/* syscall.h - System call interface for Pactor64 */
#ifndef _SYSCALL_H
#define _SYSCALL_H

#include "pactor64.h"

/* Linux x86-64 compatible syscall numbers */
#define SYS_READ    0
#define SYS_WRITE   1
#define SYS_OPEN    2
#define SYS_CLOSE   3
#define SYS_LSEEK   8
#define SYS_BRK     12
#define SYS_IOCTL   16
#define SYS_PIPE    22
#define SYS_DUP     32
#define SYS_GETPID  39
#define SYS_EXIT    60
#define SYS_GETUID  102
#define SYS_GETGID  104

/* MSR addresses for SYSCALL support */
#define MSR_STAR    0xC0000081
#define MSR_LSTAR   0xC0000082
#define MSR_FMASK   0xC0000084

#define MAX_SYSCALL 128

/* Initialize the syscall interface (sets up STAR/LSTAR MSRs) */
void syscall_init(void);

/* The syscall handler (called from assembly stub) */
uint64_t syscall_dispatch(uint64_t num, uint64_t arg1, uint64_t arg2,
                          uint64_t arg3, uint64_t arg4, uint64_t arg5);

/* Assembly syscall entry point */
extern void syscall_entry(void);

/* Return from userspace back to kernel shell (called from sys_exit) */
extern void return_to_kernel(void) __attribute__((noreturn));

/* Low-level MSR read/write */
static inline uint64_t read_msr(uint32_t msr) {
    uint32_t lo, hi;
    __asm__ volatile ("rdmsr" : "=a"(lo), "=d"(hi) : "c"(msr));
    return ((uint64_t)hi << 32) | lo;
}

static inline void write_msr(uint32_t msr, uint64_t val) {
    uint32_t lo = (uint32_t)val;
    uint32_t hi = (uint32_t)(val >> 32);
    __asm__ volatile ("wrmsr" : : "a"(lo), "d"(hi), "c"(msr));
}

#endif /* _SYSCALL_H */