[PATCH v2 1/5] gdbstub: Rename back gdb_handlesig

[PATCH v2 1/5] gdbstub: Rename back gdb_handlesig

[Gustavo Romero]

Rename gdb_handlesig_reason back to gdb_handlesig. There is no need to
add a wrapper for gdb_handlesig and rename it when a new parameter is
added.

Signed-off-by: Gustavo Romero <gustavo.romero@linaro.org>
---
 gdbstub/user.c         |  8 ++++----
 include/gdbstub/user.h | 15 ++-------------
 linux-user/main.c      |  2 +-
 linux-user/signal.c    |  2 +-
 4 files changed, 8 insertions(+), 19 deletions(-)

diff --git a/gdbstub/user.c b/gdbstub/user.c
index 14918d1a21..a157e67f95 100644
--- a/gdbstub/user.c
+++ b/gdbstub/user.c
@@ -131,7 +131,7 @@ void gdb_qemu_exit(int code)
     exit(code);
 }
 
-int gdb_handlesig_reason(CPUState *cpu, int sig, const char *reason)
+int gdb_handlesig(CPUState *cpu, int sig, const char *reason)
 {
     char buf[256];
     int n;
@@ -510,7 +510,7 @@ 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);
+    gdb_handlesig(gdbserver_state.c_cpu, 0, NULL);
 }
 
 static bool should_catch_syscall(int num)
@@ -528,7 +528,7 @@ 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_reason(cs, gdb_target_sigtrap(), reason);
+        gdb_handlesig(cs, gdb_target_sigtrap(), reason);
     }
 }
 
@@ -536,7 +536,7 @@ 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_reason(cs, gdb_target_sigtrap(), reason);
+        gdb_handlesig(cs, gdb_target_sigtrap(), reason);
     }
 }
 
diff --git a/include/gdbstub/user.h b/include/gdbstub/user.h
index 68b6534130..6647af2123 100644
--- a/include/gdbstub/user.h
+++ b/include/gdbstub/user.h
@@ -10,7 +10,7 @@
 #define GDBSTUB_USER_H
 
 /**
- * gdb_handlesig_reason() - yield control to gdb
+ * 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
@@ -25,18 +25,7 @@
  * or 0 if no signal should be delivered, ie the signal that caused
  * us to stop should be ignored.
  */
-int gdb_handlesig_reason(CPUState *, int, const char *);
-
-/**
- * gdb_handlesig() - yield control to gdb
- * @cpu CPU
- * @sig: if non-zero, the signal number which caused us to stop
- * @see gdb_handlesig_reason()
- */
-static inline int gdb_handlesig(CPUState *cpu, int sig)
-{
-    return gdb_handlesig_reason(cpu, sig, NULL);
-}
+int gdb_handlesig(CPUState *, int, const char *);
 
 /**
  * gdb_signalled() - inform remote gdb of sig exit
diff --git a/linux-user/main.c b/linux-user/main.c
index 551acf1661..049fd85a2a 100644
--- a/linux-user/main.c
+++ b/linux-user/main.c
@@ -1014,7 +1014,7 @@ int main(int argc, char **argv, char **envp)
                     gdbstub);
             exit(EXIT_FAILURE);
         }
-        gdb_handlesig(cpu, 0);
+        gdb_handlesig(cpu, 0, NULL);
     }
 
 #ifdef CONFIG_SEMIHOSTING
diff --git a/linux-user/signal.c b/linux-user/signal.c
index d3e62ab030..a57c45de35 100644
--- a/linux-user/signal.c
+++ b/linux-user/signal.c
@@ -1180,7 +1180,7 @@ static void handle_pending_signal(CPUArchState *cpu_env, int sig,
     /* dequeue signal */
     k->pending = 0;
 
-    sig = gdb_handlesig(cpu, sig);
+    sig = gdb_handlesig(cpu, sig, NULL);
     if (!sig) {
         sa = NULL;
         handler = TARGET_SIG_IGN;
-- 
2.34.1

[PATCH v2 2/5] linux-user: Move tswap_siginfo out of target code

[Gustavo Romero]

Move tswap_siginfo from target code to handle_pending_signal. This will
allow some cleanups and having the siginfo ready to be used in gdbstub.

Signed-off-by: Gustavo Romero <gustavo.romero@linaro.org>
Suggested-by: Richard Henderson <richard.henderson@linaro.org>
---
 linux-user/aarch64/signal.c     |  2 +-
 linux-user/alpha/signal.c       |  2 +-
 linux-user/arm/signal.c         |  2 +-
 linux-user/hexagon/signal.c     |  2 +-
 linux-user/hppa/signal.c        |  2 +-
 linux-user/i386/signal.c        |  6 +++---
 linux-user/loongarch64/signal.c |  2 +-
 linux-user/m68k/signal.c        |  4 ++--
 linux-user/microblaze/signal.c  |  2 +-
 linux-user/mips/signal.c        |  4 ++--
 linux-user/nios2/signal.c       |  2 +-
 linux-user/openrisc/signal.c    |  2 +-
 linux-user/ppc/signal.c         |  4 ++--
 linux-user/riscv/signal.c       |  2 +-
 linux-user/s390x/signal.c       |  2 +-
 linux-user/sh4/signal.c         |  2 +-
 linux-user/signal-common.h      |  2 --
 linux-user/signal.c             | 10 ++++++++--
 linux-user/sparc/signal.c       |  2 +-
 linux-user/xtensa/signal.c      |  2 +-
 20 files changed, 31 insertions(+), 27 deletions(-)

diff --git a/linux-user/aarch64/signal.c b/linux-user/aarch64/signal.c
index a1e22d526d..bc7a13800d 100644
--- a/linux-user/aarch64/signal.c
+++ b/linux-user/aarch64/signal.c
@@ -670,7 +670,7 @@ static void target_setup_frame(int usig, struct target_sigaction *ka,
     aarch64_set_svcr(env, 0, R_SVCR_SM_MASK | R_SVCR_ZA_MASK);
 
     if (info) {
-        tswap_siginfo(&frame->info, info);
+        frame->info = *info;
         env->xregs[1] = frame_addr + offsetof(struct target_rt_sigframe, info);
         env->xregs[2] = frame_addr + offsetof(struct target_rt_sigframe, uc);
     }
diff --git a/linux-user/alpha/signal.c b/linux-user/alpha/signal.c
index 4ec42994d4..896c2c148a 100644
--- a/linux-user/alpha/signal.c
+++ b/linux-user/alpha/signal.c
@@ -173,7 +173,7 @@ void setup_rt_frame(int sig, struct target_sigaction *ka,
         goto give_sigsegv;
     }
 
-    tswap_siginfo(&frame->info, info);
+    frame->info = *info;
 
     __put_user(0, &frame->uc.tuc_flags);
     __put_user(0, &frame->uc.tuc_link);
diff --git a/linux-user/arm/signal.c b/linux-user/arm/signal.c
index f77f692c63..420fc04cfa 100644
--- a/linux-user/arm/signal.c
+++ b/linux-user/arm/signal.c
@@ -357,7 +357,7 @@ void setup_rt_frame(int usig, struct target_sigaction *ka,
 
     info_addr = frame_addr + offsetof(struct rt_sigframe, info);
     uc_addr = frame_addr + offsetof(struct rt_sigframe, sig.uc);
-    tswap_siginfo(&frame->info, info);
+    frame->info = *info;
 
     setup_sigframe(&frame->sig.uc, set, env);
 
diff --git a/linux-user/hexagon/signal.c b/linux-user/hexagon/signal.c
index 60fa7e1bce..492b51f155 100644
--- a/linux-user/hexagon/signal.c
+++ b/linux-user/hexagon/signal.c
@@ -162,7 +162,7 @@ void setup_rt_frame(int sig, struct target_sigaction *ka,
     }
 
     setup_ucontext(&frame->uc, env, set);
-    tswap_siginfo(&frame->info, info);
+    frame->info = *info;
     /*
      * The on-stack signal trampoline is no longer executed;
      * however, the libgcc signal frame unwinding code checks
diff --git a/linux-user/hppa/signal.c b/linux-user/hppa/signal.c
index d08a97dae6..8960175da3 100644
--- a/linux-user/hppa/signal.c
+++ b/linux-user/hppa/signal.c
@@ -127,7 +127,7 @@ void setup_rt_frame(int sig, struct target_sigaction *ka,
         goto give_sigsegv;
     }
 
