[v3,0/6] Hexagon: add lldb support

Message

Matheus Tavares Bernardino May 4, 2023, 3:37 p.m. UTC

This series allows hexagon programs to be debugged under qemu user-mode
through LLDB and qemu's gdbstub. LLDB implements the GDB remote serial
protocol, so most of the necessary changes are in the Hexagon part itself.
However, one fix is needed at the arch-independent side too.

Changes in v3:
- Patches 1 & 2: added Alex ack.
- Patch 1:       added missing allow_stop_reply guard to
                 gdbstub/user.c:gdb_exit().
- Patches 3 & 5: replaced qRegisterInfo with gdb-xml.
- Patch 6:       Used force_sig_fault().

v2: https://lore.kernel.org/qemu-devel/[e-mail]/
v1: https://lore.kernel.org/qemu-devel/[e-mail]/

Brian Cain (1):
  Hexagon (gdbstub): fix p3:0 read and write via stub

Matheus Tavares Bernardino (4):
  gdbstub: only send stop-reply packets when allowed to
  gdbstub: add test for untimely stop-reply packets
  Hexagon: add core gdbstub xml data for LLDB
  Hexagon (linux-user/hexagon): handle breakpoints

Taylor Simpson (1):
  Hexagon (gdbstub): add HVX support

 MAINTAINERS                                   |  1 +
 configs/targets/hexagon-linux-user.mak        |  1 +
 gdbstub/internals.h                           |  5 +
 target/hexagon/internal.h                     |  2 +
 gdbstub/gdbstub.c                             | 37 +++++--
 gdbstub/softmmu.c                             | 13 ++-
 gdbstub/user.c                                | 24 +++--
 linux-user/hexagon/cpu_loop.c                 |  3 +
 target/hexagon/cpu.c                          |  9 +-
 target/hexagon/gdbstub.c                      | 84 ++++++++++++++++
 gdb-xml/hexagon-core.xml                      | 84 ++++++++++++++++
 gdb-xml/hexagon-hvx.xml                       | 96 +++++++++++++++++++
 tests/guest-debug/run-test.py                 | 16 +++-
 .../multiarch/system/Makefile.softmmu-target  | 16 +++-
 14 files changed, 366 insertions(+), 25 deletions(-)
 create mode 100644 gdb-xml/hexagon-core.xml
 create mode 100644 gdb-xml/hexagon-hvx.xml

Range-diff against v2:
1:  b4ec188e67 ! 1:  a49c0897fc gdbstub: only send stop-reply packets when allowed to
    @@ gdbstub/softmmu.c: void gdb_exit(int code)
      }
     
      ## gdbstub/user.c ##
    +@@ gdbstub/user.c: void gdb_exit(int code)
    + 
    +     trace_gdbstub_op_exiting((uint8_t)code);
    + 
    +-    snprintf(buf, sizeof(buf), "W%02x", (uint8_t)code);
    +-    gdb_put_packet(buf);
    ++    if (gdbserver_state.allow_stop_reply) {
    ++        snprintf(buf, sizeof(buf), "W%02x", (uint8_t)code);
    ++        gdb_put_packet(buf);
    ++        gdbserver_state.allow_stop_reply = false;
    ++    }
    + }
    + 
    + int gdb_handlesig(CPUState *cpu, int sig)
     @@ gdbstub/user.c: int gdb_handlesig(CPUState *cpu, int sig)
      
          if (sig != 0) {
2:  a91ec99036 = 2:  a30d93b9a8 gdbstub: add test for untimely stop-reply packets
3:  40aa60ee50 < -:  ---------- gdbstub: add support for the qRegisterInfo query
4:  090707eea1 < -:  ---------- Hexagon: support qRegisterInfo at gdbstub
-:  ---------- > 3:  d25a3a7933 Hexagon: add core gdbstub xml data for LLDB
5:  06ed954dab ! 4:  32e7de567c Hexagon (gdbstub): fix p3:0 read and write via stub
    @@ Metadata
      ## Commit message ##
         Hexagon (gdbstub): fix p3:0 read and write via stub
     
