diff options
| -rw-r--r-- | gdb/ChangeLog | 16 | ||||
| -rw-r--r-- | gdb/gdbarch.h | 6 | ||||
| -rwxr-xr-x | gdb/gdbarch.sh | 4 | ||||
| -rw-r--r-- | gdb/infrun.c | 15 | ||||
| -rw-r--r-- | gdb/rs6000-tdep.c | 68 | ||||
| -rw-r--r-- | gdb/testsuite/ChangeLog | 6 | ||||
| -rw-r--r-- | gdb/testsuite/gdb.arch/ppc64-atomic-inst.exp | 50 |
7 files changed, 131 insertions, 34 deletions
diff --git a/gdb/ChangeLog b/gdb/ChangeLog index 33cb8fa..af26b58 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,5 +1,21 @@ 2015-08-07 Pedro Alves <palves@redhat.com> + * infrun.c (displaced_step_prepare_throw): Return -1 if + gdbarch_displaced_step_copy_insn returns NULL. Update intro + comment. + * rs6000-tdep.c (LWARX_MASK, LWARX_INSTRUCTION, LDARX_INSTRUCTION) + (STWCX_MASK, STWCX_INSTRUCTION, STDCX_INSTRUCTION): Move higher up + in file. + (ppc_displaced_step_copy_insn): New function. + (ppc_displaced_step_fixup): Update comment. + (rs6000_gdbarch_init): Install ppc_displaced_step_copy_insn as + gdbarch_displaced_step_copy_insn hook. + * gdbarch.sh (displaced_step_copy_insn): Document what happens on + NULL return. + * gdbarch.h: Regenerate. + +2015-08-07 Pedro Alves <palves@redhat.com> + * inferior.h (struct inferior) <displaced_stepping_failed>: New field. * infrun.c (use_displaced_stepping_now_p): New parameter 'inf'. diff --git a/gdb/gdbarch.h b/gdb/gdbarch.h index d714281..c1e2c1a 100644 --- a/gdb/gdbarch.h +++ b/gdb/gdbarch.h @@ -923,7 +923,11 @@ extern void set_gdbarch_max_insn_length (struct gdbarch *gdbarch, ULONGEST max_i If your architecture doesn't need to adjust instructions before single-stepping them, consider using simple_displaced_step_copy_insn - here. */ + here. + + If the instruction cannot execute out of line, return NULL. The + core falls back to stepping past the instruction in-line instead in + that case. */ extern int gdbarch_displaced_step_copy_insn_p (struct gdbarch *gdbarch); diff --git a/gdb/gdbarch.sh b/gdb/gdbarch.sh index 14a5f9c..994a87b 100755 --- a/gdb/gdbarch.sh +++ b/gdb/gdbarch.sh @@ -763,6 +763,10 @@ V:ULONGEST:max_insn_length:::0:0 # If your architecture doesn't need to adjust instructions before # single-stepping them, consider using simple_displaced_step_copy_insn # here. +# +# If the instruction cannot execute out of line, return NULL. The +# core falls back to stepping past the instruction in-line instead in +# that case. M:struct displaced_step_closure *:displaced_step_copy_insn:CORE_ADDR from, CORE_ADDR to, struct regcache *regs:from, to, regs # Return true if GDB should use hardware single-stepping to execute diff --git a/gdb/infrun.c b/gdb/infrun.c index 157c12c..21aa8cf 100644 --- a/gdb/infrun.c +++ b/gdb/infrun.c @@ -1711,7 +1711,9 @@ displaced_step_dump_bytes (struct ui_file *file, explain how we handle this case instead. Returns 1 if preparing was successful -- this thread is going to be - stepped now; or 0 if displaced stepping this thread got queued. */ + stepped now; 0 if displaced stepping this thread got queued; or -1 + if this instruction can't be displaced stepped. */ + static int displaced_step_prepare_throw (ptid_t ptid) { @@ -1795,9 +1797,14 @@ displaced_step_prepare_throw (ptid_t ptid) closure = gdbarch_displaced_step_copy_insn (gdbarch, original, copy, regcache); - - /* We don't support the fully-simulated case at present. */ - gdb_assert (closure); + if (closure == NULL) + { + /* The architecture doesn't know how or want to displaced step + this instruction or instruction sequence. Fallback to + stepping over the breakpoint in-line. */ + do_cleanups (old_cleanups); + return -1; + } /* Save the information we need to fix things up if the step succeeds. */ diff --git a/gdb/rs6000-tdep.c b/gdb/rs6000-tdep.c index 5176fa0..785f451 100644 --- a/gdb/rs6000-tdep.c +++ b/gdb/rs6000-tdep.c @@ -974,6 +974,61 @@ rs6000_breakpoint_from_pc (struct gdbarch *gdbarch, CORE_ADDR *bp_addr, #define BXL_INSN 0x4c000000 #define BP_INSN 0x7C000008 +/* Instruction masks used during single-stepping of atomic + sequences. */ +#define LWARX_MASK 0xfc0007fe +#define LWARX_INSTRUCTION 0x7c000028 +#define LDARX_INSTRUCTION 0x7c0000A8 +#define STWCX_MASK 0xfc0007ff +#define STWCX_INSTRUCTION 0x7c00012d +#define STDCX_INSTRUCTION 0x7c0001ad + +/* We can't displaced step atomic sequences. Otherwise this is just + like simple_displaced_step_copy_insn. */ + +static struct displaced_step_closure * +ppc_displaced_step_copy_insn (struct gdbarch *gdbarch, + CORE_ADDR from, CORE_ADDR to, + struct regcache *regs) +{ + size_t len = gdbarch_max_insn_length (gdbarch); + gdb_byte *buf = xmalloc (len); + struct cleanup *old_chain = make_cleanup (xfree, buf); + enum bfd_endian byte_order = gdbarch_byte_order (gdbarch); + int insn; + + read_memory (from, buf, len); + + insn = extract_signed_integer (buf, PPC_INSN_SIZE, byte_order); + + /* Assume all atomic sequences start with a lwarx/ldarx instruction. */ + if ((insn & LWARX_MASK) == LWARX_INSTRUCTION + || (insn & LWARX_MASK) == LDARX_INSTRUCTION) + { + if (debug_displaced) + { + fprintf_unfiltered (gdb_stdlog, + "displaced: can't displaced step " + "atomic sequence at %s\n", + paddress (gdbarch, from)); + } + do_cleanups (old_chain); + return NULL; + } + + write_memory (to, buf, len); + + if (debug_displaced) + { + fprintf_unfiltered (gdb_stdlog, "displaced: copy %s->%s: ", + paddress (gdbarch, from), paddress (gdbarch, to)); + displaced_step_dump_bytes (gdb_stdlog, buf, len); + } + + discard_cleanups (old_chain); + return (struct displaced_step_closure *) buf; +} + /* Fix up the state of registers and memory after having single-stepped a displaced instruction. */ static void @@ -983,8 +1038,7 @@ ppc_displaced_step_fixup (struct gdbarch *gdbarch, struct regcache *regs) { enum bfd_endian byte_order = gdbarch_byte_order (gdbarch); - /* Since we use simple_displaced_step_copy_insn, our closure is a - copy of the instruction. */ + /* Our closure is a copy of the instruction. */ ULONGEST insn = extract_unsigned_integer ((gdb_byte *) closure, PPC_INSN_SIZE, byte_order); ULONGEST opcode = 0; @@ -1077,14 +1131,6 @@ ppc_displaced_step_hw_singlestep (struct gdbarch *gdbarch, return 1; } -/* Instruction masks used during single-stepping of atomic sequences. */ -#define LWARX_MASK 0xfc0007fe -#define LWARX_INSTRUCTION 0x7c000028 -#define LDARX_INSTRUCTION 0x7c0000A8 -#define STWCX_MASK 0xfc0007ff -#define STWCX_INSTRUCTION 0x7c00012d -#define STDCX_INSTRUCTION 0x7c0001ad - /* Checks for an atomic