tokio: fix cache line size for RISC-V

Currently tokio uses cache line size data from Go, which is not
sufficient at least for T-Head C910 cores.

The RISC-V Profiles document defines a maximum 64 bytes cache line for
RVA22U64 (although the maximum is 128 bytes for RVA20U64), and the Linux
kernel currently assumes 64B cache line too.

Change the cache line size used to 64 bytes to match Linux and RVA22U64.

Signed-off-by: Icenowy Zheng <uwu@icenowy.me>

tokio/src/runtime/io/scheduled_io.rs

@@ -44,25 +44,20 @@ use std::task::{Context, Poll, Waker};
     ),
     repr(align(128))
 )]
-// arm, mips, mips64, riscv64, sparc, and hexagon have 32-byte cache line size.
+// arm, mips, mips64, sparc, and hexagon have 32-byte cache line size.
 //
 // Sources:
 // - https://github.com/golang/go/blob/3dd58676054223962cd915bb0934d1f9f489d4d2/src/internal/cpu/cpu_arm.go#L7
 // - https://github.com/golang/go/blob/3dd58676054223962cd915bb0934d1f9f489d4d2/src/internal/cpu/cpu_mips.go#L7
 // - https://github.com/golang/go/blob/3dd58676054223962cd915bb0934d1f9f489d4d2/src/internal/cpu/cpu_mipsle.go#L7
 // - https://github.com/golang/go/blob/3dd58676054223962cd915bb0934d1f9f489d4d2/src/internal/cpu/cpu_mips64x.go#L9
-// - https://github.com/golang/go/blob/3dd58676054223962cd915bb0934d1f9f489d4d2/src/internal/cpu/cpu_riscv64.go#L7
 // - https://github.com/torvalds/linux/blob/3516bd729358a2a9b090c1905bd2a3fa926e24c6/arch/sparc/include/asm/cache.h#L17
 // - https://github.com/torvalds/linux/blob/3516bd729358a2a9b090c1905bd2a3fa926e24c6/arch/hexagon/include/asm/cache.h#L12
-//
-// riscv32 is assumed not to exceed the cache line size of riscv64.
 #[cfg_attr(
     any(
         target_arch = "arm",
         target_arch = "mips",
         target_arch = "mips64",
-        target_arch = "riscv32",
-        target_arch = "riscv64",
         target_arch = "sparc",
         target_arch = "hexagon",
     ),
@@ -79,12 +74,13 @@ use std::task::{Context, Poll, Waker};
 // - https://github.com/golang/go/blob/3dd58676054223962cd915bb0934d1f9f489d4d2/src/internal/cpu/cpu_s390x.go#L7
 // - https://github.com/torvalds/linux/blob/3516bd729358a2a9b090c1905bd2a3fa926e24c6/arch/s390/include/asm/cache.h#L13
 #[cfg_attr(target_arch = "s390x", repr(align(256)))]
-// x86, wasm, and sparc64 have 64-byte cache line size.
+// x86, riscv, wasm, and sparc64 have 64-byte cache line size.
 //
 // Sources:
 // - https://github.com/golang/go/blob/dda2991c2ea0c5914714469c4defc2562a907230/src/internal/cpu/cpu_x86.go#L9
 // - https://github.com/golang/go/blob/3dd58676054223962cd915bb0934d1f9f489d4d2/src/internal/cpu/cpu_wasm.go#L7
 // - https://github.com/torvalds/linux/blob/3516bd729358a2a9b090c1905bd2a3fa926e24c6/arch/sparc/include/asm/cache.h#L19
+// - https://github.com/torvalds/linux/blob/3516bd729358a2a9b090c1905bd2a3fa926e24c6/arch/riscv/include/asm/cache.h#L10
 //
 // All others are assumed to have 64-byte cache line size.
 #[cfg_attr(
@@ -95,8 +91,6 @@ use std::task::{Context, Poll, Waker};
         target_arch = "arm",
         target_arch = "mips",
         target_arch = "mips64",
-        target_arch = "riscv32",
-        target_arch = "riscv64",
         target_arch = "sparc",
         target_arch = "hexagon",
         target_arch = "m68k",