    +    Signed-off-by: Brian Cain <[e-mail]>
         Co-authored-by: Sid Manning <[e-mail]>
         Signed-off-by: Sid Manning <[e-mail]>
    -    Signed-off-by: Brian Cain <[e-mail]>
         Co-authored-by: Matheus Tavares Bernardino <[e-mail]>
         Signed-off-by: Matheus Tavares Bernardino <[e-mail]>
         Reviewed-by: Taylor Simpson <[e-mail]>
6:  880c86bf2b ! 5:  17cb32f34d Hexagon (gdbstub): add HVX support
    @@ Metadata
      ## Commit message ##
         Hexagon (gdbstub): add HVX support
     
    +    Signed-off-by: Taylor Simpson <[e-mail]>
         Co-authored-by: Brian Cain <[e-mail]>
         Signed-off-by: Brian Cain <[e-mail]>
    -    Signed-off-by: Taylor Simpson <[e-mail]>
         Co-authored-by: Matheus Tavares Bernardino <[e-mail]>
         Signed-off-by: Matheus Tavares Bernardino <[e-mail]>
     
    - ## target/hexagon/gdbstub.c ##
    + ## configs/targets/hexagon-linux-user.mak ##
    +@@
    + TARGET_ARCH=hexagon
    +-TARGET_XML_FILES=gdb-xml/hexagon-core.xml
    ++TARGET_XML_FILES=gdb-xml/hexagon-core.xml gdb-xml/hexagon-hvx.xml
    +
    + ## target/hexagon/internal.h ##
     @@
    - #include "cpu.h"
    - #include "internal.h"
      
