[ARM] Make thumb2_breakpoint static again
This patch makes thumb2_breakpoint static. When writing this patch, I find the only reason we keep thumb2_breakpoint extern is that it is used as an argument passed to arm_gdbserver_get_next_pcs. However, field arm_thumb2_breakpoint is only used in a null check in thumb_get_next_pcs_raw, so I wonder why do need to pass thumb2_breakpoint to arm_gdbserver_get_next_pcs. thumb2_breakpoint was added by Daniel Jacobowitz in order to support single-step IT block https://sourceware.org/ml/gdb-patches/2010-01/msg00624.html the logic there was if we have 32-bit thumb-2 breakpoint defined, we can safely single-step IT block, otherwise, we can't. Daniel didn't want to use 16-bit thumb BKPT instruction, because it triggers even on instruction which should be executed. Secondly, using 16-bit thumb illegal instruction on top of 32-bit thumb instruction may break the meaning of original IT blocks, because the other 16-bit can be regarded as an instruction. See more explanations from Daniel's kernel patch http://www.spinics.net/lists/arm-kernel/msg80476.html Let us back to this patch, GDB/GDBserver can safely single step IT block if thumb2_breakpoint is defined, but the single step logic doesn't have to know the thumb-2 breakpoint instruction. Only breakpoint insertion mechanism decides to use which breakpoint instruction. In the software single step code, instead of pass thumb2_breakpoint, we can pass a boolean variable has_thumb2_breakpoint indicate whether the target has thumb-2 breakpoint defined, which is equivalent to the original code. Regression tested on arm-linux. No regression. gdb: 2016-01-14 Yao Qi <yao.qi@linaro.org> * arch/arm-get-next-pcs.c (arm_get_next_pcs_ctor): Change argument arm_thumb2_breakpoint to has_thumb2_breakpoint. (thumb_get_next_pcs_raw): Check has_thumb2_breakpoint instead. * arch/arm-get-next-pcs.h (struct arm_get_next_pcs) <arm_thumb2_breakpoint>: Remove. <has_thumb2_breakpoint>: New field. (arm_get_next_pcs_ctor): Update declaration. * arm-linux-tdep.c (arm_linux_software_single_step): Pass 1 to arm_get_next_pcs_ctor. * arm-tdep.c (arm_software_single_step): Pass 0 to arm_get_next_pcs_ctor. gdb/gdbserver: 2016-01-14 Yao Qi <yao.qi@linaro.org> * linux-aarch32-low.c (thumb2_breakpoint): Make it static. * linux-aarch32-low.h (thumb2_breakpoint): Remove declaration. * linux-arm-low.c (arm_gdbserver_get_next_pcs): Pass 1 to arm_get_next_pcs_ctor.
This commit is contained in:
Yao Qi
parent
fccbac73f9
commit
1b451dda5f
9 changed files with 33 additions and 12 deletions
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@ -1,3 +1,18 @@
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2016-01-14 Yao Qi <yao.qi@linaro.org>
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* arch/arm-get-next-pcs.c (arm_get_next_pcs_ctor): Change
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argument arm_thumb2_breakpoint to has_thumb2_breakpoint.
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(thumb_get_next_pcs_raw): Check has_thumb2_breakpoint
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instead.
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* arch/arm-get-next-pcs.h (struct arm_get_next_pcs)
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<arm_thumb2_breakpoint>: Remove.
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<has_thumb2_breakpoint>: New field.
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(arm_get_next_pcs_ctor): Update declaration.
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* arm-linux-tdep.c (arm_linux_software_single_step): Pass
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1 to arm_get_next_pcs_ctor.
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* arm-tdep.c (arm_software_single_step): Pass 0 to
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arm_get_next_pcs_ctor.
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2016-01-13 Ulrich Weigand <uweigand@de.ibm.com>
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* MAINTAINERS: Add Andreas Arnez as s390 target maintainer.
