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Diffstat (limited to 'gitlab/issues/target_ppc/host_missing/accel_missing/1955.toml')
| -rw-r--r-- | gitlab/issues/target_ppc/host_missing/accel_missing/1955.toml | 34 |
1 files changed, 34 insertions, 0 deletions
diff --git a/gitlab/issues/target_ppc/host_missing/accel_missing/1955.toml b/gitlab/issues/target_ppc/host_missing/accel_missing/1955.toml new file mode 100644 index 000000000..592b7a769 --- /dev/null +++ b/gitlab/issues/target_ppc/host_missing/accel_missing/1955.toml @@ -0,0 +1,34 @@ +id = 1955 +title = "powerpc instruction 'mffsl' not emulated on POWER8" +state = "closed" +created_at = "2023-10-22T16:59:43.540Z" +closed_at = "2023-10-25T05:44:08.050Z" +labels = ["target: ppc"] +url = "https://gitlab.com/qemu-project/qemu/-/issues/1955" +host-os = "Ubuntu 22.04" +host-arch = "x86_64" +qemu-version = "8.0.2" +guest-os = "Debian 12" +guest-arch = "ppc, ppc64" +description = """Since 2019, the function feenableexcept() in GNU libc makes use of the "mffsl" instruction. +See https://sourceware.org/git/?p=glibc.git;a=blob;f=sysdeps/powerpc/fpu/feenablxcpt.c;h=b111ceaa4e2e1864fcbe043ccda34e03e9f14062;hb=HEAD#l28 +and https://sourceware.org/git/?p=glibc.git;a=blob;f=sysdeps/powerpc/fpu/fenv_libc.h;h=a2a12d914b47e99746003482b349a0675cc5ad34;hb=HEAD#l57 + +In the emulated Debian system, executables that make use of this instruction crash with SIGILL. +Likewise, under gdb (in the emulated system), there is a SIGILL at the 'mffsl' instruction. + +From the comments in the above glibc source, added by Paul A. Clarke <pc@us.ibm.com>: + "Nicely, it turns out that the 'mffsl' instruction will decode to + 'mffs' on architectures older than "power9" because the additional + bits set for 'mffsl' are "don't care" for 'mffs'. 'mffs' is a superset + of 'mffsl'." + +This is indeed what I observe by compiling and running the attached program foo.c on a hardware machine with a POWER8 CPU: That program does not crash with a SIGILL.""" +reproduce = """1. Either run the attached 'test-fenv-except-tracking-5.ppc' (32-bit) program under qemu-system-ppc. +2. Or run the the attached 'test-fenv-except-tracking-5.ppc64' (64-bit) program under qemu-system-ppc64 with -cpu POWER8. +3. Or compile and run the attached foo.c and run it under QEMU.""" +additional = """[test-fenv-except-tracking-5.ppc.xz](/uploads/8222ebac115e8a865d5e520b25d423ff/test-fenv-except-tracking-5.ppc.xz) + +[test-fenv-except-tracking-5.ppc64.xz](/uploads/d0522723541a46e11ab55b8f45dfb574/test-fenv-except-tracking-5.ppc64.xz) + +[foo.c](/uploads/35d8b3b1e5b39ecb6a2a899132858ded/foo.c)""" |