Support for DTrace USDT probes in x86_64 targets.
This patch adds the target-specific code in order to support the calculation of DTrace probes arguments in x86_64 targets, and also the enabling and disabling of probes. This is done by implementing the `dtrace_*' gdbarch handlers. gdb/ChangeLog: 2015-02-17 Jose E. Marchesi <jose.marchesi@oracle.com> * amd64-linux-tdep.c: Include "parser-defs.h" and "user-regs.h". (amd64_dtrace_parse_probe_argument): New function. (amd64_dtrace_probe_is_enabled): Likewise. (amd64_dtrace_enable_probe): Likewise. (amd64_dtrace_disable_probe): Likewise. (amd64_linux_init_abi): Register the `gdbarch_dtrace_probe_argument', `gdbarch_dtrace_enable_probe', `gdbarch_dtrace_disable_probe' and `gdbarch_dtrace_probe_is_enabled' hooks. (amd64_dtrace_disabled_probe_sequence_1): New constant. (amd64_dtrace_disabled_probe_sequence_2): Likewise. (amd64_dtrace_enable_probe_sequence): Likewise. (amd64_dtrace_disable_probe_sequence): Likewise.
This commit is contained in:
Jose E. Marchesi
parent
d4777acbc9
commit
c3e3045e5c
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@ -1,3 +1,19 @@
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2015-02-17 Jose E. Marchesi <jose.marchesi@oracle.com>
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* amd64-linux-tdep.c: Include "parser-defs.h" and "user-regs.h".
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(amd64_dtrace_parse_probe_argument): New function.
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(amd64_dtrace_probe_is_enabled): Likewise.
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(amd64_dtrace_enable_probe): Likewise.
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(amd64_dtrace_disable_probe): Likewise.
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(amd64_linux_init_abi): Register the
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`gdbarch_dtrace_probe_argument', `gdbarch_dtrace_enable_probe',
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`gdbarch_dtrace_disable_probe' and
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`gdbarch_dtrace_probe_is_enabled' hooks.
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(amd64_dtrace_disabled_probe_sequence_1): New constant.
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(amd64_dtrace_disabled_probe_sequence_2): Likewise.
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(amd64_dtrace_enable_probe_sequence): Likewise.
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(amd64_dtrace_disable_probe_sequence): Likewise.
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2015-01-17 Jose E. Marchesi <jose.marchesi@oracle.com>
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* breakpoint.c (BREAK_ARGS_HELP): Help string updated to mention
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@ -28,6 +28,8 @@
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#include "gdbtypes.h"
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#include "reggroups.h"
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#include "regset.h"
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#include "parser-defs.h"
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#include "user-regs.h"
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#include "amd64-linux-tdep.h"
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#include "i386-linux-tdep.h"
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#include "linux-tdep.h"
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@ -1643,6 +1645,146 @@ amd64_linux_iterate_over_regset_sections (struct gdbarch *gdbarch,
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&amd64_linux_xstateregset, "XSAVE extended state", cb_data);
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}
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/* The instruction sequences used in x86_64 machines for a
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disabled is-enabled probe. */
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const gdb_byte amd64_dtrace_disabled_probe_sequence_1[] = {
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/* xor %rax, %rax */ 0x48, 0x33, 0xc0,
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/* nop */ 0x90,
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/* nop */ 0x90
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};
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const gdb_byte amd64_dtrace_disabled_probe_sequence_2[] = {
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/* xor %rax, %rax */ 0x48, 0x33, 0xc0,
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/* ret */ 0xc3,
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/* nop */ 0x90
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};
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/* The instruction sequence used in x86_64 machines for enabling a
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DTrace is-enabled probe. */
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const gdb_byte amd64_dtrace_enable_probe_sequence[] = {
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/* mov $0x1, %eax */ 0xb8, 0x01, 0x00, 0x00, 0x00
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};
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/* The instruction sequence used in x86_64 machines for disabling a
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DTrace is-enabled probe. */
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const gdb_byte amd64_dtrace_disable_probe_sequence[] = {
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/* xor %rax, %rax; nop; nop */ 0x48, 0x33, 0xC0, 0x90, 0x90
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};
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/* Implementation of `gdbarch_dtrace_probe_is_enabled', as defined in
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gdbarch.h. */
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static int
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amd64_dtrace_probe_is_enabled (struct gdbarch *gdbarch, CORE_ADDR addr)
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{
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gdb_byte buf[5];
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/* This function returns 1 if the instructions at ADDR do _not_
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follow any of the amd64_dtrace_disabled_probe_sequence_*
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patterns.
