coreboot-kgpe-d16/src/arch/x86/c_start.S

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#include <cpu/x86/post_code.h>
/* Place the stack in the bss section. It's not necessary to define it in the
* the linker script. */
.section .bss, "aw", @nobits
.global _stack
.global _estack
.align CONFIG_STACK_SIZE
_stack:
.space CONFIG_MAX_CPUS*CONFIG_STACK_SIZE
_estack:
#if CONFIG_COOP_MULTITASKING
.global thread_stacks
thread_stacks:
.space CONFIG_STACK_SIZE*CONFIG_NUM_THREADS
#endif
New mechanism to define SRAM/memory map with automatic bounds checking This patch creates a new mechanism to define the static memory layout (primarily in SRAM) for a given board, superseding the brittle mass of Kconfigs that we were using before. The core part is a memlayout.ld file in the mainboard directory (although boards are expected to just include the SoC default in most cases), which is the primary linker script for all stages (though not rmodules for now). It uses preprocessor macros from <memlayout.h> to form a different valid linker script for all stages while looking like a declarative, boilerplate-free map of memory addresses to the programmer. Linker asserts will automatically guarantee that the defined regions cannot overlap. Stages are defined with a maximum size that will be enforced by the linker. The file serves to both define and document the memory layout, so that the documentation cannot go missing or out of date. The mechanism is implemented for all boards in the ARM, ARM64 and MIPS architectures, and should be extended onto all systems using SRAM in the future. The CAR/XIP environment on x86 has very different requirements and the layout is generally not as static, so it will stay like it is and be unaffected by this patch (save for aligning some symbol names for consistency and sharing the new common ramstage linker script include). BUG=None TEST=Booted normally and in recovery mode, checked suspend/resume and the CBMEM console on Falco, Blaze (both normal and vboot2), Pinky and Pit. Compiled Ryu, Storm and Urara, manually compared the disassemblies with ToT and looked for red flags. Change-Id: Ifd2276417f2036cbe9c056f17e42f051bcd20e81 Signed-off-by: Patrick Georgi <pgeorgi@chromium.org> Original-Commit-Id: f1e2028e7ebceeb2d71ff366150a37564595e614 Original-Change-Id: I005506add4e8fcdb74db6d5e6cb2d4cb1bd3cda5 Original-Signed-off-by: Julius Werner <jwerner@chromium.org> Original-Reviewed-on: https://chromium-review.googlesource.com/213370 Reviewed-on: http://review.coreboot.org/9283 Tested-by: build bot (Jenkins) Reviewed-by: Stefan Tauner <stefan.tauner@gmx.at> Reviewed-by: Aaron Durbin <adurbin@google.com>
2014-08-21 00:29:56 +02:00
.section ".text._start", "ax", @progbits
#ifdef __x86_64__
.code64
#else
.code32
#endif
.globl _start
_start:
cli
lgdt %cs:gdtaddr
#ifndef __x86_64__
ljmp $0x10, $1f
#endif
1: movl $0x18, %eax
movl %eax, %ds
movl %eax, %es
movl %eax, %ss
movl %eax, %fs
movl %eax, %gs
#ifdef __x86_64__
mov $0x48, %ecx
call SetCodeSelector
#endif
post_code(POST_ENTRY_C_START) /* post 13 */
cld
/** poison the stack. Code should not count on the
* stack being full of zeros. This stack poisoning
* recently uncovered a bug in the broadcast SIPI
* code.
*/
leal _stack, %edi
movl $_estack, %ecx
subl %edi, %ecx
shrl $2, %ecx /* it is 32 bit aligned, right? */
movl $0xDEADBEEF, %eax
rep
stosl
/* set new stack */
movl $_estack, %esp
#if CONFIG_COOP_MULTITASKING
/* Push the thread pointer. */
push $0
#endif
/* Push the cpu index and struct cpu */
push $0
push $0
/* Initialize the Interrupt Descriptor table */
leal _idt, %edi
leal vec0, %ebx
movl $(0x10 << 16), %eax /* cs selector */
1: movw %bx, %ax
movl %ebx, %edx
movw $0x8E00, %dx /* Interrupt gate - dpl=0, present */
movl %eax, 0(%edi)
movl %edx, 4(%edi)
addl $6, %ebx
addl $8, %edi
cmpl $_idt_end, %edi
jne 1b
/* Load the Interrupt descriptor table */
#ifndef __x86_64__
lidt idtarg
#else
// FIXME port table to x64 - lidt idtarg
#endif
/*
* Now we are finished. Memory is up, data is copied and
* bss is cleared. Now we call the main routine and
* let it do the rest.
