target/xtensa: add linux-user support

Import list of syscalls from the kernel source. Conditionalize code/data
that is only used with softmmu. Implement exception handlers. Implement
signal hander (only the core registers for now, no coprocessors or TIE).

Cc: Riku Voipio <riku.voipio@iki.fi>
Cc: Laurent Vivier <laurent@vivier.eu>
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>

1 files changed, 255 insertions, 1 deletions

diff --git a/linux-user/signal.c b/linux-user/signal.c
index 2ce5d7a3c7..24b6f38b42 100644
--- a/linux-user/signal.c
+++ b/linux-user/signal.c
@@ -7051,6 +7051,260 @@ long do_rt_sigreturn(CPUArchState *env)
     return -TARGET_QEMU_ESIGRETURN;
 }
 
+#elif defined(TARGET_XTENSA)
+
+struct target_sigcontext {
+    abi_ulong sc_pc;
+    abi_ulong sc_ps;
+    abi_ulong sc_lbeg;
+    abi_ulong sc_lend;
+    abi_ulong sc_lcount;
+    abi_ulong sc_sar;
+    abi_ulong sc_acclo;
+    abi_ulong sc_acchi;
+    abi_ulong sc_a[16];
+    abi_ulong sc_xtregs;
+};
+
+struct target_ucontext {
+    abi_ulong tuc_flags;
+    abi_ulong tuc_link;
+    target_stack_t tuc_stack;
+    struct target_sigcontext tuc_mcontext;
+    target_sigset_t tuc_sigmask;
+};
+
+struct target_rt_sigframe {
+    target_siginfo_t info;
+    struct target_ucontext uc;
+    /* TODO: xtregs */
+    uint8_t retcode[6];
+    abi_ulong window[4];
+};
+
+static abi_ulong get_sigframe(struct target_sigaction *sa,
+                              CPUXtensaState *env,
+                              unsigned long framesize)
+{
+    abi_ulong sp = env->regs[1];
+
+    /* This is the X/Open sanctioned signal stack switching.  */
+    if ((sa->sa_flags & TARGET_SA_ONSTACK) != 0 && !sas_ss_flags(sp)) {
+        sp = target_sigaltstack_used.ss_sp + target_sigaltstack_used.ss_size;
+    }
+    return (sp - framesize) & -16;
+}
+
+static int flush_window_regs(CPUXtensaState *env)
+{
+    const uint32_t nareg_mask = env->config->nareg - 1;
+    uint32_t wb = env->sregs[WINDOW_BASE];
+    uint32_t ws = (xtensa_replicate_windowstart(env) >> (wb + 1)) &
+        ((1 << env->config->nareg / 4) - 1);
+    uint32_t d = ctz32(ws) + 1;
+    uint32_t sp;
+    abi_long ret = 0;
+
+    wb += d;
+    ws >>= d;
+
+    xtensa_sync_phys_from_window(env);
+    sp = env->phys_regs[(wb * 4 + 1) & nareg_mask];
+
+    while (ws && ret == 0) {
+        int d;
+        int i;
+        int idx;
+
+        if (ws & 0x1) {
+            ws >>= 1;
+            d = 1;
+        } else if (ws & 0x2) {
+            ws >>= 2;
+            d = 2;
+            for (i = 0; i < 4; ++i) {
+                idx = (wb * 4 + 4 + i) & nareg_mask;
+                ret |= put_user_ual(env->phys_regs[idx], sp + (i - 12) * 4);
+            }
+        } else if (ws & 0x4) {
+            ws >>= 3;
+            d = 3;
+            for (i = 0; i < 8; ++i) {
+                idx = (wb * 4 + 4 + i) & nareg_mask;
+                ret |= put_user_ual(env->phys_regs[idx], sp + (i - 16) * 4);
+            }
+        } else {
+            g_assert_not_reached();
+        }
+        sp = env->phys_regs[((wb + d) * 4 + 1) & nareg_mask];
