Refactor: loadvdso (#7)

* fix: fix pvclock support

* refactor: run cargo fmt

* refactor: run cargo clippy

* refactor: update

* refactor: run cargo fmt

Author: muou000

Cargo.toml

@@ -4,10 +4,12 @@ version = "0.1.1"
 edition = "2024"
 
 [dependencies]
-axerrno = { git = "https://github.com/Starry-OS/axerrno.git", rev = "f1e2bca" }
+axerrno = "0.2"
 axplat = "0.2"
 log = "0.4"
 xmas-elf = "0.9"
 rand_pcg = { version = "0.3", default-features = false }
 rand_core = { version = "0.6", default-features = false }
+kernel-elf-parser = { git = "https://github.com/Starry-OS/kernel_elf_parser.git", rev = "fdcce74" }
+memory_addr = "0.4"
 cfg-if = "1.0"

src/vdso.rs

@@ -1,13 +1,14 @@
 //! vDSO data management.
 extern crate alloc;
 extern crate log;
-use alloc::alloc::alloc_zeroed;
+use alloc::{alloc::alloc_zeroed, vec::Vec};
 use core::alloc::Layout;
 
 use axerrno::{AxError, AxResult};
 use axplat::{mem::virt_to_phys, time::monotonic_time_nanos};
-
-const PAGE_SIZE_4K: usize = 4096;
+use kernel_elf_parser::{AuxEntry, AuxType};
+use log::{info, warn};
+use memory_addr::{MemoryAddr, PAGE_SIZE_4K};
 
 /// Global vDSO data instance
 #[unsafe(link_section = ".data")]
@@ -18,11 +19,15 @@ pub fn init_vdso_data() {
     unsafe {
         let data_ptr = core::ptr::addr_of_mut!(VDSO_DATA);
         (*data_ptr).time_update();
-        log::info!("vDSO data initialized at {:#x}", data_ptr as usize);
+        info!("vDSO data initialized at {:#x}", data_ptr as usize);
         #[cfg(target_arch = "aarch64")]
         {
             crate::vdso_data::enable_cntvct_access();
-            log::info!("vDSO CNTVCT access enabled");
+            info!("vDSO CNTVCT access enabled");
+        }
+        #[cfg(target_arch = "x86_64")]
+        {
+            (*data_ptr).enable_pvclock();
         }
         #[cfg(target_arch = "x86_64")]
         {
@@ -122,3 +127,133 @@ pub fn calculate_vdso_aslr_addr(
 
