From ecd39d620b0a3938dc3a80721e8aa436075d2916 Mon Sep 17 00:00:00 2001 From: Maxim Levitsky Date: Thu, 11 Nov 2021 12:06:02 +0100 Subject: [PATCH] gdbstub: reject unsupported flags in handle_set_qemu_sstep MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit handle_query_qemu_sstepbits is reporting NOIRQ and NOTIMER bits even if they are not supported (as is the case with record/replay). Instead, store the supported singlestep flags and reject any unsupported bits in handle_set_qemu_sstep. This removes the need for the get_sstep_flags() wrapper. While at it, move the variables in GDBState, instead of using global variables. Signed-off-by: Maxim Levitsky [Extracted from Maxim's patch into a separate commit. - Paolo] Signed-off-by: Paolo Bonzini Reviewed-by: Alex Bennée Message-Id: <20211111110604.207376-4-pbonzini@redhat.com> Signed-off-by: Paolo Bonzini --- gdbstub.c | 75 ++++++++++++++++++++++++++++++++++++------------------- 1 file changed, 49 insertions(+), 26 deletions(-) diff --git a/gdbstub.c b/gdbstub.c index 141d7bc4ec..a955175fd4 100644 --- a/gdbstub.c +++ b/gdbstub.c @@ -368,27 +368,10 @@ typedef struct GDBState { gdb_syscall_complete_cb current_syscall_cb; GString *str_buf; GByteArray *mem_buf; + int sstep_flags; + int supported_sstep_flags; } GDBState; -/* By default use no IRQs and no timers while single stepping so as to - * make single stepping like an ICE HW step. - */ -static int sstep_flags = SSTEP_ENABLE|SSTEP_NOIRQ|SSTEP_NOTIMER; - -/* Retrieves flags for single step mode. */ -static int get_sstep_flags(void) -{ - /* - * In replay mode all events written into the log should be replayed. - * That is why NOIRQ flag is removed in this mode. - */ - if (replay_mode != REPLAY_MODE_NONE) { - return SSTEP_ENABLE; - } else { - return sstep_flags; - } -} - static GDBState gdbserver_state; static void init_gdbserver_state(void) @@ -399,6 +382,26 @@ static void init_gdbserver_state(void) gdbserver_state.str_buf = g_string_new(NULL); gdbserver_state.mem_buf = g_byte_array_sized_new(MAX_PACKET_LENGTH); gdbserver_state.last_packet = g_byte_array_sized_new(MAX_PACKET_LENGTH + 4); + + /* + * In replay mode all events will come from the log and can't be + * suppressed otherwise we would break determinism. However as those + * events are tied to the number of executed instructions we won't see + * them occurring every time we single step. + */ + if (replay_mode != REPLAY_MODE_NONE) { + gdbserver_state.supported_sstep_flags = SSTEP_ENABLE; + } else { + gdbserver_state.supported_sstep_flags = + SSTEP_ENABLE | SSTEP_NOIRQ | SSTEP_NOTIMER; + } + + /* + * By default use no IRQs and no timers while single stepping so as to + * make single stepping like an ICE HW step. + */ + gdbserver_state.sstep_flags = gdbserver_state.supported_sstep_flags; + } #ifndef CONFIG_USER_ONLY @@ -505,7 +508,7 @@ static int gdb_continue_partial(char *newstates) CPU_FOREACH(cpu) { if (newstates[cpu->cpu_index] == 's') { trace_gdbstub_op_stepping(cpu->cpu_index); - cpu_single_step(cpu, sstep_flags); + cpu_single_step(cpu, gdbserver_state.sstep_flags); } } gdbserver_state.running_state = 1; @@ -524,7 +527,7 @@ static int gdb_continue_partial(char *newstates) break; /* nothing to do here */ case 's': trace_gdbstub_op_stepping(cpu->cpu_index); - cpu_single_step(cpu, get_sstep_flags()); + cpu_single_step(cpu, gdbserver_state.sstep_flags); cpu_resume(cpu); flag = 1; break; @@ -1883,7 +1886,7 @@ static void handle_step(GArray *params, void *user_ctx) gdb_set_cpu_pc((target_ulong)get_param(params, 0)->val_ull); } - cpu_single_step(gdbserver_state.c_cpu, get_sstep_flags()); + cpu_single_step(gdbserver_state.c_cpu, gdbserver_state.sstep_flags); gdb_continue(); } @@ -2017,24 +2020,44 @@ static void handle_v_commands(GArray *params, void *user_ctx) static void handle_query_qemu_sstepbits(GArray *params, void *user_ctx) { - g_string_printf(gdbserver_state.str_buf, "ENABLE=%x,NOIRQ=%x,NOTIMER=%x", - SSTEP_ENABLE, SSTEP_NOIRQ, SSTEP_NOTIMER); + g_string_printf(gdbserver_state.str_buf, "ENABLE=%x", SSTEP_ENABLE); + + if (gdbserver_state.supported_sstep_flags & SSTEP_NOIRQ) { + g_string_append_printf(gdbserver_state.str_buf, ",NOIRQ=%x", + SSTEP_NOIRQ); + } + + if (gdbserver_state.supported_sstep_flags & SSTEP_NOTIMER) { + g_string_append_printf(gdbserver_state.str_buf, ",NOTIMER=%x", + SSTEP_NOTIMER); + } + put_strbuf(); } static void handle_set_qemu_sstep(GArray *params, void *user_ctx) { + int new_sstep_flags; + if (!params->len) { return; } - sstep_flags = get_param(params, 0)->val_ul; + new_sstep_flags = get_param(params, 0)->val_ul; + + if (new_sstep_flags & ~gdbserver_state.supported_sstep_flags) { + put_packet("E22"); + return; + } + + gdbserver_state.sstep_flags = new_sstep_flags; put_packet("OK"); } static void handle_query_qemu_sstep(GArray *params, void *user_ctx) { - g_string_printf(gdbserver_state.str_buf, "0x%x", sstep_flags); + g_string_printf(gdbserver_state.str_buf, "0x%x", + gdbserver_state.sstep_flags); put_strbuf(); }