arch/x86_64/syscall.c


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#include "arch/x86_64/processor.h"
#include <stddef.h>
    
__attribute__((naked))
void _syscall_entry(void)
{
    __asm__ volatile(" \
            pushq %%r11; \
            pushq %%rcx; \
            swapgs; \
            movq %%gs:%c[tcb], %%rax; \
            movq %%rsp, %c[sp](%%rax); \
            movq %c[ksp](%%rax), %%rsp; \
            pushq %c[sp](%%rax); \
            callq _syscall_handler; \
            swapgs; \
            popq %%rsp; \
            popq %%rcx; \
            popq %%r11; \
            sysretq;"
            ::
            [tcb] "i"(offsetof(processor_t, tcb)),
            [sp] "i"(offsetof(tcb_t, sp)),
            [ksp] "i"(offsetof(tcb_t, ksp)));
}