     (base_addr, vdso_addr)
 }
+
+/// Load vDSO into the given user address space and update auxv accordingly.
+pub fn load_vdso_data<F1, F2, F3>(auxv: &mut Vec<AuxEntry>, f1: F1, f2: F2, f3: F3) -> AxResult<()>
+where
+    F1: FnOnce(usize, axplat::mem::PhysAddr, usize) -> AxResult<()>,
+    F2: FnOnce(usize, usize) -> AxResult<()>,
+    F3: FnMut(
+        usize,
+        axplat::mem::PhysAddr,
+        usize,
+        &xmas_elf::program::ProgramHeader64,
+    ) -> AxResult<()>,
+{
+    unsafe extern "C" {
+        static vdso_start: u8;
+        static vdso_end: u8;
+    }
+    let (vdso_kstart, vdso_kend) = unsafe {
+        (
+            &vdso_start as *const u8 as usize,
+            &vdso_end as *const u8 as usize,
+        )
+    };
+    info!("vdso_kstart: {vdso_kstart:#x}, vdso_kend: {vdso_kend:#x}");
+
+    if vdso_kend <= vdso_kstart {
+        warn!(
+            "vDSO binary is missing or invalid: vdso_kstart={vdso_kstart:#x}, \
+             vdso_kend={vdso_kend:#x}. vDSO will not be loaded and AT_SYSINFO_EHDR will not be \
+             set."
+        );
+        return Err(AxError::InvalidExecutable);
+    }
+
+    let (vdso_paddr_page, vdso_bytes, vdso_size, vdso_page_offset, alloc_info) =
+        prepare_vdso_pages(vdso_kstart, vdso_kend).map_err(|_| AxError::InvalidExecutable)?;
+
+    let mut alloc_guard = crate::guard::VdsoAllocGuard::new(alloc_info);
+
+    let (_base_addr, vdso_user_addr) =
+        calculate_vdso_aslr_addr(vdso_kstart, vdso_kend, vdso_page_offset);
+
+    match kernel_elf_parser::ELFHeadersBuilder::new(vdso_bytes).and_then(|b| {
+        let range = b.ph_range();
+        b.build(&vdso_bytes[range.start as usize..range.end as usize])
+    }) {
+        Ok(headers) => {
+            map_vdso_segments(
+                headers,
+                vdso_user_addr,
+                vdso_paddr_page,
+                vdso_page_offset,
+                f3,
+            )?;
+            alloc_guard.disarm();
+        }
+        Err(_) => {
+            info!("vDSO ELF parsing failed, using fallback mapping");
+            let map_user_start = if vdso_page_offset == 0 {
+                vdso_user_addr
+            } else {
+                vdso_user_addr - vdso_page_offset
+            };
+            f1(map_user_start, vdso_paddr_page, vdso_size)?;
+            alloc_guard.disarm();
+        }
+    }
+
+    map_vvar_and_push_aux(auxv, vdso_user_addr, f2)?;
+
+    Ok(())
+}
+
+fn map_vvar_and_push_aux<F>(auxv: &mut Vec<AuxEntry>, vdso_user_addr: usize, f: F) -> AxResult<()>
+where
+    F: FnOnce(usize, usize) -> AxResult<()>,
+{
+    use crate::config::VVAR_PAGES;
+    let vvar_user_addr = vdso_user_addr - VVAR_PAGES * PAGE_SIZE_4K;
+    let vvar_paddr = vdso_data_paddr();
+
+    f(vvar_user_addr, vvar_paddr)?;
+
+    info!(
+        "Mapped vvar pages at user {:#x}..{:#x} -> paddr {:#x}",
+        vvar_user_addr,
+        vvar_user_addr + VVAR_PAGES * PAGE_SIZE_4K,
+        vvar_paddr,
+    );
+
+    let aux_entry = AuxEntry::new(AuxType::SYSINFO_EHDR, vdso_user_addr);
+    auxv.push(aux_entry);
+
+    Ok(())
+}
+
+fn map_vdso_segments<F>(
+    headers: kernel_elf_parser::ELFHeaders,
+    vdso_user_addr: usize,
+    vdso_paddr_page: axplat::mem::PhysAddr,
+    vdso_page_offset: usize,
+    mut f: F,
+) -> AxResult<()>
+where
+    F: FnMut(
+        usize,
+        axplat::mem::PhysAddr,
+        usize,
+        &xmas_elf::program::ProgramHeader64,
+    ) -> AxResult<()>,
+{
+    info!("vDSO ELF parsed successfully, mapping segments");
+    for ph in headers
+        .ph
+        .iter()
+        .filter(|ph| ph.get_type() == Ok(xmas_elf::program::Type::Load))
+    {
+        let vaddr = ph.virtual_addr as usize;
+        let seg_pad = vaddr.align_offset_4k() + vdso_page_offset;
+        let seg_align_size =
+            (ph.mem_size as usize + seg_pad + PAGE_SIZE_4K - 1) & !(PAGE_SIZE_4K - 1);
+
+        let map_base_user = vdso_user_addr & !(PAGE_SIZE_4K - 1);
+        let seg_user_start = map_base_user + vaddr.align_down_4k();
+        let seg_paddr = vdso_paddr_page + vaddr.align_down_4k();
+
+        f(seg_user_start, seg_paddr, seg_align_size, ph)?;
+    }
+    Ok(())
+}

src/vdso_time_data.rs

@@ -39,6 +39,12 @@ pub struct VdsoClock {
     pub _unused: u32,
 }
 
+impl Default for VdsoClock {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
 impl VdsoClock {
     /// Create a new VdsoClock with default values.
     pub const fn new() -> Self {

src/x86_64/vdso_data.rs

@@ -106,5 +106,5 @@ fn register_pvclock(cpu_id: usize) {
     let offset = cpu_id * core::mem::size_of::<crate::x86_64::pvclock_data::PvClockTimeInfo>();
     let paddr = base + offset as u64;
     crate::x86_64::pvclock_data::register_kvm_clock(paddr);
-    log::info!("PVCLOCK registered for cpu {} at {:#x}", cpu_id, paddr);
+    log::info!("PVCLOCK registered for cpu {cpu_id} at {paddr:#x}");
 }