i386: move kernel

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 578 insertions, 0 deletions

diff --git a/arch/x86/kernel/head_32.S b/arch/x86/kernel/head_32.S
new file mode 100644
index 0000000..9150ca9
--- /dev/null
+++ b/arch/x86/kernel/head_32.S
@@ -0,0 +1,578 @@
+/*
+ *  linux/arch/i386/kernel/head.S -- the 32-bit startup code.
+ *
+ *  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/linkage.h>
+#include <asm/segment.h>
+#include <asm/page.h>
+#include <asm/pgtable.h>
+#include <asm/desc.h>
+#include <asm/cache.h>
+#include <asm/thread_info.h>
+#include <asm/asm-offsets.h>
+#include <asm/setup.h>
+
+/*
+ * 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:
+ *  - one bit for each possible page, but only in low memory, which means
+ *     2^32/4096/8 = 128K worst case (4G/4G split.)
+ *  - enough space to map all low memory, which means
+ *     (2^32/4096) / 1024 pages (worst case, non PAE)
+ *     (2^32/4096) / 512 + 4 pages (worst case for PAE)
+ *  - a few pages for allocator use before the kernel pagetable has
+ *     been set up
+ *
+ * Modulo rounding, each megabyte assigned here requires a kilobyte of
+ * memory, which is currently unreclaimed.
+ *
+ * This should be a multiple of a page.
+ */
+LOW_PAGES = 1<<(32-PAGE_SHIFT_asm)
+
+#if PTRS_PER_PMD > 1
+PAGE_TABLE_SIZE = (LOW_PAGES / PTRS_PER_PMD) + PTRS_PER_PGD
+#else
+PAGE_TABLE_SIZE = (LOW_PAGES / PTRS_PER_PGD)
+#endif
+BOOTBITMAP_SIZE = LOW_PAGES / 8
+ALLOCATOR_SLOP = 4
+
+INIT_MAP_BEYOND_END = BOOTBITMAP_SIZE + (PAGE_TABLE_SIZE + ALLOCATOR_SLOP)*PAGE_SIZE_asm
+
+/*
+ * 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.
+ */
+.section .text.head,"ax",@progbits
+ENTRY(startup_32)
+
+/*
+ * Set segments to known values.
+ */
+	cld
+	lgdt boot_gdt_descr - __PAGE_OFFSET
+	movl $(__BOOT_DS),%eax
+	movl %eax,%ds
+	movl %eax,%es
+	movl %eax,%fs
+	movl %eax,%gs
+
+/*
+ * Clear BSS first so that there are no surprises...
+ * No need to cld as DF is already clear from cld above...
+ */
+	xorl %eax,%eax
+	movl $__bss_start - __PAGE_OFFSET,%edi
+	movl $__bss_stop - __PAGE_OFFSET,%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 $(boot_params - __PAGE_OFFSET),%edi
+	movl $(PARAM_SIZE/4),%ecx
+	cld
+	rep
+	movsl
+	movl boot_params - __PAGE_OFFSET + NEW_CL_POINTER,%esi
+	andl %esi,%esi
+	jnz 2f			# New command line protocol
+	cmpw $(OLD_CL_MAGIC),OLD_CL_MAGIC_ADDR
+	jne 1f
+	movzwl OLD_CL_OFFSET,%esi
+	addl $(OLD_CL_BASE_ADDR),%esi
+2:
+	movl $(boot_command_line - __PAGE_OFFSET),%edi
+	movl $(COMMAND_LINE_SIZE/4),%ecx
+	rep
+	movsl
+1:
+
+/*
+ * Initialize page tables.  This creates a PDE and a set of page
+ * tables, which are located immediately beyond _end.  The variable
+ * init_pg_tables_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+sizeof(page tables)+INIT_MAP_BEYOND_END.
+ *
+ * Warning: don't use %esi or the stack in this code.  However, %esp
+ * can be used as a GPR if you really need it...
+ */
+page_pde_offset = (__PAGE_OFFSET >> 20);
+
+	movl $(pg0 - __PAGE_OFFSET), %edi
+	movl $(swapper_pg_dir - __PAGE_OFFSET), %edx
+	movl $0x007, %eax			/* 0x007 = PRESENT+RW+USER */
+10:
+	leal 0x007(%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 and including INIT_MAP_BEYOND_END */
+	/* bytes beyond the end of our own page tables; the +0x007 is the attribute bits */
+	leal (INIT_MAP_BEYOND_END+0x007)(%edi),%ebp
+	cmpl %ebp,%eax
+	jb 10b
+	movl %edi,(init_pg_tables_end - __PAGE_OFFSET)
+
+	xorl %ebx,%ebx				/* This is the boot CPU (BSP) */
+	jmp 3f
+/*
+ * 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
+ */
+
+#ifndef CONFIG_HOTPLUG_CPU
+.section .init.text,"ax",@progbits
+#endif
+
+	/* Do an early initialization of the fixmap area */
+	movl $(swapper_pg_dir - __PAGE_OFFSET), %edx
+	movl $(swapper_pg_pmd - __PAGE_OFFSET), %eax
+	addl $0x007, %eax			/* 0x007 = PRESENT+RW+USER */
+	movl %eax, 4092(%edx)
+
+#ifdef CONFIG_SMP
+ENTRY(startup_32_smp)
+	cld
+	movl $(__BOOT_DS),%eax
+	movl %eax,%ds
+	movl %eax,%es
+	movl %eax,%fs
+	movl %eax,%gs
+
+/*
+ *	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!
