From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 22673 invoked by alias); 17 Oct 2014 12:35:32 -0000 Mailing-List: contact gdb-patches-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-patches-owner@sourceware.org Received: (qmail 22663 invoked by uid 89); 17 Oct 2014 12:35:31 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=1.4 required=5.0 tests=AWL,BAYES_00,LIKELY_SPAM_BODY,RP_MATCHES_RCVD,SPF_PASS,UNPARSEABLE_RELAY,URIBL_BLACK autolearn=no version=3.3.2 X-HELO: userp1040.oracle.com Received: from userp1040.oracle.com (HELO userp1040.oracle.com) (156.151.31.81) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with (AES256-SHA encrypted) ESMTPS; Fri, 17 Oct 2014 12:35:29 +0000 Received: from acsinet21.oracle.com (acsinet21.oracle.com [141.146.126.237]) by userp1040.oracle.com (Sentrion-MTA-4.3.2/Sentrion-MTA-4.3.2) with ESMTP id s9HCZQFY025136 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK); Fri, 17 Oct 2014 12:35:27 GMT Received: from aserz7021.oracle.com (aserz7021.oracle.com [141.146.126.230]) by acsinet21.oracle.com (8.14.4+Sun/8.14.4) with ESMTP id s9HCZPEx001002 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Fri, 17 Oct 2014 12:35:25 GMT Received: from abhmp0013.oracle.com (abhmp0013.oracle.com [141.146.116.19]) by aserz7021.oracle.com (8.14.4+Sun/8.14.4) with ESMTP id s9HCZPN4000993; Fri, 17 Oct 2014 12:35:25 GMT Received: from termi.oracle.com (/62.156.150.204) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Fri, 17 Oct 2014 05:35:24 -0700 From: jose.marchesi@oracle.com (Jose E. Marchesi) To: Pedro Alves Cc: gdb-patches@sourceware.org Subject: Re: [PATCH V2 6/9] Support for DTrace USDT probes in x86_64 targets. References: <1412961772-16249-1-git-send-email-jose.marchesi@oracle.com> <1412961772-16249-7-git-send-email-jose.marchesi@oracle.com> <544041A7.50802@gmail.com> Date: Fri, 17 Oct 2014 12:35:00 -0000 In-Reply-To: <544041A7.50802@gmail.com> (Pedro Alves's message of "Thu, 16 Oct 2014 23:07:35 +0100") Message-ID: <874mv2yime.fsf@oracle.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.3.50 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-IsSubscribed: yes X-SW-Source: 2014-10/txt/msg00469.txt.bz2 Hi Pedro. Thanks for your suggestions. I updated the patch addressing them. 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: 2014-10-17 Jose E. Marchesi * amd64-linux-tdep.c (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. diff --git a/gdb/ChangeLog b/gdb/ChangeLog index a2251a3..1bbe3c1 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,5 +1,20 @@ 2014-10-17 Jose E. Marchesi + * amd64-linux-tdep.c (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. + +2014-10-17 Jose E. Marchesi + * breakpoint.c (BREAK_ARGS_HELP): help string updated to mention the -probe-dtrace new vpossible value for PROBE_MODIFIER. * configure.ac (CONFIG_OBS): dtrace-probe.o added if BFD can diff --git a/gdb/amd64-linux-tdep.c b/gdb/amd64-linux-tdep.c index edbb1b3..9fe68b9 100644 --- a/gdb/amd64-linux-tdep.c +++ b/gdb/amd64-linux-tdep.c @@ -28,6 +28,8 @@ #include "gdbtypes.h" #include "reggroups.h" #include "regset.h" +#include "parser-defs.h" +#include "user-regs.h" #include "amd64-linux-tdep.h" #include "i386-linux-tdep.h" #include "linux-tdep.h" @@ -1643,6 +1645,146 @@ amd64_linux_iterate_over_regset_sections (struct gdbarch *gdbarch, &amd64_linux_xstateregset, "XSAVE extended state", cb_data); } +/* The instruction sequences used in x86_64 machines for a + disabled is-enabled probe. */ + +const gdb_byte amd64_dtrace_disabled_probe_sequence_1[] = { + /* xor %rax, %rax */ 0x48, 0x33, 0xc0, + /* nop */ 0x90, + /* nop */ 0x90 +}; + +const gdb_byte amd64_dtrace_disabled_probe_sequence_2[] = { + /* xor %rax, %rax */ 0x48, 0x33, 0xc0, + /* ret */ 0xc3, + /* nop */ 0x90 +}; + +/* The instruction sequence used in x86_64 machines for enabling a + DTrace is-enabled probe. */ + +const gdb_byte amd64_dtrace_enable_probe_sequence[] = { + /* mov $0x1, %eax */ 0xb8, 0x01, 0x00, 0x00, 0x00 +}; + +/* The instruction sequence used in x86_64 machines for disabling a + DTrace is-enabled