i#3544 RV64: Refine fault translation and signal handling (#6461)

Refine fault translation and signal handling, part of the
linux.signalXXXX tests works on real hardware; however, they do not work
on QEMU, so we can't enable them on CI.

Issue: #3544

core/arch/arch.c

@@ -3866,6 +3866,14 @@ set_stolen_reg_val(priv_mcontext_t *mc, reg_t newval)
 {
     *(reg_t *)(((byte *)mc) + opnd_get_reg_dcontext_offs(dr_reg_stolen)) = newval;
 }
+
+#    ifdef RISCV64
+void
+set_tp_reg_val(priv_mcontext_t *mc, reg_t newval)
+{
+    *(reg_t *)(((byte *)mc) + opnd_get_reg_dcontext_offs(DR_REG_TP)) = newval;
+}
+#    endif
 #endif
 
 #ifdef PROFILE_RDTSC

core/arch/arch.h

@@ -1569,7 +1569,7 @@ translate_x86_to_x64(dcontext_t *dcontext, instrlist_t *ilist,
                      DR_PARAM_INOUT instr_t **instr);
 #endif
 
-#ifdef AARCHXX
+#if defined(AARCHXX) || defined(RISCV64)
 bool
 instr_is_ldstex_mangling(dcontext_t *dcontext, instr_t *inst);
 #endif

core/arch/arch_exports.h

@@ -470,6 +470,10 @@ reg_t
 get_stolen_reg_val(priv_mcontext_t *context);
 void
 set_stolen_reg_val(priv_mcontext_t *mc, reg_t newval);
+#    ifdef RISCV64
+void
+set_tp_reg_val(priv_mcontext_t *mc, reg_t newval);
+#    endif
 #endif
 const char *
 get_branch_type_name(ibl_branch_type_t branch_type);

core/arch/riscv64/mangle.c

@@ -272,8 +272,7 @@ patch_mov_immed_arch(dcontext_t *dcontext, ptr_int_t val, byte *pc, instr_t *fir
 bool
 instr_check_xsp_mangling(dcontext_t *dcontext, instr_t *inst, int *xsp_adjust)
 {
-    /* FIXME i#3544: Not implemented */
-    ASSERT_NOT_IMPLEMENTED(false);
+    /* Does not apply to RISC-V. */
     return false;
 }
 
@@ -648,6 +647,48 @@ mangle_special_registers(dcontext_t *dcontext, instrlist_t *ilist, instr_t *inst
     return next_instr;
 }
 
+/***************************************************************************
+ * LR/SC sequence mangling.
+ */
+
+bool
+instr_is_ldstex_mangling(dcontext_t *dcontext, instr_t *instr)
+{
+    /* This should be kept in sync with mangle_exclusive_monitor_op(). */
+    if (!instr_is_our_mangling(instr))
+        return false;
+
+    opnd_t memop = opnd_create_null();
+    if (instr_get_opcode(instr) == OP_sd)
+        memop = instr_get_src(instr, 0);
+    else if (instr_get_opcode(instr) == OP_ld)
+        memop = instr_get_dst(instr, 0);
+    if (opnd_is_base_disp(memop)) {
+        ASSERT(opnd_get_index(memop) == DR_REG_NULL && opnd_get_scale(memop) == 0);
+        uint offs = opnd_get_disp(memop);
+        if (opnd_get_base(memop) == dr_reg_stolen && offs >= TLS_LRSC_ADDR_SLOT &&
+            offs <= TLS_LRSC_SIZE_SLOT)
+            return true;
+    }
+
+    ptr_int_t val;
+    if (instr_get_opcode(instr) == OP_fence || instr_get_opcode(instr) == OP_bne ||
+        /* Check for sc.w/d+bne+jal pattern.  */
+        (instr_get_opcode(instr) == OP_jal && instr_get_prev(instr) != NULL &&
+         instr_get_opcode(instr_get_prev(instr)) == OP_bne &&
+         instr_get_prev(instr_get_prev(instr)) != NULL &&
+         instr_is_exclusive_store(instr_get_prev(instr_get_prev(instr)))) ||
+        instr_is_exclusive_load(instr) || instr_is_exclusive_store(instr) ||
+        (instr_is_mov_constant(instr, &val) &&
+         /* XXX: These are fragile, should we look backward a bit to check for more
+            specific patterns? */
+         (val == 1 /* cas fail */ || val == -1 /* reservation invalidation */ ||
+          val == 4 /* lr.w/sc.w size */ || val == 8 /* lr.d/sc.d size */)))
+        return true;
+
+    return false;
+}
+
 static instr_t *
 mangle_exclusive_load(dcontext_t *dcontext, instrlist_t *ilist, instr_t *instr,
                       instr_t *next_instr)

