From 9e8cd0bf0736251614a23275048762877c3ad471 Mon Sep 17 00:00:00 2001
From: Peter Limkilde Svendsen <peter.limkilde@gmail.com>
Date: Wed, 24 Mar 2021 00:02:39 +0100
Subject: [PATCH] Centralize page size info in platform abstraction
---
src/header/unistd/sysconf.rs | 8 ++++++--
src/ld_so/mod.rs | 13 ++++++++-----
src/ld_so/tcb.rs | 24 +++++++++++++++---------
src/platform/linux/mod.rs | 4 ++++
src/platform/pal/mod.rs | 5 +++++
src/platform/redox/mod.rs | 4 ++++
6 files changed, 42 insertions(+), 16 deletions(-)
diff --git a/src/header/unistd/sysconf.rs b/src/header/unistd/sysconf.rs
index 103ab07d..423d4d49 100644
--- a/src/header/unistd/sysconf.rs
+++ b/src/header/unistd/sysconf.rs
@@ -1,6 +1,8 @@
+use core::convert::TryInto;
+
use crate::{
header::errno,
- platform::{self, types::*},
+ platform::{self, types::*, Pal, Sys},
};
// POSIX.1 {
@@ -39,7 +41,9 @@ pub extern "C" fn sysconf(name: c_int) -> c_long {
_SC_STREAM_MAX => 16,
_SC_TZNAME_MAX => -1,
_SC_VERSION => 200809,
- _SC_PAGESIZE => 4096,
+ _SC_PAGESIZE => Sys::getpagesize()
+ .try_into()
+ .expect("page size not representable as type `long`"),
_SC_RE_DUP_MAX => 32767,
_SC_GETPW_R_SIZE_MAX => -1,
_SC_LOGIN_NAME_MAX => 256,
diff --git a/src/ld_so/mod.rs b/src/ld_so/mod.rs
index e4e62282..9ee7ea53 100644
--- a/src/ld_so/mod.rs
+++ b/src/ld_so/mod.rs
@@ -2,9 +2,11 @@ use core::{mem, ptr};
use goblin::elf::program_header::{self, program_header32, program_header64, ProgramHeader};
use self::tcb::{Master, Tcb};
-use crate::{header::sys_auxv::AT_NULL, start::Stack};
-
-pub const PAGE_SIZE: usize = 4096;
+use crate::{
+ header::sys_auxv::AT_NULL,
+ platform::{Pal, Sys},
+ start::Stack,
+};
#[cfg(target_os = "redox")]
pub const PATH_SEP: char = ';';
@@ -64,9 +66,10 @@ pub fn static_init(sp: &'static Stack) {
_ => panic!("unknown AT_PHENT size {}", phent),
};
- let voff = ph.p_vaddr as usize % PAGE_SIZE;
+ let page_size = Sys::getpagesize();
+ let voff = ph.p_vaddr as usize % page_size;
let vaddr = ph.p_vaddr as usize - voff;
- let vsize = ((ph.p_memsz as usize + voff + PAGE_SIZE - 1) / PAGE_SIZE) * PAGE_SIZE;
+ let vsize = ((ph.p_memsz as usize + voff + page_size - 1) / page_size) * page_size;
match ph.p_type {
program_header::PT_TLS => {
diff --git a/src/ld_so/tcb.rs b/src/ld_so/tcb.rs
index 0493f303..a1058c94 100644
--- a/src/ld_so/tcb.rs
+++ b/src/ld_so/tcb.rs
@@ -2,9 +2,12 @@ use alloc::vec::Vec;
use core::{mem, ptr, slice};
use goblin::error::{Error, Result};
-use crate::{header::sys_mman, ld_so::linker::Linker, sync::mutex::Mutex};
-
-use super::PAGE_SIZE;
+use crate::{
+ header::sys_mman,
+ ld_so::linker::Linker,
+ platform::{Pal, Sys},
+ sync::mutex::Mutex,
+};
#[repr(C)]
#[derive(Debug)]
@@ -29,11 +32,11 @@ impl Master {
pub struct Tcb {
/// Pointer to the end of static TLS. Must be the first member
pub tls_end: *mut u8,
- /// Size of the memory allocated for the static TLS in bytes (multiple of PAGE_SIZE)
