| // Copyright 2016 The Fuchsia Authors |
| // Copyright (c) 2015 Travis Geiselbrecht |
| // |
| // Use of this source code is governed by a MIT-style |
| // license that can be found in the LICENSE file or at |
| // https://opensource.org/licenses/MIT |
| |
| #include <asm.h> |
| #include <arch/defines.h> |
| |
| /* void x86_64_context_switch(uint64_t *oldsp, uint64_t newsp) */ |
| FUNCTION(x86_64_context_switch) |
| /* save the old context and restore the new */ |
| /* This layout should match struct x86_64_context_switch_frame */ |
| push_reg %rbx |
| push_reg %rbp |
| push_reg %r12 |
| push_reg %r13 |
| push_reg %r14 |
| push_reg %r15 |
| |
| movq %rsp,(%rdi) |
| movq %rsi,%rsp |
| |
| pop_reg %r15 |
| pop_reg %r14 |
| pop_reg %r13 |
| pop_reg %r12 |
| pop_reg %rbp |
| pop_reg %rbx |
| |
| retq |
| END_FUNCTION(x86_64_context_switch) |
| |
| #include <arch/x86/mp.h> |
| |
| /* void arch_spin_lock(unsigned long *lock) */ |
| FUNCTION(arch_spin_lock) |
| /* fetch the current cpu number + 1 */ |
| mov %gs:PERCPU_CPU_NUM_OFFSET, %rsi |
| inc %rsi |
| |
| .Ltake_lock: |
| xor %rax, %rax |
| lock cmpxchg %rsi, (%rdi) |
| jnz .Lspin |
| ret |
| |
| .Lspin: |
| pause |
| cmpq $0, (%rdi) |
| je .Ltake_lock |
| jmp .Lspin |
| END_FUNCTION(arch_spin_lock) |
| |
| /* int arch_spin_trylock(unsigned long *lock) */ |
| FUNCTION(arch_spin_trylock) |
| /* fetch the current cpu number + 1 */ |
| mov %gs:PERCPU_CPU_NUM_OFFSET, %rsi |
| inc %rsi |
| |
| xor %rax, %rax |
| lock cmpxchg %rsi, (%rdi) |
| /* we return 0 to indicate success. %rax contains the value found by cmpxchg, |
| * which is already 0 if we got the lock */ |
| ret |
| END_FUNCTION(arch_spin_trylock) |
| |
| /* void arch_spin_unlock(spin_lock_t *lock) */ |
| FUNCTION(arch_spin_unlock) |
| movq $0, (%rdi) |
| ret |
| END_FUNCTION(arch_spin_unlock) |
| |
| /* rep stos version of page zero */ |
| FUNCTION(arch_zero_page) |
| xorl %eax, %eax /* set %rax = 0 */ |
| mov $PAGE_SIZE >> 3, %rcx |
| cld |
| |
| rep stosq |
| |
| ret |
| END_FUNCTION(arch_zero_page) |
| |
| // This clobbers %rax and memory below %rsp, but preserves all other registers. |
| FUNCTION(load_startup_idt) |
| lea _idt_startup(%rip), %rax |
| movw $(16 * 256) - 1, -16(%rsp) |
| movq %rax, -16+2(%rsp) |
| lidt -16(%rsp) |
| ret |
| END_FUNCTION(load_startup_idt) |