+        for (i = 0; i < 4; ++i) {
+            idx = (wb * 4 + i) & nareg_mask;
+            ret |= put_user_ual(env->phys_regs[idx], sp + (i - 4) * 4);
+        }
+        wb += d;
+    }
+    return ret == 0;
+}
+
+static int setup_sigcontext(struct target_rt_sigframe *frame,
+                            CPUXtensaState *env)
+{
+    struct target_sigcontext *sc = &frame->uc.tuc_mcontext;
+    int i;
+
+    __put_user(env->pc, &sc->sc_pc);
+    __put_user(env->sregs[PS], &sc->sc_ps);
+    __put_user(env->sregs[LBEG], &sc->sc_lbeg);
+    __put_user(env->sregs[LEND], &sc->sc_lend);
+    __put_user(env->sregs[LCOUNT], &sc->sc_lcount);
+    if (!flush_window_regs(env)) {
+        return 0;
+    }
+    for (i = 0; i < 16; ++i) {
+        __put_user(env->regs[i], sc->sc_a + i);
+    }
+    __put_user(0, &sc->sc_xtregs);
+    /* TODO: xtregs */
+    return 1;
+}
+
+static void setup_rt_frame(int sig, struct target_sigaction *ka,
+                           target_siginfo_t *info,
+                           target_sigset_t *set, CPUXtensaState *env)
+{
+    abi_ulong frame_addr;
+    struct target_rt_sigframe *frame;
+    uint32_t ra;
+    int i;
+
+    frame_addr = get_sigframe(ka, env, sizeof(*frame));
+    trace_user_setup_rt_frame(env, frame_addr);
+
+    if (!lock_user_struct(VERIFY_WRITE, frame, frame_addr, 0)) {
+        goto give_sigsegv;
+    }
+
+    if (ka->sa_flags & SA_SIGINFO) {
+        tswap_siginfo(&frame->info, info);
+    }
+
+    __put_user(0, &frame->uc.tuc_flags);
+    __put_user(0, &frame->uc.tuc_link);
+    __put_user(target_sigaltstack_used.ss_sp,
+               &frame->uc.tuc_stack.ss_sp);
+    __put_user(sas_ss_flags(env->regs[1]),
+               &frame->uc.tuc_stack.ss_flags);
+    __put_user(target_sigaltstack_used.ss_size,
+               &frame->uc.tuc_stack.ss_size);
+    if (!setup_sigcontext(frame, env)) {
+        unlock_user_struct(frame, frame_addr, 0);
+        goto give_sigsegv;
+    }
+    for (i = 0; i < TARGET_NSIG_WORDS; ++i) {
+        __put_user(set->sig[i], &frame->uc.tuc_sigmask.sig[i]);
+    }
+
+    if (ka->sa_flags & TARGET_SA_RESTORER) {
+        ra = ka->sa_restorer;
+    } else {
+        ra = frame_addr + offsetof(struct target_rt_sigframe, retcode);
+#ifdef TARGET_WORDS_BIGENDIAN
+        /* Generate instruction:  MOVI a2, __NR_rt_sigreturn */
+        __put_user(0x22, &frame->retcode[0]);
+        __put_user(0x0a, &frame->retcode[1]);
+        __put_user(TARGET_NR_rt_sigreturn, &frame->retcode[2]);
+        /* Generate instruction:  SYSCALL */
+        __put_user(0x00, &frame->retcode[3]);
+        __put_user(0x05, &frame->retcode[4]);
+        __put_user(0x00, &frame->retcode[5]);
+#else
+        /* Generate instruction:  MOVI a2, __NR_rt_sigreturn */
+        __put_user(0x22, &frame->retcode[0]);
+        __put_user(0xa0, &frame->retcode[1]);
+        __put_user(TARGET_NR_rt_sigreturn, &frame->retcode[2]);
+        /* Generate instruction:  SYSCALL */
+        __put_user(0x00, &frame->retcode[3]);
+        __put_user(0x50, &frame->retcode[4]);
+        __put_user(0x00, &frame->retcode[5]);
