From f84e313e0278222eb88b9ca29311f0df71abd001 Mon Sep 17 00:00:00 2001 From: Gustavo Romero Date: Sat, 9 Mar 2024 03:08:59 +0000 Subject: [PATCH] gdbstub: Save target's siginfo MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Save target's siginfo into gdbserver_state so it can be used later, for example, in any stub that requires the target's si_signo and si_code. This change affects only linux-user mode. Signed-off-by: Gustavo Romero Suggested-by: Richard Henderson Message-Id: <20240309030901.1726211-4-gustavo.romero@linaro.org> Signed-off-by: Alex Bennée Reviewed-by: Richard Henderson --- bsd-user/main.c | 2 +- bsd-user/signal.c | 5 ++++- gdbstub/user.c | 23 +++++++++++++++++++---- include/gdbstub/user.h | 6 +++++- linux-user/main.c | 2 +- linux-user/signal.c | 5 ++++- 6 files changed, 34 insertions(+), 9 deletions(-) diff --git a/bsd-user/main.c b/bsd-user/main.c index 3dc285e5b7..01b313756e 100644 --- a/bsd-user/main.c +++ b/bsd-user/main.c @@ -606,7 +606,7 @@ int main(int argc, char **argv) if (gdbstub) { gdbserver_start(gdbstub); - gdb_handlesig(cpu, 0); + gdb_handlesig(cpu, 0, NULL, NULL, 0); } cpu_loop(env); /* never exits */ diff --git a/bsd-user/signal.c b/bsd-user/signal.c index 3ac50c2d71..e5a773ddde 100644 --- a/bsd-user/signal.c +++ b/bsd-user/signal.c @@ -27,6 +27,9 @@ #include "hw/core/tcg-cpu-ops.h" #include "host-signal.h" +/* target_siginfo_t must fit in gdbstub's siginfo save area. */ +QEMU_BUILD_BUG_ON(sizeof(target_siginfo_t) > MAX_SIGINFO_LENGTH); + static struct target_sigaction sigact_table[TARGET_NSIG]; static void host_signal_handler(int host_sig, siginfo_t *info, void *puc); static void target_to_host_sigset_internal(sigset_t *d, @@ -889,7 +892,7 @@ static void handle_pending_signal(CPUArchState *env, int sig, k->pending = 0; - sig = gdb_handlesig(cpu, sig); + sig = gdb_handlesig(cpu, sig, NULL, &k->info, sizeof(k->info)); if (!sig) { sa = NULL; handler = TARGET_SIG_IGN; diff --git a/gdbstub/user.c b/gdbstub/user.c index 520987fddc..cf693bfbc4 100644 --- a/gdbstub/user.c +++ b/gdbstub/user.c @@ -95,6 +95,8 @@ typedef struct { enum GDBForkState fork_state; int fork_sockets[2]; pid_t fork_peer_pid, fork_peer_tid; + uint8_t siginfo[MAX_SIGINFO_LENGTH]; + unsigned long siginfo_len; } GDBUserState; static GDBUserState gdbserver_user_state; @@ -190,7 +192,8 @@ void gdb_qemu_exit(int code) exit(code); } -int gdb_handlesig(CPUState *cpu, int sig, const char *reason) +int gdb_handlesig(CPUState *cpu, int sig, const char *reason, void *siginfo, + int siginfo_len) { char buf[256]; int n; @@ -199,6 +202,18 @@ int gdb_handlesig(CPUState *cpu, int sig, const char *reason) return sig; } + if (siginfo) { + /* + * Save target-specific siginfo. + * + * siginfo size, i.e. siginfo_len, is asserted at compile-time to fit in + * gdbserver_user_state.siginfo, usually in the source file calling + * gdb_handlesig. See, for instance, {linux,bsd}-user/signal.c. + */ + memcpy(gdbserver_user_state.siginfo, siginfo, siginfo_len); + gdbserver_user_state.siginfo_len = siginfo_len; + } + /* disable single step if it was enabled */ cpu_single_step(cpu, 0); tb_flush(cpu); @@ -746,7 +761,7 @@ void gdb_breakpoint_remove_all(CPUState *cs) void gdb_syscall_handling(const char *syscall_packet) { gdb_put_packet(syscall_packet); - gdb_handlesig(gdbserver_state.c_cpu, 0, NULL); + gdb_handlesig(gdbserver_state.c_cpu, 0, NULL, NULL, 0); } static bool should_catch_syscall(int num) @@ -764,7 +779,7 @@ void gdb_syscall_entry(CPUState *cs, int num) { if (should_catch_syscall(num)) { g_autofree char *reason = g_strdup_printf("syscall_entry:%x;", num); - gdb_handlesig(cs, gdb_target_sigtrap(), reason); + gdb_handlesig(cs, gdb_target_sigtrap(), reason, NULL, 0); } } @@ -772,7 +787,7 @@ void gdb_syscall_return(CPUState *cs, int num) { if (should_catch_syscall(num)) { g_autofree char *reason = g_strdup_printf("syscall_return:%x;", num); - gdb_handlesig(cs, gdb_target_sigtrap(), reason); + gdb_handlesig(cs, gdb_target_sigtrap(), reason, NULL, 0); } } diff --git a/include/gdbstub/user.h b/include/gdbstub/user.h index 4fc88f8a25..3b8358e3da 100644 --- a/include/gdbstub/user.h +++ b/include/gdbstub/user.h @@ -9,11 +9,15 @@ #ifndef GDBSTUB_USER_H #define GDBSTUB_USER_H +#define MAX_SIGINFO_LENGTH 128 + /** * gdb_handlesig() - yield control to gdb * @cpu: CPU * @sig: if non-zero, the signal number which caused us to stop * @reason: stop reason for stop reply packet or NULL + * @siginfo: target-specific siginfo struct + * @siginfo_len: target-specific siginfo struct length * * This function yields control to gdb, when a user-mode-only target * needs to stop execution. If @sig is non-zero, then we will send a @@ -25,7 +29,7 @@ * or 0 if no signal should be delivered, ie the signal that caused * us to stop should be ignored. */ -int gdb_handlesig(CPUState *, int, const char *); +int gdb_handlesig(CPUState *, int, const char *, void *, int); /** * gdb_signalled() - inform remote gdb of sig exit diff --git a/linux-user/main.c b/linux-user/main.c index 55aa11c9b4..9277df2e9d 100644 --- a/linux-user/main.c +++ b/linux-user/main.c @@ -1018,7 +1018,7 @@ int main(int argc, char **argv, char **envp) gdbstub); exit(EXIT_FAILURE); } - gdb_handlesig(cpu, 0, NULL); + gdb_handlesig(cpu, 0, NULL, NULL, 0); } #ifdef CONFIG_SEMIHOSTING diff --git a/linux-user/signal.c b/linux-user/signal.c index 2db4d12ef6..a93148a4cb 100644 --- a/linux-user/signal.c +++ b/linux-user/signal.c @@ -34,6 +34,9 @@ #include "user/safe-syscall.h" #include "tcg/tcg.h" +/* target_siginfo_t must fit in gdbstub's siginfo save area. */ +QEMU_BUILD_BUG_ON(sizeof(target_siginfo_t) > MAX_SIGINFO_LENGTH); + static struct target_sigaction sigact_table[TARGET_NSIG]; static void host_signal_handler(int host_signum, siginfo_t *info, @@ -1184,7 +1187,7 @@ static void handle_pending_signal(CPUArchState *cpu_env, int sig, */ tswap_siginfo(&k->info, &k->info); - sig = gdb_handlesig(cpu, sig, NULL); + sig = gdb_handlesig(cpu, sig, NULL, &k->info, sizeof(k->info)); if (!sig) { sa = NULL; handler = TARGET_SIG_IGN;