>From 6ce760bc19546e4d139732e9a5eb44b578dd834b Mon Sep 17 00:00:00 2001
From: Richard Henderson <rth@twiddle.net>
Date: Wed, 29 Jun 2016 22:12:55 -0700
Subject: [PATCH v7 06/35] tcg: Add EXCP_ATOMIC
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When we cannot emulate an atomic operation within a parallel
context, this exception allows us to stop the world and try
again in a serial context.
Reviewed-by: Emilio G. Cota <cota@braap.org>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Richard Henderson <rth@twiddle.net>
---
cpu-exec-common.c | 6 ++++++
cpu-exec.c | 30 ++++++++++++++++++++++++++++++
cpus.c | 2 ++
include/exec/cpu-all.h | 1 +
include/exec/exec-all.h | 1 +
include/qemu-common.h | 1 +
linux-user/main.c | 45 +++++++++++++++++++++++++++++++++++++++++++++
tcg/tcg.h | 1 +
translate-all.c | 1 +
9 files changed, 88 insertions(+)
@@ -77,3 +77,9 @@ void cpu_loop_exit_restore(CPUState *cpu, uintptr_t pc)
}
siglongjmp(cpu->jmp_env, 1);
}
+
+void cpu_loop_exit_atomic(CPUState *cpu, uintptr_t pc)
+{
+ cpu->exception_index = EXCP_ATOMIC;
+ cpu_loop_exit_restore(cpu, pc);
+}
@@ -222,6 +222,36 @@ static void cpu_exec_nocache(CPUState *cpu, int max_cycles,
}
#endif
+static void cpu_exec_step(CPUState *cpu)
+{
+ CPUArchState *env = (CPUArchState *)cpu->env_ptr;
+ TranslationBlock *tb;
+ target_ulong cs_base, pc;
+ uint32_t flags;
+
+ cpu_get_tb_cpu_state(env, &pc, &cs_base, &flags);
+ tb = tb_gen_code(cpu, pc, cs_base, flags,
+ 1 | CF_NOCACHE | CF_IGNORE_ICOUNT);
+ tb->orig_tb = NULL;
+ /* execute the generated code */
+ trace_exec_tb_nocache(tb, pc);
+ cpu_tb_exec(cpu, tb);
+ tb_phys_invalidate(tb, -1);
+ tb_free(tb);
+}
+
+void cpu_exec_step_atomic(CPUState *cpu)
+{
+ start_exclusive();
+
+ /* Since we got here, we know that parallel_cpus must be true. */
+ parallel_cpus = false;
+ cpu_exec_step(cpu);
+ parallel_cpus = true;
+
+ end_exclusive();
+}
+
struct tb_desc {
target_ulong pc;
target_ulong cs_base;
@@ -1497,6 +1497,8 @@ static void tcg_exec_all(void)
if (r == EXCP_DEBUG) {
cpu_handle_guest_debug(cpu);
break;
+ } else if (r == EXCP_ATOMIC) {
+ cpu_exec_step_atomic(cpu);
}
} else if (cpu->stop || cpu->stopped) {
if (cpu->unplug) {
@@ -31,6 +31,7 @@
#define EXCP_DEBUG 0x10002 /* cpu stopped after a breakpoint or singlestep */
#define EXCP_HALTED 0x10003 /* cpu is halted (waiting for external event) */
#define EXCP_YIELD 0x10004 /* cpu wants to yield timeslice to another */
+#define EXCP_ATOMIC 0x10005 /* stop-the-world and emulate atomic */
/* some important defines:
*
@@ -60,6 +60,7 @@ TranslationBlock *tb_gen_code(CPUState *cpu,
void cpu_exec_init(CPUState *cpu, Error **errp);
void QEMU_NORETURN cpu_loop_exit(CPUState *cpu);
void QEMU_NORETURN cpu_loop_exit_restore(CPUState *cpu, uintptr_t pc);
+void QEMU_NORETURN cpu_loop_exit_atomic(CPUState *cpu, uintptr_t pc);
#if !defined(CONFIG_USER_ONLY)
void cpu_reloading_memory_map(void);
@@ -80,6 +80,7 @@ void tcg_exec_init(unsigned long tb_size);
bool tcg_enabled(void);
void cpu_exec_init_all(void);
+void cpu_exec_step_atomic(CPUState *cpu);
/**
* Sends a (part of) iovec down a socket, yielding when the socket is full, or
@@ -354,6 +354,9 @@ void cpu_loop(CPUX86State *env)
}
}
break;
+ case EXCP_ATOMIC:
+ cpu_exec_step_atomic(cs);
+ break;
default:
pc = env->segs[R_CS].base + env->eip;
EXCP_DUMP(env, "qemu: 0x%08lx: unhandled CPU exception 0x%x - aborting\n",
@@ -848,6 +851,9 @@ void cpu_loop(CPUARMState *env)
case EXCP_YIELD:
/* nothing to do here for user-mode, just resume guest code */
break;
+ case EXCP_ATOMIC:
+ cpu_exec_step_atomic(cs);
+ break;
