diff options
Diffstat (limited to 'src/cpu/x86/64bit')
| -rw-r--r-- | src/cpu/x86/64bit/mode_switch.S | 70 |
1 files changed, 70 insertions, 0 deletions
diff --git a/src/cpu/x86/64bit/mode_switch.S b/src/cpu/x86/64bit/mode_switch.S new file mode 100644 index 0000000000..eea104bcf3 --- /dev/null +++ b/src/cpu/x86/64bit/mode_switch.S @@ -0,0 +1,70 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ + +.text +.code64 + .section ".text.protected_mode_call", "ax", @progbits + .globl protected_mode_call_narg +protected_mode_call_narg: + + push %rbp + mov %rsp, %rbp + /* Preserve registers */ + push %rbx + push %r12 + push %r13 + push %r14 + push %r15 + + /* Arguments to stack */ + push %rdi + push %rsi + push %rdx + push %rcx + + #include <cpu/x86/64bit/exit32.inc> + + movl -48(%ebp), %eax /* Argument count */ + movl -64(%ebp), %edx /* Argument 0 */ + movl -72(%ebp), %ecx /* Argument 1 */ + + /* Align the stack */ + andl $0xFFFFFFF0, %esp + test %eax, %eax + je 1f /* Zero arguments */ + + subl $1, %eax + test %eax, %eax + je 2f /* One argument */ + + /* Two arguments */ + subl $8, %esp + pushl %ecx /* Argument 1 */ + pushl %edx /* Argument 0 */ + jmp 1f +2: + subl $12, %esp + pushl %edx /* Argument 0 */ + +1: + movl -56(%ebp), %ebx /* Function to call */ + call *%ebx + movl %eax, %ebx + + /* Preserves ebx */ + #include <cpu/x86/64bit/entry64.inc> + + /* Place return value in rax */ + movl %ebx, %eax + + /* Restore registers */ + mov -40(%rbp), %r15 + mov -32(%rbp), %r14 + mov -24(%rbp), %r13 + mov -16(%rbp), %r12 + mov -8(%rbp), %rbx + + /* Restore stack pointer */ + mov %rbp, %rsp + pop %rbp + + ret |