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x86: Support jumping from SPL to U-Boot 

Add a rough function to handle jumping from 32-bit SPL to 64-bit U-Boot.
This still needs work to clean it up.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
This commit is contained in:
Simon Glass 2017-01-16 07:04:15 -07:00 committed by Bin Meng
parent c2bf0dfaa3
commit fa5fcb3bc6
3 changed files with 76 additions and 0 deletions
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3
arch/x86/cpu/call64.S
View File

@ -81,6 +81,9 @@ lret_target:
jmp *%eax /* Jump to the 64-bit target */
.data
.align 16
.globl gdt64
gdt64:
gdt:
.word gdt_end - gdt - 1
.long gdt /* Fixed up by code above */

64
arch/x86/cpu/i386/cpu.c
View File

@ -503,6 +503,70 @@ int cpu_jump_to_64bit(ulong setup_base, ulong target)
return -EFAULT;
}
/*
* Jump from SPL to U-Boot
*
* This function is work-in-progress with many issues to resolve.
*
* It works by setting up several regions:
* ptr - a place to put the code that jumps into 64-bit mode
* gdt - a place to put the global descriptor table
* pgtable - a place to put the page tables
*
* The cpu_call64() code is copied from ROM and then manually patched so that
* it has the correct GDT address in RAM. U-Boot is copied from ROM into
* its pre-relocation address. Then we jump to the cpu_call64() code in RAM,
* which changes to 64-bit mode and starts U-Boot.
*/
int cpu_jump_to_64bit_uboot(ulong target)
{
typedef void (*func_t)(ulong pgtable, ulong setup_base, ulong target);
uint32_t *pgtable;
func_t func;
/* TODO(sjg@chromium.org): Find a better place for this */
pgtable = (uint32_t *)0x1000000;
if (!pgtable)
return -ENOMEM;
build_pagetable(pgtable);
/* TODO(sjg@chromium.org): Find a better place for this */
char *ptr = (char *)0x3000000;
char *gdt = (char *)0x3100000;
extern char gdt64[];
memcpy(ptr, cpu_call64, 0x1000);
memcpy(gdt, gdt64, 0x100);
/*
* TODO(sjg@chromium.org): This manually inserts the pointers into
* the code. Tidy this up to avoid this.
*/
func = (func_t)ptr;
ulong ofs = (ulong)cpu_call64 - (ulong)ptr;
*(ulong *)(ptr + 7) = (ulong)gdt;
*(ulong *)(ptr + 0xc) = (ulong)gdt + 2;
*(ulong *)(ptr + 0x13) = (ulong)gdt;
*(ulong *)(ptr + 0x117 - 0xd4) -= ofs;
/*
* Copy U-Boot from ROM
* TODO(sjg@chromium.org): Figure out a way to get the text base
* correctly here, and in the device-tree binman definition.
*
* Also consider using FIT so we get the correct image length and
* parameters.
*/
memcpy((char *)target, (char *)0xfff00000, 0x100000);
/* Jump to U-Boot */
func((ulong)pgtable, 0, (ulong)target);
return -EFAULT;
}
#ifdef CONFIG_SMP
static int enable_smis(struct udevice *cpu, void *unused)
{

9
arch/x86/include/asm/cpu.h
View File

@ -263,6 +263,15 @@ void cpu_call32(ulong code_seg32, ulong target, ulong table);
*/
int cpu_jump_to_64bit(ulong setup_base, ulong target);
/**
* cpu_jump_to_64bit_uboot() - special function to jump from SPL to U-Boot
*
* This handles calling from 32-bit SPL to 64-bit U-Boot.
*
* @target: Address of U-Boot in RAM
*/
int cpu_jump_to_64bit_uboot(ulong target);
/**
* cpu_get_family_model() - Get the family and model for the CPU
*