From patchwork Fri Oct 10 17:22:49 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Jose E. Marchesi" X-Patchwork-Id: 3195 Received: (qmail 32077 invoked by alias); 10 Oct 2014 17:18:15 -0000 Mailing-List: contact gdb-patches-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Unsubscribe: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-patches-owner@sourceware.org Delivered-To: mailing list gdb-patches@sourceware.org Received: (qmail 31969 invoked by uid 89); 10 Oct 2014 17:18:14 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-1.2 required=5.0 tests=AWL, BAYES_00, LIKELY_SPAM_BODY, RP_MATCHES_RCVD, SPF_PASS, UNPARSEABLE_RELAY autolearn=no version=3.3.2 X-HELO: aserp1040.oracle.com Received: from aserp1040.oracle.com (HELO aserp1040.oracle.com) (141.146.126.69) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with (AES256-SHA encrypted) ESMTPS; Fri, 10 Oct 2014 17:18:09 +0000 Received: from acsinet22.oracle.com (acsinet22.oracle.com [141.146.126.238]) by aserp1040.oracle.com (Sentrion-MTA-4.3.2/Sentrion-MTA-4.3.2) with ESMTP id s9AHI7cK030244 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Fri, 10 Oct 2014 17:18:07 GMT Received: from userz7022.oracle.com (userz7022.oracle.com [156.151.31.86]) by acsinet22.oracle.com (8.14.4+Sun/8.14.4) with ESMTP id s9AHI6Jg027310 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO) for ; Fri, 10 Oct 2014 17:18:06 GMT Received: from abhmp0008.oracle.com (abhmp0008.oracle.com [141.146.116.14]) by userz7022.oracle.com (8.14.5+Sun/8.14.4) with ESMTP id s9AHI5Qu029788 for ; Fri, 10 Oct 2014 17:18:05 GMT Received: from termi.uk.oracle.com (/10.175.211.52) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Fri, 10 Oct 2014 10:18:05 -0700 From: "Jose E. Marchesi" To: gdb-patches@sourceware.org Subject: [PATCH V2 6/9] Support for DTrace USDT probes in x86_64 targets. Date: Fri, 10 Oct 2014 19:22:49 +0200 Message-Id: <1412961772-16249-7-git-send-email-jose.marchesi@oracle.com> In-Reply-To: <1412961772-16249-1-git-send-email-jose.marchesi@oracle.com> References: <1412961772-16249-1-git-send-email-jose.marchesi@oracle.com> X-IsSubscribed: yes 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: 2014-10-10 Jose E. Marchesi * amd64-linux-tdep.h: Prototypes for `amd64_dtrace_parse_probe_argument', `amd64_dtrace_enable_probe', `amd64_dtrace_disable_probe' and `gdbarch_dtrace_probe_is_enabled'. * 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'. --- gdb/ChangeLog | 14 +++++ gdb/amd64-linux-tdep.c | 158 ++++++++++++++++++++++++++++++++++++++++++++++++ gdb/amd64-linux-tdep.h | 11 ++++ 3 files changed, 183 insertions(+) diff --git a/gdb/amd64-linux-tdep.c b/gdb/amd64-linux-tdep.c index edbb1b3..04b3140 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 +1645,156 @@ amd64_linux_iterate_over_regset_sections (struct gdbarch *gdbarch, &amd64_linux_xstateregset, "XSAVE extended state", cb_data); } +/* Implementation of `gdbarch_dtrace_probe_is_enabled', as defined in + gdbarch.h. */ + +int +amd64_dtrace_probe_is_enabled (struct gdbarch *gdbarch, CORE_ADDR addr) +{ + gdb_byte buf[5]; + read_memory (addr - 3, buf, 5); + + /* The instruction sequence used in x86_64 machines for a disabled + is-enabled probe is: + + xor %rax, %rax => 48 33 C0 + ADDR: nop => 90 + nop => 90 + + or + + xor %rax, %rax => 48 33 C0 + ADDR: ret => c3 + nop => 90 + + This function returns 1 if the instructions at ADDR do _not_ + follow any of these patterns. + + Note that ADDR is offset 3 bytes from the beginning of these + sequences. */ + + return !((buf[0] == 0x48) && (buf[1] == 0x33) && (buf[2] == 0xc0) /* xor */ + && ((buf[3] == 0x90) || (buf[3] == 0xc3)) /* nop | ret */ + && (buf[4] == 0x90)); /* nop */ +} + +/* Implementation of `gdbarch_dtrace_enable_probe', as defined in + gdbarch.h. */ + +void +amd64_dtrace_enable_probe (struct gdbarch *gdbarch, CORE_ADDR addr) +{ + /* We use the following instruction sequence for enabling an + is-enabled probe: + + mov $0x1, %eax => b8 01 00 00 00 + + Note also that ADDR is offset 3 bytes from the beginning of the + sequence. */ + + gdb_byte buf[5]; + + buf[0] = 0xb8; + buf[1] = 0x01; + buf[2] = 0x00; + buf[3] = 0x00; + buf[4] = 0x00; + + write_memory (addr - 3, buf, 5); +} + +/* Implementation of `gdbarch_dtrace_disable_probe', as defined in + gdbarch.h. */ + +void +amd64_dtrace_disable_probe (struct gdbarch *gdbarch, CORE_ADDR addr) +{ + /* We use the following instruction sequence for disabling an + is-enabled probe: + + xor %rax, %rax; nop; nop => 48 33 C0 90 90 + + Note that ADDR is offset 3 bytes from the beginning of the + sequence. */ + + gdb_byte buf[5]; + + buf[0] = 0x48; + buf[1] = 0x33; + buf[2] = 0xc0; + buf[3] = 0x90; + buf[4] = 0x90; + + write_memory (addr - 3, buf, 5); +} + +/* Implementation of `gdbarch_dtrace_parse_probe_argument', as defined + in gdbarch.h. */ + +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; + static 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. */ + }; + + /* 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) + { + 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 +2059,12 @@ 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 diff --git a/gdb/amd64-linux-tdep.h b/gdb/amd64-linux-tdep.h index 25563b8..1edb83b 100644 --- a/gdb/amd64-linux-tdep.h +++ b/gdb/amd64-linux-tdep.h @@ -594,4 +594,15 @@ enum amd64_x32_syscall { amd64_x32_sys_getsockopt = (amd64_x32_syscall_bit + 542), }; +/* DTrace related functions. */ + +extern void amd64_dtrace_parse_probe_argument (struct gdbarch *gdbarch, + struct parser_state *pstate, + int narg); + +extern int amd64_dtrace_probe_is_enabled (struct gdbarch *gdbarch, CORE_ADDR addr); + +extern void amd64_dtrace_enable_probe (struct gdbarch *gdbarch, CORE_ADDR addr); +extern void amd64_dtrace_disable_probe (struct gdbarch *gdbarch, CORE_ADDR addr); + #endif /* amd64-linux-tdep.h */