core/arch/x86_code.c

@@ -306,7 +306,7 @@ new_thread_setup(priv_mcontext_t *mc)
     ASSERT(rc != -1); /* this better be a new thread */
     dcontext = get_thread_private_dcontext();
     ASSERT(dcontext != NULL);
-#    ifdef AARCHXX
+#    if defined(AARCHXX) || defined(RISCV64)
     set_app_lib_tls_base_from_clone_record(dcontext, crec);
 #    endif
 #    ifdef ARM

core/translate.c

@@ -132,6 +132,8 @@ instr_is_inline_syscall_jmp(dcontext_t *dcontext, instr_t *inst)
              /* A32 uses a regular jump */
              instr_get_opcode(inst) == OP_b) &&
             opnd_is_instr(instr_get_target(inst)));
+#    elif defined(RISCV64)
+    return (instr_get_opcode(inst) == OP_jal && opnd_is_instr(instr_get_target(inst)));
 #    else
     ASSERT_NOT_IMPLEMENTED(false);
     return false;
@@ -304,14 +306,14 @@ translate_walk_track_pre_instr(dcontext_t *tdcontext, instr_t *inst,
         walk->unsupported_mangle = false;
         walk->xsp_adjust = 0;
         for (reg_id_t r = 0; r < REG_SPILL_NUM; r++) {
-#ifndef AARCHXX
+#ifdef X86
             /* we should have seen a restore for every spill, unless at
              * fragment-ending jump to ibl, which shouldn't come here
              */
             ASSERT(walk->reg_spill_offs[r] == UINT_MAX);
             walk->reg_spill_offs[r] = UINT_MAX; /* be paranoid */
 #else
-            /* On AArchXX we do spill registers across app instrs and mangle
+            /* On AArchXX/RISCV64 we do spill registers across app instrs and mangle
              * regions, though right now only the following routines do this:
              * - mangle_stolen_reg()
              * - mangle_gpr_list_read()
@@ -399,9 +401,6 @@ translate_walk_track_post_instr(dcontext_t *tdcontext, instr_t *inst,
          * comment above for post-mangling traces), and so for local
          * spills like rip-rel and ind branches this is fine.
          */
-#if defined(RISCV64)
-        ASSERT_NOT_IMPLEMENTED(false);
-#endif
         if (instr_is_cti(inst) &&
 #ifdef X86
             /* Do not reset for a trace-cmp jecxz or jmp (32-bit) or
@@ -420,10 +419,7 @@ translate_walk_track_post_instr(dcontext_t *tdcontext, instr_t *inst,
               (!opnd_is_pc(instr_get_target(inst)) ||
                (opnd_get_pc(instr_get_target(inst)) >= walk->start_cache &&
                 opnd_get_pc(instr_get_target(inst)) < walk->end_cache))))
-#elif defined(RISCV64)
-            /* FIXME i#3544: Not implemented */
-            false
-#else
+#elif defined(AARCHXX)
             /* Do not reset for cbnz/bne in ldstex mangling, nor for the b after strex. */
             !(instr_get_opcode(inst) == OP_cbnz ||
               (instr_get_opcode(inst) == OP_b &&
@@ -432,6 +428,17 @@ translate_walk_track_post_instr(dcontext_t *tdcontext, instr_t *inst,
               (instr_get_opcode(inst) == OP_b &&
                (instr_get_prev(inst) != NULL &&
                 instr_is_exclusive_store(instr_get_prev(inst)))))
+#elif defined(RISCV64)
+            /* Do not reset for bne in LR/SC mangling, nor for the jal after SC.
+             * This should be kept in sync with mangle_exclusive_monitor_op().
+             */
+            !(instr_get_opcode(inst) == OP_bne ||
+              (instr_get_opcode(inst) == OP_jal && instr_get_prev(inst) != NULL &&
+               instr_get_opcode(instr_get_prev(inst)) == OP_bne &&
+               instr_get_prev(instr_get_prev(inst)) != NULL &&
+               instr_is_exclusive_store(instr_get_prev(instr_get_prev(inst)))))
+#else
+#    error Unsupported architecture
 #endif
         ) {
             /* FIXME i#1551: add ARM version of the series of trace cti checks above */
@@ -547,7 +554,7 @@ translate_walk_track_post_instr(dcontext_t *tdcontext, instr_t *inst,
             /* nothing to do */
         }
 #endif
-#ifdef AARCHXX
+#if defined(AARCHXX) || defined(RISCV64)
         else if (instr_is_ldstex_mangling(tdcontext, inst)) {
             /* nothing to do */
         }

