From 57e4b81e1c2a7e2aa068fa60f91fee3b36cf4208 Mon Sep 17 00:00:00 2001 From: Berkus Decker Date: Sun, 9 Aug 2020 21:56:09 +0300 Subject: [PATCH] Implement power-efficient sleep after boot-up * arch-based crates, inspired by Redox * Do not burn cpu uselessly. * Start using cortex-a registers. * Important: initialise stack pointer! --- Cargo.lock | 25 +++++++++++++++++++++++ linker/aarch64.ld | 2 +- nucleus/Cargo.toml | 1 + nucleus/src/arch/README.md | 5 +++++ nucleus/src/arch/aarch64/mod.rs | 36 +++++++++++++++++++++++++++++++++ nucleus/src/arch/mod.rs | 5 +++++ nucleus/src/main.rs | 16 +++++++++++---- 7 files changed, 85 insertions(+), 5 deletions(-) create mode 100644 nucleus/src/arch/README.md create mode 100644 nucleus/src/arch/aarch64/mod.rs create mode 100644 nucleus/src/arch/mod.rs diff --git a/Cargo.lock b/Cargo.lock index df3f804..2e40f57 100644 --- a/Cargo.lock +++ b/Cargo.lock @@ -26,6 +26,14 @@ dependencies = [ "rustc_version 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)", ] +[[package]] +name = "cortex-a" +version = "3.0.4" +source = "registry+https://github.com/rust-lang/crates.io-index" +dependencies = [ + "register 0.5.1 (registry+https://github.com/rust-lang/crates.io-index)", +] + [[package]] name = "nodrop" version = "0.1.14" @@ -44,6 +52,14 @@ name = "r0" version = "0.2.2" source = "registry+https://github.com/rust-lang/crates.io-index" +[[package]] +name = "register" +version = "0.5.1" +source = "registry+https://github.com/rust-lang/crates.io-index" +dependencies = [ + "tock-registers 0.5.0 (registry+https://github.com/rust-lang/crates.io-index)", +] + [[package]] name = "rlibc" version = "1.0.0" @@ -70,6 +86,11 @@ name = "semver-parser" version = "0.7.0" source = "registry+https://github.com/rust-lang/crates.io-index" +[[package]] +name = "tock-registers" +version = "0.5.0" +source = "registry+https://github.com/rust-lang/crates.io-index" + [[package]] name = "ux" version = "0.1.3" @@ -79,6 +100,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index" name = "vesper" version = "0.0.1" dependencies = [ + "cortex-a 3.0.4 (registry+https://github.com/rust-lang/crates.io-index)", "qemu-exit 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)", "r0 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)", "rlibc 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)", @@ -101,12 +123,15 @@ dependencies = [ "checksum bit_field 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)" = "ed8765909f9009617974ab6b7d332625b320b33c326b1e9321382ef1999b5d56" "checksum bitflags 1.2.1 (registry+https://github.com/rust-lang/crates.io-index)" = "cf1de2fe8c75bc145a2f577add951f8134889b4795d47466a54a5c846d691693" "checksum cast 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)" = "4b9434b9a5aa1450faa3f9cb14ea0e8c53bb5d2b3c1bfd1ab4fc03e9f33fbfb0" +"checksum cortex-a 3.0.4 (registry+https://github.com/rust-lang/crates.io-index)" = "6922a40af4d1a2deac8c963b9f3e57311b8912490740234f1ad182425c547f80" "checksum nodrop 0.1.14 (registry+https://github.com/rust-lang/crates.io-index)" = "72ef4a56884ca558e5ddb05a1d1e7e1bfd9a68d9ed024c21704cc98872dae1bb" "checksum qemu-exit 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)" = "95533662c327a4b3be4203123662b7eca1c39d73d66020c52280e4ff0e9c9a41" "checksum r0 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)" = "e2a38df5b15c8d5c7e8654189744d8e396bddc18ad48041a500ce52d6948941f" +"checksum register 0.5.1 (registry+https://github.com/rust-lang/crates.io-index)" = "deaba5b0e477d21f61a57504bb5cef4a1e86de30300b457d38971c1cfc98b815" "checksum rlibc 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)" = "fc874b127765f014d792f16763a81245ab80500e2ad921ed4ee9e82481ee08fe" "checksum rustc_version 