pvmfw: Add system register read/write macros
Adds read_sysreg and write_sysreg macros to read/write from system
registers.
Test: atest MicrodroidTestApp
Change-Id: I2a501fcb2871da26e8c3a5ec778d7ad244301a24
diff --git a/pvmfw/src/exceptions.rs b/pvmfw/src/exceptions.rs
index 03fc220..42f4c3b 100644
--- a/pvmfw/src/exceptions.rs
+++ b/pvmfw/src/exceptions.rs
@@ -14,22 +14,21 @@
//! Exception handlers.
-use crate::helpers::page_4kb_of;
-use core::arch::asm;
+use crate::{helpers::page_4kb_of, read_sysreg};
use vmbase::console;
use vmbase::{console::emergency_write_str, eprintln, power::reboot};
-const ESR_32BIT_EXT_DABT: u64 = 0x96000010;
+const ESR_32BIT_EXT_DABT: usize = 0x96000010;
const UART_PAGE: usize = page_4kb_of(console::BASE_ADDRESS);
#[no_mangle]
extern "C" fn sync_exception_current(_elr: u64, _spsr: u64) {
- let esr = read_esr();
- let far = read_far();
+ let esr = read_sysreg!("esr_el1");
+ let far = read_sysreg!("far_el1");
// Don't print to the UART if we're handling the exception it could raise.
- if esr != ESR_32BIT_EXT_DABT || page_4kb_of(far as usize) != UART_PAGE {
+ if esr != ESR_32BIT_EXT_DABT || page_4kb_of(far) != UART_PAGE {
emergency_write_str("sync_exception_current\n");
- print_esr(esr);
+ eprintln!("esr={esr:#08x}");
}
reboot();
}
@@ -48,17 +47,17 @@
#[no_mangle]
extern "C" fn serr_current(_elr: u64, _spsr: u64) {
- let esr = read_esr();
+ let esr = read_sysreg!("esr_el1");
emergency_write_str("serr_current\n");
- print_esr(esr);
+ eprintln!("esr={esr:#08x}");
reboot();
}
#[no_mangle]
extern "C" fn sync_lower(_elr: u64, _spsr: u64) {
- let esr = read_esr();
+ let esr = read_sysreg!("esr_el1");
emergency_write_str("sync_lower\n");
- print_esr(esr);
+ eprintln!("esr={esr:#08x}");
reboot();
}
@@ -76,31 +75,8 @@
#[no_mangle]
extern "C" fn serr_lower(_elr: u64, _spsr: u64) {
- let esr = read_esr();
+ let esr = read_sysreg!("esr_el1");
emergency_write_str("serr_lower\n");
- print_esr(esr);
+ eprintln!("esr={esr:#08x}");
reboot();
}
-
-#[inline]
-fn read_esr() -> u64 {
- let mut esr: u64;
- unsafe {
- asm!("mrs {esr}, esr_el1", esr = out(reg) esr);
- }
- esr
-}
-
-#[inline]
-fn print_esr(esr: u64) {
- eprintln!("esr={:#08x}", esr);
-}
-
-#[inline]
-fn read_far() -> u64 {
- let mut far: u64;
- unsafe {
- asm!("mrs {far}, far_el1", far = out(reg) far);
- }
- far
-}
diff --git a/pvmfw/src/helpers.rs b/pvmfw/src/helpers.rs
index e6e3406..9560d8d 100644
--- a/pvmfw/src/helpers.rs
+++ b/pvmfw/src/helpers.rs
@@ -22,6 +22,39 @@
pub const GUEST_PAGE_SIZE: usize = SIZE_4KB;
+/// Read a value from a system register.
+#[macro_export]
+macro_rules! read_sysreg {
+ ($sysreg:literal) => {{
+ let mut r: usize;
+ // Safe because it reads a system register and does not affect Rust.
+ unsafe {
+ core::arch::asm!(
+ concat!("mrs {}, ", $sysreg),
+ out(reg) r,
+ options(nomem, nostack, preserves_flags),
+ )
+ }
+ r
+ }};
+}
+
+/// Write a value to a system register.
+#[macro_export]
+macro_rules! write_sysreg {
+ ($sysreg:literal, $val:expr) => {{
+ let value: usize = $val;
+ // Safe because it writes a system register and does not affect Rust.
+ unsafe {
+ core::arch::asm!(
+ concat!("msr ", $sysreg, ", {}"),
+ in(reg) value,
+ options(nomem, nostack, preserves_flags),
+ )
+ }
+ }};
+}
+
/// Computes the largest multiple of the provided alignment smaller or equal to the address.
///
/// Note: the result is undefined if alignment isn't a power of two.
@@ -78,9 +111,7 @@
fn min_dcache_line_size() -> usize {
const DMINLINE_SHIFT: usize = 16;
const DMINLINE_MASK: usize = 0xf;
- let ctr_el0: usize;
-
- unsafe { asm!("mrs {x}, ctr_el0", x = out(reg) ctr_el0) }
+ let ctr_el0 = read_sysreg!("ctr_el0");
// DminLine: log2 of the number of words in the smallest cache line of all the data caches.
let dminline = (ctr_el0 >> DMINLINE_SHIFT) & DMINLINE_MASK;