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Note that ADDR is offset 3 bytes from the beginning of these
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sequences. */
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read_code (addr - 3, buf, 5);
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return (memcmp (buf, amd64_dtrace_disabled_probe_sequence_1, 5) != 0
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&& memcmp (buf, amd64_dtrace_disabled_probe_sequence_2, 5) != 0);
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}
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/* Implementation of `gdbarch_dtrace_enable_probe', as defined in
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gdbarch.h. */
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static void
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amd64_dtrace_enable_probe (struct gdbarch *gdbarch, CORE_ADDR addr)
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{
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/* Note also that ADDR is offset 3 bytes from the beginning of
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amd64_dtrace_enable_probe_sequence. */
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write_memory (addr - 3, amd64_dtrace_enable_probe_sequence, 5);
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}
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/* Implementation of `gdbarch_dtrace_disable_probe', as defined in
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gdbarch.h. */
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static void
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amd64_dtrace_disable_probe (struct gdbarch *gdbarch, CORE_ADDR addr)
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{
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/* Note also that ADDR is offset 3 bytes from the beginning of
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amd64_dtrace_disable_probe_sequence. */
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write_memory (addr - 3, amd64_dtrace_disable_probe_sequence, 5);
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}
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/* Implementation of `gdbarch_dtrace_parse_probe_argument', as defined
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in gdbarch.h. */
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static void
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amd64_dtrace_parse_probe_argument (struct gdbarch *gdbarch,
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struct parser_state *pstate,
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int narg)
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{
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enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
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struct frame_info *this_frame = get_selected_frame (NULL);
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struct stoken str;
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/* DTrace probe arguments can be found on the ABI-defined places for
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regular arguments at the current PC. The probe abstraction
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currently supports up to 12 arguments for probes. */
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if (narg < 6)
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{
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static const int arg_reg_map[6] =
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{
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AMD64_RDI_REGNUM, /* Arg 1. */
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AMD64_RSI_REGNUM, /* Arg 2. */
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AMD64_RDX_REGNUM, /* Arg 3. */
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AMD64_RCX_REGNUM, /* Arg 4. */
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AMD64_R8_REGNUM, /* Arg 5. */
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AMD64_R9_REGNUM /* Arg 6. */
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};
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int regno = arg_reg_map[narg];
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const char *regname = user_reg_map_regnum_to_name (gdbarch, regno);
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write_exp_elt_opcode (pstate, OP_REGISTER);
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str.ptr = regname;
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str.length = strlen (regname);
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write_exp_string (pstate, str);
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write_exp_elt_opcode (pstate, OP_REGISTER);
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}
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else
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{
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/* Additional arguments are passed on the stack. */
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CORE_ADDR sp;
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const char *regname = user_reg_map_regnum_to_name (gdbarch, AMD64_RSP_REGNUM);
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/* Displacement. */
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write_exp_elt_opcode (pstate, OP_LONG);
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write_exp_elt_type (pstate, builtin_type (gdbarch)->builtin_long);
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write_exp_elt_longcst (pstate, narg - 6);
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write_exp_elt_opcode (pstate, OP_LONG);
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/* Register: SP. */
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write_exp_elt_opcode (pstate, OP_REGISTER);
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str.ptr = regname;
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str.length = strlen (regname);
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write_exp_string (pstate, str);
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write_exp_elt_opcode (pstate, OP_REGISTER);
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write_exp_elt_opcode (pstate, BINOP_ADD);
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/* Cast to long. */
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write_exp_elt_opcode (pstate, UNOP_CAST);
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write_exp_elt_type (pstate,
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lookup_pointer_type (builtin_type (gdbarch)->builtin_long));
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write_exp_elt_opcode (pstate, UNOP_CAST);
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write_exp_elt_opcode (pstate, UNOP_IND);
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}
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}
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static void
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amd64_linux_init_abi_common(struct gdbarch_info info, struct gdbarch *gdbarch)
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{
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@ -1907,6 +2049,12 @@ amd64_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
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/* GNU/Linux uses SVR4-style shared libraries. */
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set_solib_svr4_fetch_link_map_offsets
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(gdbarch, svr4_lp64_fetch_link_map_offsets);
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/* Register DTrace handlers. */
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set_gdbarch_dtrace_parse_probe_argument (gdbarch, amd64_dtrace_parse_probe_argument);
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set_gdbarch_dtrace_probe_is_enabled (gdbarch, amd64_dtrace_probe_is_enabled);
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set_gdbarch_dtrace_enable_probe (gdbarch, amd64_dtrace_enable_probe);
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set_gdbarch_dtrace_disable_probe (gdbarch, amd64_dtrace_disable_probe);
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}
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static void
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