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Switch to naked_asm

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This commit is contained in:
Jeremy Soller
2025-01-14 15:59:07 -07:00
parent 495c3708f3
commit 668a123b9a
13 changed files with 61 additions and 101 deletions
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src/arch/aarch64/interrupt/handler.rs
+10 -13
View File
@@ -381,7 +381,7 @@ macro_rules! exception_stack {
unsafe extern "C" fn inner($stack: &mut $crate::arch::aarch64::interrupt::InterruptStack) {
$code
}
core::arch::asm!(concat!(
core::arch::naked_asm!(concat!(
// Backup all userspace registers to stack
push_preserved!(),
push_scratch!(),
@@ -398,21 +398,18 @@ macro_rules! exception_stack {
pop_preserved!(),
"eret\n",
), sym inner, options(noreturn));
), sym inner);
}
};
}
#[naked]
pub unsafe extern "C" fn enter_usermode() -> ! {
core::arch::asm!(
concat!(
"blr x28\n",
// Restore all userspace registers
pop_special!(),
pop_scratch!(),
pop_preserved!(),
"eret\n",
),
options(noreturn)
);
core::arch::naked_asm!(concat!(
"blr x28\n",
// Restore all userspace registers
pop_special!(),
pop_scratch!(),
pop_preserved!(),
"eret\n",
));
}
src/arch/aarch64/mod.rs
+2 -3
View File
@@ -43,7 +43,7 @@ pub use arch_copy_to_user as arch_copy_from_user;
#[link_section = ".usercopy-fns"]
pub unsafe extern "C" fn arch_copy_to_user(dst: usize, src: usize, len: usize) -> u8 {
// x0, x1, x2
core::arch::asm!(
core::arch::naked_asm!(
"
mov x4, x0
mov x0, 0
@@ -61,8 +61,7 @@ pub unsafe extern "C" fn arch_copy_to_user(dst: usize, src: usize, len: usize) -
b 2b
3:
ret
",
options(noreturn)
"
);
}
src/arch/riscv64/interrupt/handler.rs
+11 -14
View File
@@ -302,18 +302,15 @@ macro_rules! pop_registers {
#[naked]
pub unsafe extern "C" fn enter_usermode() -> ! {
core::arch::asm!(
concat!(
"jalr s11\n",
"li t0, 1 << 8\n", // force U mode on sret
"csrc sstatus, t0\n",
"li t0, 0x6000\n", // set FS to dirty (enable FPU in U mode)
"csrs sstatus, t0\n",
"addi t0, sp, 32 * 8\n", // save S mode stack to percpu
"sd t0, 8(tp)\n",
pop_registers!(),
"sret\n",
),
options(noreturn)
)
core::arch::naked_asm!(concat!(
"jalr s11\n",
"li t0, 1 << 8\n", // force U mode on sret
"csrc sstatus, t0\n",
"li t0, 0x6000\n", // set FS to dirty (enable FPU in U mode)
"csrs sstatus, t0\n",
"addi t0, sp, 32 * 8\n", // save S mode stack to percpu
"sd t0, 8(tp)\n",
pop_registers!(),
"sret\n",
))
}
src/arch/riscv64/mod.rs
+3 -4
View File
@@ -14,14 +14,14 @@ pub mod stop;
pub mod time;
pub use ::rmm::RiscV64Sv48Arch as CurrentRmmArch;
use core::arch::asm;
use core::arch::naked_asm;
pub use arch_copy_to_user as arch_copy_from_user;
#[link_section = ".usercopy-fns"]
#[naked]
pub unsafe extern "C" fn arch_copy_to_user(dst: usize, src: usize, len: usize) -> u8 {
asm!(
naked_asm!(
"
addi sp, sp, -16
sd fp, 0(sp)
@@ -58,8 +58,7 @@ pub unsafe extern "C" fn arch_copy_to_user(dst: usize, src: usize, len: usize) -
bne a2, x0, 4b
5: mv a0, x0
