diff options
Diffstat (limited to 'results/classifier/deepseek-2/output/debug/1364501')
| -rw-r--r-- | results/classifier/deepseek-2/output/debug/1364501 | 21 |
1 files changed, 0 insertions, 21 deletions
diff --git a/results/classifier/deepseek-2/output/debug/1364501 b/results/classifier/deepseek-2/output/debug/1364501 deleted file mode 100644 index 2b015b24..00000000 --- a/results/classifier/deepseek-2/output/debug/1364501 +++ /dev/null @@ -1,21 +0,0 @@ - -Gdb hangs when trying to single-step after an invalid instruction - -When using Gdb to remote-debug a program and manually setting its PC to point to an address containing an invalid instruction, then doing a single step Qemu will never return control to the remote Gdb. - -For instance, let's say address 0x114 contains an invalid instruction. On the remote Gdb, we'd do: - -(gdb) set $pc = 0x114 -(gdb) stepi - -After doing that we won't get the (gdb) prompt unless we do a Ctrl-C. If we do so we'll be left at 0x114 instead of going towards the exception handler as we should. This happens with stepi, step and next. If instead of single-stepping we used continue, the program will proceed into the exception handler as it should. - -The reason this is happening is that when Qemu realizes it's about to translate an instruction it doesn't recognize it'll generate a call to helper_exception_with_syndrome(), which will register the exception and then call cpu_loop_exit(). At the same time, because we're doing a single-step, Qemu will also generate a call to helper_exception_internal() passing it an EXCP_DEBUG, which lets the system know it'll give control back to the remote debugger, and it also ends with a call to cpu_loop_exit(). However, because the syndrome exception calls cpu_loop_exit() first, the call to the internal exception won't be reached and Qemu will be stuck in a loop without returning control to the remote debugger. - -What makes this a bit tricky to fix is that we must call cpu_loop_exit() at the end of helper_exception_with_syndrome(), otherwise the target exception will go undetected and its handler won't be excecuted. - -Tested on latest head by emulating a Stellaris lm3s6965 board and running RTEMS 4.11: - -$ qemu-system-arm -nographic -s -S -M lm3s6965evb -kernel my_rtems_app - -Commit hash in qemu.git: 30eaca3acdf17d7bcbd1213eb149c02037edfb0b \ No newline at end of file |