rust.patch

diff --git a/compiler/rustc_target/src/spec/mod.rs b/compiler/rustc_target/src/spec/mod.rs
index fe07d1167..07e786b6c 100644
--- a/compiler/rustc_target/src/spec/mod.rs
+++ b/compiler/rustc_target/src/spec/mod.rs
@@ -1731,6 +1731,7 @@ fn $module() {

     ("x86_64-unikraft-linux-musl", x86_64_unikraft_linux_musl),

+    ("riscv32em-athena-zkvm-elf", riscv32em_athena_zkvm_elf),
     ("riscv32i-unknown-none-elf", riscv32i_unknown_none_elf),
     ("riscv32im-risc0-zkvm-elf", riscv32im_risc0_zkvm_elf),
     ("riscv32im-unknown-none-elf", riscv32im_unknown_none_elf),
diff --git a/src/bootstrap/src/lib.rs b/src/bootstrap/src/lib.rs
index cde090637..07c9c5758 100644
--- a/src/bootstrap/src/lib.rs
+++ b/src/bootstrap/src/lib.rs
@@ -95,6 +95,10 @@
     /* Extra values not defined in the built-in targets yet, but used in std */
     (Some(Mode::Std), "target_env", Some(&["libnx", "p2"])),
     (Some(Mode::Std), "target_os", Some(&["visionos"])),
+    // #[cfg(bootstrap)] zkvm
+    (Some(Mode::Std), "target_os", Some(&["zkvm"])),
+    // #[cfg(bootstrap)] athena
+    (Some(Mode::Std), "target_vendor", Some(&["athena", "succinct"])),
     (Some(Mode::Std), "target_arch", Some(&["arm64ec", "spirv", "nvptx", "xtensa"])),
     (Some(Mode::ToolStd), "target_os", Some(&["visionos"])),
     /* Extra names used by dependencies */
diff --git a/src/tools/build-manifest/src/main.rs b/src/tools/build-manifest/src/main.rs
index bed76263b..121843a30 100644
--- a/src/tools/build-manifest/src/main.rs
+++ b/src/tools/build-manifest/src/main.rs
@@ -125,6 +125,7 @@
     "powerpc-unknown-linux-gnu",
     "powerpc64-unknown-linux-gnu",
     "powerpc64le-unknown-linux-gnu",
+    "riscv32em-athena-zkvm-elf",
     "riscv32i-unknown-none-elf",
     "riscv32im-risc0-zkvm-elf",
     "riscv32im-unknown-none-elf",
diff --git a/compiler/rustc_target/src/spec/targets/riscv32em_athena_zkvm_elf.rs b/compiler/rustc_target/src/spec/targets/riscv32em_athena_zkvm_elf.rs
new file mode 100644
index 00000000..a84f76c2
--- /dev/null
+++ b/compiler/rustc_target/src/spec/targets/riscv32em_athena_zkvm_elf.rs
@@ -0,0 +1,44 @@
+use crate::spec::{Cc, LinkerFlavor, Lld, PanicStrategy, RelocModel};
+use crate::spec::{Target, TargetOptions};
+
+pub fn target() -> Target {
+    Target {
+        data_layout: "e-m:e-p:32:32-i64:64-n32-S32".into(),
+        llvm_target: "riscv32".into(),
+        metadata: crate::spec::TargetMetadata {
+            description: None,
+            tier: None,
+            host_tools: None,
+            std: None,
+        },
+        pointer_width: 32,
+        arch: "riscv32".into(),
+
+        options: TargetOptions {
+            os: "zkvm".into(),
+            vendor: "athena".into(),
+            linker_flavor: LinkerFlavor::Gnu(Cc::No, Lld::Yes),
+            linker: Some("rust-lld".into()),
+            cpu: "generic-rv32".into(),
+
+            // Some crates (*cough* crossbeam) assume you have 64 bit
+            // atomics if the target name is not in a hardcoded list.
+            // Since zkvm is singlethreaded and all operations are
+            // atomic, I guess we can just say we support 64-bit
+            // atomics.
+            max_atomic_width: Some(64),
+            atomic_cas: true,
+
+            features: "+e,+m".into(),
+            llvm_abiname: "ilp32e".into(),
+            executables: true,
+            panic_strategy: PanicStrategy::Abort,
+            relocation_model: RelocModel::Static,
+            emit_debug_gdb_scripts: false,
+            eh_frame_header: false,
+            singlethread: true,
+            ..Default::default()
+        },
+    }
+}
+