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| author | Giancarlo Frix <gfrix@rocketsoftware.com> | 2020-12-06 14:30:53 +0400 |
|---|---|---|
| committer | Joel Brobecker <brobecker@adacore.com> | 2020-12-06 14:30:53 +0400 |
| commit | 47c4623c7587a0008597a4a10a7f32bbac1f7ad4 (patch) | |
| tree | 3635a19482020049d708fbfd98044752c8781ea1 | |
| parent | bc6989cbd3aa046fa35914466c9aa34d5550f7c2 (diff) | |
| download | gdb-47c4623c7587a0008597a4a10a7f32bbac1f7ad4.zip gdb-47c4623c7587a0008597a4a10a7f32bbac1f7ad4.tar.gz gdb-47c4623c7587a0008597a4a10a7f32bbac1f7ad4.tar.bz2 | |
s390: Fix BC instruction breakpoint handling
This fixes a long-lived bug in the s390 port.
When trying to step over a breakpoint set on a BC (branch on condition)
instruction with displaced stepping on IBM Z, gdb would incorrectly
adjust the pc regardless of whether or not the branch was taken. Since
the branch target is an absolute address, this would cause the inferior
to jump around wildly whenever the branch was taken, either crashing it
or causing it to behave unpredictably.
It turns out that the logic to handle BC instructions correctly was in
the code, but that the enum value representing its opcode has always
been incorrect.
This patch corrects the enum value to the actual opcode, fixing the
stepping problem. The enum value is also used in the prologue analysis
code, so this also fixes a minor bug where more of the prologue would
be read than was necessary.
gdb/ChangeLog:
PR breakpoints/27009
* s390-tdep.h (op_bc): Correct BC opcode value.
| -rw-r--r-- | gdb/ChangeLog | 5 | ||||
| -rw-r--r-- | gdb/s390-tdep.h | 2 |
2 files changed, 6 insertions, 1 deletions
diff --git a/gdb/ChangeLog b/gdb/ChangeLog index e2bb19d..6d30484 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,3 +1,8 @@ +2020-12-06 Giancarlo Frix <gfrix@rocketsoftware.com> (tiny change) + + PR breakpoints/27009 + * s390-tdep.h (op_bc): Correct BC opcode value. + 2020-12-04 Shahab Vahedi <shahab@synopsys.com> PR tdep/27015 diff --git a/gdb/s390-tdep.h b/gdb/s390-tdep.h index c0ea9cf..fc8918f 100644 --- a/gdb/s390-tdep.h +++ b/gdb/s390-tdep.h @@ -117,7 +117,7 @@ enum op_basr = 0x0d, op_bas = 0x4d, op_bcr = 0x07, - op_bc = 0x0d, + op_bc = 0x47, op_bctr = 0x06, op_bctgr = 0xb946, op_bct = 0x46, |