From 1f9d7cd6a6a6bb90276cfdafaae8e4425f0be1c7 Mon Sep 17 00:00:00 2001
From: Zhouqi Jiang <luojia@hust.edu.cn>
Date: Thu, 24 Oct 2024 16:04:10 +0800
Subject: [PATCH] riscv64: use SBI SRST extension instead of legacy SBI for
 system shutdown

Legacy SBI have been deprecated years ago (on Jun 9, 2021). Modern
RISC-V SBI firmware would use SBI SRST extension to shutdown an S-mode
environment; we use `sbi-rt` crate for this purpose. Unused feature gate
`opensbi` is removed, as RISC-V SBI support does not usually satisfy
which implementation we'd use, unless e.g. fixing implementation-specific
bugs.

Signed-off-by: Zhouqi Jiang <luojia@hust.edu.cn>
---
 Cargo.lock         | 16 ++++++++++++++++
 riscv64/Cargo.toml |  2 +-
 riscv64/src/sbi.rs |  6 ++++--
 3 files changed, 21 insertions(+), 3 deletions(-)

diff --git a/Cargo.lock b/Cargo.lock
index ea85257..6da4c4c 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -243,8 +243,24 @@ name = "riscv64"
 version = "0.1.0"
 dependencies = [
  "port",
+ "sbi-rt",
 ]
 
+[[package]]
+name = "sbi-rt"
+version = "0.0.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7fbaa69be1eedc61c426e6d489b2260482e928b465360576900d52d496a58bd0"
+dependencies = [
+ "sbi-spec",
+]
+
+[[package]]
+name = "sbi-spec"
+version = "0.0.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e6e36312fb5ddc10d08ecdc65187402baba4ac34585cb9d1b78522ae2358d890"
+
 [[package]]
 name = "serde"
 version = "1.0.210"
diff --git a/riscv64/Cargo.toml b/riscv64/Cargo.toml
index a2a6a1b..d10fec6 100644
--- a/riscv64/Cargo.toml
+++ b/riscv64/Cargo.toml
@@ -8,9 +8,9 @@ default-target = "riscv64gc-unknown-none-elf"
 
 [dependencies]
 port = { path = "../port" }
+sbi-rt = "0.0.3"
 
 [features]
-opensbi = []
 
 [lints.rust]
 unexpected_cfgs = { level = "warn", check-cfg = ['cfg(platform, values("nezha"))', 'cfg(platform, values("virt"))'] }
diff --git a/riscv64/src/sbi.rs b/riscv64/src/sbi.rs
index db35524..8c6e4e1 100644
--- a/riscv64/src/sbi.rs
+++ b/riscv64/src/sbi.rs
@@ -49,6 +49,8 @@ pub fn _consgetb() -> u8 {
 }
 
 pub fn shutdown() -> ! {
-    sbi_call_legacy(SBI_SHUTDOWN, 0, 0, 0);
-    panic!("shutdown failed!");
+    sbi_rt::system_reset(sbi_rt::Shutdown, sbi_rt::NoReason);
+    loop {
+        unsafe { core::arch::asm!("wfi") }
+    }
 }