-    tswap_siginfo(&frame->info, info);
+    frame->info = *info;
     frame->uc.tuc_flags = 0;
     frame->uc.tuc_link = 0;
 
diff --git a/linux-user/i386/signal.c b/linux-user/i386/signal.c
index bc5d45302e..cfe70fc5cf 100644
--- a/linux-user/i386/signal.c
+++ b/linux-user/i386/signal.c
@@ -430,7 +430,7 @@ void setup_frame(int sig, struct target_sigaction *ka,
     setup_sigcontext(&frame->sc, &frame->fpstate, env, set->sig[0],
             frame_addr + offsetof(struct sigframe, fpstate));
 
-    for(i = 1; i < TARGET_NSIG_WORDS; i++) {
+    for (i = 1; i < TARGET_NSIG_WORDS; i++) {
         __put_user(set->sig[i], &frame->extramask[i - 1]);
     }
 
@@ -490,7 +490,7 @@ void setup_rt_frame(int sig, struct target_sigaction *ka,
     __put_user(addr, &frame->puc);
 #endif
     if (ka->sa_flags & TARGET_SA_SIGINFO) {
-        tswap_siginfo(&frame->info, info);
+        frame->info = *info;
     }
 
     /* Create the ucontext.  */
@@ -504,7 +504,7 @@ void setup_rt_frame(int sig, struct target_sigaction *ka,
     setup_sigcontext(&frame->uc.tuc_mcontext, &frame->fpstate, env,
             set->sig[0], frame_addr + offsetof(struct rt_sigframe, fpstate));
 
-    for(i = 0; i < TARGET_NSIG_WORDS; i++) {
+    for (i = 0; i < TARGET_NSIG_WORDS; i++) {
         __put_user(set->sig[i], &frame->uc.tuc_sigmask.sig[i]);
     }
 
diff --git a/linux-user/loongarch64/signal.c b/linux-user/loongarch64/signal.c
index 39ea82c814..1a322f9697 100644
--- a/linux-user/loongarch64/signal.c
+++ b/linux-user/loongarch64/signal.c
@@ -376,7 +376,7 @@ void setup_rt_frame(int sig, struct target_sigaction *ka,
         extctx.end.haddr = (void *)frame + (extctx.end.gaddr - frame_addr);
     }
 
-    tswap_siginfo(&frame->rs_info, info);
+    frame->rs_info = *info;
 
     __put_user(0, &frame->rs_uc.tuc_flags);
     __put_user(0, &frame->rs_uc.tuc_link);
diff --git a/linux-user/m68k/signal.c b/linux-user/m68k/signal.c
index 5f35354487..77555781aa 100644
--- a/linux-user/m68k/signal.c
+++ b/linux-user/m68k/signal.c
@@ -295,7 +295,7 @@ void setup_rt_frame(int sig, struct target_sigaction *ka,
     uc_addr = frame_addr + offsetof(struct target_rt_sigframe, uc);
     __put_user(uc_addr, &frame->puc);
 
-    tswap_siginfo(&frame->info, info);
+    frame->info = *info;
 
     /* Create the ucontext */
 
@@ -307,7 +307,7 @@ void setup_rt_frame(int sig, struct target_sigaction *ka,
     if (err)
         goto give_sigsegv;
 
-    for(i = 0; i < TARGET_NSIG_WORDS; i++) {
+    for (i = 0; i < TARGET_NSIG_WORDS; i++) {
         __put_user(set->sig[i], &frame->uc.tuc_sigmask.sig[i]);
     }
 
diff --git a/linux-user/microblaze/signal.c b/linux-user/microblaze/signal.c
index 5188d74025..f6d47d76ff 100644
--- a/linux-user/microblaze/signal.c
+++ b/linux-user/microblaze/signal.c
@@ -147,7 +147,7 @@ void setup_rt_frame(int sig, struct target_sigaction *ka,
         return;
     }
 
-    tswap_siginfo(&frame->info, info);
+    frame->info = *info;
 
     __put_user(0, &frame->uc.tuc_flags);
     __put_user(0, &frame->uc.tuc_link);
diff --git a/linux-user/mips/signal.c b/linux-user/mips/signal.c
index 58a9d7a8a3..d69a5d73dd 100644
--- a/linux-user/mips/signal.c
+++ b/linux-user/mips/signal.c
@@ -303,7 +303,7 @@ void setup_rt_frame(int sig, struct target_sigaction *ka,
         goto give_sigsegv;
     }
 
-    tswap_siginfo(&frame->rs_info, info);
+    frame->rs_info = *info;
 
     __put_user(0, &frame->rs_uc.tuc_flags);
     __put_user(0, &frame->rs_uc.tuc_link);
@@ -311,7 +311,7 @@ void setup_rt_frame(int sig, struct target_sigaction *ka,
 
     setup_sigcontext(env, &frame->rs_uc.tuc_mcontext);
 
-    for(i = 0; i < TARGET_NSIG_WORDS; i++) {
+    for (i = 0; i < TARGET_NSIG_WORDS; i++) {
         __put_user(set->sig[i], &frame->rs_uc.tuc_sigmask.sig[i]);
     }
 
diff --git a/linux-user/nios2/signal.c b/linux-user/nios2/signal.c
index 32b3dc99c6..64c345f409 100644
--- a/linux-user/nios2/signal.c
+++ b/linux-user/nios2/signal.c
@@ -157,7 +157,7 @@ void setup_rt_frame(int sig, struct target_sigaction *ka,
         return;
     }
 
-    tswap_siginfo(&frame->info, info);
+    frame->info = *info;
 
     /* Create the ucontext.  */
     __put_user(0, &frame->uc.tuc_flags);
diff --git a/linux-user/openrisc/signal.c b/linux-user/openrisc/signal.c
index be8b68784a..cb74a9fe5e 100644
--- a/linux-user/openrisc/signal.c
+++ b/linux-user/openrisc/signal.c
@@ -103,7 +103,7 @@ void setup_rt_frame(int sig, struct target_sigaction *ka,
     }
 
     if (ka->sa_flags & SA_SIGINFO) {
-        tswap_siginfo(&frame->info, info);
+        frame->info = *info;
     }
 
     __put_user(0, &frame->uc.tuc_flags);
diff --git a/linux-user/ppc/signal.c b/linux-user/ppc/signal.c
index 7e7302823b..0ebfc0b26b 100644
--- a/linux-user/ppc/signal.c
+++ b/linux-user/ppc/signal.c
@@ -493,7 +493,7 @@ void setup_rt_frame(int sig, struct target_sigaction *ka,
     if (!lock_user_struct(VERIFY_WRITE, rt_sf, rt_sf_addr, 1))
         goto sigsegv;
 
-    tswap_siginfo(&rt_sf->info, info);
+    rt_sf->info = *info;
 
     __put_user(0, &rt_sf->uc.tuc_flags);
     __put_user(0, &rt_sf->uc.tuc_link);
@@ -502,7 +502,7 @@ void setup_rt_frame(int sig, struct target_sigaction *ka,
     __put_user(h2g (&rt_sf->uc.tuc_mcontext),
                &rt_sf->uc.tuc_regs);
 #endif
-    for(i = 0; i < TARGET_NSIG_WORDS; i++) {
+    for (i = 0; i < TARGET_NSIG_WORDS; i++) {
         __put_user(set->sig[i], &rt_sf->uc.tuc_sigmask.sig[i]);
     }
 
diff --git a/linux-user/riscv/signal.c b/linux-user/riscv/signal.c
index 941eadce87..358fa1d82d 100644
--- a/linux-user/riscv/signal.c
+++ b/linux-user/riscv/signal.c
@@ -125,7 +125,7 @@ void setup_rt_frame(int sig, struct target_sigaction *ka,
     }
 
     setup_ucontext(&frame->uc, env, set);
-    tswap_siginfo(&frame->info, info);
+    frame->info = *info;
 
     env->pc = ka->_sa_handler;
     env->gpr[xSP] = frame_addr;
diff --git a/linux-user/s390x/signal.c b/linux-user/s390x/signal.c
index b40f738a70..df49c24708 100644
--- a/linux-user/s390x/signal.c
+++ b/linux-user/s390x/signal.c
@@ -267,7 +267,7 @@ void setup_rt_frame(int sig, struct target_sigaction *ka,
     }
 
