jmp.h

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#pragma once

#ifdef OS_LINUX
#if defined(__x86_64__)

typedef struct __exec_context_t {
    // This is the space for general purpose registers
    unsigned long long rax;
    unsigned long long rdx;
    unsigned long long rcx;
    unsigned long long rbx;
    unsigned long long rsp;
    unsigned long long rbp;
    unsigned long long rsi;
    unsigned long long rdi;
    unsigned long long r8;
    unsigned long long r9;
    unsigned long long r10;
    unsigned long long r11;
    unsigned long long r12;
    unsigned long long r13;
    unsigned long long r14;
    unsigned long long r15;
    unsigned long long rip;
    unsigned long long flags;

    // Space for FPU registers
    unsigned char fpu[512] __attribute__((aligned(16))); // fxsave wants 16-byte aligned memory
} exec_context_t;

#define set_jmp(env)    ({\
                int _set_ret;\
                __asm__ __volatile__ ("pushq %rdi"); \
                _set_ret = _set_jmp(env); \
                __asm__ __volatile__ ("add $8, %rsp"); \
                _set_ret;\
            })

#define long_jmp(env, val)  _long_jmp(env, val)

long long _set_jmp(exec_context_t *env);



__attribute__((__noreturn__))
void _long_jmp(exec_context_t *env, long long val);



extern void context_create(exec_context_t *creat, void (*fn)(void *), void *args, void *stack, size_t stack_size);


// As mentioned, using direct calls to _set_jmp or _long_jmp is not safe.
// Here we poison their explicit usage, forcing the code base to rely
// on wrapper macros.
// on wrapper macros.
#pragma GCC poison _set_jmp _long_jmp


#endif  /* defined(__x86_64__) */
#endif  /* OS_LINUX */