa(stack_start),%ecx | 
|  |  | 
|  | /* test KEEP_SEGMENTS flag to see if the bootloader is asking | 
|  | us to not reload segments */ | 
|  | testb $(1<<6), BP_loadflags(%esi) | 
|  | jnz 2f | 
|  |  | 
|  | /* | 
|  | * 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 | 
|  | 2: | 
|  | 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 | 
|  | /* Early load ucode on BSP. */ | 
|  | call load_ucode_bsp | 
|  | #endif | 
|  |  | 
|  | /* | 
|  | * Initialize page tables.  This creates a PDE and a set of page | 
|  | * tables, which are located immediately beyond __brk_base.  The variable | 
|  | * _brk_end is set up to point to the first "safe" location. | 
|  | * Mappings are created both at virtual address 0 (identity mapping) | 
|  | * and PAGE_OFFSET for up to _end. | 
|  | */ | 
|  | #ifdef CONFIG_X86_PAE | 
|  |  | 
|  | /* | 
|  | * In PAE mode initial_page_table is statically defined to contain | 
|  | * enough entries to cover the VMSPLIT option (that is the top 1, 2 or 3 | 
|  | * entries). The identity mapping is handled by pointing two PGD entries | 
|  | * to the first kernel PMD. | 
|  | * | 
|  | * Note the upper half of each PMD or PTE are always zero at this stage. | 
|  | */ | 
|  |  | 
|  | #define KPMDS (((-__PAGE_OFFSET) >> 30) & 3) /* Number of kernel PMDs */ | 
|  |  | 
|  | xorl %ebx,%ebx				/* %ebx is kept at zero */ | 
|  |  | 
|  | movl $pa(__brk_base), %edi | 
|  | movl $pa(initial_pg_pmd), %edx | 
|  | movl $PTE_IDENT_ATTR, %eax | 
|  | 10: | 
|  | leal PDE_IDENT_ATTR(%edi),%ecx		/* Create PMD entry */ | 
|  | movl %ecx,(%edx)			/* Store PMD entry */ | 
|  | /* Upper half already zero */ | 
|  | addl $8,%edx | 
|  | movl $512,%ecx | 
|  | 11: | 
|  | stosl | 
|  | xchgl %eax,%ebx | 
|  | stosl | 
|  | xchgl %eax,%ebx | 
|  | addl $0x1000,%eax | 
|  | loop 11b | 
|  |  | 
|  | /* | 
|  | * End condition: we must map up to the end + MAPPING_BEYOND_END. | 
|  | */ | 
|  | movl $pa(_end) + MAPPING_BEYOND_END + PTE_IDENT_ATTR, %ebp | 
|  | cmpl %ebp,%eax | 
|  | jb 10b | 
|  | 1: | 
|  | addl $__PAGE_OFFSET, %edi | 
|  | movl %edi, pa(_brk_end) | 
|  | shrl $12, %eax | 
|  | movl %eax, pa(max_pfn_mapped) | 
|  |  | 
|  | /* Do early initialization of the fixmap area */ | 
|  | movl $pa(initial_pg_fixmap)+PDE_IDENT_ATTR,%eax | 
|  | movl %eax,pa(initial_pg_pmd+0x1000*KPMDS-8) | 
|  | #else	/* Not PAE */ | 
|  |  | 
|  | page_pde_offset = (__PAGE_OFFSET >> 20); | 
|  |  | 
|  | movl $pa(__brk_base), %edi | 
|  | movl $pa(initial_page_table), %edx | 
|  | movl $PTE_IDENT_ATTR, %eax | 
|  | 10: | 
|  | leal PDE_IDENT_ATTR(%edi),%ecx		/* Create PDE entry */ | 
|  | movl %ecx,(%edx)			/* Store identity PDE entry */ | 
|  | movl %ecx,page_pde_offset(%edx)		/* Store kernel PDE entry */ | 
|  | addl $4,%edx | 
|  | movl $1024, %ecx | 
|  | 11: | 
|  | stosl | 
|  | addl $0x1000,%eax | 
|  | loop 11b | 
|  | /* | 
|  | * End condition: we must map up to the end + MAPPING_BEYOND_END. | 
|  | */ | 
|  | movl $pa(_end) + MAPPING_BEYOND_END + PTE_IDENT_ATTR, %ebp | 
|  | cmpl %ebp,%eax | 
|  | jb 10b | 
|  | addl $__PAGE_OFFSET, %edi | 
|  | movl %edi, pa(_brk_end) | 
|  | shrl $12, %eax | 
|  | movl %eax, pa(max_pfn_mapped) | 
|  |  | 
|  | /* Do early initialization of the fixmap area */ | 