     /* Create siginfo on the signal stack. */
-    tswap_siginfo(&frame->info, info);
+    frame->info = *info;
 
     /* Create ucontext on the signal stack. */
     uc_flags = 0;
diff --git a/linux-user/sh4/signal.c b/linux-user/sh4/signal.c
index c16c2c2d57..9ecc026fae 100644
--- a/linux-user/sh4/signal.c
+++ b/linux-user/sh4/signal.c
@@ -233,7 +233,7 @@ void setup_rt_frame(int sig, struct target_sigaction *ka,
         goto give_sigsegv;
     }
 
-    tswap_siginfo(&frame->info, info);
+    frame->info = *info;
 
     /* Create the ucontext.  */
     __put_user(0, &frame->uc.tuc_flags);
diff --git a/linux-user/signal-common.h b/linux-user/signal-common.h
index 3e2dc604c2..f02d2b6b64 100644
--- a/linux-user/signal-common.h
+++ b/linux-user/signal-common.h
@@ -43,8 +43,6 @@ void host_to_target_sigset_internal(target_sigset_t *d,
                                     const sigset_t *s);
 void target_to_host_sigset_internal(sigset_t *d,
                                     const target_sigset_t *s);
-void tswap_siginfo(target_siginfo_t *tinfo,
-                   const target_siginfo_t *info);
 void set_sigmask(const sigset_t *set);
 void force_sig(int sig);
 void force_sigsegv(int oldsig);
diff --git a/linux-user/signal.c b/linux-user/signal.c
index a57c45de35..7a4c8e416e 100644
--- a/linux-user/signal.c
+++ b/linux-user/signal.c
@@ -409,8 +409,8 @@ static inline void host_to_target_siginfo_noswap(target_siginfo_t *tinfo,
     tinfo->si_code = deposit32(si_code, 16, 16, si_type);
 }
 
-void tswap_siginfo(target_siginfo_t *tinfo,
-                   const target_siginfo_t *info)
+static void tswap_siginfo(target_siginfo_t *tinfo,
+                          const target_siginfo_t *info)
 {
     int si_type = extract32(info->si_code, 16, 16);
     int si_code = sextract32(info->si_code, 0, 16);
@@ -1180,6 +1180,12 @@ static void handle_pending_signal(CPUArchState *cpu_env, int sig,
     /* dequeue signal */
     k->pending = 0;
 
+    /*
+     * Writes out siginfo values byteswapped, accordingly to the target. It also
+     * cleans the si_type from si_code making it correct for the target.
+     */
+    tswap_siginfo(&k->info, &k->info);
+
     sig = gdb_handlesig(cpu, sig, NULL);
     if (!sig) {
         sa = NULL;
diff --git a/linux-user/sparc/signal.c b/linux-user/sparc/signal.c
index c2dc1000e2..f164b74032 100644
--- a/linux-user/sparc/signal.c
+++ b/linux-user/sparc/signal.c
@@ -333,7 +333,7 @@ void setup_rt_frame(int sig, struct target_sigaction *ka,
 
     __put_user(0, &sf->rwin_save);  /* TODO: save_rwin_state */
 
-    tswap_siginfo(&sf->info, info);
+    sf->info = *info;
     tswap_sigset(&sf->mask, set);
     target_save_altstack(&sf->stack, env);
 
diff --git a/linux-user/xtensa/signal.c b/linux-user/xtensa/signal.c
index 32dcfa5229..11e60c3c82 100644
--- a/linux-user/xtensa/signal.c
+++ b/linux-user/xtensa/signal.c
@@ -184,7 +184,7 @@ void setup_rt_frame(int sig, struct target_sigaction *ka,
     }
 
     if (ka->sa_flags & SA_SIGINFO) {
-        tswap_siginfo(&frame->info, info);
+        frame->info = *info;
     }
 
     __put_user(0, &frame->uc.tuc_flags);
-- 
2.34.1

[PATCH v2 3/5] gdbstub: Save target's siginfo

[Gustavo Romero]

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 <gustavo.romero@linaro.org>
Suggested-by: Richard Henderson <richard.henderson@linaro.org>
---
 gdbstub/internals.h    |  3 +++
 gdbstub/user-target.c  |  3 ++-
 gdbstub/user.c         | 14 ++++++++++----
 include/gdbstub/user.h |  6 +++++-
 linux-user/main.c      |  2 +-
 linux-user/signal.c    |  5 ++++-
 6 files changed, 25 insertions(+), 8 deletions(-)

diff --git a/gdbstub/internals.h b/gdbstub/internals.h
index 56b7c13b75..a7cc69dab3 100644
--- a/gdbstub/internals.h
+++ b/gdbstub/internals.h
@@ -58,6 +58,9 @@ typedef struct GDBState {
     int line_csum; /* checksum at the end of the packet */
     GByteArray *last_packet;
     int signal;
+#ifdef CONFIG_USER_ONLY
+    uint8_t siginfo[MAX_SIGINFO_LENGTH];
+#endif
     bool multiprocess;
     GDBProcess *processes;
     int process_num;
diff --git a/gdbstub/user-target.c b/gdbstub/user-target.c
index b7d4c37cd8..215bf33ab3 100644
--- a/gdbstub/user-target.c
+++ b/gdbstub/user-target.c
@@ -10,11 +10,12 @@
 #include "qemu/osdep.h"
 #include "exec/gdbstub.h"
 #include "qemu.h"
-#include "internals.h"
 #ifdef CONFIG_LINUX
 #include "linux-user/loader.h"
 #include "linux-user/qemu.h"
+#include "gdbstub/user.h"
 #endif
+#include "internals.h"
 
 /*
  * Map target signal numbers to GDB protocol signal numbers and vice
diff --git a/gdbstub/user.c b/gdbstub/user.c
index a157e67f95..777fa78ef4 100644
--- a/gdbstub/user.c
+++ b/gdbstub/user.c
@@ -131,7 +131,8 @@ 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;
@@ -140,6 +141,11 @@ int gdb_handlesig(CPUState *cpu, int sig, const char *reason)
         return sig;
     }
 
+    if (siginfo) {
+        /* Save target-specific siginfo. */
+        memcpy(gdbserver_state.siginfo, siginfo, siginfo_len);
+    }
+
     /* disable single step if it was enabled */
     cpu_single_step(cpu, 0);
     tb_flush(cpu);
@@ -510,7 +516,7 @@ 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)
@@ -528,7 +534,7 @@ 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);
     }
 }
 
@@ -536,7 +542,7 @@ 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 6647af2123..0ec9a7e596 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 049fd85a2a..3187be48d6 100644
--- a/linux-user/main.c
+++ b/linux-user/main.c
@@ -1014,7 +1014,7 @@ 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 7a4c8e416e..98d1eacffe 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,
@@ -1186,7 +1189,7 @@ 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;
-- 
2.34.1

[PATCH v2 4/5] gdbstub: Add Xfer:siginfo:read stub

[Gustavo Romero]

Add stub to handle Xfer:siginfo:read packet query that requests the
machine's siginfo data.

This is used when GDB user executes 'print $_siginfo' and when the
machine stops due to a signal, for instance, on SIGSEGV. The information
in siginfo allows GDB to determiner further details on the signal, like
the fault address/insn when the SIGSEGV is caught.