+ *	So we do not try to touch it unless we really have
+ *	some bits in it to set.  This won't work if the BSP
+ *	implements cr4 but this AP does not -- very unlikely
+ *	but be warned!  The same applies to the pse feature
+ *	if not equally supported. --macro
+ *
+ *	NOTE! We have to correct for the fact that we're
+ *	not yet offset PAGE_OFFSET..
+ */
+#define cr4_bits mmu_cr4_features-__PAGE_OFFSET
+	movl cr4_bits,%edx
+	andl %edx,%edx
+	jz 6f
+	movl %cr4,%eax		# Turn on paging options (PSE,PAE,..)
+	orl %edx,%eax
+	movl %eax,%cr4
+
+	btl $5, %eax		# check if PAE is enabled
+	jnc 6f
+
+	/* Check if extended functions are implemented */
+	movl $0x80000000, %eax
+	cpuid
+	cmpl $0x80000000, %eax
+	jbe 6f
+	mov $0x80000001, %eax
+	cpuid
+	/* Execute Disable bit supported? */
+	btl $20, %edx
+	jnc 6f
+
+	/* Setup EFER (Extended Feature Enable Register) */
+	movl $0xc0000080, %ecx
+	rdmsr
+
+	btsl $11, %eax
+	/* Make changes effective */
+	wrmsr
+
+6:
+	/* This is a secondary processor (AP) */
+	xorl %ebx,%ebx
+	incl %ebx
+
+#endif /* CONFIG_SMP */
+3:
+
+/*
+ * Enable paging
+ */
+	movl $swapper_pg_dir-__PAGE_OFFSET,%eax
+	movl %eax,%cr3		/* set the page table pointer.. */
+	movl %cr0,%eax
+	orl $0x80000000,%eax
+	movl %eax,%cr0		/* ..and set paging (PG) bit */
+	ljmp $__BOOT_CS,$1f	/* Clear prefetch and normalize %eip */
+1:
+	/* Set up the stack pointer */
+	lss stack_start,%esp
+
+/*
+ * Initialize eflags.  Some BIOS's leave bits like NT set.  This would
+ * confuse the debugger if this code is traced.
+ * XXX - best to initialize before switching to protected mode.
+ */
+	pushl $0
+	popfl
+
+#ifdef CONFIG_SMP
+	andl %ebx,%ebx
+	jz  1f				/* Initial CPU cleans BSS */
+	jmp checkCPUtype
+1:
+#endif /* CONFIG_SMP */
+
+/*
+ * start system 32-bit setup. We need to re-do some of the things done
+ * in 16-bit mode for the "real" operations.
+ */
+	call setup_idt
+
+checkCPUtype:
+
+	movl $-1,X86_CPUID		#  -1 for no CPUID initially
+
+/* check if it is 486 or 386. */
+/*
+ * XXX - this does a lot of unnecessary setup.  Alignment checks don't
+ * apply at our cpl of 0 and the stack ought to be aligned already, and
+ * we don't need to preserve eflags.
+ */
+
+	movb $3,X86		# at least 386
+	pushfl			# push EFLAGS
+	popl %eax		# get EFLAGS
+	movl %eax,%ecx		# save original EFLAGS
+	xorl $0x240000,%eax	# flip AC and ID bits in EFLAGS
+	pushl %eax		# copy to EFLAGS
+	popfl			# set EFLAGS
+	pushfl			# get new EFLAGS
+	popl %eax		# put it in eax
+	xorl %ecx,%eax		# change in flags
+	pushl %ecx		# restore original EFLAGS
+	popfl
+	testl $0x40000,%eax	# check if AC bit changed
+	je is386
+
+	movb $4,X86		# at least 486
+	testl $0x200000,%eax	# check if ID bit changed
+	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
+	jmp 2f
+
+is386:	movl $2,%ecx		# set MP
+2:	movl %cr0,%eax
+	andl $0x80000011,%eax	# Save PG,PE,ET
+	orl %ecx,%eax
+	movl %eax,%cr0
+
+	call check_x87
+	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 %eax,%fs			# gets reset once there's real percpu
+
+	movl $(__USER_DS),%eax		# DS/ES contains default USER segment
+	movl %eax,%ds
+	movl %eax,%es
+
+	xorl %eax,%eax			# Clear GS and LDT
+	movl %eax,%gs
+	lldt %ax
+
+	cld			# gcc2 wants the direction flag cleared at all times
+	pushl $0		# fake return address for unwinder
+#ifdef CONFIG_SMP
+	movb ready, %cl
+	movb $1, ready
+	cmpb $0,%cl		# the first CPU calls start_kernel
+	je   1f
+	movl $(__KERNEL_PERCPU), %eax
+	movl %eax,%fs		# set this cpu's percpu
+	jmp initialize_secondary # all other CPUs call initialize_secondary
+1:
+#endif /* CONFIG_SMP */
+	jmp start_kernel
+
+/*
+ * We depend on ET to be correct. This checks for 287/387.
