gdbstub: Allow target CPUs to specify watchpoint STOP_BEFORE_ACCESS flag

GDB assumes that watchpoint set via the gdbstub remote protocol will
behave in the same way as hardware watchpoints for the target. In
particular, whether the CPU stops with the PC before or after the insn
which triggers the watchpoint is target dependent. Allow guest CPU
code to specify which behaviour to use. This fixes a bug where with
guest CPUs which stop before the accessing insn GDB would manually
step forward over what it thought was the insn and end up one insn
further forward than it should be.

We set this flag for the CPU architectures which set
gdbarch_have_nonsteppable_watchpoint in gdb 7.7:
ARM, CRIS, LM32, MIPS and Xtensa.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com>
Tested-by: Max Filippov <jcmvbkbc@gmail.com>
Tested-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com>
Tested-by: Michael Walle <michael@walle.cc> (for lm32)
Message-id: 1410545057-14014-1-git-send-email-peter.maydell@linaro.org
7 files changed
tree: a9ed9fa651dc7a884600cfef65da71211eb6031f
  1. audio/
  2. backends/
  3. block/
  4. bsd-user/
  5. default-configs/
  6. disas/
  7. docs/
  8. fpu/
  9. fsdev/
  10. gdb-xml/
  11. hw/
  12. include/
  13. libcacard/
  14. libdecnumber/
  15. linux-headers/
  16. linux-user/
  17. net/
  18. pc-bios/
  19. po/
  20. qapi/
  21. qga/
  22. qobject/
  23. qom/
  24. roms/
  25. scripts/
  26. slirp/
  27. stubs/
  28. sysconfigs/
  29. target-alpha/
  30. target-arm/
  31. target-cris/
  32. target-i386/
  33. target-lm32/
  34. target-m68k/
  35. target-microblaze/
  36. target-mips/
  37. target-moxie/
  38. target-openrisc/
  39. target-ppc/
  40. target-s390x/
  41. target-sh4/
  42. target-sparc/
  43. target-tricore/
  44. target-unicore32/
  45. target-xtensa/
  46. tcg/
  47. tests/
  48. trace/
  49. ui/
  50. util/
  51. .exrc
  52. .gitignore
  53. .gitmodules
  54. .mailmap
  55. .travis.yml
  56. aio-posix.c
  57. aio-win32.c
  58. arch_init.c
  59. async.c
  60. balloon.c
  61. block-migration.c
  62. block.c
  63. blockdev-nbd.c
  64. blockdev.c
  65. blockjob.c
  66. bt-host.c
  67. bt-vhci.c
  68. Changelog
  69. CODING_STYLE
  70. configure
  71. COPYING
  72. COPYING.LIB
  73. coroutine-gthread.c
  74. coroutine-sigaltstack.c
  75. coroutine-ucontext.c
  76. coroutine-win32.c
  77. cpu-exec.c
  78. cpus.c
  79. cputlb.c
  80. device-hotplug.c
  81. device_tree.c
  82. disas.c
  83. dma-helpers.c
  84. dump.c
  85. exec.c
  86. gdbstub.c
  87. HACKING
  88. hmp-commands.hx
  89. hmp.c
  90. hmp.h
  91. iohandler.c
  92. ioport.c
  93. iothread.c
  94. kvm-all.c
  95. kvm-stub.c
  96. LICENSE
  97. main-loop.c
  98. MAINTAINERS
  99. Makefile
  100. Makefile.objs
  101. Makefile.target
  102. memory.c
  103. memory_mapping.c
  104. migration-exec.c
  105. migration-fd.c
  106. migration-rdma.c
  107. migration-tcp.c
  108. migration-unix.c
  109. migration.c
  110. module-common.c
  111. monitor.c
  112. nbd.c
  113. numa.c
  114. os-posix.c
  115. os-win32.c
  116. page_cache.c
  117. qapi-schema.json
  118. qdev-monitor.c
  119. qdict-test-data.txt
  120. qemu-bridge-helper.c
  121. qemu-char.c
  122. qemu-coroutine-io.c
  123. qemu-coroutine-lock.c
  124. qemu-coroutine-sleep.c
  125. qemu-coroutine.c
  126. qemu-doc.texi
  127. qemu-file.c
  128. qemu-img-cmds.hx
  129. qemu-img.c
  130. qemu-img.texi
  131. qemu-io-cmds.c
  132. qemu-io.c
  133. qemu-log.c
  134. qemu-nbd.c
  135. qemu-nbd.texi
  136. qemu-options-wrapper.h
  137. qemu-options.h
  138. qemu-options.hx
  139. qemu-seccomp.c
  140. qemu-tech.texi
  141. qemu-timer.c
  142. qemu.nsi
  143. qemu.sasl
  144. qmp-commands.hx
  145. qmp.c
  146. qtest.c
  147. README
  148. rules.mak
  149. savevm.c
  150. softmmu_template.h
  151. spice-qemu-char.c
  152. tcg-runtime.c
  153. tci.c
  154. thread-pool.c
  155. thunk.c
  156. tpm.c
  157. trace-events
  158. translate-all.c
  159. translate-all.h
  160. user-exec.c
  161. VERSION
  162. version.rc
  163. vl.c
  164. vmstate.c
  165. xbzrle.c
  166. xen-common-stub.c
  167. xen-common.c
  168. xen-hvm-stub.c
  169. xen-hvm.c
  170. xen-mapcache.c