sequence of instructions beginning with a LWARX/LDARX instruction and ending with a STWCX/STDCX instruction. If such a sequence is found, attempt to step through it. A breakpoint is placed at the end of @@ -5923,7 +5969,7 @@ rs6000_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches) /* Setup displaced stepping. */ set_gdbarch_displaced_step_copy_insn (gdbarch, - simple_displaced_step_copy_insn); + ppc_displaced_step_copy_insn); set_gdbarch_displaced_step_hw_singlestep (gdbarch, ppc_displaced_step_hw_singlestep); set_gdbarch_displaced_step_fixup (gdbarch, ppc_displaced_step_fixup); diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog index cb69f08..813b249 100644 --- a/gdb/testsuite/ChangeLog +++ b/gdb/testsuite/ChangeLog @@ -1,5 +1,11 @@ 2015-08-07 Pedro Alves <palves@redhat.com> + * gdb.arch/ppc64-atomic-inst.exp (do_test): New procedure, move + tests here. + (top level): Run do_test with and without displaced stepping. + +2015-08-07 Pedro Alves <palves@redhat.com> + * gdb.base/valgrind-disp-step.c: New file. * gdb.base/valgrind-disp-step.exp: New file. diff --git a/gdb/testsuite/gdb.arch/ppc64-atomic-inst.exp b/gdb/testsuite/gdb.arch/ppc64-atomic-inst.exp index d251425..08518fb 100644 --- a/gdb/testsuite/gdb.arch/ppc64-atomic-inst.exp +++ b/gdb/testsuite/gdb.arch/ppc64-atomic-inst.exp @@ -32,27 +32,41 @@ if { [prepare_for_testing ${testfile}.exp ${testfile} ${srcfile} {debug quiet}] return -1 } -if ![runto_main] then { - untested "could not run to main" - return -1 -} +# The test proper. DISPLACED is true if we should try with displaced +# stepping. +proc do_test { displaced } { + global decimal hex + + if ![runto_main] then { + untested "could not run to main" + return -1 + } + + gdb_test_no_output "set displaced-stepping $displaced" -set bp1 [gdb_get_line_number "lwarx"] -gdb_breakpoint "$bp1" "Breakpoint $decimal at $hex" \ - "Set the breakpoint at the start of the lwarx/stwcx sequence" + set bp1 [gdb_get_line_number "lwarx"] + gdb_breakpoint "$bp1" "Breakpoint $decimal at $hex" \ + "Set the breakpoint at the start of the lwarx/stwcx sequence" -set bp2 [gdb_get_line_number "ldarx"] -gdb_breakpoint "$bp2" "Breakpoint $decimal at $hex" \ - "Set the breakpoint at the start of the ldarx/stdcx sequence" + set bp2 [gdb_get_line_number "ldarx"] + gdb_breakpoint "$bp2" "Breakpoint $decimal at $hex" \ + "Set the breakpoint at the start of the ldarx/stdcx sequence" -gdb_test continue "Continuing.*Breakpoint $decimal.*" \ - "Continue until lwarx/stwcx start breakpoint" + gdb_test continue "Continuing.*Breakpoint $decimal.*" \ + "Continue until lwarx/stwcx start breakpoint" -gdb_test nexti "bne.*1b" \ - "Step through the lwarx/stwcx sequence" + gdb_test nexti "bne.*1b" \ + "Step through the lwarx/stwcx sequence" -gdb_test continue "Continuing.*Breakpoint $decimal.*" \ - "Continue until ldarx/stdcx start breakpoint" + gdb_test continue "Continuing.*Breakpoint $decimal.*" \ + "Continue until ldarx/stdcx start breakpoint" -gdb_test nexti "bne.*1b" \ - "Step through the ldarx/stdcx sequence" + gdb_test nexti "bne.*1b" \ + "Step through the ldarx/stdcx sequence" +} + +foreach displaced { "off" "on" } { + with_test_prefix "displaced=$displaced" { + do_test $displaced + } +} |