|  | movl $pa(initial_pg_fixmap)+PDE_IDENT_ATTR,%eax | 
|  | movl %eax,pa(initial_page_table+0xffc) | 
|  | #endif | 
|  |  | 
|  | #ifdef CONFIG_PARAVIRT | 
|  | /* This is can only trip for a broken bootloader... */ | 
|  | cmpw $0x207, pa(boot_params + BP_version) | 
|  | jb default_entry | 
|  |  | 
|  | /* Paravirt-compatible boot parameters.  Look to see what architecture | 
|  | we're booting under. */ | 
|  | movl pa(boot_params + BP_hardware_subarch), %eax | 
|  | cmpl $num_subarch_entries, %eax | 
|  | jae bad_subarch | 
|  |  | 
|  | movl pa(subarch_entries)(,%eax,4), %eax | 
|  | subl $__PAGE_OFFSET, %eax | 
|  | jmp *%eax | 
|  |  | 
|  | bad_subarch: | 
|  | WEAK(lguest_entry) | 
|  | WEAK(xen_entry) | 
|  | /* Unknown implementation; there's really | 
|  | nothing we can do at this point. */ | 
|  | ud2a | 
|  |  | 
|  | __INITDATA | 
|  |  | 
|  | subarch_entries: | 
|  | .long default_entry		/* normal x86/PC */ | 
|  | .long lguest_entry		/* lguest hypervisor */ | 
|  | .long xen_entry			/* Xen hypervisor */ | 
|  | .long default_entry		/* Moorestown MID */ | 
|  | num_subarch_entries = (. - subarch_entries) / 4 | 
|  | .previous | 
|  | #else | 
|  | jmp default_entry | 
|  | #endif /* CONFIG_PARAVIRT */ | 
|  |  | 
|  | #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(). | 
|  | */ | 
|  | ENTRY(start_cpu0) | 
|  | movl stack_start, %ecx | 
|  | movl %ecx, %esp | 
|  | jmp  *(initial_code) | 
|  | ENDPROC(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 | 
|  | */ | 
|  | ENTRY(startup_32_smp) | 
|  | cld | 
|  | movl $(__BOOT_DS),%eax | 
|  | movl %eax,%ds | 
|  | movl %eax,%es | 
|  | movl %eax,%fs | 
|  | movl %eax,%gs | 
|  | movl pa(stack_start),%ecx | 
|  | movl %eax,%ss | 
|  | leal -__PAGE_OFFSET(%ecx),%esp | 
|  |  | 
|  | #ifdef CONFIG_MICROCODE_EARLY | 
|  | /* Early load ucode on AP. */ | 
|  | call load_ucode_ap | 
|  | #endif | 
|  |  | 
|  |  | 
|  | default_entry: | 
|  | #define CR0_STATE	(X86_CR0_PE | X86_CR0_MP | X86_CR0_ET | \ | 
|  | X86_CR0_NE | X86_CR0_WP | X86_CR0_AM | \ | 
|  | X86_CR0_PG) | 
|  | 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 enable_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 enable_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 enable_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 enable_paging | 
|  |  | 
|  | /* Clear bogus XD_DISABLE bits */ | 
|  | call verify_cpu | 
|  |  | 
|  | mov $0x80000001, %eax | 
|  | cpuid | 
|  | /* Execute Disable bit supported? */ | 
|  | btl $(X86_FEATURE_NX & 31), %edx | 
|  | jnc enable_paging | 
|  |  | 
|  | /* Setup EFER (Extended Feature Enable Register) */ | 
|  | movl $MSR_EFER, %ecx | 
|  | rdmsr | 
|  |  | 
|  | btsl $_EFER_NX, %eax | 
|  | /* Make changes effective */ | 
|  | wrmsr | 
|  |  | 
|  | enable_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 is486 | 
|  |  | 
|  | /* 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 is486 | 
|  |  | 
|  | 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_MASK | 
|  | movl %edx,X86_CAPABILITY | 
|  |  | 
|  | is486: | 
|  | 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 | 
|  | lidt idt_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 | 
|  |  | 
|  | movl $(__KERNEL_STACK_CANARY),%eax | 
|  | movl %eax,%gs | 
|  |  | 
|  | xorl %eax,%eax			# Clear LDT | 
