bjorn3
cf3d7a74f6
git-subtree-dir: bootstrap git-subtree-mainline:16e0cb79b9git-subtree-split:6898d8b14c
48 lines
1.1 KiB
Rust
48 lines
1.1 KiB
Rust
use core::mem;
|
|
use syscall::{data::Map, flag::MapFlags, number::SYS_FMAP};
|
|
|
|
const STACK_SIZE: usize = 64 * 1024; // 64 KiB
|
|
pub const USERMODE_END: usize = 1 << 47; // Assuming Sv48; it should work with Sv57 also
|
|
pub const STACK_START: usize = USERMODE_END - STACK_SIZE;
|
|
|
|
static MAP: Map = Map {
|
|
offset: 0,
|
|
size: STACK_SIZE,
|
|
flags: MapFlags::PROT_READ
|
|
.union(MapFlags::PROT_WRITE)
|
|
.union(MapFlags::MAP_PRIVATE)
|
|
.union(MapFlags::MAP_FIXED_NOREPLACE),
|
|
address: STACK_START, // highest possible user address
|
|
};
|
|
|
|
core::arch::global_asm!(
|
|
"
|
|
.globl _start
|
|
_start:
|
|
# Setup a stack.
|
|
li a7, {number}
|
|
li a0, {fd}
|
|
la a1, {map} # pointer to Map struct
|
|
li a2, {map_size} # size of Map struct
|
|
ecall
|
|
|
|
# Test for success (nonzero value).
|
|
bne a0, x0, 2f
|
|
# (failure)
|
|
unimp
|
|
2:
|
|
li sp, {stack_size}
|
|
add sp, sp, a0
|
|
mv fp, x0
|
|
|
|
jal start
|
|
# `start` must never return.
|
|
unimp
|
|
",
|
|
fd = const usize::MAX, // dummy fd indicates anonymous map
|
|
map = sym MAP,
|
|
map_size = const mem::size_of::<Map>(),
|
|
number = const SYS_FMAP,
|
|
stack_size = const STACK_SIZE,
|
|
);
|