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Fix a huge immediate allocation in loading

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This commit is contained in:
Zhang Junyang
2024-03-13 17:29:51 +08:00
committed by Tate, Hongliang Tian
parent 4eff679eac
commit 132d36bf20
1 changed files with 20 additions and 10 deletions
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30
kernel/aster-nix/src/process/program_loader/elf/load_elf.rs
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@ -27,7 +27,7 @@ use crate::{
vm::{
perms::VmPerms,
vmar::Vmar,
vmo::{Vmo, VmoOptions, VmoRightsOp},
vmo::{Vmo, VmoFlags, VmoOptions, VmoRightsOp},
},
};
@ -279,14 +279,25 @@ fn init_segment_vmo(program_header: &ProgramHeader64, elf_file: &Dentry) -> Resu
};
let segment_vmo = {
let vmo_offset = file_offset.align_down(PAGE_SIZE);
let map_start = virtual_addr.align_down(PAGE_SIZE);
let map_end = (virtual_addr + program_header.mem_size as usize).align_up(PAGE_SIZE);
let vmo_size = map_end - map_start;
let parent_range = {
let start = file_offset.align_down(PAGE_SIZE);
let end = (file_offset + program_header.file_size as usize).align_up(PAGE_SIZE);
start..end
};
let vmo_size = {
let vmap_start = virtual_addr.align_down(PAGE_SIZE);
let vmap_end = (virtual_addr + program_header.mem_size as usize).align_up(PAGE_SIZE);
vmap_end - vmap_start
};
debug_assert!(vmo_size >= (program_header.file_size as usize).align_up(PAGE_SIZE));
page_cache_vmo
.new_cow_child(vmo_offset..vmo_offset + vmo_size)?
.alloc()?
let segment_vmo = page_cache_vmo
.new_cow_child(parent_range)?
.flags(VmoFlags::RESIZABLE)
.alloc()?;
if vmo_size > segment_vmo.size() {
segment_vmo.resize(vmo_size)?;
};
segment_vmo
};
// Write zero as paddings. There are head padding and tail padding.
@ -294,7 +305,6 @@ fn init_segment_vmo(program_header: &ProgramHeader64, elf_file: &Dentry) -> Resu
// then the bytes in first page from start to virtual address should be padded zeros.
// Tail padding: If the segment's mem_size is larger than file size,
// then the bytes that are not backed up by file content should be zeros.(usually .data/.bss sections).
// FIXME: Head padding may be removed.
// Head padding.
let page_offset = file_offset % PAGE_SIZE;
@ -306,7 +316,7 @@ fn init_segment_vmo(program_header: &ProgramHeader64, elf_file: &Dentry) -> Resu
let segment_vmo_size = segment_vmo.size();
let tail_padding_offset = program_header.file_size as usize + page_offset;
if segment_vmo_size > tail_padding_offset {
let buffer = vec![0u8; segment_vmo_size - tail_padding_offset];
let buffer = vec![0u8; (segment_vmo_size - tail_padding_offset) % PAGE_SIZE];
segment_vmo.write_bytes(tail_padding_offset, &buffer)?;
}
Ok(segment_vmo.to_dyn())