From a146d58ca0375a12f23dc5a4bd25adfa3423114f Mon Sep 17 00:00:00 2001 From: Aaron Durbin Date: Fri, 8 Feb 2013 16:56:51 -0600 Subject: ramstage: prepare for relocation The current ramstage code contains uses of symbols that cause issues when the ramstage is relocatable. There are 2 scenarios resolved by this patch: 1. Absolute symbols that are actually sizes/limits. The symbols are problematic when relocating a program because there is no way to distinguish a symbol that shouldn't be relocated and one that can. The only way to handle these symbols is to write a program to post process the relocations and keep a whitelist of ones that shouldn't be relocated. I don't believe that is a route that should be taken so fix the users of these sizes/limits encoded as absolute symbols to calculate the size at runtime or dereference a variable in memory containing the size/limit. 2. Absoulte symbols that were relocated to a fixed address. These absolute symbols are generated by assembly files to be placed at a fixed location. Again, these symbols are problematic because one can't distinguish a symbol that can't be relocated. The symbols are again resolved at runtime to allow for proper relocation. For the symbols defining a size either use 2 symbols and calculate the difference or provide a variable in memory containing the size. Change-Id: I1ef2bfe6fd531308218bcaac5dcccabf8edf932c Signed-off-by: Aaron Durbin Reviewed-on: http://review.coreboot.org/2789 Tested-by: build bot (Jenkins) Reviewed-by: Marc Jones --- src/device/oprom/realmode/x86.c | 45 ++++++++++++++++++++++++++----------- src/device/oprom/realmode/x86.h | 8 +++---- src/device/oprom/realmode/x86_asm.S | 15 +++++++------ 3 files changed, 44 insertions(+), 24 deletions(-) (limited to 'src/device') diff --git a/src/device/oprom/realmode/x86.c b/src/device/oprom/realmode/x86.c index 5fd11b59a5..94b65e1abc 100644 --- a/src/device/oprom/realmode/x86.c +++ b/src/device/oprom/realmode/x86.c @@ -36,16 +36,37 @@ #include #include +/* The following symbols cannot be used directly. They need to be fixed up + * to point to the correct address location after the code has been copied + * to REALMODE_BASE. Absolute symbols are not used because those symbols are + * relocated when a relocatable ramstage is enabled. + */ +extern unsigned char __realmode_call, __realmode_interrupt; +extern unsigned char __realmode_buffer; + +#define PTR_TO_REAL_MODE(sym)\ + (void *)(REALMODE_BASE + ((char *)&(sym) - (char *)&__realmode_code)) + /* to have a common register file for interrupt handlers */ X86EMU_sysEnv _X86EMU_env; void (*realmode_call)(u32 addr, u32 eax, u32 ebx, u32 ecx, u32 edx, - u32 esi, u32 edi) asmlinkage = - (void *)&__realmode_call; + u32 esi, u32 edi) asmlinkage; void (*realmode_interrupt)(u32 intno, u32 eax, u32 ebx, u32 ecx, u32 edx, - u32 esi, u32 edi) asmlinkage = - (void *)&__realmode_interrupt; + u32 esi, u32 edi) asmlinkage; + +static void setup_realmode_code(void) +{ + memcpy(REALMODE_BASE, &__realmode_code, __realmode_code_size); + + /* Ensure the global pointers are relocated properly. */ + realmode_call = PTR_TO_REAL_MODE(__realmode_call); + realmode_interrupt = PTR_TO_REAL_MODE(__realmode_interrupt); + + printk(BIOS_SPEW, "Real mode stub @%p: %d bytes\n", REALMODE_BASE, + __realmode_code_size); +} static void setup_rombios(void) { @@ -149,7 +170,7 @@ static void write_idt_stub(void *target, u8 intnum) { unsigned char *codeptr; codeptr = (unsigned char *) target; - memcpy(codeptr, &__idt_handler, (size_t)&__idt_handler_size); + memcpy(codeptr, &__idt_handler, __idt_handler_size); codeptr[3] = intnum; /* modify int# in the code stub. */ } @@ -163,7 +184,7 @@ static void setup_realmode_idt(void) */ for (i = 0; i < 