From 68f81d60196eb201b209873cf53258f13b0046b9 Mon Sep 17 00:00:00 2001 From: Richard Henderson Date: Fri, 15 Dec 2017 18:19:42 +0000 Subject: [PATCH] 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 Uros Bizjak 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. --- 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 292929df5f4..6a5c74bbbf2 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,3 +1,14 @@ +2017-12-15 Richard Henderson + Uros Bizjak + + 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 * unittests/memory-map-selftests.c: Wrap test with HAVE_LIBEXPAT. diff --git a/gdb/alpha-tdep.c b/gdb/alpha-tdep.c index 21199bd9880..07144ceb4e7 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 -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 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 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 59549452c09..8a8c4c6d3ec 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) -- 2.30.2