diff options
Diffstat (limited to 'arch/i386/kernel/head.S')
| -rw-r--r-- | arch/i386/kernel/head.S | 118 |
1 files changed, 30 insertions, 88 deletions
diff --git a/arch/i386/kernel/head.S b/arch/i386/kernel/head.S index 3fa7f93..9b10af6 100644 --- a/arch/i386/kernel/head.S +++ b/arch/i386/kernel/head.S @@ -34,17 +34,32 @@ /* * 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.) + * 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. */ -#define INIT_MAP_BEYOND_END (128*1024) +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, @@ -147,8 +162,7 @@ page_pde_offset = (__PAGE_OFFSET >> 20); /* * 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_table GDT - * for us. + * 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 @@ -318,12 +332,12 @@ is386: movl $2,%ecx # set MP movl %eax,%cr0 call check_x87 - call setup_pda 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 @@ -333,16 +347,17 @@ is386: movl $2,%ecx # set MP movl %eax,%gs lldt %ax - movl $(__KERNEL_PDA),%eax - mov %eax,%fs - 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 - jne initialize_secondary # all other CPUs call initialize_secondary + 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 @@ -366,23 +381,6 @@ check_x87: ret /* - * Point the GDT at this CPU's PDA. On boot this will be - * cpu_gdt_table and boot_pda; for secondary CPUs, these will be - * that CPU's GDT and PDA. - */ -ENTRY(setup_pda) - /* get the PDA pointer */ - movl start_pda, %eax - - /* slot the PDA address into the GDT */ - mov early_gdt_descr+2, %ecx - mov %ax, (__KERNEL_PDA+0+2)(%ecx) /* base & 0x0000ffff */ - shr $16, %eax - mov %al, (__KERNEL_PDA+4+0)(%ecx) /* base & 0x00ff0000 */ - mov %ah, (__KERNEL_PDA+4+3)(%ecx) /* base & 0xff000000 */ - ret - -/* * setup_idt * * sets up a idt with 256 entries pointing to @@ -554,9 +552,6 @@ ENTRY(empty_zero_page) * This starts the data section. */ .data -ENTRY(start_pda) - .long boot_pda - ENTRY(stack_start) .long init_thread_union+THREAD_SIZE .long __BOOT_DS @@ -588,7 +583,7 @@ fault_msg: .word 0 # 32 bit align gdt_desc.address boot_gdt_descr: .word __BOOT_DS+7 - .long boot_gdt_table - __PAGE_OFFSET + .long boot_gdt - __PAGE_OFFSET .word 0 # 32-bit align idt_desc.address idt_descr: @@ -599,67 +594,14 @@ idt_descr: .word 0 # 32 bit align gdt_desc.address ENTRY(early_gdt_descr) .word GDT_ENTRIES*8-1 - .long cpu_gdt_table + .long per_cpu__gdt_page /* Overwritten for secondary CPUs */ /* - * The boot_gdt_table must mirror the equivalent in setup.S and is + * The boot_gdt must mirror the equivalent in setup.S and is * used only for booting. */ .align L1_CACHE_BYTES -ENTRY(boot_gdt_table) +ENTRY(boot_gdt) .fill GDT_ENTRY_BOOT_CS,8,0 .quad 0x00cf9a000000ffff /* kernel 4GB code at 0x00000000 */ .quad 0x00cf92000000ffff /* kernel 4GB data at 0x00000000 */ - -/* - * The Global Descriptor Table contains 28 quadwords, per-CPU. - */ - .align L1_CACHE_BYTES -ENTRY(cpu_gdt_table) - .quad 0x0000000000000000 /* NULL descriptor */ - .quad 0x0000000000000000 /* 0x0b reserved */ - .quad 0x0000000000000000 /* 0x13 reserved */ - .quad 0x0000000000000000 /* 0x1b reserved */ - .quad 0x0000000000000000 /* 0x20 unused */ - .quad 0x0000000000000000 /* 0x28 unused */ - .quad 0x0000000000000000 /* 0x33 TLS entry 1 */ - .quad 0x0000000000000000 /* 0x3b TLS entry 2 */ - .quad 0x0000000000000000 /* 0x43 TLS entry 3 */ - .quad 0x0000000000000000 /* 0x4b reserved */ - .quad 0x0000000000000000 /* 0x53 reserved */ - .quad 0x0000000000000000 /* 0x5b reserved */ - - .quad 0x00cf9a000000ffff /* 0x60 kernel 4GB code at 0x00000000 */ - .quad 0x00cf92000000ffff /* 0x68 kernel 4GB data at 0x00000000 */ - .quad 0x00cffa000000ffff /* 0x73 user 4GB code at 0x00000000 */ - .quad 0x00cff2000000ffff /* 0x7b user 4GB data at 0x00000000 */ - - .quad 0x0000000000000000 /* 0x80 TSS descriptor */ - .quad 0x0000000000000000 /* 0x88 LDT descriptor */ - - /* - * Segments used for calling PnP BIOS have byte granularity. - * They code segments and data segments have fixed 64k limits, - * the transfer segment sizes are set at run time. - */ - .quad 0x00409a000000ffff /* 0x90 32-bit code */ - .quad 0x00009a000000ffff /* 0x98 16-bit code */ - .quad 0x000092000000ffff /* 0xa0 16-bit data */ - .quad 0x0000920000000000 /* 0xa8 16-bit data */ - .quad 0x0000920000000000 /* 0xb0 16-bit data */ - - /* - * The APM segments have byte granularity and their bases - * are set at run time. All have 64k limits. - */ - .quad 0x00409a000000ffff /* 0xb8 APM CS code */ - .quad 0x00009a000000ffff /* 0xc0 APM CS 16 code (16 bit) */ - .quad 0x004092000000ffff /* 0xc8 APM DS data */ - - .quad 0x00c0920000000000 /* 0xd0 - ESPFIX SS */ - .quad 0x00cf92000000ffff /* 0xd8 - PDA */ - .quad 0x0000000000000000 /* 0xe0 - unused */ - .quad 0x0000000000000000 /* 0xe8 - unused */ - .quad 0x0000000000000000 /* 0xf0 - unused */ - .quad 0x0000000000000000 /* 0xf8 - GDT entry 31: double-fault TSS */ - |