default:
error:
EXCP_DUMP(env, "qemu: unhandled CPU exception 0x%x - aborting\n", trapnr);
@@ -1048,6 +1054,9 @@ void cpu_loop(CPUARMState *env)
case EXCP_YIELD:
/* nothing to do here for user-mode, just resume guest code */
break;
+ case EXCP_ATOMIC:
+ cpu_exec_step_atomic(cs);
+ break;
default:
EXCP_DUMP(env, "qemu: unhandled CPU exception 0x%x - aborting\n", trapnr);
abort();
@@ -1139,6 +1148,9 @@ void cpu_loop(CPUUniCore32State *env)
}
}
break;
+ case EXCP_ATOMIC:
+ cpu_exec_step_atomic(cs);
+ break;
default:
goto error;
}
@@ -1412,6 +1424,9 @@ void cpu_loop (CPUSPARCState *env)
}
}
break;
+ case EXCP_ATOMIC:
+ cpu_exec_step_atomic(cs);
+ break;
default:
printf ("Unhandled trap: 0x%x\n", trapnr);
cpu_dump_state(cs, stderr, fprintf, 0);
@@ -1951,6 +1966,9 @@ void cpu_loop(CPUPPCState *env)
case EXCP_INTERRUPT:
/* just indicate that signals should be handled asap */
break;
+ case EXCP_ATOMIC:
+ cpu_exec_step_atomic(cs);
+ break;
default:
cpu_abort(cs, "Unknown exception 0x%x. Aborting\n", trapnr);
break;
@@ -2626,6 +2644,9 @@ done_syscall:
}
}
break;
+ case EXCP_ATOMIC:
+ cpu_exec_step_atomic(cs);
+ break;
default:
error:
EXCP_DUMP(env, "qemu: unhandled CPU exception 0x%x - aborting\n", trapnr);
@@ -2713,6 +2734,9 @@ void cpu_loop(CPUOpenRISCState *env)
case EXCP_NR:
qemu_log_mask(CPU_LOG_INT, "\nNR\n");
break;
+ case EXCP_ATOMIC:
+ cpu_exec_step_atomic(cs);
+ break;
default:
EXCP_DUMP(env, "\nqemu: unhandled CPU exception %#x - aborting\n",
trapnr);
@@ -2789,6 +2813,9 @@ void cpu_loop(CPUSH4State *env)
queue_signal(env, info.si_signo, QEMU_SI_FAULT, &info);
break;
+ case EXCP_ATOMIC:
+ cpu_exec_step_atomic(cs);
+ break;
default:
printf ("Unhandled trap: 0x%x\n", trapnr);
cpu_dump_state(cs, stderr, fprintf, 0);
@@ -2856,6 +2883,9 @@ void cpu_loop(CPUCRISState *env)
}
}
break;
+ case EXCP_ATOMIC:
+ cpu_exec_step_atomic(cs);
+ break;
default:
printf ("Unhandled trap: 0x%x\n", trapnr);
cpu_dump_state(cs, stderr, fprintf, 0);
@@ -2972,6 +3002,9 @@ void cpu_loop(CPUMBState *env)
}
}
break;
+ case EXCP_ATOMIC:
+ cpu_exec_step_atomic(cs);
+ break;
default:
printf ("Unhandled trap: 0x%x\n", trapnr);
cpu_dump_state(cs, stderr, fprintf, 0);
@@ -3075,6 +3108,9 @@ void cpu_loop(CPUM68KState *env)
}
}
break;
+ case EXCP_ATOMIC:
+ cpu_exec_step_atomic(cs);
+ break;
default:
EXCP_DUMP(env, "qemu: unhandled CPU exception 0x%x - aborting\n", trapnr);
abort();
@@ -3311,6 +3347,9 @@ void cpu_loop(CPUAlphaState *env)
case EXCP_INTERRUPT:
/* Just indicate that signals should be handled asap. */
break;
+ case EXCP_ATOMIC:
+ cpu_exec_step_atomic(cs);
+ break;
default:
printf ("Unhandled trap: 0x%x\n", trapnr);
cpu_dump_state(cs, stderr, fprintf, 0);
@@ -3440,6 +3479,9 @@ void cpu_loop(CPUS390XState *env)
queue_signal(env, info.si_signo, QEMU_SI_FAULT, &info);
break;
+ case EXCP_ATOMIC:
+ cpu_exec_step_atomic(cs);
+ break;
default:
fprintf(stderr, "Unhandled trap: 0x%x\n", trapnr);
cpu_dump_state(cs, stderr, fprintf, 0);
@@ -3694,6 +3736,9 @@ void cpu_loop(CPUTLGState *env)
case TILEGX_EXCP_REG_UDN_ACCESS:
gen_sigill_reg(env);
break;
+ case EXCP_ATOMIC:
+ cpu_exec_step_atomic(cs);
+ break;
default:
fprintf(stderr, "trapnr is %d[0x%x].\n", trapnr, trapnr);
g_assert_not_reached();
@@ -704,6 +704,7 @@ struct TCGContext {
};
extern TCGContext tcg_ctx;
+extern bool parallel_cpus;
static inline void tcg_set_insn_param(int op_idx, int arg, TCGArg v)
{
@@ -119,6 +119,7 @@ static void *l1_map[V_L1_SIZE];
/* code generation context */
TCGContext tcg_ctx;
+bool parallel_cpus;
/* translation block context */
#ifdef CONFIG_USER_ONLY
--
2.7.4