[llvm] [RISCV] Add the CSR names from Smrnmi. (PR #83370)

[Craig Topper via llvm-commits]

https://github.com/topperc created https://github.com/llvm/llvm-project/pull/83370

Specification is here
https://github.com/riscv/riscv-isa-manual/blob/main/src/rnmi.adoc

CSRs numbers defined here
https://github.com/riscv/riscv-isa-manual/blob/main/src/priv-csrs.adoc

SiFive has hardware that implements this extension.

I'm not sure where it is in the ratifcation process. It doesn't look to have recent progress.

>From af89185bcbb70be5161bf78a45a9fd94b400fead Mon Sep 17 00:00:00 2001
From: Craig Topper <craig.topper at sifive.com>
Date: Wed, 28 Feb 2024 19:09:21 -0800
Subject: [PATCH] [RISCV] Add the CSR names from Smrnmi.

Specification is here
https://github.com/riscv/riscv-isa-manual/blob/main/src/rnmi.adoc

CSRs numbers defined here
https://github.com/riscv/riscv-isa-manual/blob/main/src/priv-csrs.adoc

SiFive has hardware that implements this extension.

I'm not sure where it is in the ratifcation process. It doesn't
look to have recent progress.
---
 llvm/docs/ReleaseNotes.rst                   |  1 +
 llvm/lib/Target/RISCV/RISCVSystemOperands.td |  9 ++++
 llvm/test/MC/RISCV/rv32-machine-csr-names.s  | 56 ++++++++++++++++++++
 3 files changed, 66 insertions(+)

diff --git a/llvm/docs/ReleaseNotes.rst b/llvm/docs/ReleaseNotes.rst
index 51b6527f65bb04..d7f075f5c5b3dd 100644
--- a/llvm/docs/ReleaseNotes.rst
+++ b/llvm/docs/ReleaseNotes.rst
@@ -103,6 +103,7 @@ Changes to the RISC-V Backend
 * Codegen support was added for the Zimop (May-Be-Operations) extension.
 * The experimental Ssnpm, Smnpm, Smmpm, Sspm, and Supm 0.8.1 Pointer Masking extensions are supported.
 * The experimental Ssqosid extension is supported.
+* Added the CSR names from the draft specification of Resumable Non-Maskable Interrupts (Smrnmi).
 
 Changes to the WebAssembly Backend
 ----------------------------------
diff --git a/llvm/lib/Target/RISCV/RISCVSystemOperands.td b/llvm/lib/Target/RISCV/RISCVSystemOperands.td
index 79f977e5b32266..01c2767119502c 100644
--- a/llvm/lib/Target/RISCV/RISCVSystemOperands.td
+++ b/llvm/lib/Target/RISCV/RISCVSystemOperands.td
@@ -418,7 +418,16 @@ def : SysReg<"vsieh", 0x214>;
 def : SysReg<"vsiph", 0x254>;
 } // isRV32Only
 
+//===-----------------------------------------------
 // Jump Vector Table CSR
 //===-----------------------------------------------
 
 def : SysReg<"jvt", 0x017>;
+
+//===-----------------------------------------------
+// Resumable Non-Maskable Interrupts(Smrnmi) CSRs
+//===-----------------------------------------------
+def : SysReg<"mnscratch", 0x740>;
+def : SysReg<"mnepc", 0x741>;
+def : SysReg<"mncause", 0x742>;
+def : SysReg<"mnstatus", 0x744>;
diff --git a/llvm/test/MC/RISCV/rv32-machine-csr-names.s b/llvm/test/MC/RISCV/rv32-machine-csr-names.s
index e7a6d9ce718f2c..016f448d8dac63 100644
--- a/llvm/test/MC/RISCV/rv32-machine-csr-names.s
+++ b/llvm/test/MC/RISCV/rv32-machine-csr-names.s
@@ -1149,3 +1149,59 @@ csrrs t2, 0x319, zero
 csrrs t1, miph, zero
 # uimm12
 csrrs t2, 0x354, zero
+
+################################################
+# Resumable Non-Maskable Interrupts(Smrnmi) CSRs
+################################################
+
+# mnscratch
+# name
+# CHECK-INST: csrrs t1, mnscratch, zero
+# CHECK-ENC: encoding: [0x73,0x23,0x00,0x74]
+# CHECK-INST-ALIAS: csrr t1, mnscratch
+# uimm12
+# CHECK-INST: csrrs t2, mnscratch, zero
+# CHECK-ENC: encoding: [0xf3,0x23,0x00,0x74]
+# CHECK-INST-ALIAS: csrr t2, mnscratch
+csrrs t1, mnscratch, zero
+# uimm12
+csrrs t2, 0x740, zero
+
+# mnepc
+# name
+# CHECK-INST: csrrs t1, mnepc, zero
+# CHECK-ENC: encoding: [0x73,0x23,0x10,0x74]
+# CHECK-INST-ALIAS: csrr t1, mnepc
+# uimm12
+# CHECK-INST: csrrs t2, mnepc, zero
+# CHECK-ENC: encoding: [0xf3,0x23,0x10,0x74]
+# CHECK-INST-ALIAS: csrr t2, mnepc
+csrrs t1, mnepc, zero
+# uimm12
+csrrs t2, 0x741, zero
+
+# mncause
+# name
+# CHECK-INST: csrrs t1, mncause, zero
+# CHECK-ENC: encoding: [0x73,0x23,0x20,0x74]
+# CHECK-INST-ALIAS: csrr t1, mncause
+# uimm12
+# CHECK-INST: csrrs t2, mncause, zero
+# CHECK-ENC: encoding: [0xf3,0x23,0x20,0x74]
+# CHECK-INST-ALIAS: csrr t2, mncause
+csrrs t1, mncause, zero
+# uimm12
+csrrs t2, 0x742, zero
+
+# mnstatus
+# name
+# CHECK-INST: csrrs t1, mnstatus, zero
+# CHECK-ENC: encoding: [0x73,0x23,0x40,0x74]
+# CHECK-INST-ALIAS: csrr t1, mnstatus
+# uimm12
+# CHECK-INST: csrrs t2, mnstatus, zero
+# CHECK-ENC: encoding: [0xf3,0x23,0x40,0x74]
+# CHECK-INST-ALIAS: csrr t2, mnstatus
+csrrs t1, mnstatus, zero
+# uimm12
+csrrs t2, 0x744, zero