From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:55384) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gMqmB-000409-3A for qemu-devel@nongnu.org; Wed, 14 Nov 2018 03:43:56 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1gMqm9-0006mh-RX for qemu-devel@nongnu.org; Wed, 14 Nov 2018 03:43:55 -0500 References: <20181110081147.4027-1-luc.michel@greensocs.com> <20181110081147.4027-4-luc.michel@greensocs.com> <20181113110636.GH1148@toto> From: Luc Michel Message-ID: Date: Wed, 14 Nov 2018 09:43:27 +0100 MIME-Version: 1.0 In-Reply-To: <20181113110636.GH1148@toto> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: quoted-printable Subject: Re: [Qemu-devel] [Qemu-arm] [PATCH v5 03/16] gdbstub: add multiprocess support to '?' packets List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Edgar E. Iglesias" Cc: qemu-devel@nongnu.org, Peter Maydell , Eduardo Habkost , alistair@alistair23.me, mark.burton@greensocs.com, =?UTF-8?Q?Philippe_Mathieu-Daud=c3=a9?= , saipava@xilinx.com, edgari@xilinx.com, qemu-arm@nongnu.org Hi Edgar, On 11/13/18 12:06 PM, Edgar E. Iglesias wrote: > On Sat, Nov 10, 2018 at 09:11:34AM +0100, Luc Michel wrote: >> The gdb_get_cpu_pid() function does the PID lookup for the given CPU. = It >> checks if the CPU is a direct child of a CPU cluster. If it is, the >> returned PID is the cluster ID plus one (cluster IDs start at 0, GDB >> PIDs at 1). When the CPU is not a child of such a container, the PID o= f >> the first process is returned. >> >> The gdb_fmt_thread_id() function generates the string to be used to id= entify >> a given thread, in a response packet for the peer. This function >> supports generating thread IDs when multiprocess mode is enabled (in t= he >> form `p.'). >> >> Use them in the reply to a '?' request. >> >> Signed-off-by: Luc Michel >> Acked-by: Alistair Francis >=20 >=20 > This is also theoretical but: > When looking at this, it seems like you could have lazily created > the s->processes array entries (if you find a cluster but the > no valid entry in s->processes). Then we could perhaps eliminate the > scan of all objects at startup and also support CPU/Cluster hotplug. Yes you are right, this could be an improvement to this series to add cluster hotplug support (CPU hotplug is actually supported). It's a little bit tricky though since we would have to maintain the s->processes array and properly signal to GDB when a process dies. Cheers, Luc >=20 > Anyway, this looks good to me! > Reviewed-by: Edgar E. Iglesias >=20 > Cheers, > Edgar >=20 >=20 >> --- >> gdbstub.c | 60 +++++++++++++++++++++++++++++++++++++++++++++++++++++-= - >> 1 file changed, 58 insertions(+), 2 deletions(-) >> >> diff --git a/gdbstub.c b/gdbstub.c >> index 0d70b89598..d26bad4b67 100644 >> --- a/gdbstub.c >> +++ b/gdbstub.c >> @@ -638,10 +638,52 @@ static int memtox(char *buf, const char *mem, in= t len) >> } >> } >> return p - buf; >> } >> =20 >> +static uint32_t gdb_get_cpu_pid(const GDBState *s, CPUState *cpu) >> +{ >> +#ifndef CONFIG_USER_ONLY >> + gchar *path, *name; >> + Object *obj; >> + CPUClusterState *cluster; >> + uint32_t ret; >> + >> + path =3D object_get_canonical_path(OBJECT(cpu)); >> + name =3D object_get_canonical_path_component(OBJECT(cpu)); >> + >> + if (path =3D=3D NULL) { >> + ret =3D s->processes[0].pid; >> + goto out; >> + } >> + >> + /* >> + * Retrieve the CPU parent path by removing the last '/' and the = CPU name >> + * from the CPU canonical path. */ >> + path[strlen(path) - strlen(name) - 1] =3D '\0'; >> + >> + obj =3D object_resolve_path_type(path, TYPE_CPU_CLUSTER, NULL); >> + >> + if (obj =3D=3D NULL) { >> + ret =3D s->processes[0].pid; >> + goto out; >> + } >> + >> + cluster =3D CPU_CLUSTER(obj); >> + ret =3D cluster->cluster_id + 1; >> + >> +out: >> + g_free(name); >> + g_free(path); >> + >> + return ret; >> + >> +#else >> + return s->processes[0].pid; >> +#endif >> +} >> + >> static const char *get_feature_xml(const char *p, const char **newp, >> CPUClass *cc) >> { >> size_t len; >> int i; >> @@ -907,10 +949,23 @@ static CPUState *find_cpu(uint32_t thread_id) >> } >> =20 >> return NULL; >> } >> =20 >> +static char *gdb_fmt_thread_id(const GDBState *s, CPUState *cpu, >> + char *buf, size_t buf_size) >> +{ >> + if (s->multiprocess) { >> + snprintf(buf, buf_size, "p%02x.%02x", >> + gdb_get_cpu_pid(s, cpu), cpu_gdb_index(cpu)); >> + } else { >> + snprintf(buf, buf_size, "%02x", cpu_gdb_index(cpu)); >> + } >> + >> + return buf; >> +} >> + >> static int is_query_packet(const char *p, const char *query, char sep= arator) >> { >> unsigned int query_len =3D strlen(query); >> =20 >> return strncmp(p, query, query_len) =3D=3D 0 && >> @@ -1018,22 +1073,23 @@ static int gdb_handle_packet(GDBState *s, cons= t char *line_buf) >> const char *p; >> uint32_t thread; >> int ch, reg_size, type, res; >> uint8_t mem_buf[MAX_PACKET_LENGTH]; >> char buf[sizeof(mem_buf) + 1 /* trailing NUL */]; >> + char thread_id[16]; >> uint8_t *registers; >> target_ulong addr, len; >> =20 >> trace_gdbstub_io_command(line_buf); >> =20 >> p =3D line_buf; >> ch =3D *p++; >> switch(ch) { >> case '?': >> /* TODO: Make this return the correct value for user-mode. *= / >> - snprintf(buf, sizeof(buf), "T%02xthread:%02x;", GDB_SIGNAL_TR= AP, >> - cpu_gdb_index(s->c_cpu)); >> + snprintf(buf, sizeof(buf), "T%02xthread:%s;", GDB_SIGNAL_TRAP= , >> + gdb_fmt_thread_id(s, s->c_cpu, thread_id, sizeof(thr= ead_id))); >> put_packet(s, buf); >> /* Remove all the breakpoints when this query is issued, >> * because gdb is doing and initial connect and the state >> * should be cleaned up. >> */ >> --=20 >> 2.19.1 >> >>