diff options
Diffstat (limited to 'src/device/oprom/realmode/x86_asm.S')
| -rw-r--r-- | src/device/oprom/realmode/x86_asm.S | 23 |
1 files changed, 22 insertions, 1 deletions
diff --git a/src/device/oprom/realmode/x86_asm.S b/src/device/oprom/realmode/x86_asm.S index 87348cdc22..ec82e53ec5 100644 --- a/src/device/oprom/realmode/x86_asm.S +++ b/src/device/oprom/realmode/x86_asm.S @@ -43,6 +43,10 @@ __idt_handler_size: .globl __realmode_code __realmode_code: +/* Realmode function return. */ +__realmode_ret = RELOCATED(.) + .long 0 + /* Realmode IDT pointer structure. */ __realmode_idt = RELOCATED(.) .word 1023 /* 16 bit limit */ @@ -167,6 +171,13 @@ __lcall_instr = RELOCATED(.) .word 0x0000, 0x0000 /* ************************************ */ + /* + * Here is end of real mode call and time to go back to protected mode. + * Before that its better to store current eax into some memory address + * so that context persist in protected mode too. + */ + mov %eax, __realmode_ret + /* If we got here, we are just about done. * Need to get back to protected mode. */ @@ -196,7 +207,8 @@ __lcall_instr = RELOCATED(.) popa /* and exit */ - // TODO return AX from OPROM call + /* return AX from OPROM call */ + mov __realmode_ret, %eax ret .globl __realmode_interrupt @@ -291,6 +303,13 @@ __realmode_interrupt: __intXX_instr = RELOCATED(.) .byte 0xcd, 0x00 /* This becomes intXX */ + /* + * Here is end of real mode call and time to go back to protected mode. + * Before that its better to store current eax into some memory address + * so that context persist in protected mode too. + */ + mov %eax, __realmode_ret + /* Ok, the job is done, now go back to protected mode coreboot */ movl %cr0, %eax orl $PE, %eax @@ -314,6 +333,8 @@ __intXX_instr = RELOCATED(.) movl __stack, %esp popf popa + /* return AX from OPROM call */ + mov __realmode_ret, %eax ret /* This is the 16-bit interrupt entry point called by the IDT stub code. |