    + int hexagon_gdb_read_register(CPUState *cpu, GByteArray *buf, int reg);
    + int hexagon_gdb_write_register(CPUState *cpu, uint8_t *buf, int reg);
    ++int hexagon_hvx_gdb_read_register(CPUHexagonState *env, GByteArray *mem_buf, int n);
    ++int hexagon_hvx_gdb_write_register(CPUHexagonState *env, uint8_t *mem_buf, int n);
    + 
    + void hexagon_debug_vreg(CPUHexagonState *env, int regnum);
    + void hexagon_debug_qreg(CPUHexagonState *env, int regnum);
    +
    + ## target/hexagon/cpu.c ##
    +@@
    + #include "hw/qdev-properties.h"
    + #include "fpu/softfloat-helpers.h"
    + #include "tcg/tcg.h"
    ++#include "exec/gdbstub.h"
    + 
    + static void hexagon_v67_cpu_init(Object *obj)
    + {
    +@@ target/hexagon/cpu.c: static void hexagon_cpu_realize(DeviceState *dev, Error **errp)
    +         return;
    +     }
    + 
    ++    gdb_register_coprocessor(cs, hexagon_hvx_gdb_read_register,
    ++                             hexagon_hvx_gdb_write_register,
    ++                             NUM_VREGS + NUM_QREGS,
    ++                             "hexagon-hvx.xml", 0);
    ++
    +     qemu_init_vcpu(cs);
    +     cpu_reset(cs);
    + 
    +
    + ## target/hexagon/gdbstub.c ##
    +@@ target/hexagon/gdbstub.c: int hexagon_gdb_write_register(CPUState *cs, uint8_t *mem_buf, int n)
    + 
    +     g_assert_not_reached();
    + }
    ++
     +static int gdb_get_vreg(CPUHexagonState *env, GByteArray *mem_buf, int n)
     +{
     +    int total = 0;
    @@ target/hexagon/gdbstub.c
     +    return total;
     +}
     +
    - int hexagon_gdb_read_register(CPUState *cs, GByteArray *mem_buf, int n)
    - {
    -     HexagonCPU *cpu = HEXAGON_CPU(cs);
    -@@ target/hexagon/gdbstub.c: int hexagon_gdb_read_register(CPUState *cs, GByteArray *mem_buf, int n)
    -     if (n < TOTAL_PER_THREAD_REGS) {
    -         return gdb_get_regl(mem_buf, env->gpr[n]);
    -     }
    -+    n -= TOTAL_PER_THREAD_REGS;
    -+
    ++int hexagon_hvx_gdb_read_register(CPUHexagonState *env, GByteArray *mem_buf, int n)
    ++{
     +    if (n < NUM_VREGS) {
     +        return gdb_get_vreg(env, mem_buf, n);
     +    }
    @@ target/hexagon/gdbstub.c: int hexagon_gdb_read_register(CPUState *cs, GByteArray
     +    if (n < NUM_QREGS) {
     +        return gdb_get_qreg(env, mem_buf, n);
     +    }
    - 
    -     g_assert_not_reached();
    - }
    - 
    ++
    ++    g_assert_not_reached();
    ++}
    ++
     +static int gdb_put_vreg(CPUHexagonState *env, uint8_t *mem_buf, int n)
     +{
     +    int i;
    @@ target/hexagon/gdbstub.c: int hexagon_gdb_read_register(CPUState *cs, GByteArray
     +    return MAX_VEC_SIZE_BYTES / 8;
     +}
     +
    - int hexagon_gdb_write_register(CPUState *cs, uint8_t *mem_buf, int n)
    - {
    -     HexagonCPU *cpu = HEXAGON_CPU(cs);
    -@@ target/hexagon/gdbstub.c: int hexagon_gdb_write_register(CPUState *cs, uint8_t *mem_buf, int n)
    -         env->gpr[n] = ldtul_p(mem_buf);
    -         return sizeof(target_ulong);
    -     }
    -+    n -= TOTAL_PER_THREAD_REGS;
    -+
    -+    if (n < NUM_VREGS) {
    ++int hexagon_hvx_gdb_write_register(CPUHexagonState *env, uint8_t *mem_buf, int n)
    ++{
    ++   if (n < NUM_VREGS) {
     +        return gdb_put_vreg(env, mem_buf, n);
     +    }
     +    n -= NUM_VREGS;
    @@ target/hexagon/gdbstub.c: int hexagon_gdb_write_register(CPUState *cs, uint8_t *
     +    if (n < NUM_QREGS) {
     +        return gdb_put_qreg(env, mem_buf, n);
     +    }
    - 
    -     g_assert_not_reached();
    - }
    ++
    ++    g_assert_not_reached();
    ++}
    +
    + ## gdb-xml/hexagon-hvx.xml (new) ##
    +@@
    ++<?xml version="1.0"?>
    ++<!--
    ++  Copyright(c) 2023 Qualcomm Innovation Center, Inc. All Rights Reserved.
    ++
    ++  This work is licensed under the terms of the GNU GPL, version 2 or
    ++  (at your option) any later version. See the COPYING file in the
    ++  top-level directory.
    ++
    ++  Note: this file is intended to be use with LLDB, so it contains fields
    ++  that may be unknown to GDB. For more information on such fields, please
    ++  see:
    ++  https://github.com/llvm/llvm-project/blob/287aa6c4536408413b860e61fca0318a27214cf3/lldb/docs/lldb-gdb-remote.txt#L738-L860
    ++  https://github.com/llvm/llvm-project/blob/287aa6c4536408413b860e61fca0318a27214cf3/lldb/source/Plugins/Process/gdb-remote/ProcessGDBRemote.cpp#L4275-L4335
    ++-->
    ++
    ++<!DOCTYPE feature SYSTEM "gdb-target.dtd">
    ++<feature name="org.gnu.gdb.hexagon.hvx">
    ++
    ++  <vector id="vud" type="uint64" count="16"/>
    ++  <vector id="vd" type="int64" count="16"/>
    ++  <vector id="vuw" type="uint32" count="32"/>
    ++  <vector id="vw" type="int32" count="32"/>
    ++  <vector id="vuh" type="uint16" count="64"/>
    ++  <vector id="vh" type="int16" count="64"/>
    ++  <vector id="vub" type="uint8" count="128"/>
    ++  <vector id="vb" type="int8" count="128"/>
    ++  <union id="hex_vec">
    ++    <field name="ud" type="vud"/>
    ++    <field name="d" type="vd"/>
    ++    <field name="uw" type="vuw"/>
    ++    <field name="w" type="vw"/>
    ++    <field name="uh" type="vuh"/>
    ++    <field name="h" type="vh"/>
    ++    <field name="ub" type="vub"/>
    ++    <field name="b" type="vb"/>
    ++  </union>
    ++
    ++  <flags id="ui2" size="1">
    ++    <field name="0" start="0" end="0"/>
    ++    <field name="1" start="1" end="1"/>
    ++  </flags>
    ++  <flags id="ui4" size="1">
    ++    <field name="0" start="0" end="0"/>
    ++    <field name="1" start="1" end="1"/>
