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[binutils-gdb] Fix PR19061, gdb hangs/spins-on-cpu when debugging any program on Alpha
- From: Pedro Alves <palves at sourceware dot org>
- To: gdb-cvs at sourceware dot org
- Date: 15 Dec 2017 18:21:21 -0000
- Subject: [binutils-gdb] Fix PR19061, gdb hangs/spins-on-cpu when debugging any program on Alpha
https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=68f81d60196eb201b209873cf53258f13b0046b9
commit 68f81d60196eb201b209873cf53258f13b0046b9
Author: Richard Henderson <rth@redhat.com>
Date: Fri Dec 15 18:19:42 2017 +0000
Fix PR19061, gdb hangs/spins-on-cpu when debugging any program on Alpha
This fixes PR19061, where gdb hangs/spins-on-cpu when debugging any
program on Alpha.
(This patch is Uros' forward port of the patch from comment #5
of the PR [1].)
Patch was tested on alphaev68-linux-gnu, also tested with gcc's
testsuite, where it fixed all hangs in guality.exp and
simulate-thread.exp testcases.
[1] https://sourceware.org/bugzilla/show_bug.cgi?id=19061#c5
gdb/ChangeLog:
2017-12-15 Richard Henderson <rth@redhat.com>
Uros Bizjak <ubizjak@gmail.com>
PR gdb/19061
* alpha-tdep.c (alpha_software_single_step): Call
alpha_deal_with_atomic_sequence here.
(set_gdbarch_software_single_step): Set to
alpha_software_single_step.
* nat/linux-ptrace.h [__alpha__]: Define GDB_ARCH_IS_TRAP_BRKPT
and GDB_ARCH_IS_TRAP_HWBKPT.
Diff:
---
gdb/ChangeLog | 11 +++++++++++
gdb/alpha-tdep.c | 18 ++++++++++++------
gdb/nat/linux-ptrace.h | 5 +++++
3 files changed, 28 insertions(+), 6 deletions(-)
diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 292929d..6a5c74b 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,14 @@
+2017-12-15 Richard Henderson <rth@redhat.com>
+ Uros Bizjak <ubizjak@gmail.com>
+
+ PR gdb/19061
+ * alpha-tdep.c (alpha_software_single_step): Call
+ alpha_deal_with_atomic_sequence here.
+ (set_gdbarch_software_single_step): Set to
+ alpha_software_single_step.
+ * nat/linux-ptrace.h [__alpha__]: Define GDB_ARCH_IS_TRAP_BRKPT
+ and GDB_ARCH_IS_TRAP_HWBKPT.
+
2017-12-15 Yao Qi <yao.qi@linaro.org>
* unittests/memory-map-selftests.c: Wrap test with HAVE_LIBEXPAT.
diff --git a/gdb/alpha-tdep.c b/gdb/alpha-tdep.c
index 21199bd..07144ce 100644
--- a/gdb/alpha-tdep.c
+++ b/gdb/alpha-tdep.c
@@ -767,10 +767,8 @@ static const int stq_c_opcode = 0x2f;
the sequence. */
static std::vector<CORE_ADDR>
-alpha_deal_with_atomic_sequence (struct regcache *regcache)
+alpha_deal_with_atomic_sequence (struct gdbarch *gdbarch, CORE_ADDR pc)
{
- struct gdbarch *gdbarch = regcache->arch ();
- CORE_ADDR pc = regcache_read_pc (regcache);
CORE_ADDR breaks[2] = {-1, -1};
CORE_ADDR loc = pc;
CORE_ADDR closing_insn; /* Instruction that closes the atomic sequence. */
@@ -1723,9 +1721,17 @@ alpha_next_pc (struct regcache *regcache, CORE_ADDR pc)
std::vector<CORE_ADDR>
alpha_software_single_step (struct regcache *regcache)
{
- CORE_ADDR pc = alpha_next_pc (regcache, regcache_read_pc (regcache));
+ struct gdbarch *gdbarch = regcache->arch ();
+
+ CORE_ADDR pc = regcache_read_pc (regcache);
+
+ std::vector<CORE_ADDR> next_pcs
+ = alpha_deal_with_atomic_sequence (gdbarch, pc);
+ if (!next_pcs.empty ())
+ return next_pcs;
- return {pc};
+ CORE_ADDR next_pc = alpha_next_pc (regcache, pc);
+ return {next_pc};
}
@@ -1821,7 +1827,7 @@ alpha_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
set_gdbarch_cannot_step_breakpoint (gdbarch, 1);
/* Handles single stepping of atomic sequences. */
- set_gdbarch_software_single_step (gdbarch, alpha_deal_with_atomic_sequence);
+ set_gdbarch_software_single_step (gdbarch, alpha_software_single_step);
/* Hook in ABI-specific overrides, if they have been registered. */
gdbarch_init_osabi (info, gdbarch);
diff --git a/gdb/nat/linux-ptrace.h b/gdb/nat/linux-ptrace.h
index 5954945..8a8c4c6 100644
--- a/gdb/nat/linux-ptrace.h
+++ b/gdb/nat/linux-ptrace.h
@@ -155,6 +155,8 @@ struct buffer;
Beginning with Linux 4.6, the MIPS port reports proper TRAP_BRKPT and
TRAP_HWBKPT codes, so we also match them.
+ The Alpha kernel uses TRAP_BRKPT for all traps.
+
The generic Linux target code should use GDB_ARCH_IS_TRAP_* instead
of TRAP_* to abstract out these peculiarities. */
#if defined __i386__ || defined __x86_64__
@@ -166,6 +168,9 @@ struct buffer;
#elif defined __mips__
# define GDB_ARCH_IS_TRAP_BRKPT(X) ((X) == SI_KERNEL || (X) == TRAP_BRKPT)
# define GDB_ARCH_IS_TRAP_HWBKPT(X) ((X) == SI_KERNEL || (X) == TRAP_HWBKPT)
+#elif defined __alpha__
+# define GDB_ARCH_IS_TRAP_BRKPT(X) ((X) == TRAP_BRKPT)
+# define GDB_ARCH_IS_TRAP_HWBKPT(X) ((X) == TRAP_BRKPT)
#else
# define GDB_ARCH_IS_TRAP_BRKPT(X) ((X) == TRAP_BRKPT)
# define GDB_ARCH_IS_TRAP_HWBKPT(X) ((X) == TRAP_HWBKPT)