+#endif
+    }
+    env->sregs[PS] = PS_UM | (3 << PS_RING_SHIFT);
+    if (xtensa_option_enabled(env->config, XTENSA_OPTION_WINDOWED_REGISTER)) {
+        env->sregs[PS] |= PS_WOE | (1 << PS_CALLINC_SHIFT);
+    }
+    memset(env->regs, 0, sizeof(env->regs));
+    env->pc = ka->_sa_handler;
+    env->regs[1] = frame_addr;
+    env->sregs[WINDOW_BASE] = 0;
+    env->sregs[WINDOW_START] = 1;
+
+    env->regs[4] = (ra & 0x3fffffff) | 0x40000000;
+    env->regs[6] = sig;
+    env->regs[7] = frame_addr + offsetof(struct target_rt_sigframe, info);
+    env->regs[8] = frame_addr + offsetof(struct target_rt_sigframe, uc);
+    unlock_user_struct(frame, frame_addr, 1);
+    return;
+
+give_sigsegv:
+    force_sigsegv(sig);
+    return;
+}
+
+static void restore_sigcontext(CPUXtensaState *env,
+                               struct target_rt_sigframe *frame)
+{
+    struct target_sigcontext *sc = &frame->uc.tuc_mcontext;
+    uint32_t ps;
+    int i;
+
+    __get_user(env->pc, &sc->sc_pc);
+    __get_user(ps, &sc->sc_ps);
+    __get_user(env->sregs[LBEG], &sc->sc_lbeg);
+    __get_user(env->sregs[LEND], &sc->sc_lend);
+    __get_user(env->sregs[LCOUNT], &sc->sc_lcount);
+
+    env->sregs[WINDOW_BASE] = 0;
+    env->sregs[WINDOW_START] = 1;
+    env->sregs[PS] = deposit32(env->sregs[PS],
+                               PS_CALLINC_SHIFT,
+                               PS_CALLINC_LEN,
+                               extract32(ps, PS_CALLINC_SHIFT,
+                                         PS_CALLINC_LEN));
+    for (i = 0; i < 16; ++i) {
+        __get_user(env->regs[i], sc->sc_a + i);
+    }
+    /* TODO: xtregs */
+}
+
+long do_rt_sigreturn(CPUXtensaState *env)
+{
+    abi_ulong frame_addr = env->regs[1];
+    struct target_rt_sigframe *frame;
+    sigset_t set;
+
+    trace_user_do_rt_sigreturn(env, frame_addr);
+    if (!lock_user_struct(VERIFY_READ, frame, frame_addr, 1)) {
+        goto badframe;
+    }
+    target_to_host_sigset(&set, &frame->uc.tuc_sigmask);
+    set_sigmask(&set);
+
+    restore_sigcontext(env, frame);
+
+    if (do_sigaltstack(frame_addr +
+                       offsetof(struct target_rt_sigframe, uc.tuc_stack),
+                       0, get_sp_from_cpustate(env)) == -TARGET_EFAULT) {
+        goto badframe;
+    }
+    unlock_user_struct(frame, frame_addr, 0);
+    return -TARGET_QEMU_ESIGRETURN;
+
+badframe:
+    unlock_user_struct(frame, frame_addr, 0);
+    force_sig(TARGET_SIGSEGV);
+    return -TARGET_QEMU_ESIGRETURN;
+}
+
 #else
 
 static void setup_frame(int sig, struct target_sigaction *ka,
@@ -7154,7 +7408,7 @@ static void handle_pending_signal(CPUArchState *cpu_env, int sig,
         || defined(TARGET_OPENRISC) || defined(TARGET_TILEGX) \
         || defined(TARGET_PPC64) || defined(TARGET_HPPA) \
         || defined(TARGET_NIOS2) || defined(TARGET_X86_64) \
-        || defined(TARGET_RISCV)
+        || defined(TARGET_RISCV) || defined(TARGET_XTENSA)
         /* These targets do not have traditional signals.  */
         setup_rt_frame(sig, sa, &k->info, &target_old_set, cpu_env);
 #else