Signed-off-by: Gustavo Romero <gustavo.romero@linaro.org>
---
 gdbstub/gdbstub.c     |  8 ++++++++
 gdbstub/internals.h   |  1 +
 gdbstub/user-target.c | 23 +++++++++++++++++++++++
 3 files changed, 32 insertions(+)

diff --git a/gdbstub/gdbstub.c b/gdbstub/gdbstub.c
index 2909bc8c69..ab38cea46b 100644
--- a/gdbstub/gdbstub.c
+++ b/gdbstub/gdbstub.c
@@ -1651,6 +1651,8 @@ static void handle_query_supported(GArray *params, void *user_ctx)
         g_string_append(gdbserver_state.str_buf, ";qXfer:auxv:read+");
     }
     g_string_append(gdbserver_state.str_buf, ";QCatchSyscalls+");
+
+    g_string_append(gdbserver_state.str_buf, ";qXfer:siginfo:read+");
 #endif
     g_string_append(gdbserver_state.str_buf, ";qXfer:exec-file:read+");
 #endif
@@ -1799,6 +1801,12 @@ static const GdbCmdParseEntry gdb_gen_query_table[] = {
         .cmd_startswith = 1,
         .schema = "l,l0"
     },
+    {
+        .handler = gdb_handle_query_xfer_siginfo,
+        .cmd = "Xfer:siginfo:read::",
+        .cmd_startswith = 1,
+        .schema = "l,l0"
+     },
 #endif
     {
         .handler = gdb_handle_query_xfer_exec_file,
diff --git a/gdbstub/internals.h b/gdbstub/internals.h
index a7cc69dab3..15c01c525a 100644
--- a/gdbstub/internals.h
+++ b/gdbstub/internals.h
@@ -193,6 +193,7 @@ typedef union GdbCmdVariant {
 void gdb_handle_query_rcmd(GArray *params, void *user_ctx); /* softmmu */
 void gdb_handle_query_offsets(GArray *params, void *user_ctx); /* user */
 void gdb_handle_query_xfer_auxv(GArray *params, void *user_ctx); /*user */
+void gdb_handle_query_xfer_siginfo(GArray *params, void *user_ctx); /*user */
 void gdb_handle_v_file_open(GArray *params, void *user_ctx); /* user */
 void gdb_handle_v_file_close(GArray *params, void *user_ctx); /* user */
 void gdb_handle_v_file_pread(GArray *params, void *user_ctx); /* user */
diff --git a/gdbstub/user-target.c b/gdbstub/user-target.c
index 215bf33ab3..93739852b0 100644
--- a/gdbstub/user-target.c
+++ b/gdbstub/user-target.c
@@ -285,6 +285,29 @@ void gdb_handle_query_xfer_auxv(GArray *params, void *user_ctx)
     gdb_put_packet_binary(gdbserver_state.str_buf->str,
                       gdbserver_state.str_buf->len, true);
 }
+
+void gdb_handle_query_xfer_siginfo(GArray *params, void *user_ctx)
+{
+    unsigned long offset, len;
+    uint8_t *siginfo_offset;
+
+    offset = get_param(params, 0)->val_ul;
+    len = get_param(params, 1)->val_ul;
+
+    if (offset + len > sizeof(target_siginfo_t)) {
+        /* Invalid offset and/or requested length. */
+        gdb_put_packet("E01");
+        return;
+    }
+
+    siginfo_offset = (uint8_t *)gdbserver_state.siginfo + offset;
+
+    /* Reply */
+    g_string_assign(gdbserver_state.str_buf, "l");
+    gdb_memtox(gdbserver_state.str_buf, (const char *)siginfo_offset, len);
+    gdb_put_packet_binary(gdbserver_state.str_buf->str,
+                          gdbserver_state.str_buf->len, true);
+}
 #endif
 
 static const char *get_filename_param(GArray *params, int i)
-- 
2.34.1

[PATCH v2 5/5] tests/tcg: Add multiarch test for Xfer:siginfo:read stub

[Gustavo Romero]

Add multiarch test for testing if Xfer:siginfo:read query is properly
handled by gdbstub.

Signed-off-by: Gustavo Romero <gustavo.romero@linaro.org>
---
 tests/tcg/multiarch/Makefile.target           | 10 ++++++-
 .../gdbstub/test-qxfer-siginfo-read.py        | 26 +++++++++++++++++++
 tests/tcg/multiarch/segfault.c                | 14 ++++++++++
 3 files changed, 49 insertions(+), 1 deletion(-)
 create mode 100644 tests/tcg/multiarch/gdbstub/test-qxfer-siginfo-read.py
 create mode 100644 tests/tcg/multiarch/segfault.c

diff --git a/tests/tcg/multiarch/Makefile.target b/tests/tcg/multiarch/Makefile.target
index f11f3b084d..5ab4ba89b2 100644
--- a/tests/tcg/multiarch/Makefile.target
+++ b/tests/tcg/multiarch/Makefile.target
@@ -71,6 +71,13 @@ run-gdbstub-qxfer-auxv-read: sha1
 		--bin $< --test $(MULTIARCH_SRC)/gdbstub/test-qxfer-auxv-read.py, \
 	basic gdbstub qXfer:auxv:read support)
 
+run-gdbstub-qxfer-siginfo-read: segfault
+	$(call run-test, $@, $(GDB_SCRIPT) \
+		--gdb $(GDB) \
+		--qemu $(QEMU) --qargs "$(QEMU_OPTS)" \
+		--bin "$< -s" --test $(MULTIARCH_SRC)/gdbstub/test-qxfer-siginfo-read.py, \
+	basic gdbstub qXfer:siginfo:read support)
+
 run-gdbstub-proc-mappings: sha1
 	$(call run-test, $@, $(GDB_SCRIPT) \
 		--gdb $(GDB) \
@@ -113,7 +120,8 @@ endif
 EXTRA_RUNS += run-gdbstub-sha1 run-gdbstub-qxfer-auxv-read \
 	      run-gdbstub-proc-mappings run-gdbstub-thread-breakpoint \
 	      run-gdbstub-registers run-gdbstub-prot-none \
-	      run-gdbstub-catch-syscalls
+	      run-gdbstub-catch-syscalls \
+	      run-gdbstub-qxfer-siginfo-read
 
 # ARM Compatible Semi Hosting Tests
 #
diff --git a/tests/tcg/multiarch/gdbstub/test-qxfer-siginfo-read.py b/tests/tcg/multiarch/gdbstub/test-qxfer-siginfo-read.py
new file mode 100644
index 0000000000..862596b07a
--- /dev/null
+++ b/tests/tcg/multiarch/gdbstub/test-qxfer-siginfo-read.py
@@ -0,0 +1,26 @@
+from __future__ import print_function
+#
+# Test gdbstub Xfer:siginfo:read stub.
+#
+# The test runs a binary that causes a SIGSEGV and then looks for additional
+# info about the signal through printing GDB's '$_siginfo' special variable,
+# which sends a Xfer:siginfo:read query to the gdbstub.
+#
+# The binary causes a SIGSEGV at dereferencing a pointer with value 0xdeadbeef,
+# so the test looks for and checks if this address is correctly reported by the
+# gdbstub.
+#
+# This is launched via tests/guest-debug/run-test.py
+#
+
+import gdb
+from test_gdbstub import main, report
+
+def run_test():
+    "Run through the test"
+
+    gdb.execute("continue", False, True)
+    resp = gdb.execute("print/x $_siginfo", False, True)
+    report(resp.find("si_addr = 0xdeadbeef"), "Found fault address.")
+
+main(run_test)
diff --git a/tests/tcg/multiarch/segfault.c b/tests/tcg/multiarch/segfault.c
new file mode 100644
index 0000000000..e6c8ff31ca
--- /dev/null
+++ b/tests/tcg/multiarch/segfault.c
@@ -0,0 +1,14 @@
+#include <stdio.h>
+#include <string.h>
+
+/* Cause a segfault for testing purposes. */
+
+int main(int argc, char *argv[])
+{
+    int *ptr = (void *)0xdeadbeef;
+
+    if (argc == 2 && strcmp(argv[1], "-s") == 0) {
+        /* Cause segfault. */
+        printf("%d\n", *ptr);
+    }
+}
-- 
2.34.1

Re: [PATCH v2 1/5] gdbstub: Rename back gdb_handlesig

[Alex Bennée]

Gustavo Romero <gustavo.romero@linaro.org> writes:

> Rename gdb_handlesig_reason back to gdb_handlesig. There is no need to
> add a wrapper for gdb_handlesig and rename it when a new parameter is
> added.
>
> Signed-off-by: Gustavo Romero <gustavo.romero@linaro.org>

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>

-- 
Alex Bennée
Virtualisation Tech Lead @ Linaro

Re: [PATCH v2 2/5] linux-user: Move tswap_siginfo out of target code

[Alex Bennée]

Gustavo Romero <gustavo.romero@linaro.org> writes:

> Move tswap_siginfo from target code to handle_pending_signal. This will
> allow some cleanups and having the siginfo ready to be used in gdbstub.
>
> Signed-off-by: Gustavo Romero <gustavo.romero@linaro.org>
> Suggested-by: Richard Henderson <richard.henderson@linaro.org>
> ---
>  linux-user/aarch64/signal.c     |  2 +-
>  linux-user/alpha/signal.c       |  2 +-
>  linux-user/arm/signal.c         |  2 +-
>  linux-user/hexagon/signal.c     |  2 +-
>  linux-user/hppa/signal.c        |  2 +-
>  linux-user/i386/signal.c        |  6 +++---
>  linux-user/loongarch64/signal.c |  2 +-
>  linux-user/m68k/signal.c        |  4 ++--
>  linux-user/microblaze/signal.c  |  2 +-
>  linux-user/mips/signal.c        |  4 ++--
>  linux-user/nios2/signal.c       |  2 +-
>  linux-user/openrisc/signal.c    |  2 +-
>  linux-user/ppc/signal.c         |  4 ++--
>  linux-user/riscv/signal.c       |  2 +-
>  linux-user/s390x/signal.c       |  2 +-
>  linux-user/sh4/signal.c         |  2 +-
>  linux-user/signal-common.h      |  2 --
>  linux-user/signal.c             | 10 ++++++++--
>  linux-user/sparc/signal.c       |  2 +-
>  linux-user/xtensa/signal.c      |  2 +-
>  20 files changed, 31 insertions(+), 27 deletions(-)
>
> diff --git a/linux-user/aarch64/signal.c b/linux-user/aarch64/signal.c
<snip>
> --- a/linux-user/signal.c
> +++ b/linux-user/signal.c
> @@ -409,8 +409,8 @@ static inline void host_to_target_siginfo_noswap(target_siginfo_t *tinfo,
>      tinfo->si_code = deposit32(si_code, 16, 16, si_type);
>  }
>  
> -void tswap_siginfo(target_siginfo_t *tinfo,
> -                   const target_siginfo_t *info)
> +static void tswap_siginfo(target_siginfo_t *tinfo,
> +                          const target_siginfo_t *info)
>  {
>      int si_type = extract32(info->si_code, 16, 16);
>      int si_code = sextract32(info->si_code, 0, 16);
> @@ -1180,6 +1180,12 @@ static void handle_pending_signal(CPUArchState *cpu_env, int sig,
>      /* dequeue signal */
>      k->pending = 0;
>  
> +    /*
> +     * Writes out siginfo values byteswapped, accordingly to the target. It also
> +     * cleans the si_type from si_code making it correct for the target.
> +     */
> +    tswap_siginfo(&k->info, &k->info);
> +

I'm not sure I like this, you have the same pointer to both a const and
non-const arg. Do we assert we come through this once per signal and
don't risk double swapping the contents?

-- 
Alex Bennée
Virtualisation Tech Lead @ Linaro

Re: [PATCH v2 1/5] gdbstub: Rename back gdb_handlesig

[Richard Henderson]

On 3/7/24 08:26, Gustavo Romero wrote:
> Rename gdb_handlesig_reason back to gdb_handlesig. There is no need to
> add a wrapper for gdb_handlesig and rename it when a new parameter is
> added.
> 
> Signed-off-by: Gustavo Romero <gustavo.romero@linaro.org>
> ---
>   gdbstub/user.c         |  8 ++++----
>   include/gdbstub/user.h | 15 ++-------------
>   linux-user/main.c      |  2 +-
>   linux-user/signal.c    |  2 +-
>   4 files changed, 8 insertions(+), 19 deletions(-)

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>

r~

Re: [PATCH v2 2/5] linux-user: Move tswap_siginfo out of target code

[Richard Henderson]

On 3/7/24 08:26, Gustavo Romero wrote:
> Move tswap_siginfo from target code to handle_pending_signal. This will
> allow some cleanups and having the siginfo ready to be used in gdbstub.
> 
> Signed-off-by: Gustavo Romero<gustavo.romero@linaro.org>
> Suggested-by: Richard Henderson<richard.henderson@linaro.org>
> ---
>   linux-user/aarch64/signal.c     |  2 +-
>   linux-user/alpha/signal.c       |  2 +-
>   linux-user/arm/signal.c         |  2 +-
>   linux-user/hexagon/signal.c     |  2 +-
>   linux-user/hppa/signal.c        |  2 +-
>   linux-user/i386/signal.c        |  6 +++---
>   linux-user/loongarch64/signal.c |  2 +-
>   linux-user/m68k/signal.c        |  4 ++--
>   linux-user/microblaze/signal.c  |  2 +-
>   linux-user/mips/signal.c        |  4 ++--
>   linux-user/nios2/signal.c       |  2 +-
>   linux-user/openrisc/signal.c    |  2 +-
>   linux-user/ppc/signal.c         |  4 ++--
>   linux-user/riscv/signal.c       |  2 +-
>   linux-user/s390x/signal.c       |  2 +-
>   linux-user/sh4/signal.c         |  2 +-
>   linux-user/signal-common.h      |  2 --
>   linux-user/signal.c             | 10 ++++++++--
>   linux-user/sparc/signal.c       |  2 +-
>   linux-user/xtensa/signal.c      |  2 +-
>   20 files changed, 31 insertions(+), 27 deletions(-)

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>

r~

Re: [PATCH v2 2/5] linux-user: Move tswap_siginfo out of target code

[Richard Henderson]

On 3/7/24 09:21, Alex Bennée wrote:
>> +    /*
>> +     * Writes out siginfo values byteswapped, accordingly to the target. It also
>> +     * cleans the si_type from si_code making it correct for the target.
>> +     */
>> +    tswap_siginfo(&k->info, &k->info);
>> +
> 
> I'm not sure I like this, you have the same pointer to both a const and
> non-const arg. Do we assert we come through this once per signal and
> don't risk double swapping the contents?
> 

I suggested this as an intermediate step -- the function will work perfectly fine with 
dest == source.  Follow-up patches should clean this up further, but I told Gustavo to not 
get distracted from his goal with *too* much cleanup.


r~

Re: [PATCH v2 3/5] gdbstub: Save target's siginfo

[Richard Henderson]

On 3/7/24 08:26, Gustavo Romero wrote:
> 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 <gustavo.romero@linaro.org>
> Suggested-by: Richard Henderson <richard.henderson@linaro.org>
> ---
>   gdbstub/internals.h    |  3 +++
>   gdbstub/user-target.c  |  3 ++-
>   gdbstub/user.c         | 14 ++++++++++----
>   include/gdbstub/user.h |  6 +++++-
>   linux-user/main.c      |  2 +-
>   linux-user/signal.c    |  5 ++++-
>   6 files changed, 25 insertions(+), 8 deletions(-)
> 
> diff --git a/gdbstub/internals.h b/gdbstub/internals.h
> index 56b7c13b75..a7cc69dab3 100644
> --- a/gdbstub/internals.h
> +++ b/gdbstub/internals.h
> @@ -58,6 +58,9 @@ typedef struct GDBState {
>       int line_csum; /* checksum at the end of the packet */
>       GByteArray *last_packet;
>       int signal;
> +#ifdef CONFIG_USER_ONLY
> +    uint8_t siginfo[MAX_SIGINFO_LENGTH];
> +#endif

If we this in GDBUserState in user.c -- no need for ifdefs then.

> --- a/gdbstub/user-target.c
> +++ b/gdbstub/user-target.c
> @@ -10,11 +10,12 @@
>   #include "qemu/osdep.h"
>   #include "exec/gdbstub.h"
>   #include "qemu.h"
> -#include "internals.h"
>   #ifdef CONFIG_LINUX
>   #include "linux-user/loader.h"
>   #include "linux-user/qemu.h"
> +#include "gdbstub/user.h"
>   #endif
> +#include "internals.h"
>   
>   /*
>    * Map target signal numbers to GDB protocol signal numbers and vice

Why are any changes required here?
Perhaps this is improper patch split from one of the others?

> @@ -140,6 +141,11 @@ int gdb_handlesig(CPUState *cpu, int sig, const char *reason)
>           return sig;
>       }
>   
> +    if (siginfo) {
> +        /* Save target-specific siginfo. */
> +        memcpy(gdbserver_state.siginfo, siginfo, siginfo_len);
> +    }

A comment here about asserting the size at compile-time elsewhere would be welcome for 
future code browsers.

Need to record siginfo_len for later use -- you don't want to expose all 128 bytes if the 
actual structure is smaller.