+ */
+check_x87:
+	movb $0,X86_HARD_MATH
+	clts
+	fninit
+	fstsw %ax
+	cmpb $0,%al
+	je 1f
+	movl %cr0,%eax		/* no coprocessor: have to set bits */
+	xorl $4,%eax		/* set EM */
+	movl %eax,%cr0
+	ret
+	ALIGN
+1:	movb $1,X86_HARD_MATH
+	.byte 0xDB,0xE4		/* fsetpm for 287, ignored by 387 */
+	ret
+
+/*
+ *  setup_idt
+ *
+ *  sets up a idt with 256 entries pointing to
+ *  ignore_int, interrupt gates. It doesn't actually load
+ *  idt - that can be done only after paging has been enabled
+ *  and the kernel moved to PAGE_OFFSET. Interrupts
+ *  are enabled elsewhere, when we can be relatively
+ *  sure everything is ok.
+ *
+ *  Warning: %esi is live across this function.
+ */
+setup_idt:
+	lea ignore_int,%edx
+	movl $(__KERNEL_CS << 16),%eax
+	movw %dx,%ax		/* selector = 0x0010 = cs */
+	movw $0x8E00,%dx	/* interrupt gate - dpl=0, present */
+
+	lea idt_table,%edi
+	mov $256,%ecx
+rp_sidt:
+	movl %eax,(%edi)
+	movl %edx,4(%edi)
+	addl $8,%edi
+	dec %ecx
+	jne rp_sidt
+
+.macro	set_early_handler handler,trapno
+	lea \handler,%edx
+	movl $(__KERNEL_CS << 16),%eax
+	movw %dx,%ax
+	movw $0x8E00,%dx	/* interrupt gate - dpl=0, present */
+	lea idt_table,%edi
+	movl %eax,8*\trapno(%edi)
+	movl %edx,8*\trapno+4(%edi)
+.endm
+
+	set_early_handler handler=early_divide_err,trapno=0
+	set_early_handler handler=early_illegal_opcode,trapno=6
+	set_early_handler handler=early_protection_fault,trapno=13
+	set_early_handler handler=early_page_fault,trapno=14
+
+	ret
+
+early_divide_err:
+	xor %edx,%edx
+	pushl $0	/* fake errcode */
+	jmp early_fault
+
+early_illegal_opcode:
+	movl $6,%edx
+	pushl $0	/* fake errcode */
+	jmp early_fault
+
+early_protection_fault:
+	movl $13,%edx
+	jmp early_fault
+
+early_page_fault:
+	movl $14,%edx
+	jmp early_fault
+
+early_fault:
+	cld
+#ifdef CONFIG_PRINTK
+	movl $(__KERNEL_DS),%eax
+	movl %eax,%ds
+	movl %eax,%es
+	cmpl $2,early_recursion_flag
+	je hlt_loop
+	incl early_recursion_flag
+	movl %cr2,%eax
+	pushl %eax
+	pushl %edx		/* trapno */
+	pushl $fault_msg
+#ifdef CONFIG_EARLY_PRINTK
+	call early_printk
+#else
+	call printk
+#endif
+#endif
+hlt_loop:
+	hlt
+	jmp hlt_loop
+
+/* 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
+#ifdef CONFIG_EARLY_PRINTK
+	call early_printk
+#else
+	call printk
+#endif
+	addl $(5*4),%esp
+	popl %ds
+	popl %es
+	popl %edx
+	popl %ecx
+	popl %eax
+#endif
+	iret
+
+.section .text
+/*
+ * Real beginning of normal "text" segment
+ */
+ENTRY(stext)
+ENTRY(_stext)
+
+/*
+ * BSS section
+ */
+.section ".bss.page_aligned","wa"
+	.align PAGE_SIZE_asm
+ENTRY(swapper_pg_dir)
+	.fill 1024,4,0
+ENTRY(swapper_pg_pmd)
+	.fill 1024,4,0
+ENTRY(empty_zero_page)
+	.fill 4096,1,0
+
+/*
+ * This starts the data section.
+ */
+.data
+ENTRY(stack_start)
+	.long init_thread_union+THREAD_SIZE
+	.long __BOOT_DS
+
+ready:	.byte 0
+
+early_recursion_flag:
+	.long 0
+
+int_msg:
+	.asciz "Unknown interrupt or fault at EIP %p %p %p\n"
+
+fault_msg:
+	.ascii "Int %d: CR2 %p  err %p  EIP %p  CS %p  flags %p\n"
+	.asciz "Stack: %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:
+ */
+
+.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 per_cpu__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 */