+ /// Size of the memory allocated for the static TLS in bytes (multiple of page size)
pub tls_len: usize,
/// Pointer to this structure
pub tcb_ptr: *mut Tcb,
- /// Size of the memory allocated for this structure in bytes (should be PAGE_SIZE)
+ /// Size of the memory allocated for this structure in bytes (should be same as page size)
pub tcb_len: usize,
/// Pointer to a list of initial TLS data
pub masters_ptr: *mut Master,
@@ -50,7 +53,8 @@ pub struct Tcb {
impl Tcb {
/// Create a new TCB
pub unsafe fn new(size: usize) -> Result<&'static mut Self> {
- let (tls, tcb_page) = Self::os_new(round_up(size, PAGE_SIZE))?;
+ let page_size = Sys::getpagesize();
+ let (tls, tcb_page) = Self::os_new(round_up(size, page_size))?;
let tcb_ptr = tcb_page.as_mut_ptr() as *mut Self;
trace!("New TCB: {:p}", tcb_ptr);
@@ -185,7 +189,8 @@ impl Tcb {
/// OS specific code to create a new TLS and TCB - Linux
#[cfg(target_os = "linux")]
unsafe fn os_new(size: usize) -> Result<(&'static mut [u8], &'static mut [u8])> {
- let tls_tcb = Self::map(size + PAGE_SIZE)?;
+ let page_size = Sys::getpagesize();
+ let tls_tcb = Self::map(size + page_size)?;
Ok(tls_tcb.split_at_mut(size))
}
@@ -195,12 +200,13 @@ impl Tcb {
use crate::header::unistd;
//TODO: better method of finding fs offset
let pid = unistd::getpid();
- let tcb_addr = 0xB000_0000 + pid as usize * PAGE_SIZE;
+ let page_size = Sys::getpagesize();
+ let tcb_addr = 0xB000_0000 + pid as usize * page_size;
let tls = Self::map(size)?;
Ok((
tls,
//TODO: Consider allocating TCB as part of TLS
- slice::from_raw_parts_mut(tcb_addr as *mut u8, PAGE_SIZE),
+ slice::from_raw_parts_mut(tcb_addr as *mut u8, page_size),
))
}
diff --git a/src/platform/linux/mod.rs b/src/platform/linux/mod.rs
index 7e996a0f..2190237d 100644
--- a/src/platform/linux/mod.rs
+++ b/src/platform/linux/mod.rs
@@ -242,6 +242,10 @@ impl Pal for Sys {
e(unsafe { syscall!(GETGID) }) as gid_t
}
+ fn getpagesize() -> usize {
+ 4096
+ }
+
fn getpgid(pid: pid_t) -> pid_t {
e(unsafe { syscall!(GETPGID, pid) }) as pid_t
}
diff --git a/src/platform/pal/mod.rs b/src/platform/pal/mod.rs
index f7984dac..dd953b85 100644
--- a/src/platform/pal/mod.rs
+++ b/src/platform/pal/mod.rs
@@ -85,6 +85,11 @@ pub trait Pal {
fn getgid() -> gid_t;
+ /* Note that this is distinct from the legacy POSIX function
+ * getpagesize(), which returns a c_int. On some Linux platforms,
+ * page size may be determined through a syscall ("getpagesize"). */
+ fn getpagesize() -> usize;
+
fn getpgid(pid: pid_t) -> pid_t;
fn getpid() -> pid_t;
diff --git a/src/platform/redox/mod.rs b/src/platform/redox/mod.rs
index 580fd47f..c651ec34 100644
--- a/src/platform/redox/mod.rs
+++ b/src/platform/redox/mod.rs
@@ -604,6 +604,10 @@ impl Pal for Sys {
e(syscall::getgid()) as gid_t
}
+ fn getpagesize() -> usize {
+ 4096
+ }
+
fn getpgid(pid: pid_t) -> pid_t {
e(syscall::getpgid(pid as usize)) as pid_t
}
--
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