From: Thomas Gleixner Date: Thu, 11 Oct 2007 09:12:06 +0000 (+0200) Subject: i386: prepare shared kernel/efi_stub.S X-Git-Url: http://drtracing.org/?a=commitdiff_plain;h=f797f57a60514eea6fc03644c14e80691dd25727;p=deliverable%2Flinux.git i386: prepare shared kernel/efi_stub.S Signed-off-by: Thomas Gleixner Signed-off-by: Ingo Molnar --- diff --git a/arch/i386/kernel/Makefile b/arch/i386/kernel/Makefile index 52b0041583cf..f31a7f039e94 100644 --- a/arch/i386/kernel/Makefile +++ b/arch/i386/kernel/Makefile @@ -33,7 +33,7 @@ obj-$(CONFIG_KPROBES) += kprobes.o obj-$(CONFIG_MODULES) += module.o obj-y += sysenter.o vsyscall.o obj-$(CONFIG_ACPI_SRAT) += srat_32.o -obj-$(CONFIG_EFI) += efi.o efi_stub.o +obj-$(CONFIG_EFI) += efi.o efi_stub_32.o obj-$(CONFIG_DOUBLEFAULT) += doublefault.o obj-$(CONFIG_VM86) += vm86_32.o obj-$(CONFIG_EARLY_PRINTK) += early_printk.o diff --git a/arch/i386/kernel/efi_stub.S b/arch/i386/kernel/efi_stub.S deleted file mode 100644 index ef00bb77d7e4..000000000000 --- a/arch/i386/kernel/efi_stub.S +++ /dev/null @@ -1,122 +0,0 @@ -/* - * EFI call stub for IA32. - * - * This stub allows us to make EFI calls in physical mode with interrupts - * turned off. - */ - -#include -#include - -/* - * efi_call_phys(void *, ...) is a function with variable parameters. - * All the callers of this function assure that all the parameters are 4-bytes. - */ - -/* - * In gcc calling convention, EBX, ESP, EBP, ESI and EDI are all callee save. - * So we'd better save all of them at the beginning of this function and restore - * at the end no matter how many we use, because we can not assure EFI runtime - * service functions will comply with gcc calling convention, too. - */ - -.text -ENTRY(efi_call_phys) - /* - * 0. The function can only be called in Linux kernel. So CS has been - * set to 0x0010, DS and SS have been set to 0x0018. In EFI, I found - * the values of these registers are the same. And, the corresponding - * GDT entries are identical. So I will do nothing about segment reg - * and GDT, but change GDT base register in prelog and epilog. - */ - - /* - * 1. Now I am running with EIP = + PAGE_OFFSET. - * But to make it smoothly switch from virtual mode to flat mode. - * The mapping of lower virtual memory has been created in prelog and - * epilog. - */ - movl $1f, %edx - subl $__PAGE_OFFSET, %edx - jmp *%edx -1: - - /* - * 2. Now on the top of stack is the return - * address in the caller of efi_call_phys(), then parameter 1, - * parameter 2, ..., param n. To make things easy, we save the return - * address of efi_call_phys in a global variable. - */ - popl %edx - movl %edx, saved_return_addr - /* get the function pointer into ECX*/ - popl %ecx - movl %ecx, efi_rt_function_ptr - movl $2f, %edx - subl $__PAGE_OFFSET, %edx - pushl %edx - - /* - * 3. Clear PG bit in %CR0. - */ - movl %cr0, %edx - andl $0x7fffffff, %edx - movl %edx, %cr0 - jmp 1f -1: - - /* - * 4. Adjust stack pointer. - */ - subl $__PAGE_OFFSET, %esp - - /* - * 5. Call the physical function. - */ - jmp *%ecx - -2: - /* - * 6. After EFI runtime service returns, control will return to - * following instruction. We'd better readjust stack pointer first. - */ - addl $__PAGE_OFFSET, %esp - - /* - * 7. Restore PG bit - */ - movl %cr0, %edx - orl $0x80000000, %edx - movl %edx, %cr0 - jmp 1f -1: - /* - * 8. Now restore the virtual mode from flat mode by - * adding EIP with PAGE_OFFSET. - */ - movl $1f, %edx - jmp *%edx -1: - - /* - * 9. Balance the stack. And because EAX contain the return value, - * we'd better not clobber it. - */ - leal efi_rt_function_ptr, %edx - movl (%edx), %ecx - pushl %ecx - - /* - * 10. Push the saved return address onto the stack and return. - */ - leal saved_return_addr, %edx - movl (%edx), %ecx - pushl %ecx - ret -.previous - -.data -saved_return_addr: - .long 0 -efi_rt_function_ptr: - .long 0 diff --git a/arch/i386/kernel/efi_stub_32.S b/arch/i386/kernel/efi_stub_32.S new file mode 100644 index 000000000000..ef00bb77d7e4 --- /dev/null +++ b/arch/i386/kernel/efi_stub_32.S @@ -0,0 +1,122 @@ +/* + * EFI call stub for IA32. + * + * This stub allows us to make EFI calls in physical mode with interrupts + * turned off. + */ + +#include +#include + +/* + * efi_call_phys(void *, ...) is a function with variable parameters. + * All the callers of this function assure that all the parameters are 4-bytes. + */ + +/* + * In gcc calling convention, EBX, ESP, EBP, ESI and EDI are all callee save. + * So we'd better save all of them at the beginning of this function and restore + * at the end no matter how many we use, because we can not assure EFI runtime + * service functions will comply with gcc calling convention, too. + */ + +.text +ENTRY(efi_call_phys) + /* + * 0. The function can only be called in Linux kernel. So CS has been + * set to 0x0010, DS and SS have been set to 0x0018. In EFI, I found + * the values of these registers are the same. And, the corresponding + * GDT entries are identical. So I will do nothing about segment reg + * and GDT, but change GDT base register in prelog and epilog. + */ + + /* + * 1. Now I am running with EIP = + PAGE_OFFSET. + * But to make it smoothly switch from virtual mode to flat mode. + * The mapping of lower virtual memory has been created in prelog and + * epilog. + */ + movl $1f, %edx + subl $__PAGE_OFFSET, %edx + jmp *%edx +1: + + /* + * 2. Now on the top of stack is the return + * address in the caller of efi_call_phys(), then parameter 1, + * parameter 2, ..., param n. To make things easy, we save the return + * address of efi_call_phys in a global variable. + */ + popl %edx + movl %edx, saved_return_addr + /* get the function pointer into ECX*/ + popl %ecx + movl %ecx, efi_rt_function_ptr + movl $2f, %edx + subl $__PAGE_OFFSET, %edx + pushl %edx + + /* + * 3. Clear PG bit in %CR0. + */ + movl %cr0, %edx + andl $0x7fffffff, %edx + movl %edx, %cr0 + jmp 1f +1: + + /* + * 4. Adjust stack pointer. + */ + subl $__PAGE_OFFSET, %esp + + /* + * 5. Call the physical function. + */ + jmp *%ecx + +2: + /* + * 6. After EFI runtime service returns, control will return to + * following instruction. We'd better readjust stack pointer first. + */ + addl $__PAGE_OFFSET, %esp + + /* + * 7. Restore PG bit + */ + movl %cr0, %edx + orl $0x80000000, %edx + movl %edx, %cr0 + jmp 1f +1: + /* + * 8. Now restore the virtual mode from flat mode by + * adding EIP with PAGE_OFFSET. + */ + movl $1f, %edx + jmp *%edx +1: + + /* + * 9. Balance the stack. And because EAX contain the return value, + * we'd better not clobber it. + */ + leal efi_rt_function_ptr, %edx + movl (%edx), %ecx + pushl %ecx + + /* + * 10. Push the saved return address onto the stack and return. + */ + leal saved_return_addr, %edx + movl (%edx), %ecx + pushl %ecx + ret +.previous + +.data +saved_return_addr: + .long 0 +efi_rt_function_ptr: + .long 0