    ++    <field name="2" start="2" end="2"/>
    ++    <field name="3" start="3" end="3"/>
    ++  </flags>
    ++  <vector id="vpd" type="uint8" count="16"/>
    ++  <vector id="vpw" type="ui4" count="32"/>
    ++  <vector id="vph" type="ui2" count="64"/>
    ++  <vector id="vpb" type="bool" count="128"/>
    ++  <union id="hex_vec_pred">
    ++    <field name="d" type="vpd"/>
    ++    <field name="w" type="vpw"/>
    ++    <field name="h" type="vph"/>
    ++    <field name="b" type="vpb"/>
    ++  </union>
    ++
    ++  <reg name="v0"  bitsize="1024" offset="256"  encoding="vector" format="hex" group="HVX Vector Registers" dwarf_regnum="88"/>
    ++  <reg name="v1"  bitsize="1024" offset="384"  encoding="vector" format="hex" group="HVX Vector Registers" dwarf_regnum="89"/>
    ++  <reg name="v2"  bitsize="1024" offset="512"  encoding="vector" format="hex" group="HVX Vector Registers" dwarf_regnum="90"/>
    ++  <reg name="v3"  bitsize="1024" offset="640"  encoding="vector" format="hex" group="HVX Vector Registers" dwarf_regnum="91"/>
    ++  <reg name="v4"  bitsize="1024" offset="768"  encoding="vector" format="hex" group="HVX Vector Registers" dwarf_regnum="92"/>
    ++  <reg name="v5"  bitsize="1024" offset="896"  encoding="vector" format="hex" group="HVX Vector Registers" dwarf_regnum="93"/>
    ++  <reg name="v6"  bitsize="1024" offset="1024" encoding="vector" format="hex" group="HVX Vector Registers" dwarf_regnum="94"/>
    ++  <reg name="v7"  bitsize="1024" offset="1152" encoding="vector" format="hex" group="HVX Vector Registers" dwarf_regnum="95"/>
    ++  <reg name="v8"  bitsize="1024" offset="1280" encoding="vector" format="hex" group="HVX Vector Registers" dwarf_regnum="96"/>
    ++  <reg name="v9"  bitsize="1024" offset="1408" encoding="vector" format="hex" group="HVX Vector Registers" dwarf_regnum="97"/>
    ++  <reg name="v10" bitsize="1024" offset="1536" encoding="vector" format="hex" group="HVX Vector Registers" dwarf_regnum="98"/>
    ++  <reg name="v11" bitsize="1024" offset="1664" encoding="vector" format="hex" group="HVX Vector Registers" dwarf_regnum="99"/>
    ++  <reg name="v12" bitsize="1024" offset="1792" encoding="vector" format="hex" group="HVX Vector Registers" dwarf_regnum="100"/>
    ++  <reg name="v13" bitsize="1024" offset="1920" encoding="vector" format="hex" group="HVX Vector Registers" dwarf_regnum="101"/>
    ++  <reg name="v14" bitsize="1024" offset="2048" encoding="vector" format="hex" group="HVX Vector Registers" dwarf_regnum="102"/>
    ++  <reg name="v15" bitsize="1024" offset="2176" encoding="vector" format="hex" group="HVX Vector Registers" dwarf_regnum="103"/>
    ++  <reg name="v16" bitsize="1024" offset="2304" encoding="vector" format="hex" group="HVX Vector Registers" dwarf_regnum="104"/>
    ++  <reg name="v17" bitsize="1024" offset="2432" encoding="vector" format="hex" group="HVX Vector Registers" dwarf_regnum="105"/>
    ++  <reg name="v18" bitsize="1024" offset="2560" encoding="vector" format="hex" group="HVX Vector Registers" dwarf_regnum="106"/>
    ++  <reg name="v19" bitsize="1024" offset="2688" encoding="vector" format="hex" group="HVX Vector Registers" dwarf_regnum="107"/>
    ++  <reg name="v20" bitsize="1024" offset="2816" encoding="vector" format="hex" group="HVX Vector Registers" dwarf_regnum="108"/>
    ++  <reg name="v21" bitsize="1024" offset="2944" encoding="vector" format="hex" group="HVX Vector Registers" dwarf_regnum="109"/>
    ++  <reg name="v22" bitsize="1024" offset="3072" encoding="vector" format="hex" group="HVX Vector Registers" dwarf_regnum="110"/>
    ++  <reg name="v23" bitsize="1024" offset="3200" encoding="vector" format="hex" group="HVX Vector Registers" dwarf_regnum="111"/>
    ++  <reg name="v24" bitsize="1024" offset="3328" encoding="vector" format="hex" group="HVX Vector Registers" dwarf_regnum="112"/>
    ++  <reg name="v25" bitsize="1024" offset="3456" encoding="vector" format="hex" group="HVX Vector Registers" dwarf_regnum="113"/>
    ++  <reg name="v26" bitsize="1024" offset="3584" encoding="vector" format="hex" group="HVX Vector Registers" dwarf_regnum="114"/>
    ++  <reg name="v27" bitsize="1024" offset="3712" encoding="vector" format="hex" group="HVX Vector Registers" dwarf_regnum="115"/>
    ++  <reg name="v28" bitsize="1024" offset="3840" encoding="vector" format="hex" group="HVX Vector Registers" dwarf_regnum="116"/>
    ++  <reg name="v29" bitsize="1024" offset="3968" encoding="vector" format="hex" group="HVX Vector Registers" dwarf_regnum="117"/>
    ++  <reg name="v30" bitsize="1024" offset="4096" encoding="vector" format="hex" group="HVX Vector Registers" dwarf_regnum="118"/>
    ++  <reg name="v31" bitsize="1024" offset="4224" encoding="vector" format="hex" group="HVX Vector Registers" dwarf_regnum="119"/>
    ++  <reg name="q0"  bitsize="128"  offset="4352" encoding="vector" format="hex" group="HVX Vector Registers" dwarf_regnum="120"/>
    ++  <reg name="q1"  bitsize="128"  offset="4368" encoding="vector" format="hex" group="HVX Vector Registers" dwarf_regnum="121"/>
    ++  <reg name="q2"  bitsize="128"  offset="4384" encoding="vector" format="hex" group="HVX Vector Registers" dwarf_regnum="122"/>
    ++  <reg name="q3"  bitsize="128"  offset="4400" encoding="vector" format="hex" group="HVX Vector Registers" dwarf_regnum="123"/>
    ++
    ++</feature>
7:  3ff83e45a5 ! 6:  c287a129dc Hexagon (linux-user/hexagon): handle breakpoints
    @@
      ## Metadata ##
    -Author: Taylor Simpson <[e-mail]>
    +Author: Matheus Tavares Bernardino <[e-mail]>
     