*/
post_code(POST_PRE_HARDWAREMAIN) /* post fe */
#if CONFIG_GDB_WAIT
call gdb_hw_init
call gdb_stub_breakpoint
#endif
call main
/* NOTREACHED */
.Lhlt:
post_code(POST_DEAD_CODE) /* post ee */
hlt
jmp .Lhlt
vec0:
push $0 /* error code */
push $0 /* vector */
jmp int_hand
vec1:
push $0 /* error code */
push $1 /* vector */
jmp int_hand
vec2:
push $0 /* error code */
push $2 /* vector */
jmp int_hand
vec3:
push $0 /* error code */
push $3 /* vector */
jmp int_hand
vec4:
push $0 /* error code */
push $4 /* vector */
jmp int_hand
vec5:
push $0 /* error code */
push $5 /* vector */
jmp int_hand
vec6:
push $0 /* error code */
push $6 /* vector */
jmp int_hand
vec7:
push $0 /* error code */
push $7 /* vector */
jmp int_hand
vec8:
/* error code */
push $8 /* vector */
jmp int_hand
.word 0x9090
vec9:
push $0 /* error code */
push $9 /* vector */
jmp int_hand
vec10:
/* error code */
push $10 /* vector */
jmp int_hand
.word 0x9090
vec11:
/* error code */
push $11 /* vector */
jmp int_hand
.word 0x9090
vec12:
/* error code */
push $12 /* vector */
jmp int_hand
.word 0x9090
vec13:
/* error code */
push $13 /* vector */
jmp int_hand
.word 0x9090
vec14:
/* error code */
push $14 /* vector */
jmp int_hand
.word 0x9090
vec15:
push $0 /* error code */
push $15 /* vector */
jmp int_hand
vec16:
push $0 /* error code */
push $16 /* vector */
jmp int_hand
vec17:
/* error code */
push $17 /* vector */
jmp int_hand
.word 0x9090
vec18:
push $0 /* error code */
push $18 /* vector */
jmp int_hand
vec19:
push $0 /* error code */
push $19 /* vector */
jmp int_hand
int_hand:
/* At this point, on x86-32, on the stack there is:
* 0(%esp) vector
* 4(%esp) error code
* 8(%esp) eip
* 12(%esp) cs
* 16(%esp) eflags
*/
#ifdef __x86_64__
push %rdi
push %rsi
push %rbp
/* Original stack pointer */
lea 32(%rsp), %rbp
push %rbp
push %rbx
push %rdx
push %rcx
push %rax
push %rsp /* Pointer to structure on the stack */
call x86_exception
pop %rax /* Drop the pointer */
pop %rax
pop %rcx
pop %rdx
pop %rbx
pop %rbp /* Ignore saved %rsp value */
pop %rbp
pop %rsi
pop %rdi
add $8, %rsp /* pop of the vector and error code */
#else
pushl %edi
pushl %esi
pushl %ebp
/* Original stack pointer */
leal 32(%esp), %ebp
pushl %ebp
pushl %ebx
pushl %edx
pushl %ecx
pushl %eax
pushl %esp /* Pointer to structure on the stack */
call x86_exception
pop %eax /* Drop the pointer */
popl %eax
popl %ecx
popl %edx
popl %ebx
popl %ebp /* Ignore saved %esp value */
popl %ebp
popl %esi
popl %edi
addl $8, %esp /* pop of the vector and error code */
#endif
iret
#if CONFIG_GDB_WAIT
.globl gdb_stub_breakpoint
gdb_stub_breakpoint:
#ifdef __x86_64__
pop %rax /* Return address */
pushfl
push %cs
push %rax /* Return address */
push $0 /* No error code */
push $32 /* vector 32 is user defined */
#else
popl %eax /* Return address */
pushfl
pushl %cs
pushl %eax /* Return address */
pushl $0 /* No error code */
pushl $32 /* vector 32 is user defined */
#endif
jmp int_hand
#endif
.globl gdt, gdt_end, idtarg
gdtaddr:
.word gdt_end - gdt - 1
#ifdef __x86_64__
.quad gdt
#else
.long gdt /* we know the offset */
#endif
.data
/* This is the gdt for GCC part of coreboot.