ret
",
options(noreturn)
"
)
}
src/arch/x86/interrupt/handler.rs
+16 -30
View File
@@ -276,7 +276,7 @@ macro_rules! interrupt_stack {
$code
}
}
core::arch::asm!(concat!(
core::arch::naked_asm!(concat!(
// Backup all userspace registers to stack
"push eax\n",
push_scratch!(),
@@ -306,11 +306,7 @@ macro_rules! interrupt_stack {
"iretd\n",
),
inner = sym inner,
options(noreturn),
);
}
};
@@ -327,7 +323,7 @@ macro_rules! interrupt {
$code
}
core::arch::asm!(concat!(
core::arch::naked_asm!(concat!(
// Backup all userspace registers to stack
"push eax\n",
push_scratch!(),
@@ -352,10 +348,7 @@ macro_rules! interrupt {
"iretd\n",
),
inner = sym inner,
options(noreturn),
);
}
};
@@ -373,7 +366,7 @@ macro_rules! interrupt_error {
}
}
core::arch::asm!(concat!(
core::arch::naked_asm!(concat!(
// Move eax into code's place, put code in last instead (to be
// compatible with InterruptStack)
"xchg [esp], eax\n",
@@ -414,24 +407,20 @@ macro_rules! interrupt_error {
// The error code has already been popped, so use the regular macro.
"iretd\n",
),
inner = sym inner,
options(noreturn));
inner = sym inner);
}
};
}
#[naked]
unsafe extern "C" fn usercopy_trampoline() {
core::arch::asm!(
core::arch::naked_asm!(
"
pop esi
pop edi
mov eax, 1
ret
",
options(noreturn)
"
);
}
@@ -454,18 +443,15 @@ impl ArchIntCtx for InterruptStack {
#[naked]
pub unsafe extern "C" fn enter_usermode() {
core::arch::asm!(
concat!(
// TODO: Unmap PTI
// $crate::arch::x86::pti::unmap();
core::arch::naked_asm!(concat!(
// TODO: Unmap PTI
// $crate::arch::x86::pti::unmap();
// Exit kernel TLS segment
exit_gs!(),
// Restore all userspace registers
pop_preserved!(),
pop_scratch!(),
"iretd\n",
),
options(noreturn)
)
// Exit kernel TLS segment
exit_gs!(),
// Restore all userspace registers
pop_preserved!(),
pop_scratch!(),
"iretd\n",
))
}
src/arch/x86/mod.rs
+2 -3
View File
@@ -32,7 +32,7 @@ pub mod flags {
#[naked]
#[link_section = ".usercopy-fns"]
pub unsafe extern "C" fn arch_copy_to_user(dst: usize, src: usize, len: usize) -> u8 {
core::arch::asm!(
core::arch::naked_asm!(
"
push edi
push esi
@@ -47,8 +47,7 @@ pub unsafe extern "C" fn arch_copy_to_user(dst: usize, src: usize, len: usize) -
xor eax, eax
ret
",
options(noreturn)
"
);
}
pub use arch_copy_to_user as arch_copy_from_user;
src/arch/x86_64/interrupt/handler.rs
+4 -10
View File
@@ -369,7 +369,7 @@ macro_rules! interrupt_stack {
$code
}
}
core::arch::asm!(concat!(
core::arch::naked_asm!(concat!(
// Clear direction flag, required by ABI when running any Rust code in the kernel.
"cld;",
@@ -407,9 +407,6 @@ macro_rules! interrupt_stack {
IA32_GS_BASE = const(x86::msr::IA32_GS_BASE),
PCR_GDT_OFFSET = const(core::mem::offset_of!(crate::gdt::ProcessorControlRegion, gdt)),
options(noreturn),
);
}
};
@@ -426,7 +423,7 @@ macro_rules! interrupt {
$code
}
core::arch::asm!(concat!(
core::arch::naked_asm!(concat!(
// Clear direction flag, required by ABI when running any Rust code in the kernel.