|  | lldt %ax | 
|  |  | 
|  | pushl $0		# fake return address for unwinder | 
|  | jmp *(initial_code) | 
|  |  | 
|  | #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: | 
|  | /* | 
|  | * Set up a idt with 256 entries pointing to ignore_int, | 
|  | * interrupt gates. It doesn't actually load idt - that needs | 
|  | * to be done on each CPU. Interrupts are enabled elsewhere, | 
|  | * when we can be relatively sure everything is ok. | 
|  | */ | 
|  |  | 
|  | movl $idt_table,%edi | 
|  | movl $early_idt_handlers,%eax | 
|  | movl $NUM_EXCEPTION_VECTORS,%ecx | 
|  | 1: | 
|  | movl %eax,(%edi) | 
|  | movl %eax,4(%edi) | 
|  | /* interrupt gate, dpl=0, present */ | 
|  | movl $(0x8E000000 + __KERNEL_CS),2(%edi) | 
|  | addl $9,%eax | 
|  | addl $8,%edi | 
|  | loop 1b | 
|  |  | 
|  | movl $256 - NUM_EXCEPTION_VECTORS,%ecx | 
|  | movl $ignore_int,%edx | 
|  | movl $(__KERNEL_CS << 16),%eax | 
|  | movw %dx,%ax		/* selector = 0x0010 = cs */ | 
|  | movw $0x8E00,%dx	/* interrupt gate - dpl=0, present */ | 
|  | 2: | 
|  | movl %eax,(%edi) | 
|  | movl %edx,4(%edi) | 
|  | addl $8,%edi | 
|  | loop 2b | 
|  |  | 
|  | #ifdef CONFIG_CC_STACKPROTECTOR | 
|  | /* | 
|  | * Configure the stack canary. The linker can't handle this by | 
|  | * relocation.  Manually set base address in stack canary | 
|  | * segment descriptor. | 
|  | */ | 
|  | movl $gdt_page,%eax | 
|  | movl $stack_canary,%ecx | 
|  | movw %cx, 8 * GDT_ENTRY_STACK_CANARY + 2(%eax) | 
|  | shrl $16, %ecx | 
|  | movb %cl, 8 * GDT_ENTRY_STACK_CANARY + 4(%eax) | 
|  | movb %ch, 8 * GDT_ENTRY_STACK_CANARY + 7(%eax) | 
|  | #endif | 
|  |  | 
|  | andl $0,setup_once_ref	/* Once is enough, thanks */ | 
|  | ret | 
|  |  | 
|  | ENTRY(early_idt_handlers) | 
|  | # 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 | 
|  | ASM_NOP2 | 
|  | .else | 
|  | pushl $0		# Dummy error code, to make stack frame uniform | 
|  | .endif | 
|  | pushl $i		# 20(%esp) Vector number | 
|  | jmp early_idt_handler | 
|  | i = i + 1 | 
|  | .endr | 
|  | ENDPROC(early_idt_handlers) | 
|  |  | 
|  | /* This is global to keep gas from relaxing the jumps */ | 
|  | ENTRY(early_idt_handler) | 
|  | cld | 
|  | cmpl $2,%ss:early_recursion_flag | 
|  | je hlt_loop | 
|  | incl %ss:early_recursion_flag | 
|  |  | 
|  | push %eax		# 16(%esp) | 
|  | push %ecx		# 12(%esp) | 
|  | push %edx		#  8(%esp) | 
|  | push %ds		#  4(%esp) | 
|  | push %es		#  0(%esp) | 
|  | movl $(__KERNEL_DS),%eax | 
|  | movl %eax,%ds | 
|  | movl %eax,%es | 
|  |  | 
|  | cmpl $(__KERNEL_CS),32(%esp) | 
|  | jne 10f | 
|  |  | 
|  | leal 28(%esp),%eax	# Pointer to %eip | 
|  | call early_fixup_exception | 
|  | andl %eax,%eax | 
|  | jnz ex_entry		/* found an exception entry */ | 
|  |  | 
|  | 10: | 
|  | #ifdef CONFIG_PRINTK | 
|  | xorl %eax,%eax | 
|  | movw %ax,2(%esp)	/* clean up the segment values on some cpus */ | 
|  | movw %ax,6(%esp) | 
|  | movw %ax,34(%esp) | 
|  | leal  40(%esp),%eax | 
|  | pushl %eax		/* %esp before the exception */ | 
|  | pushl %ebx | 
|  | pushl %ebp | 
|  | pushl %esi | 
|  | pushl %edi | 
|  | movl %cr2,%eax | 
|  | pushl %eax | 
|  | pushl (20+6*4)(%esp)	/* trapno */ | 
|  | pushl $fault_msg | 
|  | call printk | 
|  | #endif | 
|  | call dump_stack | 