core/unix/os_public.h

@@ -205,6 +205,7 @@ typedef kernel_sigcontext_t sigcontext_t;
 #    define SC_SYSNUM_REG SC_R7
 #    define SC_RETURN_REG SC_R0
 #elif defined(RISCV64)
+#    define SC_TP SC_FIELD(sc_regs.tp)
 #    define SC_A0 SC_FIELD(sc_regs.a0)
 #    define SC_A1 SC_FIELD(sc_regs.a1)
 #    define SC_A2 SC_FIELD(sc_regs.a2)

core/unix/signal.c

@@ -3051,20 +3051,36 @@ mcontext_to_ucontext(kernel_ucontext_t *uc, priv_mcontext_t *mc)
     mcontext_to_sigcontext(&sc_full, mc, DR_MC_ALL);
 }
 
-#ifdef AARCHXX
+#if defined(AARCHXX) || defined(RISCV64)
 static void
 set_sigcxt_stolen_reg(sigcontext_t *sc, reg_t val)
 {
-    *(&sc->SC_R0 + (dr_reg_stolen - DR_REG_R0)) = val;
+    *(&sc->IF_AARCHXX_ELSE(SC_R0, SC_A0) +
+      (dr_reg_stolen - IF_AARCHXX_ELSE(DR_REG_R0, DR_REG_A0))) = val;
 }
 
 static reg_t
 get_sigcxt_stolen_reg(sigcontext_t *sc)
 {
-    return *(&sc->SC_R0 + (dr_reg_stolen - DR_REG_R0));
+    return *(&sc->IF_AARCHXX_ELSE(SC_R0, SC_A0) +
+             (dr_reg_stolen - IF_AARCHXX_ELSE(DR_REG_R0, DR_REG_A0)));
+}
+
+#    ifdef RISCV64
+static void
+set_sigcxt_tp_reg(sigcontext_t *sc, reg_t val)
+{
+    sc->SC_TP = val;
 }
 
-#    ifndef AARCH64
+static reg_t
+get_sigcxt_tp_reg(sigcontext_t *sc)
+{
+    return sc->SC_TP;
+}
+#    endif
+
+#    ifdef ARM
 static dr_isa_mode_t
 get_pc_mode_from_cpsr(sigcontext_t *sc)
 {
@@ -3251,7 +3267,11 @@ thread_set_self_context(void *cxt)
 #elif defined(ARM)
     asm("ldr  " ASM_XSP ", %0" : : "m"(xsp_for_sigreturn));
     asm("b    dynamorio_sigreturn");
-#endif /* X86/AARCH64/ARM */
+#elif defined(RISCV)
+    ASSERT_NOT_TESTED();
+    asm("addi   " ASM_XSP ", %0, 0" : : "r"(xsp_for_sigreturn));
+    asm("j      dynamorio_sigreturn");
+#endif /* X86/AARCH64/ARM/RISCV64 */
     ASSERT_NOT_REACHED();
 }
 
@@ -3370,7 +3390,6 @@ sig_has_restorer(thread_sig_info_t *info, int sig)
 #    elif defined(RISCV64)
         static const byte SIGRET_NONRT[8] = { 0 }; /* unused */
         static const byte SIGRET_RT[8] = { 0 };    /* unused */
-        ;
 #    endif
         byte buf[MAX(sizeof(SIGRET_NONRT), sizeof(SIGRET_RT))] = { 0 };
         if (d_r_safe_read(info->sighand->action[sig]->restorer, sizeof(buf), buf) &&
@@ -4048,7 +4067,7 @@ transfer_from_sig_handler_to_fcache_return(dcontext_t *dcontext, kernel_ucontext
      * still go to the private fcache_return for simplicity.
      */
     sc->SC_XIP = (ptr_uint_t)fcache_return_routine(dcontext);
-#if defined(AARCHXX)
+#if defined(AARCHXX) || defined(RISCV64)
     /* We do not have to set dr_reg_stolen in dcontext's mcontext here
      * because dcontext's mcontext is stale and we used the mcontext
      * created from recreate_app_state_internal with the original sigcontext.
@@ -4062,12 +4081,14 @@ transfer_from_sig_handler_to_fcache_return(dcontext_t *dcontext, kernel_ucontext
     dcontext->local_state->spill_space.reg_stolen = get_sigcxt_stolen_reg(sc);
     /* Now put DR's base in the sigcontext. */
     set_sigcxt_stolen_reg(sc, (reg_t)*get_dr_tls_base_addr());
-#    ifndef AARCH64
+#    ifdef RISCV64
+    set_sigcxt_tp_reg(sc, (reg_t)read_thread_register(TLS_REG_LIB));
+#    endif
+
+#    ifdef ARM
     /* We're going to our fcache_return gencode which uses DEFAULT_ISA_MODE */
     set_pc_mode_in_cpsr(sc, DEFAULT_ISA_MODE);
 #    endif
-#elif defined(RISCV64)
-    ASSERT_NOT_IMPLEMENTED(false);
 #endif
 
