x8664.h File Reference

x86-64 Linux architecture adapter: every ISA-specific construct the SDK needs, behind the arch-neutral names the rest of src/ consumes (via common/arch/arch.h). More...

#include "common/arch/types.h"

Go to the source code of this file.

Macros
#define	SYS_read   0
	read(2) syscall number
#define	SYS_write   1
	write(2) syscall number
#define	SYS_close   3
	close(2) syscall number
#define	SYS_newfstatat   262
	newfstatat(2) syscall number
#define	SYS_pread64   17
	pread64(2) syscall number
#define	SYS_mmap   9
	mmap(2) syscall number
#define	SYS_mprotect   10
	mprotect(2) syscall number
#define	SYS_munmap   11
	munmap(2) syscall number
#define	SYS_rt_sigaction   13
	rt_sigaction(2) syscall number
#define	SYS_rt_sigprocmask   14
	rt_sigprocmask(2) syscall number
#define	SYS_rt_sigreturn   15
	rt_sigreturn(2) syscall number
#define	SYS_rt_sigtimedwait   128
	rt_sigtimedwait(2) syscall number
#define	SYS_socket   41
	socket(2) syscall number
#define	SYS_sendmsg   46
	sendmsg(2) syscall number
#define	SYS_sendto   44
	sendto(2) syscall number
#define	SYS_recvfrom   45
	recvfrom(2) syscall number
#define	SYS_bind   49
	bind(2) syscall number
#define	SYS_recvmmsg   299
	recvmmsg(2) syscall number
#define	SYS_setsockopt   54
	setsockopt(2) syscall number
#define	SYS_clone   56
	clone(2) syscall number
#define	SYS_exit   60
	exit(2) syscall number
#define	SYS_gettid   186
	gettid(2) syscall number
#define	SYS_futex   202
	futex(2) syscall number
#define	SYS_sched_setaffinity   203
	sched_setaffinity(2) syscall number
#define	SYS_sched_getaffinity   204
	sched_getaffinity(2) syscall number
#define	SYS_clock_gettime   228
	clock_gettime(2) syscall number
#define	SYS_openat   257
	openat(2) syscall number
#define	SYS_mkdirat   258
	mkdirat(2) syscall number
#define	SYS_getrandom   318
	getrandom(2) syscall number
#define	SYS_fork   57
	fork(2) syscall number
#define	SYS_wait4   61
	wait4(2) syscall number
#define	SYS_kill   62
	kill(2) syscall number
#define	SYS_getpid   39
	getpid(2) syscall number
#define	SYS_getppid   110
	getppid(2) syscall number
#define	SYS_prctl   157
	prctl(2) syscall number
#define	SYS_exit_group   231
	exit_group(2) syscall number
#define	SYS_poll   7
	poll(2) syscall number
#define	SYS_getsockopt   55
	getsockopt(2) syscall number
#define	SYS_fcntl   72
	fcntl(2) syscall number
#define	SYS_bpf   321
	bpf(2) syscall number
#define	SA_RESTORER   0x04000000u
	x86_64 Linux rt_sigaction(2) requires SA_RESTORER plus a userspace trampoline that issues rt_sigreturn(2); the kernel refuses a bare handler with no restorer.
#define	syscall2(n, a, b)
	Two-argument syscall: syscall6() with the trailing arguments zeroed.
#define	syscall3(n, a, b, c)
	Three-argument syscall: syscall6() with the trailing arguments zeroed.
#define	syscall4(n, a, b, c, d)
	Four-argument syscall: syscall6() with the trailing arguments zeroed.
#define	syscall5(n, a, b, c, d, e)
	Five-argument syscall: syscall6() with the trailing argument zeroed.
#define	syscall1(n, a)
	One-argument syscall: syscall6() with the trailing arguments zeroed.
#define	WIRED_ARCH_START_ASM(entry)
	Body of a freestanding _start (to be used inside a naked function): Linux enters with RSP%16==0 and no return address on the stack; this recovers argc (rdi) and argv (rsi) from the kernel-built initial stack, 16-byte-aligns RSP for the SysV ABI's post-call state, calls entry (int entry(int argc, char** argv)), and exits with its return value.

Functions
static i64	syscall6 (i64 n, i64 a, i64 b, i64 c, i64 d, i64 e, i64 f)
	Six-argument raw x86_64 Linux syscall.
static void	wired_arch_pause (void)
	CPU spin-wait hint for busy-poll loops (x86 pause): tells the core a spin is in progress, saving power and easing hyperthread contention.
i64	wired_arch_clone_raw (i64 flags, u8 *child_stack, i32 *parent_tid, i32 *child_tid, i64 tls)
	Raw clone(2) whose child starts on a new stack (assembly trampoline in clone.c; a C wrapper cannot be used because the compiler's spills would read the parent's frame from the child).
void	wired_arch_sigreturn_restorer (void)
	Signal-return trampoline for rt_sigaction(2)'s SA_RESTORER slot: the kernel jumps here when a handler returns, and the stub issues rt_sigreturn(2) (assembly in sigret.c; there is no libc restore_rt to fall back on).

