| Message ID | 20230726183532.434380-7-npiggin@gmail.com |
|---|---|
| State | New |
| Headers | show |
| Series | ppc: record-replay fixes and enablement | expand |
Reviewed-by: Pavel Dovgalyuk <Pavel.Dovgalyuk@ispras.ru> On 26.07.2023 21:35, Nicholas Piggin wrote: > The reverse-debugging test creates a trace, then replays it and: > > 1. Steps the first 10 instructions and records their addresses. > 2. Steps backward and verifies their addresses match. > 3. Runs to (near) the end of the trace. > 4. Sets breakpoints on the first 10 instructions. > 5. Continues backward and verifies execution stops at the last > breakpoint. > > Step 5 breaks if any of the other 9 breakpoints are re-executed in the > trace after the 10th instruction is run, because those will be > unexpectedly hit when reverse continuing. This situation does arise > with the ppc pseries machine, the SLOF bios branches to its own entry > point. > > Permit this breakpoint re-execution by switching steps 4 and 5, so that > the trace will be run to the end *or* the next breakpoint hit. > Reversing from there to the 10th intsruction will not hit another > breakpoint, by definition. > > Another step is added between steps 2 and 3, which steps forward over > the first 10 instructions and verifies their addresses, to support this. > > Cc: Pavel Dovgalyuk <Pavel.Dovgalyuk@ispras.ru> > Signed-off-by: Nicholas Piggin <npiggin@gmail.com> > --- > tests/avocado/reverse_debugging.py | 25 +++++++++++++++++++++---- > 1 file changed, 21 insertions(+), 4 deletions(-) > > diff --git a/tests/avocado/reverse_debugging.py b/tests/avocado/reverse_debugging.py > index 680c314cfc..7d1a478df1 100644 > --- a/tests/avocado/reverse_debugging.py > +++ b/tests/avocado/reverse_debugging.py > @@ -150,16 +150,33 @@ def reverse_debugging(self, shift=7, args=None): > self.check_pc(g, addr) > logger.info('found position %x' % addr) > > - logger.info('seeking to the end (icount %s)' % (last_icount - 1)) > - vm.qmp('replay-break', icount=last_icount - 1) > - # continue - will return after pausing > - g.cmd(b'c', b'T02thread:01;') > + # visit the recorded instruction in forward order > + logger.info('stepping forward') > + for addr in steps: > + self.check_pc(g, addr) > + self.gdb_step(g) > + logger.info('found position %x' % addr) > > + # set breakpoints for the instructions just stepped over > logger.info('setting breakpoints') > for addr in steps: > # hardware breakpoint at addr with len=1 > g.cmd(b'Z1,%x,1' % addr, b'OK') > > + # this may hit a breakpoint if first instructions are executed > + # again > + logger.info('continuing execution') > + vm.qmp('replay-break', icount=last_icount - 1) > + # continue - will return after pausing > + # This could stop at the end and get a T02 return, or by > + # re-executing one of the breakpoints and get a T05 return. > + g.cmd(b'c') > + if self.vm_get_icount(vm) == last_icount - 1: > + logger.info('reached the end (icount %s)' % (last_icount - 1)) > + else: > + logger.info('hit a breakpoint again at %x (icount %s)' % > + (self.get_pc(g), self.vm_get_icount(vm))) > + > logger.info('running reverse continue to reach %x' % steps[-1]) > # reverse continue - will return after stopping at the breakpoint > g.cmd(b'bc', b'T05thread:01;')
diff --git a/tests/avocado/reverse_debugging.py b/tests/avocado/reverse_debugging.py index 680c314cfc..7d1a478df1 100644 --- a/tests/avocado/reverse_debugging.py +++ b/tests/avocado/reverse_debugging.py @@ -150,16 +150,33 @@ def reverse_debugging(self, shift=7, args=None): self.check_pc(g, addr) logger.info('found position %x' % addr) - logger.info('seeking to the end (icount %s)' % (last_icount - 1)) - vm.qmp('replay-break', icount=last_icount - 1) - # continue - will return after pausing - g.cmd(b'c', b'T02thread:01;') + # visit the recorded instruction in forward order + logger.info('stepping forward') + for addr in steps: + self.check_pc(g, addr) + self.gdb_step(g) + logger.info('found position %x' % addr) + # set breakpoints for the instructions just stepped over logger.info('setting breakpoints') for addr in steps: # hardware breakpoint at addr with len=1 g.cmd(b'Z1,%x,1' % addr, b'OK') + # this may hit a breakpoint if first instructions are executed + # again + logger.info('continuing execution') + vm.qmp('replay-break', icount=last_icount - 1) + # continue - will return after pausing + # This could stop at the end and get a T02 return, or by + # re-executing one of the breakpoints and get a T05 return. + g.cmd(b'c') + if self.vm_get_icount(vm) == last_icount - 1: + logger.info('reached the end (icount %s)' % (last_icount - 1)) + else: + logger.info('hit a breakpoint again at %x (icount %s)' % + (self.get_pc(g), self.vm_get_icount(vm))) + logger.info('running reverse continue to reach %x' % steps[-1]) # reverse continue - will return after stopping at the breakpoint g.cmd(b'bc', b'T05thread:01;')
The reverse-debugging test creates a trace, then replays it and: 1. Steps the first 10 instructions and records their addresses. 2. Steps backward and verifies their addresses match. 3. Runs to (near) the end of the trace. 4. Sets breakpoints on the first 10 instructions. 5. Continues backward and verifies execution stops at the last breakpoint. Step 5 breaks if any of the other 9 breakpoints are re-executed in the trace after the 10th instruction is run, because those will be unexpectedly hit when reverse continuing. This situation does arise with the ppc pseries machine, the SLOF bios branches to its own entry point. Permit this breakpoint re-execution by switching steps 4 and 5, so that the trace will be run to the end *or* the next breakpoint hit. Reversing from there to the 10th intsruction will not hit another breakpoint, by definition. Another step is added between steps 2 and 3, which steps forward over the first 10 instructions and verifies their addresses, to support this. Cc: Pavel Dovgalyuk <Pavel.Dovgalyuk@ispras.ru> Signed-off-by: Nicholas Piggin <npiggin@gmail.com> --- tests/avocado/reverse_debugging.py | 25 +++++++++++++++++++++---- 1 file changed, 21 insertions(+), 4 deletions(-)