      ## Commit message ##
         Hexagon (linux-user/hexagon): handle breakpoints
    @@ Commit message
         This enables LLDB to work with hexagon linux-user mode through the GDB
         remote protocol.
     
    -    Signed-off-by: Taylor Simpson <[e-mail]>
    +    Helped-by: Richard Henderson <[e-mail]>
         Signed-off-by: Matheus Tavares Bernardino <[e-mail]>
     
      ## linux-user/hexagon/cpu_loop.c ##
    -@@ linux-user/hexagon/cpu_loop.c: void cpu_loop(CPUHexagonState *env)
    -     target_ulong ret;
    - 
    -     for (;;) {
    -+        target_siginfo_t info;
    -         cpu_exec_start(cs);
    -         trapnr = cpu_exec(cs);
    -         cpu_exec_end(cs);
     @@ linux-user/hexagon/cpu_loop.c: void cpu_loop(CPUHexagonState *env)
              case EXCP_ATOMIC:
                  cpu_exec_step_atomic(cs);
                  break;
     +        case EXCP_DEBUG:
    -+            info = (target_siginfo_t) {
    -+                .si_signo = TARGET_SIGTRAP,
    -+                .si_errno = 0,
    -+                .si_code = TARGET_TRAP_BRKPT,
    -+                ._sifields._sigfault._addr = 0
    -+            };
    -+            queue_signal(env, info.si_signo, QEMU_SI_KILL, &info);
    ++            force_sig_fault(TARGET_SIGTRAP, TARGET_TRAP_BRKPT, 0);
     +            break;
              default:
                  EXCP_DUMP(env, "\nqemu: unhandled CPU exception %#x - aborting\n",