> @@ -510,7 +516,7 @@ 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)
> @@ -528,7 +534,7 @@ 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);
>       }
>   }
>   
> @@ -536,7 +542,7 @@ 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);
>       }

All of this makes me wonder if we should provide a different interface for syscalls, even 
if it uses the same code paths internally.

Do we want to zero the gdbserver siginfo to indicate that the contents are no longer 
valid?  I know it's not a real signal delivered to the process, but might we need to 
construct a simple siginfo struct to match the sigtrap?


r~

Re: [PATCH v2 4/5] gdbstub: Add Xfer:siginfo:read stub

[Richard Henderson]

On 3/7/24 08:26, Gustavo Romero wrote:
> +void gdb_handle_query_xfer_siginfo(GArray *params, void *user_ctx)
> +{
> +    unsigned long offset, len;
> +    uint8_t *siginfo_offset;
> +
> +    offset = get_param(params, 0)->val_ul;
> +    len = get_param(params, 1)->val_ul;
> +
> +    if (offset + len > sizeof(target_siginfo_t)) {

If you save the siginfo_len from gdb_handlesig, you can place this in user.c.

Is it really correct to reject (offset == 0) + (len == large), rather than truncate len?

> +    /* Reply */
> +    g_string_assign(gdbserver_state.str_buf, "l");
> +    gdb_memtox(gdbserver_state.str_buf, (const char *)siginfo_offset, len);

It seems easy enough to reply with the exact length remaining...


r~

Re: [PATCH v2 5/5] tests/tcg: Add multiarch test for Xfer:siginfo:read stub

[Richard Henderson]

On 3/7/24 08:26, Gustavo Romero wrote:
> Add multiarch test for testing if Xfer:siginfo:read query is properly
> handled by gdbstub.
> 
> Signed-off-by: Gustavo Romero<gustavo.romero@linaro.org>
> ---
>   tests/tcg/multiarch/Makefile.target           | 10 ++++++-
>   .../gdbstub/test-qxfer-siginfo-read.py        | 26 +++++++++++++++++++
>   tests/tcg/multiarch/segfault.c                | 14 ++++++++++
>   3 files changed, 49 insertions(+), 1 deletion(-)
>   create mode 100644 tests/tcg/multiarch/gdbstub/test-qxfer-siginfo-read.py
>   create mode 100644 tests/tcg/multiarch/segfault.c

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>

r~

Re: [PATCH v2 3/5] gdbstub: Save target's siginfo

[Alex Bennée]

Richard Henderson <richard.henderson@linaro.org> writes:

> On 3/7/24 08:26, Gustavo Romero wrote:
>> 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 <gustavo.romero@linaro.org>
>> Suggested-by: Richard Henderson <richard.henderson@linaro.org>
>> ---
>>   gdbstub/internals.h    |  3 +++
>>   gdbstub/user-target.c  |  3 ++-
>>   gdbstub/user.c         | 14 ++++++++++----
>>   include/gdbstub/user.h |  6 +++++-
>>   linux-user/main.c      |  2 +-
>>   linux-user/signal.c    |  5 ++++-
>>   6 files changed, 25 insertions(+), 8 deletions(-)
>> diff --git a/gdbstub/internals.h b/gdbstub/internals.h
>> index 56b7c13b75..a7cc69dab3 100644
>> --- a/gdbstub/internals.h
>> +++ b/gdbstub/internals.h
>> @@ -58,6 +58,9 @@ typedef struct GDBState {
>>       int line_csum; /* checksum at the end of the packet */
>>       GByteArray *last_packet;
>>       int signal;
>> +#ifdef CONFIG_USER_ONLY
>> +    uint8_t siginfo[MAX_SIGINFO_LENGTH];
>> +#endif
>
> If we this in GDBUserState in user.c -- no need for ifdefs then.

Although it does break on FreeBSD's user target:

  FAILED: libqemu-arm-bsd-user.fa.p/gdbstub_user-target.c.o 
  cc -m64 -mcx16 -Ilibqemu-arm-bsd-user.fa.p -I. -I.. -Itarget/arm -I../target/arm -I../common-user/host/x86_64 -I../bsd-user/include -Ibsd-user/freebsd -I../bsd-user/freebsd -I../bsd-user/host/x86_64 -Ibsd-user -I../bsd-user -I../bsd-user/arm -Iqapi -Itrace -Iui -Iui/shader -I/usr/local/include/capstone -I/usr/local/include/glib-2.0 -I/usr/local/lib/glib-2.0/include -I/usr/local/include -fdiagnostics-color=auto -Wall -Winvalid-pch -Werror -std=gnu11 -O2 -g -fstack-protector-strong -Wempty-body -Wendif-labels -Wexpansion-to-defined -Wformat-security -Wformat-y2k -Wignored-qualifiers -Winit-self -Wmissing-format-attribute -Wmissing-prototypes -Wnested-externs -Wold-style-definition -Wredundant-decls -Wstrict-prototypes -Wtype-limits -Wundef -Wvla -Wwrite-strings -Wno-gnu-variable-sized-type-not-at-end -Wno-initializer-overrides -Wno-missing-include-dirs -Wno-psabi -Wno-shift-negative-value -Wno-string-plus-int -Wno-tautological-type-limit-compare -Wno-typedef-redefinition -Wthread-safety -iquote . -iquote /tmp/cirrus-ci-build -iquote /tmp/cirrus-ci-build/include -iquote /tmp/cirrus-ci-build/host/include/x86_64 -iquote /tmp/cirrus-ci-build/host/include/generic -iquote /tmp/cirrus-ci-build/tcg/i386 -pthread -D_GNU_SOURCE -D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE -fno-strict-aliasing -fno-common -fwrapv -ftrivial-auto-var-init=zero -fPIE -DNEED_CPU_H '-DCONFIG_TARGET="arm-bsd-user-config-target.h"' '-DCONFIG_DEVICES="arm-bsd-user-config-devices.h"' -MD -MQ libqemu-arm-bsd-user.fa.p/gdbstub_user-target.c.o -MF libqemu-arm-bsd-user.fa.p/gdbstub_user-target.c.o.d -o libqemu-arm-bsd-user.fa.p/gdbstub_user-target.c.o -c ../gdbstub/user-target.c
  In file included from ../gdbstub/user-target.c:18:
  ../gdbstub/internals.h:62:21: error: use of undeclared identifier 'MAX_SIGINFO_LENGTH'
     62 |     uint8_t siginfo[MAX_SIGINFO_LENGTH];
        |                     ^
  1 error generated.
  [2084/6731] Compiling C object libqemu-arm

See: https://gitlab.com/stsquad/qemu/-/jobs/6345829419

<snip>

-- 
Alex Bennée
Virtualisation Tech Lead @ Linaro

Re: [PATCH v2 3/5] gdbstub: Save target's siginfo

[Gustavo Romero]

