Skip to content

Commit

Permalink
tcg: Add EXCP_ATOMIC
Browse files Browse the repository at this point in the history 
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>
  • Loading branch information
@rth7680
rth7680 committed Oct 26, 2016
1 parent 1edaeee commit fdbc2b5
Show file tree
Hide file tree
Showing 9 changed files with 88 additions and 0 deletions.
6 changes: 6 additions & 0 deletions cpu-exec-common.c
View file
Expand Up @@ -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);
}
30 changes: 30 additions & 0 deletions cpu-exec.c
View file
Expand Up @@ -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;
Expand Down
2 changes: 2 additions & 0 deletions cpus.c
View file
Expand Up @@ -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) {
Expand Down
1 change: 1 addition & 0 deletions include/exec/cpu-all.h
View file
Expand Up @@ -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:
*
Expand Down
1 change: 1 addition & 0 deletions include/exec/exec-all.h
View file
Expand Up @@ -59,6 +59,7 @@ TranslationBlock *tb_gen_code(CPUState *cpu,

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);
Expand Down
1 change: 1 addition & 0 deletions include/qemu-common.h
View file
Expand Up @@ -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);

/**
* set_preferred_target_page_bits:
Expand Down
45 changes: 45 additions & 0 deletions linux-user/main.c
View file
Expand Up @@ -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",
Expand Down Expand Up @@ -851,6 +854,9 @@ 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);
Expand Down Expand Up @@ -1051,6 +1057,9 @@ 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();
Expand Down Expand Up @@ -1142,6 +1151,9 @@ void cpu_loop(CPUUniCore32State *env)
}
}
break;
case EXCP_ATOMIC:
cpu_exec_step_atomic(cs);
break;
default:
goto error;
}
Expand Down Expand Up @@ -1415,6 +1427,9 @@ 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);
Expand Down Expand Up @@ -1954,6 +1969,9 @@ 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;
Expand Down Expand Up @@ -2649,6 +2667,9 @@ void cpu_loop(CPUMIPSState *env)
}
}
break;
case EXCP_ATOMIC:
cpu_exec_step_atomic(cs);
break;
default:
error:
EXCP_DUMP(env, "qemu: unhandled CPU exception 0x%x - aborting\n", trapnr);
Expand Down Expand Up @@ -2736,6 +2757,9 @@ 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);
Expand Down Expand Up @@ -2812,6 +2836,9 @@ 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);
Expand Down Expand Up @@ -2879,6 +2906,9 @@ 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);
Expand Down Expand Up @@ -2995,6 +3025,9 @@ 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);
Expand Down Expand Up @@ -3098,6 +3131,9 @@ 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();
Expand Down Expand Up @@ -3334,6 +3370,9 @@ 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);
Expand Down Expand Up @@ -3463,6 +3502,9 @@ 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);
Expand Down Expand Up @@ -3717,6 +3759,9 @@ 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();
Expand Down
1 change: 1 addition & 0 deletions tcg/tcg.h
View file
Expand Up @@ -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)
{
Expand Down
1 change: 1 addition & 0 deletions translate-all.c
View file
Expand Up @@ -118,6 +118,7 @@ static void *l1_map[V_L1_MAX_SIZE];

/* code generation context */
TCGContext tcg_ctx;
bool parallel_cpus;

/* translation block context */
#ifdef CONFIG_USER_ONLY
Expand Down

0 comments on commit fdbc2b5

Please sign in to comment.