"cld;",
@@ -452,8 +449,6 @@ macro_rules! interrupt {
),
inner = sym inner,
options(noreturn),
);
}
};
@@ -471,7 +466,7 @@ macro_rules! interrupt_error {
}
}
core::arch::asm!(concat!(
core::arch::naked_asm!(concat!(
// Clear direction flag, required by ABI when running any Rust code in the kernel.
"cld;",
@@ -510,8 +505,7 @@ macro_rules! interrupt_error {
inner = sym inner,
rax_offset = const(::core::mem::size_of::<$crate::interrupt::handler::PreservedRegisters>() + ::core::mem::size_of::<$crate::interrupt::handler::ScratchRegisters>() - 8),
options(noreturn));
);
}
};
}
src/arch/x86_64/interrupt/syscall.rs
+1 -3
View File
@@ -85,7 +85,7 @@ pub unsafe extern "C" fn __inner_syscall_instruction(stack: *mut InterruptStack)
#[naked]
#[allow(named_asm_labels)]
pub unsafe extern "C" fn syscall_instruction() {
core::arch::asm!(concat!(
core::arch::naked_asm!(concat!(
// Yes, this is magic. No, you don't need to understand
"swapgs;", // Swap KGSBASE with GSBASE, allowing fast TSS access.
"mov gs:[{sp}], rsp;", // Save userspace stack pointer
@@ -189,8 +189,6 @@ pub unsafe extern "C" fn syscall_instruction() {
ksp = const(offset_of!(gdt::ProcessorControlRegion, tss) + offset_of!(TaskStateSegment, rsp)),
ss_sel = const(SegmentSelector::new(gdt::GDT_USER_DATA as u16, x86::Ring::Ring3).bits()),
cs_sel = const(SegmentSelector::new(gdt::GDT_USER_CODE as u16, x86::Ring::Ring3).bits()),
options(noreturn),
);
}
extern "C" {
src/arch/x86_64/mod.rs
+5 -8
View File
@@ -44,10 +44,9 @@ pub mod flags {
pub unsafe extern "C" fn arch_copy_to_user(dst: usize, src: usize, len: usize) -> u8 {
// TODO: spectre_v1
core::arch::asm!(
alternative!(
feature: "smap",
then: ["
core::arch::naked_asm!(alternative!(
feature: "smap",
then: ["
xor eax, eax
mov rcx, rdx
stac
@@ -55,15 +54,13 @@ pub unsafe extern "C" fn arch_copy_to_user(dst: usize, src: usize, len: usize) -
clac
ret
"],
default: ["
default: ["
xor eax, eax
mov rcx, rdx
rep movsb
ret
"]
),
options(noreturn)
);
));
}
pub use arch_copy_to_user as arch_copy_from_user;
src/context/arch/aarch64.rs
+4 -7
View File
@@ -4,7 +4,7 @@ use crate::{
percpu::PercpuBlock,
syscall::FloatRegisters,
};
use core::{arch::asm, mem, mem::offset_of, ptr, sync::atomic::AtomicBool};
use core::{mem, mem::offset_of, ptr, sync::atomic::AtomicBool};
use rmm::TableKind;
use spin::Once;
use syscall::{EnvRegisters, Error, Result, ENOMEM};
@@ -206,7 +206,7 @@ pub unsafe fn empty_cr3() -> rmm::PhysicalAddress {
#[target_feature(enable = "neon")]
#[naked]
unsafe extern "C" fn fp_save(float_regs: &mut FloatRegisters) {
asm!(
core::arch::naked_asm!(
"stp q0, q1, [x0, {0} + 16 * 0]",
"stp q2, q3, [x0, {0} + 16 * 2]",
"stp q4, q5, [x0, {0} + 16 * 4]",
@@ -232,14 +232,13 @@ unsafe extern "C" fn fp_save(float_regs: &mut FloatRegisters) {
const mem::offset_of!(FloatRegisters, fp_simd_regs),
const mem::offset_of!(FloatRegisters, fpcr),