tokio/src/runtime/task/core.rs

@@ -57,25 +57,20 @@ use std::task::{Context, Poll, Waker};
     ),
     repr(align(128))
 )]
-// arm, mips, mips64, riscv64, sparc, and hexagon have 32-byte cache line size.
+// arm, mips, mips64, sparc, and hexagon have 32-byte cache line size.
 //
 // Sources:
 // - https://github.com/golang/go/blob/3dd58676054223962cd915bb0934d1f9f489d4d2/src/internal/cpu/cpu_arm.go#L7
 // - https://github.com/golang/go/blob/3dd58676054223962cd915bb0934d1f9f489d4d2/src/internal/cpu/cpu_mips.go#L7
 // - https://github.com/golang/go/blob/3dd58676054223962cd915bb0934d1f9f489d4d2/src/internal/cpu/cpu_mipsle.go#L7
 // - https://github.com/golang/go/blob/3dd58676054223962cd915bb0934d1f9f489d4d2/src/internal/cpu/cpu_mips64x.go#L9
-// - https://github.com/golang/go/blob/3dd58676054223962cd915bb0934d1f9f489d4d2/src/internal/cpu/cpu_riscv64.go#L7
 // - https://github.com/torvalds/linux/blob/3516bd729358a2a9b090c1905bd2a3fa926e24c6/arch/sparc/include/asm/cache.h#L17
 // - https://github.com/torvalds/linux/blob/3516bd729358a2a9b090c1905bd2a3fa926e24c6/arch/hexagon/include/asm/cache.h#L12
-//
-// riscv32 is assumed not to exceed the cache line size of riscv64.
 #[cfg_attr(
     any(
         target_arch = "arm",
         target_arch = "mips",
         target_arch = "mips64",
-        target_arch = "riscv32",
-        target_arch = "riscv64",
         target_arch = "sparc",
         target_arch = "hexagon",
     ),
@@ -92,12 +87,13 @@ use std::task::{Context, Poll, Waker};
 // - https://github.com/golang/go/blob/3dd58676054223962cd915bb0934d1f9f489d4d2/src/internal/cpu/cpu_s390x.go#L7
 // - https://github.com/torvalds/linux/blob/3516bd729358a2a9b090c1905bd2a3fa926e24c6/arch/s390/include/asm/cache.h#L13
 #[cfg_attr(target_arch = "s390x", repr(align(256)))]
-// x86, wasm, and sparc64 have 64-byte cache line size.
+// x86, riscv, wasm, and sparc64 have 64-byte cache line size.
 //
 // Sources:
 // - https://github.com/golang/go/blob/dda2991c2ea0c5914714469c4defc2562a907230/src/internal/cpu/cpu_x86.go#L9
 // - https://github.com/golang/go/blob/3dd58676054223962cd915bb0934d1f9f489d4d2/src/internal/cpu/cpu_wasm.go#L7
 // - https://github.com/torvalds/linux/blob/3516bd729358a2a9b090c1905bd2a3fa926e24c6/arch/sparc/include/asm/cache.h#L19
+// - https://github.com/torvalds/linux/blob/3516bd729358a2a9b090c1905bd2a3fa926e24c6/arch/riscv/include/asm/cache.h#L10
 //
 // All others are assumed to have 64-byte cache line size.
 #[cfg_attr(
@@ -108,8 +104,6 @@ use std::task::{Context, Poll, Waker};
         target_arch = "arm",
         target_arch = "mips",
         target_arch = "mips64",
-        target_arch = "riscv32",
-        target_arch = "riscv64",
         target_arch = "sparc",
         target_arch = "hexagon",
         target_arch = "m68k",

tokio/src/util/cacheline.rs

@@ -27,7 +27,7 @@ use std::ops::{Deref, DerefMut};
     ),
     repr(align(128))
 )]
-// arm, mips, mips64, and riscv64 have 32-byte cache line size.
+// arm, mips and mips64 have 32-byte cache line size.
 //
 // Sources:
 // - https://github.com/golang/go/blob/3dd58676054223962cd915bb0934d1f9f489d4d2/src/internal/cpu/cpu_arm.go#L7
@@ -40,7 +40,6 @@ use std::ops::{Deref, DerefMut};
         target_arch = "arm",
         target_arch = "mips",
         target_arch = "mips64",
-        target_arch = "riscv64",
     ),
     repr(align(32))
 )]
@@ -49,11 +48,12 @@ use std::ops::{Deref, DerefMut};
 // Sources:
 // - https://github.com/golang/go/blob/3dd58676054223962cd915bb0934d1f9f489d4d2/src/internal/cpu/cpu_s390x.go#L7
 #[cfg_attr(target_arch = "s390x", repr(align(256)))]
-// x86 and wasm have 64-byte cache line size.
+// x86, riscv and wasm have 64-byte cache line size.
 //
 // Sources:
 // - https://github.com/golang/go/blob/dda2991c2ea0c5914714469c4defc2562a907230/src/internal/cpu/cpu_x86.go#L9
 // - https://github.com/golang/go/blob/3dd58676054223962cd915bb0934d1f9f489d4d2/src/internal/cpu/cpu_wasm.go#L7
+// - https://github.com/torvalds/linux/blob/3516bd729358a2a9b090c1905bd2a3fa926e24c6/arch/riscv/include/asm/cache.h#L10
 //
 // All others are assumed to have 64-byte cache line size.
 #[cfg_attr(
@@ -64,7 +64,6 @@ use std::ops::{Deref, DerefMut};
         target_arch = "arm",
         target_arch = "mips",
         target_arch = "mips64",
-        target_arch = "riscv64",
         target_arch = "s390x",
     )),
     repr(align(64))