On current master, on x86-64 Fedora 23, I'm seeing this: +FAIL: gdb.reverse/insn-reverse.exp: rdseed: x/i $pc +FAIL: gdb.reverse/insn-reverse.exp: rdseed: x/i $pc +FAIL: gdb.reverse/insn-reverse.exp: rdseed: x/i $pc +FAIL: gdb.reverse/insn-reverse.exp: rdseed: x/i $pc +FAIL: gdb.reverse/insn-reverse.exp: rdseed: x/i $pc [... many more of the same ... ] +FAIL: gdb.reverse/insn-reverse.exp: rdseed: compare registers on insn 0:mov 0x2008b7(%rip),%eax # 0x601058 <supports_rdrand> +FAIL: gdb.reverse/insn-reverse.exp: rdseed: compare registers on insn 1:test %eax,%eax +FAIL: gdb.reverse/insn-reverse.exp: rdseed: compare registers on insn 2:je 0x4008b3 <rdseed+284> +FAIL: gdb.reverse/insn-reverse.exp: rdseed: compare registers on insn 3:rdseed %ax +FAIL: gdb.reverse/insn-reverse.exp: rdseed: compare registers on insn 4:rdseed %ax +ERROR: tcl error sourcing /home/pedro/gdb/mygit/src/gdb/testsuite/gdb.reverse/insn-reverse.exp. +ERROR: can't read "insn_array(5)": no such element in array + while executing +"gdb_assert { [string compare $pre_regs($i) $post_regs($i)] == 0 } "compare registers on insn $i:$insn_array($i)"" + ("uplevel" body line 47) + invoked from within +"uplevel 1 $body" + invoked from within +"with_test_prefix "$func" { + gdb_breakpoint $func + gdb_test "continue" + set last_insn "" + set test "disassemble $func" + gdb_test_multiple $test $test ..." + (procedure "test" line 5) + invoked from within +"test $testcase" + (file "/home/pedro/gdb/mygit/src/gdb/testsuite/gdb.reverse/insn-reverse.exp" line 128) + invoked from within +"source /home/pedro/gdb/mygit/src/gdb/testsuite/gdb.reverse/insn-reverse.exp" + ("uplevel" body line 1) + invoked from within +"uplevel #0 source /home/pedro/gdb/mygit/src/gdb/testsuite/gdb.reverse/insn-reverse.exp" + invoked from within +"catch "uplevel #0 source $test_file_name"" src/gdb/testsuite/gdb.reverse/machinestate.exp ...
gdb.log shows: (gdb) si Program received signal SIGILL, Illegal instruction. rdseed () at /home/pedro/gdb/mygit/src/gdb/testsuite/gdb.reverse/insn-reverse-x86.c:154 154 __asm__ volatile ("rdseed %%ax;" : "=r" (seed));
$ cat /proc/cpuinfo processor : 0 vendor_id : GenuineIntel cpu family : 6 model : 60 model name : Intel(R) Core(TM) i7-4810MQ CPU @ 2.80GHz stepping : 3 microcode : 0x20 cpu MHz : 3645.776 cache size : 6144 KB physical id : 0 siblings : 8 core id : 0 cpu cores : 4 apicid : 0 initial apicid : 0 fpu : yes fpu_exception : yes cpuid level : 13 wp : yes flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx pdpe1gb rdtscp lm constant_tsc arch_perfmon pebs bts rep_good nopl xtopology nonstop_tsc aperfmperf eagerfpu pni pclmulqdq dtes64 monitor ds_cpl vmx smx est tm2 ssse3 sdbg fma cx16 xtpr pdcm pcid sse4_1 sse4_2 x2apic movbe popcnt tsc_deadline_timer aes xsave avx f16c rdrand lahf_lm abm epb tpr_shadow vnmi flexpriority ept vpid fsgsbase tsc_adjust bmi1 avx2 smep bmi2 erms invpcid xsaveopt dtherm ida arat pln pts bugs : bogomips : 5586.97 clflush size : 64 cache_alignment : 64 address sizes : 39 bits physical, 48 bits virtual power management: [....]
Odd. So this is getting past the feature test even though it doesn't support rdseed. Is rdrand supported just fine?
Ah, that particular processor doesn't support rdseed, that's why. Mine does: processor : 3 vendor_id : GenuineIntel cpu family : 6 model : 78 model name : Intel(R) Core(TM) i7-6600U CPU @ 2.60GHz stepping : 3 microcode : 0x74 cpu MHz : 1094.843 cache size : 4096 KB physical id : 0 siblings : 4 core id : 1 cpu cores : 2 apicid : 3 initial apicid : 3 fpu : yes fpu_exception : yes cpuid level : 22 wp : yes flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx pdpe1gb rdtscp lm constant_tsc art arch_perfmon pebs bts rep_good nopl xtopology nonstop_tsc aperfmperf eagerfpu pni pclmulqdq dtes64 monitor ds_cpl vmx smx est tm2 ssse3 sdbg fma cx16 xtpr pdcm pcid sse4_1 sse4_2 x2apic movbe popcnt tsc_deadline_timer aes xsave avx f16c rdrand lahf_lm abm 3dnowprefetch epb intel_pt tpr_shadow vnmi flexpriority ept vpid fsgsbase tsc_adjust bmi1 hle avx2 smep bmi2 erms invpcid rtm mpx rdseed adx smap clflushopt xsaveopt xsavec xgetbv1 dtherm ida arat pln pts hwp hwp_notify hwp_act_window hwp_epp bugs : bogomips : 5615.80 clflush size : 64 cache_alignment : 64 address sizes : 39 bits physical, 48 bits virtual power management: I guess i'll need a different mechanism to test rdrand and rdseed support separately.
Proposed fix sent to the mailing list.
Fix pushed as c26db3b33b7274946e42c6656ee1c0911cefb865