libdd_libunwind_sys/
libunwind_aarch64.rs

1// Copyright 2025-Present Datadog, Inc. https://www.datadoghq.com/
2// SPDX-License-Identifier: Apache-2.0
3
4pub type UnwContext = libc::ucontext_t;
5
6pub type UnwWord = u64;
7
8// Opaque cursor structure
9#[repr(C)]
10#[derive(Debug, Copy, Clone)]
11pub struct UnwCursor {
12    pub opaque: [UnwWord; 250],
13}
14
15// Opaque address space handle (unw_addr_space_t)
16pub type UnwAddrSpaceT = *mut libc::c_void;
17
18// Opaque accessor table (unw_accessors_t); never construct directly
19#[repr(C)]
20pub struct UnwAccessors;
21
22extern "C" {
23    #[link_name = "_ULaarch64_init_local2"]
24    pub fn unw_init_local2(cursor: *mut UnwCursor, context: *mut UnwContext, flag: i32) -> i32;
25    #[link_name = "_ULaarch64_step"]
26    pub fn unw_step(cursor: *mut UnwCursor) -> i32;
27    #[link_name = "_ULaarch64_get_reg"]
28    pub fn unw_get_reg(cursor: *mut UnwCursor, reg: i32, valp: *mut UnwWord) -> i32;
29    #[link_name = "_ULaarch64_get_proc_name"]
30    pub fn unw_get_proc_name(
31        cursor: *mut UnwCursor,
32        name: *mut libc::c_char,
33        len: usize,
34        offset: *mut u64,
35    ) -> i32;
36    #[link_name = "unw_backtrace2"]
37    pub fn unw_backtrace2(
38        buffer: *mut *mut ::std::os::raw::c_void,
39        size: i32,
40        context: *mut UnwContext,
41        flag: i32,
42    ) -> i32;
43}
44
45// Remote unwinding API. Uses _Uaarch64_* symbols from libunwind-aarch64
46// because the _ULaarch64_* dont have remote support
47#[allow(improper_ctypes)]
48extern "C" {
49    #[link_name = "_Uaarch64_init_remote"]
50    pub fn unw_init_remote(
51        cursor: *mut UnwCursor,
52        addr_space: UnwAddrSpaceT,
53        arg: *mut libc::c_void,
54    ) -> i32;
55    #[link_name = "_Uaarch64_step"]
56    pub fn unw_step_remote(cursor: *mut UnwCursor) -> i32;
57    #[link_name = "_Uaarch64_get_reg"]
58    pub fn unw_get_reg_remote(cursor: *mut UnwCursor, reg: i32, valp: *mut UnwWord) -> i32;
59    #[link_name = "_Uaarch64_get_proc_name"]
60    pub fn unw_get_proc_name_remote(
61        cursor: *mut UnwCursor,
62        name: *mut libc::c_char,
63        len: usize,
64        offset: *mut UnwWord,
65    ) -> i32;
66    #[link_name = "_Uaarch64_create_addr_space"]
67    pub fn unw_create_addr_space(accessors: *mut UnwAccessors, byteorder: i32) -> UnwAddrSpaceT;
68    #[link_name = "_Uaarch64_destroy_addr_space"]
69    pub fn unw_destroy_addr_space(addr_space: UnwAddrSpaceT);
70    pub fn _UPT_create(pid: libc::pid_t) -> *mut libc::c_void;
71    pub fn _UPT_destroy(upt_info: *mut libc::c_void);
72    pub static _UPT_accessors: UnwAccessors;
73}
74
75pub const UNW_REG_IP: i32 = 30; // Instruction Pointer
76pub const UNW_REG_SP: i32 = 31; // Stack Pointer
77pub const UNW_REG_FP: i32 = 29; // Frame Pointer
78pub const UNW_INIT_LOCAL_ONLY_IP: i32 = 1;
79
80/// Saves the current CPU context into `uc_mcontext.regs`.
81/// On aarch64 libunwind does not emit a callable symbol for getcontext —
82/// it uses a C preprocessor macro with inline assembly. This is the Rust
83/// equivalent: save all GPRs, SP, LR, and PC into `uc_mcontext`.
84///
85/// # Safety
86/// `context` must be a valid, non-null pointer to a zeroed or initialized `UnwContext`.
87// This is only for testing purposes and allow the tests to work with libc and musl-libc
88#[cfg(test)]
89#[inline(always)]
90pub unsafe fn getcontext(context: *mut UnwContext) -> i32 {
91    let base = core::ptr::addr_of_mut!((*context).uc_mcontext.regs) as u64;
92    let ret: u64;
93    core::arch::asm!(
94        "stp x0, x1, [x0, #0]",
95        "stp x2, x3, [x0, #16]",
96        "stp x4, x5, [x0, #32]",
97        "stp x6, x7, [x0, #48]",
98        "stp x8, x9, [x0, #64]",
99        "stp x10, x11, [x0, #80]",
100        "stp x12, x13, [x0, #96]",
101        "stp x14, x15, [x0, #112]",
102        "stp x16, x17, [x0, #128]",
103        "stp x18, x19, [x0, #144]",
104        "stp x20, x21, [x0, #160]",
105        "stp x22, x23, [x0, #176]",
106        "stp x24, x25, [x0, #192]",
107        "stp x26, x27, [x0, #208]",
108        "stp x28, x29, [x0, #224]",
109        "mov x1, sp",
110        "stp x30, x1, [x0, #240]",
111        "adr x1, 2f",
112        "str x1, [x0, #256]",
113        "mov x0, #0",
114        "2:",
115        inout("x0") base => ret,
116        out("x1") _,
117        options(nostack, preserves_flags),
118    );
119    ret as i32
120}
libdd_libunwind_sys/libunwind_aarch64.rs

libdd_libunwind_sys/
libunwind_aarch64.rs