const mem::offset_of!(FloatRegisters, fpsr),
options(noreturn),
);
}
#[target_feature(enable = "neon")]
#[naked]
unsafe extern "C" fn fp_load(float_regs: &mut FloatRegisters) {
asm!(
core::arch::naked_asm!(
"ldp q0, q1, [x0, {0} + 16 * 0]",
"ldp q2, q3, [x0, {0} + 16 * 2]",
"ldp q4, q5, [x0, {0} + 16 * 4]",
@@ -265,7 +264,6 @@ unsafe extern "C" fn fp_load(float_regs: &mut FloatRegisters) {
const mem::offset_of!(FloatRegisters, fp_simd_regs),
const mem::offset_of!(FloatRegisters, fpcr),
const mem::offset_of!(FloatRegisters, fpsr),
options(noreturn),
);
}
@@ -287,7 +285,7 @@ pub unsafe fn switch_to(prev: &mut super::Context, next: &mut super::Context) {
#[naked]
unsafe extern "C" fn switch_to_inner(_prev: &mut Context, _next: &mut Context) {
core::arch::asm!(
core::arch::naked_asm!(
"
str x19, [x0, #{off_x19}]
ldr x19, [x1, #{off_x19}]
@@ -383,7 +381,6 @@ unsafe extern "C" fn switch_to_inner(_prev: &mut Context, _next: &mut Context) {
off_sp = const(offset_of!(Context, sp)),
switch_hook = sym crate::context::switch_finish_hook,
options(noreturn),
);
}
src/context/arch/riscv64.rs
+1 -2
View File
@@ -149,7 +149,7 @@ pub unsafe fn switch_to(prev: &mut super::Context, next: &mut super::Context) {
#[naked]
unsafe extern "C" fn switch_to_inner(prev: &mut Context, next: &mut Context) {
core::arch::asm!(r#"
core::arch::naked_asm!(r#"
sd s1, {off_s1}(a0)
ld s1, {off_s1}(a1)
@@ -219,7 +219,6 @@ unsafe extern "C" fn switch_to_inner(prev: &mut Context, next: &mut Context) {
off_sstatus = const(offset_of!(Context, sstatus)),
switch_hook = sym crate::context::switch_finish_hook,
options(noreturn),
);
}
src/context/arch/x86.rs
+1 -2
View File
@@ -252,7 +252,7 @@ pub unsafe fn switch_to(prev: &mut super::Context, next: &mut super::Context) {
unsafe extern "cdecl" fn switch_to_inner() {
use Context as Cx;
core::arch::asm!(
core::arch::naked_asm!(
// As a quick reminder for those who are unfamiliar with the System V ABI (extern "C"):
//
// - the current parameters are passed in the registers `edi`, `esi`,
@@ -306,7 +306,6 @@ unsafe extern "cdecl" fn switch_to_inner() {
off_esp = const(offset_of!(Cx, esp)),
switch_hook = sym crate::context::switch_finish_hook,
options(noreturn),
);
}
src/context/arch/x86_64.rs
+1 -2
View File
@@ -329,7 +329,7 @@ pub unsafe fn switch_to(prev: &mut super::Context, next: &mut super::Context) {
unsafe extern "sysv64" fn switch_to_inner(_prev: &mut Context, _next: &mut Context) {
use Context as Cx;
core::arch::asm!(
core::arch::naked_asm!(
// As a quick reminder for those who are unfamiliar with the System V ABI (extern "C"):
//
// - the current parameters are passed in the registers `rdi`, `rsi`,
@@ -389,7 +389,6 @@ unsafe extern "sysv64" fn switch_to_inner(_prev: &mut Context, _next: &mut Conte
off_rsp = const(offset_of!(Cx, rsp)),
switch_hook = sym crate::context::switch_finish_hook,
options(noreturn),
);
}