 #if defined(X64) || defined(ARM)
@@ -4626,7 +4647,7 @@ adjust_syscall_for_restart(dcontext_t *dcontext, thread_sig_info_t *info, int si
     } else {
         ASSERT_NOT_REACHED(); /* Inlined syscalls no longer come here. */
     }
-#ifdef AARCHXX
+#if defined(AARCHXX) || defined(RISCV64)
     /* dr_reg_stolen is holding DR's TLS on receiving a signal,
      * so we need to put the app's reg value into the ucontext instead.
      * The translation process normally does this for us, but here we're doing
@@ -4734,7 +4755,8 @@ find_next_fragment_from_gencode(dcontext_t *dcontext, sigcontext_t *sc)
         if (f == NULL && sc->SC_XCX != 0)
             f = fragment_lookup(dcontext, (app_pc)sc->SC_XCX);
 #elif defined(RISCV64)
-/* FIXME i#3544: Not implemented */
+        /* FIXME i#3544: Not implemented */
+        ASSERT_NOT_IMPLEMENTED(false);
 #else
 #    error Unsupported arch.
 #endif
@@ -6292,7 +6314,9 @@ execute_handler_from_dispatch(dcontext_t *dcontext, int sig)
         dump_sigcontext(dcontext, sc);
         LOG(THREAD, LOG_ASYNCH, 3, "\n");
     }
-    IF_AARCHXX(ASSERT(get_sigcxt_stolen_reg(sc) != (reg_t)*get_dr_tls_base_addr()));
+#    if defined(AARCHXX) || defined(RISCV64)
+    ASSERT(get_sigcxt_stolen_reg(sc) != (reg_t)*get_dr_tls_base_addr());
+#    endif
 #endif
     /* FIXME: other state?  debug regs?
      * if no syscall allowed between main_ (when frame created) and
@@ -7370,26 +7394,32 @@ handle_sigreturn(dcontext_t *dcontext, void *ucxt_param, int style)
      * look like whatever would happen to the app...
      */
     ASSERT((app_pc)sc->SC_XIP != next_pc);
-#    if defined(AARCHXX)
+#    if defined(AARCHXX) || defined(RISCV64)
     ASSERT(get_sigcxt_stolen_reg(sc) != (reg_t)*get_dr_tls_base_addr());
     /* We're called from DR and are not yet in the cache, so we want to set the
      * mcontext slot, not the TLS slot, to set the stolen reg value.
      */
     set_stolen_reg_val(get_mcontext(dcontext), get_sigcxt_stolen_reg(sc));
     /* The linkstub expects DR's TLS to be in the actual register. */
     set_sigcxt_stolen_reg(sc, (reg_t)*get_dr_tls_base_addr());
-#        ifdef AARCH64
+
+#        ifdef RISCV64
+    set_tp_reg_val(get_mcontext(dcontext), get_sigcxt_tp_reg(sc));
+    set_sigcxt_tp_reg(sc, (reg_t)read_thread_register(TLS_REG_LIB));
+#        endif
+
+#        if defined(AARCH64)
     /* On entry to the do_syscall gencode, we save X1 into TLS_REG1_SLOT.
      * Then the sigreturn would redirect the flow to the fcache_return gencode.
      * In fcache_return it recovers the values of x0 and x1 from TLS_SLOT 0 and 1.
      */
     get_mcontext(dcontext)->r1 = sc->SC_FIELD_AARCH64(1);
+#        elif defined(RISCV64)
+    get_mcontext(dcontext)->a1 = sc->SC_FIELD(sc_regs.a1);
 #        else
     /* We're going to our fcache_return gencode which uses DEFAULT_ISA_MODE */
     set_pc_mode_in_cpsr(sc, DEFAULT_ISA_MODE);
 #        endif
-#    elif defined(RISCV64)
-    ASSERT_NOT_IMPLEMENTED(false);
 #    endif
 #endif
 

