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Merge branch 'higher_half_percpu' into 'master'

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Put the KPCRs in high memory, in their own PML4.

See merge request redox-os/kernel!173
This commit is contained in:
Jeremy Soller
2021-05-06 19:25:16 +00:00
parent 2e38fab913 36b3a4a49e
commit 2c474f98f9
3 changed files with 14 additions and 29 deletions
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2
src/arch/aarch64/consts.rs
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@@ -38,8 +38,8 @@
pub const KERNEL_TMP_MISC_OFFSET: usize = KERNEL_ENV_OFFSET - PML4_SIZE;
/// Offset to kernel percpu variables
//TODO: Use 64-bit fs offset to enable this pub const KERNEL_PERCPU_OFFSET: usize = KERNEL_HEAP_OFFSET - PML4_SIZE;
pub const KERNEL_PERCPU_OFFSET: usize = KERNEL_TMP_MISC_OFFSET - PML4_SIZE;
pub const KERNEL_PERCPU_PML4: usize = (KERNEL_PERCPU_OFFSET & PML4_MASK) / PML4_SIZE;
/// Size of kernel percpu variables
pub const KERNEL_PERCPU_SIZE: usize = 64 * 1024; // 64 KB

7
src/arch/x86_64/consts.rs
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@@ -25,8 +25,8 @@
pub const KERNEL_TMP_MISC_OFFSET: usize = KERNEL_HEAP_OFFSET - PML4_SIZE;
/// Offset to kernel percpu variables
//TODO: Use 64-bit fs offset to enable this pub const KERNEL_PERCPU_OFFSET: usize = KERNEL_HEAP_OFFSET - PML4_SIZE;
pub const KERNEL_PERCPU_OFFSET: usize = 0xC000_0000;
pub const KERNEL_PERCPU_OFFSET: usize = KERNEL_TMP_MISC_OFFSET - PML4_SIZE;
pub const KERNEL_PERCPU_PML4: usize = (KERNEL_PERCPU_OFFSET & PML4_MASK)/PML4_SIZE;
/// Size of kernel percpu variables
pub const KERNEL_PERCPU_SIZE: usize = 64 * 1024; // 64 KB
@@ -41,6 +41,9 @@
/// Offset to user TCB
/// Each process has 4096 bytes, at an offset of 4096 * PID
// TODO: Get a real 64-bit offset, and allow loading ELF sections higher up than the current
// limit, iff the processor supports fsgsbase (in which case it is cheap to use 64-bit FS
// offsets).
pub const USER_TCB_OFFSET: usize = 0xB000_0000;
/// Offset to user arguments

34
src/syscall/process.rs
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@@ -405,6 +405,14 @@ pub fn clone(flags: CloneFlags, stack_base: usize) -> Result<ContextId> {
mapper.p4_mut()[crate::PHYS_PML4].set(frame, flags);
});
}
// Copy kernel percpu (similar to TLS) mapping.
{
let frame = active_ktable.p4()[crate::KERNEL_PERCPU_PML4].pointed_frame().expect("kernel TLS not mapped");
let flags = active_ktable.p4()[crate::KERNEL_PERCPU_PML4].flags();
active_ktable.with(&mut new_ktable, &mut temporary_kpage, |mapper| {
mapper.p4_mut()[crate::KERNEL_PERCPU_PML4].set(frame, flags);
});
}
if let Some(fx) = kfx_opt.take() {
context.arch.set_fx(fx.as_ptr() as usize);
@@ -445,32 +453,6 @@ pub fn clone(flags: CloneFlags, stack_base: usize) -> Result<ContextId> {
}
context.grants = grants;
} else {
// Copy percpu mapping
for cpu_id in 0..crate::cpu_count() {
extern {
// The starting byte of the thread data segment
static mut __tdata_start: u8;
// The ending byte of the thread BSS segment
static mut __tbss_end: u8;
}
let size = unsafe { & __tbss_end as *const _ as usize - & __tdata_start as *const _ as usize };
let start = crate::KERNEL_PERCPU_OFFSET + crate::KERNEL_PERCPU_SIZE * cpu_id;
let end = start + size;
let start_page = Page::containing_address(VirtualAddress::new(start));
let end_page = Page::containing_address(VirtualAddress::new(end - 1));
for page in Page::range_inclusive(start_page, end_page) {
let frame = active_ktable.translate_page(page).expect("kernel percpu not mapped");
active_ktable.with(&mut new_ktable, &mut temporary_kpage, |mapper| {
let result = mapper.map_to(page, frame, PageFlags::new().write(true));
// Ignore result due to operating on inactive table
unsafe { result.ignore(); }
});
}
}
// Move copy of image
for memory_shared in image.iter_mut() {
memory_shared.with(|memory| {