Hi Alex,

On 3/7/24 7:33 PM, Alex Bennée wrote:
> Richard Henderson <richard.henderson@linaro.org> writes:
> 
>> On 3/7/24 08:26, Gustavo Romero wrote:
>>> 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 <gustavo.romero@linaro.org>
>>> Suggested-by: Richard Henderson <richard.henderson@linaro.org>
>>> ---
>>>    gdbstub/internals.h    |  3 +++
>>>    gdbstub/user-target.c  |  3 ++-
>>>    gdbstub/user.c         | 14 ++++++++++----
>>>    include/gdbstub/user.h |  6 +++++-
>>>    linux-user/main.c      |  2 +-
>>>    linux-user/signal.c    |  5 ++++-
>>>    6 files changed, 25 insertions(+), 8 deletions(-)
>>> diff --git a/gdbstub/internals.h b/gdbstub/internals.h
>>> index 56b7c13b75..a7cc69dab3 100644
>>> --- a/gdbstub/internals.h
>>> +++ b/gdbstub/internals.h
>>> @@ -58,6 +58,9 @@ typedef struct GDBState {
>>>        int line_csum; /* checksum at the end of the packet */
>>>        GByteArray *last_packet;
>>>        int signal;
>>> +#ifdef CONFIG_USER_ONLY
>>> +    uint8_t siginfo[MAX_SIGINFO_LENGTH];
>>> +#endif
>>
>> If we this in GDBUserState in user.c -- no need for ifdefs then.
> 
> Although it does break on FreeBSD's user target:
> 
>    FAILED: libqemu-arm-bsd-user.fa.p/gdbstub_user-target.c.o
>    cc -m64 -mcx16 -Ilibqemu-arm-bsd-user.fa.p -I. -I.. -Itarget/arm -I../target/arm -I../common-user/host/x86_64 -I../bsd-user/include -Ibsd-user/freebsd -I../bsd-user/freebsd -I../bsd-user/host/x86_64 -Ibsd-user -I../bsd-user -I../bsd-user/arm -Iqapi -Itrace -Iui -Iui/shader -I/usr/local/include/capstone -I/usr/local/include/glib-2.0 -I/usr/local/lib/glib-2.0/include -I/usr/local/include -fdiagnostics-color=auto -Wall -Winvalid-pch -Werror -std=gnu11 -O2 -g -fstack-protector-strong -Wempty-body -Wendif-labels -Wexpansion-to-defined -Wformat-security -Wformat-y2k -Wignored-qualifiers -Winit-self -Wmissing-format-attribute -Wmissing-prototypes -Wnested-externs -Wold-style-definition -Wredundant-decls -Wstrict-prototypes -Wtype-limits -Wundef -Wvla -Wwrite-strings -Wno-gnu-variable-sized-type-not-at-end -Wno-initializer-overrides -Wno-missing-include-dirs -Wno-psabi -Wno-shift-negative-value -Wno-string-plus-int -Wno-tautological-type-limit-compare -Wno-typedef-redefinition -Wthread-safety -iquote . -iquote /tmp/cirrus-ci-build -iquote /tmp/cirrus-ci-build/include -iquote /tmp/cirrus-ci-build/host/include/x86_64 -iquote /tmp/cirrus-ci-build/host/include/generic -iquote /tmp/cirrus-ci-build/tcg/i386 -pthread -D_GNU_SOURCE -D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE -fno-strict-aliasing -fno-common -fwrapv -ftrivial-auto-var-init=zero -fPIE -DNEED_CPU_H '-DCONFIG_TARGET="arm-bsd-user-config-target.h"' '-DCONFIG_DEVICES="arm-bsd-user-config-devices.h"' -MD -MQ libqemu-arm-bsd-user.fa.p/gdbstub_user-target.c.o -MF libqemu-arm-bsd-user.fa.p/gdbstub_user-target.c.o.d -o libqemu-arm-bsd-user.fa.p/gdbstub_user-target.c.o -c ../gdbstub/user-target.c
>    In file included from ../gdbstub/user-target.c:18:
>    ../gdbstub/internals.h:62:21: error: use of undeclared identifier 'MAX_SIGINFO_LENGTH'
>       62 |     uint8_t siginfo[MAX_SIGINFO_LENGTH];
>          |                     ^
>    1 error generated.
>    [2084/6731] Compiling C object libqemu-arm
> 
> See: https://gitlab.com/stsquad/qemu/-/jobs/6345829419

argh, I've tested all targets for linux-user, but missed bsd-user. I've tried
once to build it but that requires a BSD-like host, which I don't have at the
moment, then I forgot about it... Let me setup one and review the change in
the light of the comments from you and Richard.

Thanks!


Cheers,
Gustavo

Re: [PATCH v2 4/5] gdbstub: Add Xfer:siginfo:read stub

[Gustavo Romero]

Hi Richard!

On 3/7/24 6:13 PM, Richard Henderson wrote:
> On 3/7/24 08:26, Gustavo Romero wrote:
>> +void gdb_handle_query_xfer_siginfo(GArray *params, void *user_ctx)
>> +{
>> +    unsigned long offset, len;
>> +    uint8_t *siginfo_offset;
>> +
>> +    offset = get_param(params, 0)->val_ul;
>> +    len = get_param(params, 1)->val_ul;
>> +
>> +    if (offset + len > sizeof(target_siginfo_t)) {
> 
> If you save the siginfo_len from gdb_handlesig, you can place this in user.c
Shouldn't all user-only stubs be placed in user-target.c? Like
gdb_handle_query_xfer_auxv and gdb_handle_query_xfer_exec_file, and since
what controls the inclusion in the build of user-target.c is CONFIG_USER_ONLY?


> Is it really correct to reject (offset == 0) + (len == large), rather than truncate len?

I think this is correct. GDB mentions briefly that an invalid offset
should be treated as an error. Thus, I think that a valid offset but
a non-existing/invalid (large) length should be treated the same,
cause in the end data on invalid offsets are being requested anyways.


>> +    /* Reply */
>> +    g_string_assign(gdbserver_state.str_buf, "l");
>> +    gdb_memtox(gdbserver_state.str_buf, (const char *)siginfo_offset, len);
> 
> It seems easy enough to reply with the exact length remaining...

I think the correct is to reply an error in case GDB asks a data
we don't have rather than returning anything else to satisfy GDB.
If offset+len is inside target_siginfo_t, than that's ok, otherwise
that's an error.


Cheers,
Gustavo

Re: [PATCH v2 3/5] gdbstub: Save target's siginfo

[Alex Bennée]

Gustavo Romero <gustavo.romero@linaro.org> writes:

> Hi Alex,
>
> On 3/7/24 7:33 PM, Alex Bennée wrote:
>> Richard Henderson <richard.henderson@linaro.org> writes:
>> 
>>> On 3/7/24 08:26, Gustavo Romero wrote:
>>>> 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 <gustavo.romero@linaro.org>
>>>> Suggested-by: Richard Henderson <richard.henderson@linaro.org>
>>>> ---
>>>>    gdbstub/internals.h    |  3 +++
>>>>    gdbstub/user-target.c  |  3 ++-
>>>>    gdbstub/user.c         | 14 ++++++++++----
>>>>    include/gdbstub/user.h |  6 +++++-
>>>>    linux-user/main.c      |  2 +-
>>>>    linux-user/signal.c    |  5 ++++-
>>>>    6 files changed, 25 insertions(+), 8 deletions(-)
>>>> diff --git a/gdbstub/internals.h b/gdbstub/internals.h
>>>> index 56b7c13b75..a7cc69dab3 100644
>>>> --- a/gdbstub/internals.h
>>>> +++ b/gdbstub/internals.h
>>>> @@ -58,6 +58,9 @@ typedef struct GDBState {
>>>>        int line_csum; /* checksum at the end of the packet */
>>>>        GByteArray *last_packet;
>>>>        int signal;
>>>> +#ifdef CONFIG_USER_ONLY
>>>> +    uint8_t siginfo[MAX_SIGINFO_LENGTH];
>>>> +#endif
>>>
>>> If we this in GDBUserState in user.c -- no need for ifdefs then.
>> Although it does break on FreeBSD's user target:
>>    FAILED: libqemu-arm-bsd-user.fa.p/gdbstub_user-target.c.o
>>    cc -m64 -mcx16 -Ilibqemu-arm-bsd-user.fa.p -I. -I.. -Itarget/arm -I../target/arm -I../common-user/host/x86_64 -I../bsd-user/include -Ibsd-user/freebsd -I../bsd-user/freebsd -I../bsd-user/host/x86_64 -Ibsd-user -I../bsd-user -I../bsd-user/arm -Iqapi -Itrace -Iui -Iui/shader -I/usr/local/include/capstone -I/usr/local/include/glib-2.0 -I/usr/local/lib/glib-2.0/include -I/usr/local/include -fdiagnostics-color=auto -Wall -Winvalid-pch -Werror -std=gnu11 -O2 -g -fstack-protector-strong -Wempty-body -Wendif-labels -Wexpansion-to-defined -Wformat-security -Wformat-y2k -Wignored-qualifiers -Winit-self -Wmissing-format-attribute -Wmissing-prototypes -Wnested-externs -Wold-style-definition -Wredundant-decls -Wstrict-prototypes -Wtype-limits -Wundef -Wvla -Wwrite-strings -Wno-gnu-variable-sized-type-not-at-end -Wno-initializer-overrides -Wno-missing-include-dirs -Wno-psabi -Wno-shift-negative-value -Wno-string-plus-int -Wno-tautological-type-limit-compare -Wno-typedef-redefinition -Wthread-safety -iquote . -iquote /tmp/cirrus-ci-build -iquote /tmp/cirrus-ci-build/include -iquote /tmp/cirrus-ci-build/host/include/x86_64 -iquote /tmp/cirrus-ci-build/host/include/generic -iquote /tmp/cirrus-ci-build/tcg/i386 -pthread -D_GNU_SOURCE -D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE -fno-strict-aliasing -fno-common -fwrapv -ftrivial-auto-var-init=zero -fPIE -DNEED_CPU_H '-DCONFIG_TARGET="arm-bsd-user-config-target.h"' '-DCONFIG_DEVICES="arm-bsd-user-config-devices.h"' -MD -MQ libqemu-arm-bsd-user.fa.p/gdbstub_user-target.c.o -MF libqemu-arm-bsd-user.fa.p/gdbstub_user-target.c.o.d -o libqemu-arm-bsd-user.fa.p/gdbstub_user-target.c.o -c ../gdbstub/user-target.c
>>    In file included from ../gdbstub/user-target.c:18:
>>    ../gdbstub/internals.h:62:21: error: use of undeclared identifier 'MAX_SIGINFO_LENGTH'
>>       62 |     uint8_t siginfo[MAX_SIGINFO_LENGTH];
>>          |                     ^
>>    1 error generated.
>>    [2084/6731] Compiling C object libqemu-arm
>> See: https://gitlab.com/stsquad/qemu/-/jobs/6345829419
>
> argh, I've tested all targets for linux-user, but missed bsd-user. I've tried
> once to build it but that requires a BSD-like host, which I don't have at the
> moment, then I forgot about it... Let me setup one and review the change in
> the light of the comments from you and Richard.