core/unix/signal_linux_riscv64.c

@@ -57,7 +57,39 @@ save_fpstate(dcontext_t *dcontext, sigframe_rt_t *frame)
 void
 dump_sigcontext(dcontext_t *dcontext, sigcontext_t *sc)
 {
-    LOG(THREAD, LOG_ASYNCH, 1, "FIXME i#3544: NYI on RISCV64");
+
+    LOG(THREAD, LOG_ASYNCH, 1, "\tpc  = " PFX "\n", sc->sc_regs.pc);
+    LOG(THREAD, LOG_ASYNCH, 1, "\tra  = " PFX "\n", sc->sc_regs.ra);
+    LOG(THREAD, LOG_ASYNCH, 1, "\tsp  = " PFX "\n", sc->sc_regs.sp);
+    LOG(THREAD, LOG_ASYNCH, 1, "\tgp  = " PFX "\n", sc->sc_regs.gp);
+    LOG(THREAD, LOG_ASYNCH, 1, "\ttp  = " PFX "\n", sc->sc_regs.tp);
+    LOG(THREAD, LOG_ASYNCH, 1, "\tt0  = " PFX "\n", sc->sc_regs.t0);
+    LOG(THREAD, LOG_ASYNCH, 1, "\tt1  = " PFX "\n", sc->sc_regs.t1);
+    LOG(THREAD, LOG_ASYNCH, 1, "\tt2  = " PFX "\n", sc->sc_regs.t2);
+    LOG(THREAD, LOG_ASYNCH, 1, "\ts0  = " PFX "\n", sc->sc_regs.s0);
+    LOG(THREAD, LOG_ASYNCH, 1, "\ts1  = " PFX "\n", sc->sc_regs.s1);
+    LOG(THREAD, LOG_ASYNCH, 1, "\ta0  = " PFX "\n", sc->sc_regs.a0);
+    LOG(THREAD, LOG_ASYNCH, 1, "\ta1  = " PFX "\n", sc->sc_regs.a1);
+    LOG(THREAD, LOG_ASYNCH, 1, "\ta2  = " PFX "\n", sc->sc_regs.a2);
+    LOG(THREAD, LOG_ASYNCH, 1, "\ta3  = " PFX "\n", sc->sc_regs.a3);
+    LOG(THREAD, LOG_ASYNCH, 1, "\ta4  = " PFX "\n", sc->sc_regs.a4);
+    LOG(THREAD, LOG_ASYNCH, 1, "\ta5  = " PFX "\n", sc->sc_regs.a5);
+    LOG(THREAD, LOG_ASYNCH, 1, "\ta6  = " PFX "\n", sc->sc_regs.a6);
+    LOG(THREAD, LOG_ASYNCH, 1, "\ta7  = " PFX "\n", sc->sc_regs.a7);
+    LOG(THREAD, LOG_ASYNCH, 1, "\ts2  = " PFX "\n", sc->sc_regs.s2);
+    LOG(THREAD, LOG_ASYNCH, 1, "\ts3  = " PFX "\n", sc->sc_regs.s3);
+    LOG(THREAD, LOG_ASYNCH, 1, "\ts4  = " PFX "\n", sc->sc_regs.s4);
+    LOG(THREAD, LOG_ASYNCH, 1, "\ts5  = " PFX "\n", sc->sc_regs.s5);
+    LOG(THREAD, LOG_ASYNCH, 1, "\ts6  = " PFX "\n", sc->sc_regs.s6);
+    LOG(THREAD, LOG_ASYNCH, 1, "\ts7  = " PFX "\n", sc->sc_regs.s7);
+    LOG(THREAD, LOG_ASYNCH, 1, "\ts8  = " PFX "\n", sc->sc_regs.s8);
+    LOG(THREAD, LOG_ASYNCH, 1, "\ts9  = " PFX "\n", sc->sc_regs.s9);
+    LOG(THREAD, LOG_ASYNCH, 1, "\ts10 = " PFX "\n", sc->sc_regs.s10);
+    LOG(THREAD, LOG_ASYNCH, 1, "\ts11 = " PFX "\n", sc->sc_regs.s11);
+    LOG(THREAD, LOG_ASYNCH, 1, "\tt3  = " PFX "\n", sc->sc_regs.t3);
+    LOG(THREAD, LOG_ASYNCH, 1, "\tt4  = " PFX "\n", sc->sc_regs.t4);
+    LOG(THREAD, LOG_ASYNCH, 1, "\tt5  = " PFX "\n", sc->sc_regs.t5);
+    LOG(THREAD, LOG_ASYNCH, 1, "\tt6  = " PFX "\n", sc->sc_regs.t6);
 }
 #endif /* DEBUG */