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)" = "138e3e0acb6c9fb258b19b67cb8abd63c00679d2851805ea151465464fe9030a" "checksum semver 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)" = "1d7eb9ef2c18661902cc47e535f9bc51b78acd254da71d375c2f6720d9a40403" "checksum semver-parser 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)" = "388a1df253eca08550bef6c72392cfe7c30914bf41df5269b68cbd6ff8f570a3" +"checksum tock-registers 0.5.0 (registry+https://github.com/rust-lang/crates.io-index)" = "70323afdb8082186c0986da0e10f6e4ed103d681c921c00597e98d9806dac20f" "checksum ux 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)" = "88dfeb711b61ce620c0cb6fd9f8e3e678622f0c971da2a63c4b3e25e88ed012f" "checksum x86_64 0.7.7 (registry+https://github.com/rust-lang/crates.io-index)" = "1f27d9168654aee1b0c1b73746caeb4aa33248f8b8c8f6e100e697fcc2a794b2" diff --git a/linker/aarch64.ld b/linker/aarch64.ld index 923ee1b..9fccde5 100644 --- a/linker/aarch64.ld +++ b/linker/aarch64.ld @@ -4,7 +4,7 @@ * Original code distributed under MIT, additional changes are under BlueOak-1.0.0 */ -ENTRY(_boot_cores); +ENTRY(karch_start); /* Symbols between __boot_start and __boot_end should be dropped after init is complete. Symbols between __ro_start and __ro_end are the kernel code. diff --git a/nucleus/Cargo.toml b/nucleus/Cargo.toml index fd83f67..ba17dc0 100644 --- a/nucleus/Cargo.toml +++ b/nucleus/Cargo.toml @@ -23,3 +23,4 @@ qemu = ["qemu-exit"] r0 = "0.2" rlibc = "1.0" qemu-exit = { version = "0.1", optional = true } +cortex-a = "3.0" diff --git a/nucleus/src/arch/README.md b/nucleus/src/arch/README.md new file mode 100644 index 0000000..b42600c --- /dev/null +++ b/nucleus/src/arch/README.md @@ -0,0 +1,5 @@ +# Architecture-specific code + +This directory contains code specific to a certain architecture. + +Implementations of arch-specific kernel calls are also placed here. diff --git a/nucleus/src/arch/aarch64/mod.rs b/nucleus/src/arch/aarch64/mod.rs new file mode 100644 index 0000000..424e8d8 --- /dev/null +++ b/nucleus/src/arch/aarch64/mod.rs @@ -0,0 +1,36 @@ +use { + crate::kmain, + cortex_a::{ + asm, + regs::{RegisterReadOnly, RegisterReadWrite, MPIDR_EL1, SP}, + }, +}; + +/// The entry to Rust, all things must be initialized +/// This is invoked from the linker script, does arch-specific init +/// and passes control to the kernel boot function kmain(). +#[no_mangle] +pub unsafe extern "C" fn karch_start() -> ! { + // Set sp to 0x80000 (just before kernel start) + const STACK_START: u64 = 0x8_0000; + + SP.set(STACK_START); + + match read_cpu_id() { + 0 => kmain(), + _ => endless_sleep(), // if not core0, indefinitely wait for events + } +} + +#[inline] +pub fn read_cpu_id() -> u64 { + const CORE_MASK: u64 = 0x3; + MPIDR_EL1.get() & CORE_MASK +} + +#[inline] +pub fn endless_sleep() -> ! { + loop { + asm::wfe(); + } +} diff --git a/nucleus/src/arch/mod.rs b/nucleus/src/arch/mod.rs new file mode 100644 index 0000000..2f826cd --- /dev/null +++ b/nucleus/src/arch/mod.rs @@ -0,0 +1,5 @@ +#[cfg(target_arch = "aarch64")] +#[macro_use] +pub mod aarch64; +#[cfg(target_arch = "aarch64")] +pub use self::aarch64::*; diff --git a/nucleus/src/main.rs b/nucleus/src/main.rs index f964b35..bc62fb9 100644 --- a/nucleus/src/main.rs +++ b/nucleus/src/main.rs @@ -1,12 +1,20 @@ #![no_std] #![no_main] -#[no_mangle] -pub extern "C" fn _boot_cores() -> ! { - loop {} +#[cfg(not(target_arch = "aarch64"))] +use architecture_not_supported_sorry; + +#[macro_use] +pub mod arch; +pub use arch::*; + +// Kernel entry point +// arch crate is responsible for calling this +pub fn kmain() -> ! { + endless_sleep() } #[panic_handler] fn panicked(_info: &core::panic::PanicInfo) -> ! { - loop {} + endless_sleep() }