* It is different from the gdt in ROMCC/ASM part of coreboot
* which is defined in entry32.inc
*
* When the machine is initially started, we use a very simple
* gdt from rom (that in entry32.inc) which only contains those
* entries we need for protected mode.
*
* When we're executing code from RAM, we want to do more complex
* stuff, like initializing PCI option roms in real mode, or doing
* a resume from a suspend to ram.
*/
gdt:
/* selgdt 0, unused */
.word 0x0000, 0x0000 /* dummy */
.byte 0x00, 0x00, 0x00, 0x00
/* selgdt 8, unused */
.word 0x0000, 0x0000 /* dummy */
.byte 0x00, 0x00, 0x00, 0x00
/* selgdt 0x10, flat code segment */
.word 0xffff, 0x0000
.byte 0x00, 0x9b, 0xcf, 0x00 /* G=1 and 0x0f, So we get 4Gbytes for limit */
/* selgdt 0x18, flat data segment */
.word 0xffff, 0x0000
#ifdef __x86_64__
.byte 0x00, 0x92, 0xcf, 0x00
#else
.byte 0x00, 0x93, 0xcf, 0x00
#endif
/* selgdt 0x20, unused */
.word 0x0000, 0x0000 /* dummy */
.byte 0x00, 0x00, 0x00, 0x00
/* The next two entries are used for executing VGA option ROMs */
/* selgdt 0x28 16 bit 64k code at 0x00000000 */
.word 0xffff, 0x0000
.byte 0, 0x9a, 0, 0
/* selgdt 0x30 16 bit 64k data at 0x00000000 */
.word 0xffff, 0x0000
.byte 0, 0x92, 0, 0
/* The next two entries are used for ACPI S3 RESUME */
/* selgdt 0x38, flat data segment 16 bit */
.word 0x0000, 0x0000 /* dummy */
.byte 0x00, 0x93, 0x8f, 0x00 /* G=1 and 0x0f, So we get 4Gbytes for limit */
/* selgdt 0x40, flat code segment 16 bit */
.word 0xffff, 0x0000
.byte 0x00, 0x9b, 0x8f, 0x00 /* G=1 and 0x0f, So we get 4Gbytes for limit */
#ifdef __x86_64__
/* selgdt 0x48, flat x64 code segment */
.word 0xffff, 0x0000
.byte 0x00, 0x9b, 0xaf, 0x00
#endif
gdt_end:
idtarg:
.word _idt_end - _idt - 1 /* limit */
.long _idt
.word 0
_idt:
.fill 20, 8, 0 # idt is uninitialized
_idt_end:
#ifdef __x86_64__
SetCodeSelector:
.intel_syntax noprefix
# save rsp because iret will align it to a 16 byte boundary
mov rdx, rsp
# use iret to jump to a 64-bit offset in a new code segment
# iret will pop cs:rip, flags, then ss:rsp
mov ax, ss # need to push ss..
push rax # push ss instuction not valid in x64 mode, so use ax
push rsp
pushfq
push rcx # cx is code segment selector from caller
mov rax, offset setCodeSelectorLongJump
push rax
# the iret will continue at next instruction, with the new cs value loaded
iretq
setCodeSelectorLongJump:
# restore rsp, it might not have been 16-byte aligned on entry
mov rsp, rdx
ret
.att_syntax prefix
.previous
.code64
#else
.previous
.code32
#endif