  make vm-build-[open|net|free]bsd

see make vm-help for details.

>
> Thanks!
>
>
> Cheers,
> Gustavo

-- 
Alex Bennée
Virtualisation Tech Lead @ Linaro

Re: [PATCH v2 3/5] gdbstub: Save target's siginfo

[Gustavo Romero]

Hi Richard,

On 3/7/24 6:09 PM, Richard Henderson wrote:
> On 3/7/24 08:26, Gustavo Romero wrote:
>> 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 <gustavo.romero@linaro.org>
>> Suggested-by: Richard Henderson <richard.henderson@linaro.org>
>> ---
>>   gdbstub/internals.h    |  3 +++
>>   gdbstub/user-target.c  |  3 ++-
>>   gdbstub/user.c         | 14 ++++++++++----
>>   include/gdbstub/user.h |  6 +++++-
>>   linux-user/main.c      |  2 +-
>>   linux-user/signal.c    |  5 ++++-
>>   6 files changed, 25 insertions(+), 8 deletions(-)
>>
>> diff --git a/gdbstub/internals.h b/gdbstub/internals.h
>> index 56b7c13b75..a7cc69dab3 100644
>> --- a/gdbstub/internals.h
>> +++ b/gdbstub/internals.h
>> @@ -58,6 +58,9 @@ typedef struct GDBState {
>>       int line_csum; /* checksum at the end of the packet */
>>       GByteArray *last_packet;
>>       int signal;
>> +#ifdef CONFIG_USER_ONLY
>> +    uint8_t siginfo[MAX_SIGINFO_LENGTH];
>> +#endif
> 
> If we this in GDBUserState in user.c -- no need for ifdefs then.

Thanks, I've moved it to user.c.


>> --- a/gdbstub/user-target.c
>> +++ b/gdbstub/user-target.c
>> @@ -10,11 +10,12 @@
>>   #include "qemu/osdep.h"
>>   #include "exec/gdbstub.h"
>>   #include "qemu.h"
>> -#include "internals.h"
>>   #ifdef CONFIG_LINUX
>>   #include "linux-user/loader.h"
>>   #include "linux-user/qemu.h"
>> +#include "gdbstub/user.h"
>>   #endif
>> +#include "internals.h"
>>   /*
>>    * Map target signal numbers to GDB protocol signal numbers and vice
> 
> Why are any changes required here?
> Perhaps this is improper patch split from one of the others?

This was intentional. Because I declared siginfo[MAX_SIGINFO_LENGTH] in
GDBState struct, which is in internals.h and MAX_SIGINFO_LENGTH is defined
in gdbstub/user.h I had to move internals.h after user.h was included so
MAX_SIGINFO_LENGTH could be found.

I'm reverting it.


>> @@ -140,6 +141,11 @@ int gdb_handlesig(CPUState *cpu, int sig, const char *reason)
>>           return sig;
>>       }
>> +    if (siginfo) {
>> +        /* Save target-specific siginfo. */
>> +        memcpy(gdbserver_state.siginfo, siginfo, siginfo_len);
>> +    }
> 
> A comment here about asserting the size at compile-time elsewhere would be welcome for future code browsers.

Done.


> Need to record siginfo_len for later use -- you don't want to expose all 128 bytes if the actual structure is smaller.

In the stub, the full size is only used to check if the requested offset+len is valid.
So the only size that matters for reading data from siginfo and assembling
the reply is the length in the query, not siginfo_len. But I agree it's better, even
more now that I moved the stub from user-target.c to user.c.


>> @@ -510,7 +516,7 @@ 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)
>> @@ -528,7 +534,7 @@ 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);
>>       }
>>   }
>> @@ -536,7 +542,7 @@ 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);
>>       }
> 
> All of this makes me wonder if we should provide a different interface for syscalls, even if it uses the same code paths internally.

Should I address it in this series? I'm sure how that interface would be.


> Do we want to zero the gdbserver siginfo to indicate that the contents are no longer valid?  I know it's not a real signal delivered to the process, but might we need to construct a simple siginfo struct to match the sigtrap?

In gdb_handlesig we always copy the full size of siginfo to gdbserver_user_state siginfo,
which is passed in siginfo_len and now recorded gdbserver siginfo_len too for later use.
Isn't that copy guaranteeing that gdbserver siginfo has always no stale data?


Cheers,
Gustavo

Re: [PATCH v2 3/5] gdbstub: Save target's siginfo

[Richard Henderson]

On 3/8/24 09:25, Alex Bennée wrote:
>    make vm-build-[open|net|free]bsd
> 
> see make vm-help for details.

That won't build freebsd user.
Something I've mentioned to you before...


r~

Re: [PATCH v2 4/5] gdbstub: Add Xfer:siginfo:read stub

[Richard Henderson]

On 3/8/24 08:30, Gustavo Romero wrote:
> Hi Richard!
> 
> On 3/7/24 6:13 PM, Richard Henderson wrote:
>> On 3/7/24 08:26, Gustavo Romero wrote:
>>> +void gdb_handle_query_xfer_siginfo(GArray *params, void *user_ctx)
>>> +{
>>> +    unsigned long offset, len;
>>> +    uint8_t *siginfo_offset;
>>> +
>>> +    offset = get_param(params, 0)->val_ul;
>>> +    len = get_param(params, 1)->val_ul;
>>> +
>>> +    if (offset + len > sizeof(target_siginfo_t)) {
>>
>> If you save the siginfo_len from gdb_handlesig, you can place this in user.c
> Shouldn't all user-only stubs be placed in user-target.c? Like
> gdb_handle_query_xfer_auxv and gdb_handle_query_xfer_exec_file, and since
> what controls the inclusion in the build of user-target.c is CONFIG_USER_ONLY?

user.c is also build for CONFIG_USER_ONLY, except that it is compiled only once, and has 
no target-specific code in it.

>> Is it really correct to reject (offset == 0) + (len == large), rather than truncate len?
> 
> I think this is correct. GDB mentions briefly that an invalid offset
> should be treated as an error. Thus, I think that a valid offset but
> a non-existing/invalid (large) length should be treated the same,
> cause in the end data on invalid offsets are being requested anyways.

Ok.


r~

Re: [PATCH v2 3/5] gdbstub: Save target's siginfo

[Alex Bennée]

Richard Henderson <richard.henderson@linaro.org> writes:

> On 3/8/24 09:25, Alex Bennée wrote:
>>    make vm-build-[open|net|free]bsd
>> see make vm-help for details.
>
> That won't build freebsd user.
> Something I've mentioned to you before...

  make vm-build-freebsd BUILD_TARGET=all

I guess the default "check" target doesn't work due to the missing cross
compilers meaning we have no check-tcg target in the default check list.

>
>
> r~

-- 
Alex Bennée
Virtualisation Tech Lead @ Linaro