|  | hlt_loop: | 
|  | hlt | 
|  | jmp hlt_loop | 
|  |  | 
|  | ex_entry: | 
|  | pop %es | 
|  | pop %ds | 
|  | pop %edx | 
|  | pop %ecx | 
|  | pop %eax | 
|  | addl $8,%esp		/* drop vector number and error code */ | 
|  | decl %ss:early_recursion_flag | 
|  | iret | 
|  | ENDPROC(early_idt_handler) | 
|  |  | 
|  | /* This is the default interrupt "handler" :-) */ | 
|  | ALIGN | 
|  | ignore_int: | 
|  | 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 | 
|  | ENDPROC(ignore_int) | 
|  | __INITDATA | 
|  | .align 4 | 
|  | early_recursion_flag: | 
|  | .long 0 | 
|  |  | 
|  | __REFDATA | 
|  | .align 4 | 
|  | ENTRY(initial_code) | 
|  | .long i386_start_kernel | 
|  | ENTRY(setup_once_ref) | 
|  | .long setup_once | 
|  |  | 
|  | /* | 
|  | * BSS section | 
|  | */ | 
|  | __PAGE_ALIGNED_BSS | 
|  | .align PAGE_SIZE | 
|  | #ifdef CONFIG_X86_PAE | 
|  | initial_pg_pmd: | 
|  | .fill 1024*KPMDS,4,0 | 
|  | #else | 
|  | ENTRY(initial_page_table) | 
|  | .fill 1024,4,0 | 
|  | #endif | 
|  | initial_pg_fixmap: | 
|  | .fill 1024,4,0 | 
|  | ENTRY(empty_zero_page) | 
|  | .fill 4096,1,0 | 
|  | ENTRY(swapper_pg_dir) | 
|  | .fill 1024,4,0 | 
|  |  | 
|  | /* | 
|  | * This starts the data section. | 
|  | */ | 
|  | #ifdef CONFIG_X86_PAE | 
|  | __PAGE_ALIGNED_DATA | 
|  | /* Page-aligned for the benefit of paravirt? */ | 
|  | .align PAGE_SIZE | 
|  | ENTRY(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 */ | 
|  | #endif | 
|  |  | 
|  | .data | 
|  | .balign 4 | 
|  | ENTRY(stack_start) | 
|  | .long init_thread_union+THREAD_SIZE | 
|  |  | 
|  | __INITRODATA | 
|  | int_msg: | 
|  | .asciz "Unknown interrupt or fault at: %p %p %p\n" | 
|  |  | 
|  | fault_msg: | 
|  | /* fault info: */ | 
|  | .ascii "BUG: Int %d: CR2 %p\n" | 
|  | /* regs pushed in early_idt_handler: */ | 
|  | .ascii "     EDI %p  ESI %p  EBP %p  EBX %p\n" | 
|  | .ascii "     ESP %p   ES %p   DS %p\n" | 
|  | .ascii "     EDX %p  ECX %p  EAX %p\n" | 
|  | /* fault frame: */ | 
|  | .ascii "     vec %p  err %p  EIP %p   CS %p  flg %p\n" | 
|  | .ascii "Stack: %p %p %p %p %p %p %p %p\n" | 
|  | .ascii "       %p %p %p %p %p %p %p %p\n" | 
|  | .asciz "       %p %p %p %p %p %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 | 
|  | .globl boot_gdt_descr | 
|  | .globl idt_descr | 
|  |  | 
|  | ALIGN | 
|  | # early boot GDT descriptor (must use 1:1 address mapping) | 
|  | .word 0				# 32 bit align gdt_desc.address | 
|  | boot_gdt_descr: | 
|  | .word __BOOT_DS+7 | 
|  | .long boot_gdt - __PAGE_OFFSET | 
|  |  | 
|  | .word 0				# 32-bit align idt_desc.address | 
|  | idt_descr: | 
|  | .word IDT_ENTRIES*8-1		# idt contains 256 entries | 
|  | .long idt_table | 
|  |  | 
|  | # boot GDT descriptor (later on used by CPU#0): | 
|  | .word 0				# 32 bit align gdt_desc.address | 
|  | ENTRY(early_gdt_descr) | 
|  | .word GDT_ENTRIES*8-1 | 
|  | .long gdt_page			/* Overwritten for secondary CPUs */ | 
|  |  | 
|  | /* | 
|  | * The boot_gdt must mirror the equivalent in setup.S and is | 
|  | * used only for booting. | 
|  | */ | 
|  | .align L1_CACHE_BYTES | 
|  | ENTRY(boot_gdt) | 
|  | .fill GDT_ENTRY_BOOT_CS,8,0 | 
|  | .quad 0x00cf9a000000ffff	/* kernel 4GB code at 0x00000000 */ | 
|  | .quad 0x00cf92000000ffff	/* kernel 4GB data at 0x00000000 */ |