1 // Copyright 2024, Linaro Limited 2 // Author(s): Manos Pitsidianakis <manos.pitsidianakis@linaro.org> 3 // SPDX-License-Identifier: GPL-2.0-or-later 4 5 #![cfg_attr(not(MESON), doc = include_str!("../README.md"))] 6 #![deny(clippy::missing_const_for_fn)] 7 8 #[rustfmt::skip] 9 pub mod bindings; 10 11 // preserve one-item-per-"use" syntax, it is clearer 12 // for prelude-like modules 13 #[rustfmt::skip] 14 pub mod prelude; 15 16 pub mod assertions; 17 pub mod bitops; 18 pub mod callbacks; 19 pub mod cell; 20 pub mod chardev; 21 pub mod errno; 22 pub mod error; 23 pub mod irq; 24 pub mod memory; 25 pub mod module; 26 pub mod qdev; 27 pub mod qom; 28 pub mod sysbus; 29 pub mod timer; 30 pub mod vmstate; 31 pub mod zeroable; 32 33 use std::{ 34 alloc::{GlobalAlloc, Layout}, 35 ffi::c_void, 36 }; 37 38 pub use error::{Error, Result}; 39 40 #[cfg(HAVE_GLIB_WITH_ALIGNED_ALLOC)] 41 extern "C" { 42 fn g_aligned_alloc0( 43 n_blocks: bindings::gsize, 44 n_block_bytes: bindings::gsize, 45 alignment: bindings::gsize, 46 ) -> bindings::gpointer; 47 fn g_aligned_free(mem: bindings::gpointer); 48 } 49 50 #[cfg(not(HAVE_GLIB_WITH_ALIGNED_ALLOC))] 51 extern "C" { 52 fn qemu_memalign(alignment: usize, size: usize) -> *mut c_void; 53 fn qemu_vfree(ptr: *mut c_void); 54 } 55 56 extern "C" { 57 fn g_malloc0(n_bytes: bindings::gsize) -> bindings::gpointer; 58 fn g_free(mem: bindings::gpointer); 59 } 60 61 /// An allocator that uses the same allocator as QEMU in C. 62 /// 63 /// It is enabled by default with the `allocator` feature. 64 /// 65 /// To set it up manually as a global allocator in your crate: 66 /// 67 /// ```ignore 68 /// use qemu_api::QemuAllocator; 69 /// 70 /// #[global_allocator] 71 /// static GLOBAL: QemuAllocator = QemuAllocator::new(); 72 /// ``` 73 #[derive(Clone, Copy, Debug)] 74 #[repr(C)] 75 pub struct QemuAllocator { 76 _unused: [u8; 0], 77 } 78 79 #[cfg_attr(all(feature = "allocator", not(test)), global_allocator)] 80 pub static GLOBAL: QemuAllocator = QemuAllocator::new(); 81 82 impl QemuAllocator { 83 // From the glibc documentation, on GNU systems, malloc guarantees 16-byte 84 // alignment on 64-bit systems and 8-byte alignment on 32-bit systems. See 85 // https://www.gnu.org/software/libc/manual/html_node/Malloc-Examples.html. 86 // This alignment guarantee also applies to Windows and Android. On Darwin 87 // and OpenBSD, the alignment is 16 bytes on both 64-bit and 32-bit systems. 88 #[cfg(all( 89 target_pointer_width = "32", 90 not(any(target_os = "macos", target_os = "openbsd")) 91 ))] 92 pub const DEFAULT_ALIGNMENT_BYTES: Option<usize> = Some(8); 93 #[cfg(all( 94 target_pointer_width = "64", 95 not(any(target_os = "macos", target_os = "openbsd")) 96 ))] 97 pub const DEFAULT_ALIGNMENT_BYTES: Option<usize> = Some(16); 98 #[cfg(all( 99 any(target_pointer_width = "32", target_pointer_width = "64"), 100 any(target_os = "macos", target_os = "openbsd") 101 ))] 102 pub const DEFAULT_ALIGNMENT_BYTES: Option<usize> = Some(16); 103 #[cfg(not(any(target_pointer_width = "32", target_pointer_width = "64")))] 104 pub const DEFAULT_ALIGNMENT_BYTES: Option<usize> = None; 105 106 pub const fn new() -> Self { 107 Self { _unused: [] } 108 } 109 } 110 111 impl Default for QemuAllocator { 112 fn default() -> Self { 113 Self::new() 114 } 115 } 116 117 // Sanity check. 118 const _: [(); 8] = [(); ::core::mem::size_of::<*mut c_void>()]; 119 120 unsafe impl GlobalAlloc for QemuAllocator { 121 unsafe fn alloc(&self, layout: Layout) -> *mut u8 { 122 if matches!(Self::DEFAULT_ALIGNMENT_BYTES, Some(default) if default.checked_rem(layout.align()) == Some(0)) 123 { 124 // SAFETY: g_malloc0() is safe to call. 125 unsafe { g_malloc0(layout.size().try_into().unwrap()).cast::<u8>() } 126 } else { 127 #[cfg(HAVE_GLIB_WITH_ALIGNED_ALLOC)] 128 { 129 // SAFETY: g_aligned_alloc0() is safe to call. 130 unsafe { 131 g_aligned_alloc0( 132 layout.size().try_into().unwrap(), 133 1, 134 layout.align().try_into().unwrap(), 135 ) 136 .cast::<u8>() 137 } 138 } 139 #[cfg(not(HAVE_GLIB_WITH_ALIGNED_ALLOC))] 140 { 141 // SAFETY: qemu_memalign() is safe to call. 142 unsafe { qemu_memalign(layout.align(), layout.size()).cast::<u8>() } 143 } 144 } 145 } 146 147 unsafe fn dealloc(&self, ptr: *mut u8, layout: Layout) { 148 if matches!(Self::DEFAULT_ALIGNMENT_BYTES, Some(default) if default.checked_rem(layout.align()) == Some(0)) 149 { 150 // SAFETY: `ptr` must have been allocated by Self::alloc thus a valid 151 // glib-allocated pointer, so `g_free`ing is safe. 152 unsafe { g_free(ptr.cast::<_>()) } 153 } else { 154 #[cfg(HAVE_GLIB_WITH_ALIGNED_ALLOC)] 155 { 156 // SAFETY: `ptr` must have been allocated by Self::alloc thus a valid aligned 157 // glib-allocated pointer, so `g_aligned_free`ing is safe. 158 unsafe { g_aligned_free(ptr.cast::<_>()) } 159 } 160 #[cfg(not(HAVE_GLIB_WITH_ALIGNED_ALLOC))] 161 { 162 // SAFETY: `ptr` must have been allocated by Self::alloc thus a valid aligned 163 // glib-allocated pointer, so `qemu_vfree`ing is safe. 164 unsafe { qemu_vfree(ptr.cast::<_>()) } 165 } 166 } 167 } 168 } 169