id = 1771
title = "Missing CASA instruction handling for SPARC qemu-user"
state = "opened"
created_at = "2023-07-18T13:21:56.422Z"
closed_at = "n/a"
labels = ["accel: TCG", "target: sparc"]
url = "https://gitlab.com/qemu-project/qemu/-/issues/1771"
host-os = "Slackware GNU/Linux"
host-arch = "x86_64"
qemu-version = "8.0.50 (git commit hash 4633c1e2c576fbabfe5c8c93f4b842504b69c096)"
guest-os = "GNU/Linux user-space"
guest-arch = "qemu-sparc (LEON3 cpu)"
description = """Qemu-sparc does not handle the CASA instruction, even if the selected CPU (in this case, LEON3) support it."""
reproduce = """1. Launch a program that use CASA instruction (any program, also "ls" on a recent glibc [>=2.31])
2. qemu-sparc will raise "Illegal instruction""""
additional = """The following patch remove the missing handling, but it needs asi load/store that is not implemented for sparc32 user-space.

```
diff -urp qemu-20230327.orig/target/sparc/translate.c qemu-20230327/target/sparc/translate.c
--- qemu-20230327.orig/target/sparc/translate.c 2023-03-27 15:41:42.000000000 +0200
+++ qemu-20230327/target/sparc/translate.c      2023-04-01 15:24:18.293176711 +0200
@@ -5521,7 +5522,7 @@ static void disas_sparc_insn(DisasContex
                 case 0x37: /* stdc */
                     goto ncp_insn;
 #endif
-#if !defined(CONFIG_USER_ONLY) || defined(TARGET_SPARC64)
+//#if !defined(CONFIG_USER_ONLY) || defined(TARGET_SPARC64)
                 case 0x3c: /* V9 or LEON3 casa */
 #ifndef TARGET_SPARC64
                     CHECK_IU_FEATURE(dc, CASA);
@@ -5529,8 +5530,8 @@ static void disas_sparc_insn(DisasContex
                     rs2 = GET_FIELD(insn, 27, 31);
                     cpu_src2 = gen_load_gpr(dc, rs2);
                     gen_cas_asi(dc, cpu_addr, cpu_src2, insn, rd);
+//#endif
                     break;
-#endif
                 default:
                     goto illegal_insn;
                 }
```"""