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@ -30,13 +30,13 @@ arm_get_next_pcs_ctor (struct arm_get_next_pcs *self,
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struct arm_get_next_pcs_ops *ops,
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int byte_order,
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int byte_order_for_code,
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const gdb_byte *arm_thumb2_breakpoint,
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int has_thumb2_breakpoint,
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struct regcache *regcache)
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{
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self->ops = ops;
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self->byte_order = byte_order;
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self->byte_order_for_code = byte_order_for_code;
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self->arm_thumb2_breakpoint = arm_thumb2_breakpoint;
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self->has_thumb2_breakpoint = has_thumb2_breakpoint;
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self->regcache = regcache;
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}
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@ -297,7 +297,7 @@ thumb_get_next_pcs_raw (struct arm_get_next_pcs *self, CORE_ADDR pc)
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flags, affecting the execution of further instructions, we may
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need to set two breakpoints. */
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if (self->arm_thumb2_breakpoint != NULL)
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if (self->has_thumb2_breakpoint)
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{
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if ((inst1 & 0xff00) == 0xbf00 && (inst1 & 0x000f) != 0)
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{
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@ -41,8 +41,9 @@ struct arm_get_next_pcs
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int byte_order;
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/* Byte order for code. */
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int byte_order_for_code;
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/* Thumb2 breakpoint instruction. */
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const gdb_byte *arm_thumb2_breakpoint;
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/* Whether the target has 32-bit thumb-2 breakpoint defined or
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not. */
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int has_thumb2_breakpoint;
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/* Registry cache. */
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struct regcache *regcache;
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};
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@ -52,7 +53,7 @@ void arm_get_next_pcs_ctor (struct arm_get_next_pcs *self,
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struct arm_get_next_pcs_ops *ops,
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int byte_order,
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int byte_order_for_code,
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const gdb_byte *arm_thumb2_breakpoint,
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int has_thumb2_breakpoint,
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struct regcache *regcache);
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/* Find the next possible PCs after the current instruction executes. */
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@ -931,7 +931,7 @@ arm_linux_software_single_step (struct frame_info *frame)
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&arm_linux_get_next_pcs_ops,
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gdbarch_byte_order (gdbarch),
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gdbarch_byte_order_for_code (gdbarch),
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gdbarch_tdep (gdbarch)->thumb2_breakpoint,
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1,
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regcache);
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next_pcs = arm_get_next_pcs (&next_pcs_ctx, regcache_read_pc (regcache));
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@ -6183,7 +6183,7 @@ arm_software_single_step (struct frame_info *frame)
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&arm_get_next_pcs_ops,
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gdbarch_byte_order (gdbarch),
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gdbarch_byte_order_for_code (gdbarch),
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gdbarch_tdep (gdbarch)->thumb2_breakpoint,
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0,
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regcache);
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next_pcs = arm_get_next_pcs (&next_pcs_ctx, regcache_read_pc (regcache));
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@ -1,3 +1,10 @@
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2016-01-14 Yao Qi <yao.qi@linaro.org>
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* linux-aarch32-low.c (thumb2_breakpoint): Make it static.
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* linux-aarch32-low.h (thumb2_breakpoint): Remove declaration.
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* linux-arm-low.c (arm_gdbserver_get_next_pcs): Pass 1 to
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arm_get_next_pcs_ctor.
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2016-01-12 Josh Stone <jistone@redhat.com>
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Philippe Waroquiers <philippe.waroquiers@skynet.be>
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@ -45,7 +45,7 @@ static const unsigned long arm_breakpoint = arm_abi_breakpoint;
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#define arm_breakpoint_len 4
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static const unsigned short thumb_breakpoint = 0xde01;
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#define thumb_breakpoint_len 2
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const unsigned short thumb2_breakpoint[] = { 0xf7f0, 0xa000 };
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static const unsigned short thumb2_breakpoint[] = { 0xf7f0, 0xa000 };
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#define thumb2_breakpoint_len 4
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/* Some older versions of GNU/Linux and Android do not define
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@ -15,8 +15,6 @@
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>. */
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extern const unsigned short thumb2_breakpoint[];
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extern struct regs_info regs_info_aarch32;
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void arm_fill_gregset (struct regcache *regcache, void *buf);
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@ -942,7 +942,7 @@ arm_gdbserver_get_next_pcs (CORE_ADDR pc, struct regcache *regcache)
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/* Byte order is ignored assumed as host. */
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0,
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0,
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(const gdb_byte *) &thumb2_breakpoint,
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1,
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regcache);
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next_pcs = arm_get_next_pcs (&next_pcs_ctx, pc);
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