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Diffstat (limited to 'results/classifier/105/other/1516408')
| -rw-r--r-- | results/classifier/105/other/1516408 | 129 |
1 files changed, 129 insertions, 0 deletions
diff --git a/results/classifier/105/other/1516408 b/results/classifier/105/other/1516408 new file mode 100644 index 00000000..8c4ffcd1 --- /dev/null +++ b/results/classifier/105/other/1516408 @@ -0,0 +1,129 @@ +other: 0.893 +assembly: 0.873 +socket: 0.872 +semantic: 0.868 +device: 0.867 +instruction: 0.860 +mistranslation: 0.841 +graphic: 0.839 +vnc: 0.804 +boot: 0.796 +KVM: 0.746 +network: 0.736 + +sh4: Unsupported syscall: 186 + +Hello! + +I'm currently testing qemu as a possibility to set up a buildd for the Debian sh4 port. + +I set up qemu and an sh4 chroot as described in the Debian Wiki [1]. This seems to be working mostly fine (besides the fact that qemu segfaults on an amd64 host while it runs fine on an i386 host, I'll file a separate bug report). However, when installing python3.4 in the sh4 chroot, qemu repeatedly printed an error message about an unimplemented syscall: 186: + +qemu: Unsupported syscall: 186 + +From the source code in linux-user/sh4/syscall_nr.h it's apparent that 186 is defined as + +#define TARGET_NR_sigaltstack 186 + +Looking at the implementation part, it becomes obvious that this syscall is not enabled for sh4: + +#if defined(TARGET_I386) || defined(TARGET_ARM) || defined(TARGET_MIPS) || \ + defined(TARGET_SPARC) || defined(TARGET_PPC) || defined(TARGET_ALPHA) || \ + defined(TARGET_M68K) || defined(TARGET_S390X) || defined(TARGET_OPENRISC) + ret = do_sigaltstack(arg1, arg2, get_sp_from_cpustate((CPUArchState *)cpu_env)); + break; +#else + goto unimplemented; +#endif + +Is there any particular reason why TARGET_NR_sigaltstack is not enabled on sh4? If not, could you enable it? + +Thanks, +Adrian + +> [1] https://wiki.debian.org/QemuUserEmulation + +I have enabled this syscall in the source code now and performing a test build and run and will report back. + +Furthermore, looking at the kernel sources, both the 32-bit and 64-bit Linux SH-specific code defines "sigaltstack" as syscall 186: + +> https://github.com/torvalds/linux/blob/master/arch/sh/kernel/syscalls_32.S#L205 +> https://github.com/torvalds/linux/blob/master/arch/sh/kernel/syscalls_64.S#L209 + +The whole syscall also doesn't appear to be architecture-specific after reading the manpage for sigaltstack. Is it? + +Will report back after further testing. + +Thanks, +Adrian + +Hello! + +The attached patch enables the sigaltstack syscall in qemu-sh4. + +The following minimal test code verifies that sigaltstack works as expected: + +============================================================= + +#include <setjmp.h> +#include <signal.h> +#include <stdlib.h> +#include <stdio.h> + +jmp_buf exit_jmp; + +void handler(int x) +{ + longjmp(exit_jmp, 1); +} + +int f(void) +{ + return f(); +} + +int main(void) +{ + stack_t sigstack; + sigstack.ss_sp = malloc(1024*1024); + sigstack.ss_size = 1024*1024; + sigstack.ss_flags = 0; + sigaltstack(&sigstack, NULL); + struct sigaction sa; + sa.sa_handler = handler; + sigemptyset(&sa.sa_mask); + sa.sa_flags = SA_ONSTACK; + sigaction(SIGSEGV, &sa, NULL); + if (setjmp(exit_jmp) == 0) + { + return f(); + } + puts("recovered"); + return 0; +} + +============================================================= + +Without sigaltstack enabled, this code produces a segmentation fault. With sigaltstack enabled, it prints out "recovered". + +Also posted on qemu-devel mailing list: + +> http://lists.nongnu.org/archive/html/qemu-devel/2015-11/msg04300.html +> http://lists.nongnu.org/archive/html/qemu-devel/2015-11/msg04301.html + +Cheers, +Adrian + +Ping. Any chance to get this merged? + +I don't think this patch could have any particular bad impact on qemu as it affects the sh4 emulation only and so far my tests with building packages on qemu-sh4 have shown no regressions. But with the patch, sigaltstack now works fine on sh4 which the above testcase also positively has proven. + +Having this bug and #1254824 fixed would help the sh4 porters in Debian quite a lot as qemu-sh4 can be used to set up a virtual buildd for this architecture. + +Adrian + +> [1] https://bugs.launchpad.net/ubuntu/+source/qemu-linaro/+bug/1254824 + +Looks like we fixed this in commit c0d35736323e5b in December, which was released as part of QEMU 2.6. + + |