Detailed Description

x86-64 Linux architecture adapter: every ISA-specific construct the SDK needs, behind the arch-neutral names the rest of src/ consumes (via common/arch/arch.h).

Nothing outside src/common/arch/ writes inline assembly or x86 builtins.

Macro Definition Documentation

syscall1

#define syscall1	(		n,
			a )

Value:

syscall6((n), (i64)(a), 0, 0, 0, 0, 0)

One-argument syscall: syscall6() with the trailing arguments zeroed.

syscall2

#define syscall2	(		n,
			a,
			b )

Value:

syscall6((n), (i64)(a), (i64)(b), 0, 0, 0, 0)

Two-argument syscall: syscall6() with the trailing arguments zeroed.

syscall3

#define syscall3	(		n,
			a,
			b,
			c )

Value:

syscall6((n), (i64)(a), (i64)(b), (i64)(c), 0, 0, 0)

Three-argument syscall: syscall6() with the trailing arguments zeroed.

syscall4

#define syscall4	(		n,
			a,
			b,
			c,
			d )

Value:

syscall6((n), (i64)(a), (i64)(b), (i64)(c), (i64)(d), 0, 0)

Four-argument syscall: syscall6() with the trailing arguments zeroed.

syscall5

#define syscall5	(		n,
			a,
			b,
			c,
			d,
			e )

Value:

syscall6((n), (i64)(a), (i64)(b), (i64)(c), (i64)(d), (i64)(e), 0)

Five-argument syscall: syscall6() with the trailing argument zeroed.

WIRED_ARCH_START_ASM

#define WIRED_ARCH_START_ASM

(

entry

)

Value:

__asm__ volatile(                    \
    "mov (%rsp), %rdi\n"             \
    "lea 8(%rsp), %rsi\n"            \
    "and $-16, %rsp\n"               \
    "call " #entry                   \
    "\n"                             \
    "mov %eax, %edi\n"               \
    "mov $60, %eax\n" /* SYS_exit */ \
    "syscall\n")

Body of a freestanding _start (to be used inside a naked function): Linux enters with RSP%16==0 and no return address on the stack; this recovers argc (rdi) and argv (rsi) from the kernel-built initial stack, 16-byte-aligns RSP for the SysV ABI's post-call state, calls entry (int entry(int argc, char** argv)), and exits with its return value.

Function Documentation

syscall6()

i64 syscall6 ( i64 n, i64 a, i64 b, i64 c, i64 d, i64 e, i64 f )

inlinestatic

Six-argument raw x86_64 Linux syscall.

Arguments follow the x86_64 syscall ABI register order: number in rax, then rdi, rsi, rdx, r10, r8, r9. rcx/r11 are clobbered by the syscall instruction. The syscall1..syscall5 wrappers pass 0 for their unused trailing arguments.

Parameters

n	syscall number (one of the SYS_* constants)
a	1st argument (rdi)
b	2nd argument (rsi)
c	3rd argument (rdx)
d	4th argument (r10)
e	5th argument (r8)
f	6th argument (r9)

Returns

the kernel's return value; negative values are -errno

wired_arch_clone_raw()

i64 wired_arch_clone_raw	(	i64	flags,
		u8 *	child_stack,
		i32 *	parent_tid,
		i32 *	child_tid,
		i64	tls )

Raw clone(2) whose child starts on a new stack (assembly trampoline in clone.c; a C wrapper cannot be used because the compiler's spills would read the parent's frame from the child).

The caller must have pushed the child's entry function and its argument as the two topmost 8-byte slots of child_stack; the child pops them, calls fn(arg), then exits(0).

Parameters

flags	CLONE_* flag mask passed straight to the kernel
child_stack	top of the child's stack, seeded with fn and arg
parent_tid	kernel writes the child tid here (CLONE_PARENT_SETTID)
child_tid	cleared+futex-woken on child exit (CLONE_CHILD_CLEARTID)
tls	new TLS descriptor (0 when unused)

Returns

the child tid in the parent, or a negative -errno

wired_arch_sigreturn_restorer()

void wired_arch_sigreturn_restorer

(

void

)

Signal-return trampoline for rt_sigaction(2)'s SA_RESTORER slot: the kernel jumps here when a handler returns, and the stub issues rt_sigreturn(2) (assembly in sigret.c; there is no libc restore_rt to fall back on).

Take its address only – it is not a callable C function.