256; i++) { idts[i].cs = 0; - idts[i].offset = 0x1000 + (i * (u32)&__idt_handler_size); + idts[i].offset = 0x1000 + (i * __idt_handler_size); write_idt_stub((void *)((u32 )idts[i].offset), i); } @@ -204,7 +225,7 @@ static u8 vbe_get_mode_info(vbe_mode_info_t * mi) { printk(BIOS_DEBUG, "VBE: Getting information about VESA mode %04x\n", mi->video_mode); - char *buffer = (char *)&__buffer; + char *buffer = PTR_TO_REAL_MODE(__realmode_buffer); u16 buffer_seg = (((unsigned long)buffer) >> 4) & 0xff00; u16 buffer_adr = ((unsigned long)buffer) & 0xffff; realmode_interrupt(0x10, VESA_GET_MODE_INFO, 0x0000, @@ -312,9 +333,8 @@ void run_bios(struct device *dev, unsigned long addr) /* Set up real-mode IDT */ setup_realmode_idt(); - memcpy(REALMODE_BASE, &__realmode_code, (size_t)&__realmode_code_size); - printk(BIOS_SPEW, "Real mode stub @%p: %d bytes\n", REALMODE_BASE, - (u32)&__realmode_code_size); + /* Make sure the code is placed. */ + setup_realmode_code(); printk(BIOS_DEBUG, "Calling Option ROM...\n"); /* TODO ES:DI Pointer to System BIOS PnP Installation Check Structure */ @@ -366,9 +386,8 @@ void do_vsmbios(void) /* Setting up realmode IDT */ setup_realmode_idt(); - memcpy(REALMODE_BASE, &__realmode_code, (size_t)&__realmode_code_size); - printk(BIOS_SPEW, "VSA: Real mode stub @%p: %d bytes\n", REALMODE_BASE, - (u32)&__realmode_code_size); + /* Make sure the code is placed. */ + setup_realmode_code(); if ((unsigned int)cbfs_load_stage(CBFS_DEFAULT_MEDIA, "vsa") != VSA2_ENTRY_POINT) { diff --git a/src/device/oprom/realmode/x86.h b/src/device/oprom/realmode/x86.h index 76d3e4643c..a811a5621e 100644 --- a/src/device/oprom/realmode/x86.h +++ b/src/device/oprom/realmode/x86.h @@ -32,10 +32,10 @@ struct realmode_idt { void x86_exception(struct eregs *info); /* From x86_asm.S */ -extern unsigned char __idt_handler, __idt_handler_size; -extern unsigned char __realmode_code, __realmode_code_size; -extern unsigned char __realmode_call, __realmode_interrupt; -extern unsigned char __buffer; +extern unsigned char __idt_handler; +extern unsigned int __idt_handler_size; +extern unsigned char __realmode_code; +extern unsigned int __realmode_code_size; extern void (*realmode_call)(u32 addr, u32 eax, u32 ebx, u32 ecx, u32 edx, u32 esi, u32 edi) asmlinkage; diff --git a/src/device/oprom/realmode/x86_asm.S b/src/device/oprom/realmode/x86_asm.S index 56ebb3a885..54cf374025 100644 --- a/src/device/oprom/realmode/x86_asm.S +++ b/src/device/oprom/realmode/x86_asm.S @@ -36,7 +36,8 @@ __idt_handler: movb $0, %al /* This instruction gets modified */ ljmp $0, $__interrupt_handler_16bit .globl __idt_handler_size -__idt_handler_size = ( . - __idt_handler) +__idt_handler_size: + .long . - __idt_handler /* In order to be independent of coreboot's position in RAM @@ -47,7 +48,6 @@ __idt_handler_size = ( . - __idt_handler) __realmode_code: /* Realmode IDT pointer structure. */ - .globl __realmode_idt __realmode_idt = RELOCATED(.) .word 1023 /* 16 bit limit */ .long 0 /* 24 bit base */ @@ -67,13 +67,13 @@ __registers = RELOCATED(.) .long 0 /* 20 - EDI */ /* 256 byte buffer, used by int10 */ - .globl __buffer -__buffer = RELOCATED(.) + .globl __realmode_buffer +__realmode_buffer: .skip 256 .code32 .globl __realmode_call -__realmode_call = RELOCATED(.) +__realmode_call: /* save all registers to the stack */ pusha pushf @@ -204,7 +204,7 @@ __lcall_instr = RELOCATED(.) ret .globl __realmode_interrupt -__realmode_interrupt = RELOCATED(.) +__realmode_interrupt: /* save all registers to the stack */ pusha pushf @@ -408,6 +408,7 @@ __interrupt_handler_16bit = RELOCATED(.) iret .globl __realmode_code_size -__realmode_code_size = (. - __realmode_code) +__realmode_code_size: + .long . - __realmode_code .code32 -- cgit v1.2.3