From 8f468636189303358da3b365c53cb03ae5497eca Mon Sep 17 00:00:00 2001 From: Luc Michel Date: Mon, 7 Jan 2019 15:23:45 +0000 Subject: [PATCH] gdbstub: introduce GDB processes MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit Add a structure GDBProcess that represents processes from the GDB semantic point of view. CPUs can be split into different processes, by grouping them under different cpu-cluster objects. Each occurrence of a cpu-cluster object implies the existence of the corresponding process in the GDB stub. The GDB process ID is derived from the corresponding cluster ID as follows: GDB PID = cluster ID + 1 This is because PIDs -1 and 0 are reserved in GDB and cannot be used by processes. A default process is created to handle CPUs that are not in a cluster. This process gets the PID of the last process PID + 1. Signed-off-by: Luc Michel Acked-by: Alistair Francis Reviewed-by: Edgar E. Iglesias Reviewed-by: Philippe Mathieu-Daudé Message-id: 20181207090135.7651-3-luc.michel@greensocs.com [PMM: fixed checkpatch nit about block comment style] Signed-off-by: Peter Maydell --- gdbstub.c | 97 +++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 97 insertions(+) diff --git a/gdbstub.c b/gdbstub.c index c4e4f9f082..9ac6f19a18 100644 --- a/gdbstub.c +++ b/gdbstub.c @@ -29,6 +29,7 @@ #include "chardev/char-fe.h" #include "sysemu/sysemu.h" #include "exec/gdbstub.h" +#include "hw/cpu/cluster.h" #endif #define MAX_PACKET_LENGTH 4096 @@ -296,6 +297,11 @@ typedef struct GDBRegisterState { struct GDBRegisterState *next; } GDBRegisterState; +typedef struct GDBProcess { + uint32_t pid; + bool attached; +} GDBProcess; + enum RSState { RS_INACTIVE, RS_IDLE, @@ -324,6 +330,9 @@ typedef struct GDBState { CharBackend chr; Chardev *mon_chr; #endif + bool multiprocess; + GDBProcess *processes; + int process_num; char syscall_buf[256]; gdb_syscall_complete_cb current_syscall_cb; } GDBState; @@ -1751,6 +1760,30 @@ void gdb_exit(CPUArchState *env, int code) #endif } +/* + * Create the process that will contain all the "orphan" CPUs (that are not + * part of a CPU cluster). Note that if this process contains no CPUs, it won't + * be attachable and thus will be invisible to the user. + */ +static void create_default_process(GDBState *s) +{ + GDBProcess *process; + int max_pid = 0; + + if (s->process_num) { + max_pid = s->processes[s->process_num - 1].pid; + } + + s->processes = g_renew(GDBProcess, s->processes, ++s->process_num); + process = &s->processes[s->process_num - 1]; + + /* We need an available PID slot for this process */ + assert(max_pid < UINT32_MAX); + + process->pid = max_pid + 1; + process->attached = false; +} + #ifdef CONFIG_USER_ONLY int gdb_handlesig(CPUState *cpu, int sig) @@ -1848,6 +1881,7 @@ static bool gdb_accept(void) s = g_malloc0(sizeof(GDBState)); s->c_cpu = first_cpu; s->g_cpu = first_cpu; + create_default_process(s); s->fd = fd; gdb_has_xml = false; @@ -2004,6 +2038,65 @@ static const TypeInfo char_gdb_type_info = { .class_init = char_gdb_class_init, }; +static int find_cpu_clusters(Object *child, void *opaque) +{ + if (object_dynamic_cast(child, TYPE_CPU_CLUSTER)) { + GDBState *s = (GDBState *) opaque; + CPUClusterState *cluster = CPU_CLUSTER(child); + GDBProcess *process; + + s->processes = g_renew(GDBProcess, s->processes, ++s->process_num); + + process = &s->processes[s->process_num - 1]; + + /* + * GDB process IDs -1 and 0 are reserved. To avoid subtle errors at + * runtime, we enforce here that the machine does not use a cluster ID + * that would lead to PID 0. + */ + assert(cluster->cluster_id != UINT32_MAX); + process->pid = cluster->cluster_id + 1; + process->attached = false; + + return 0; + } + + return object_child_foreach(child, find_cpu_clusters, opaque); +} + +static int pid_order(const void *a, const void *b) +{ + GDBProcess *pa = (GDBProcess *) a; + GDBProcess *pb = (GDBProcess *) b; + + if (pa->pid < pb->pid) { + return -1; + } else if (pa->pid > pb->pid) { + return 1; + } else { + return 0; + } +} + +static void create_processes(GDBState *s) +{ + object_child_foreach(object_get_root(), find_cpu_clusters, s); + + if (s->processes) { + /* Sort by PID */ + qsort(s->processes, s->process_num, sizeof(s->processes[0]), pid_order); + } + + create_default_process(s); +} + +static void cleanup_processes(GDBState *s) +{ + g_free(s->processes); + s->process_num = 0; + s->processes = NULL; +} + int gdbserver_start(const char *device) { trace_gdbstub_op_start(device); @@ -2060,11 +2153,15 @@ int gdbserver_start(const char *device) } else { qemu_chr_fe_deinit(&s->chr, true); mon_chr = s->mon_chr; + cleanup_processes(s); memset(s, 0, sizeof(GDBState)); s->mon_chr = mon_chr; } s->c_cpu = first_cpu; s->g_cpu = first_cpu; + + create_processes(s); + if (chr) { qemu_chr_fe_init(&s->chr, chr, &error_abort); qemu_chr_fe_set_handlers(&s->chr, gdb_chr_can_receive, gdb_chr_receive, -- 2.39.2