probe. */ + +const gdb_byte amd64_dtrace_disable_probe_sequence[] = { + /* xor %rax, %rax; nop; nop */ 0x48, 0x33, 0xC0, 0x90, 0x90 +}; + +/* Implementation of `gdbarch_dtrace_probe_is_enabled', as defined in + gdbarch.h. */ + +static int +amd64_dtrace_probe_is_enabled (struct gdbarch *gdbarch, CORE_ADDR addr) +{ + gdb_byte buf[5]; + + /* This function returns 1 if the instructions at ADDR do _not_ + follow any of the amd64_dtrace_disabled_probe_sequence_* + patterns. + + Note that ADDR is offset 3 bytes from the beginning of these + sequences. */ + + read_code (addr - 3, buf, 5); + return (memcmp (buf, amd64_dtrace_disabled_probe_sequence_1, 5) != 0 + && memcmp (buf, amd64_dtrace_disabled_probe_sequence_2, 5) != 0); +} + +/* Implementation of `gdbarch_dtrace_enable_probe', as defined in + gdbarch.h. */ + +static void +amd64_dtrace_enable_probe (struct gdbarch *gdbarch, CORE_ADDR addr) +{ + /* Note also that ADDR is offset 3 bytes from the beginning of + amd64_dtrace_enable_probe_sequence. */ + + write_memory (addr - 3, amd64_dtrace_enable_probe_sequence, 5); +} + +/* Implementation of `gdbarch_dtrace_disable_probe', as defined in + gdbarch.h. */ + +static void +amd64_dtrace_disable_probe (struct gdbarch *gdbarch, CORE_ADDR addr) +{ + /* Note also that ADDR is offset 3 bytes from the beginning of + amd64_dtrace_disable_probe_sequence. */ + + write_memory (addr - 3, amd64_dtrace_disable_probe_sequence, 5); +} + +/* Implementation of `gdbarch_dtrace_parse_probe_argument', as defined + in gdbarch.h. */ + +static void +amd64_dtrace_parse_probe_argument (struct gdbarch *gdbarch, + struct parser_state *pstate, + int narg) +{ + enum bfd_endian byte_order = gdbarch_byte_order (gdbarch); + struct frame_info *this_frame = get_selected_frame (NULL); + struct stoken str; + + /* DTrace probe arguments can be found on the ABI-defined places for + regular arguments at the current PC. The probe abstraction + currently supports up to 12 arguments for probes. */ + + if (narg < 6) + { + static const int arg_reg_map[6] = + { + AMD64_RDI_REGNUM, /* Arg 1. */ + AMD64_RSI_REGNUM, /* Arg 2. */ + AMD64_RDX_REGNUM, /* Arg 3. */ + AMD64_RCX_REGNUM, /* Arg 4. */ + AMD64_R8_REGNUM, /* Arg 5. */ + AMD64_R9_REGNUM /* Arg 6. */ + }; + int regno = arg_reg_map[narg]; + const char *regname = user_reg_map_regnum_to_name (gdbarch, regno); + + write_exp_elt_opcode (pstate, OP_REGISTER); + str.ptr = regname; + str.length = strlen (regname); + write_exp_string (pstate, str); + write_exp_elt_opcode (pstate, OP_REGISTER); + } + else + { + /* Additional arguments are passed on the stack. */ + CORE_ADDR sp; + const char *regname = user_reg_map_regnum_to_name (gdbarch, AMD64_RSP_REGNUM); + + /* Displacement. */ + write_exp_elt_opcode (pstate, OP_LONG); + write_exp_elt_type (pstate, builtin_type (gdbarch)->builtin_long); + write_exp_elt_longcst (pstate, narg - 6); + write_exp_elt_opcode (pstate, OP_LONG); + + /* Register: SP. */ + write_exp_elt_opcode (pstate, OP_REGISTER); + str.ptr = regname; + str.length = strlen (regname); + write_exp_string (pstate, str); + write_exp_elt_opcode (pstate, OP_REGISTER); + + write_exp_elt_opcode (pstate, BINOP_ADD); + + /* Cast to long. */ + write_exp_elt_opcode (pstate, UNOP_CAST); + write_exp_elt_type (pstate, + lookup_pointer_type (builtin_type (gdbarch)->builtin_long)); + write_exp_elt_opcode (pstate, UNOP_CAST); + + write_exp_elt_opcode (pstate, UNOP_IND); + } +} + static void amd64_linux_init_abi_common(struct gdbarch_info info, struct gdbarch *gdbarch) { @@ -1907,6 +2049,12 @@ amd64_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch) /* GNU/Linux uses SVR4-style shared libraries. */ set_solib_svr4_fetch_link_map_offsets (gdbarch, svr4_lp64_fetch_link_map_offsets); + + /* Register DTrace handlers. */ + set_gdbarch_dtrace_parse_probe_argument (gdbarch, amd64_dtrace_parse_probe_argument); + set_gdbarch_dtrace_probe_is_enabled (gdbarch, amd64_dtrace_probe_is_enabled); + set_gdbarch_dtrace_enable_probe (gdbarch, amd64_dtrace_enable_probe); + set_gdbarch_dtrace_disable_probe (gdbarch, amd64_dtrace_disable_probe); } static void