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target/sh4: Fix translator.c assertion failure for gUSA
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The translator loop does not allow the tb_start hook to set
dc->base.is_jmp; the only hook allowed to do that is translate_insn.

Split the work between init_disas_context where we validate
the gUSA parameters, and translate_insn where we emit code.

Tested-by: Alex Bennée <[email protected]>
Reviewed-by: Alex Bennée <[email protected]>
Signed-off-by: Richard Henderson <[email protected]>
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@rth7680
rth7680 committed Jul 9, 2018
1 parent ec7eb2a commit be0e3d7
Showing 1 changed file with 44 additions and 37 deletions.
81 changes: 44 additions & 37 deletions target/sh4/translate.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1895,35 +1895,18 @@ static void decode_opc(DisasContext * ctx)
any sequence via cpu_exec_step_atomic, we can recognize the "normal"
sequences and transform them into atomic operations as seen by the host.
*/
static int decode_gusa(DisasContext *ctx, CPUSH4State *env, int *pmax_insns)
static void decode_gusa(DisasContext *ctx, CPUSH4State *env)
{
uint16_t insns[5];
int ld_adr, ld_dst, ld_mop;
int op_dst, op_src, op_opc;
int mv_src, mt_dst, st_src, st_mop;
TCGv op_arg;

uint32_t pc = ctx->base.pc_next;
uint32_t pc_end = ctx->base.tb->cs_base;
int backup = sextract32(ctx->tbflags, GUSA_SHIFT, 8);
int max_insns = (pc_end - pc) / 2;
int i;

if (pc != pc_end + backup || max_insns < 2) {
/* This is a malformed gUSA region. Don't do anything special,
since the interpreter is likely to get confused. */
ctx->envflags &= ~GUSA_MASK;
return 0;
}

if (ctx->tbflags & GUSA_EXCLUSIVE) {
/* Regardless of single-stepping or the end of the page,
we must complete execution of the gUSA region while
holding the exclusive lock. */
*pmax_insns = max_insns;
return 0;
}

/* The state machine below will consume only a few insns.
If there are more than that in a region, fail now. */
if (max_insns > ARRAY_SIZE(insns)) {
Expand Down Expand Up @@ -2140,7 +2123,6 @@ static int decode_gusa(DisasContext *ctx, CPUSH4State *env, int *pmax_insns)
/*
* Emit the operation.
*/
tcg_gen_insn_start(pc, ctx->envflags);
switch (op_opc) {
case -1:
/* No operation found. Look for exchange pattern. */
Expand Down Expand Up @@ -2235,15 +2217,15 @@ static int decode_gusa(DisasContext *ctx, CPUSH4State *env, int *pmax_insns)
/* The entire region has been translated. */
ctx->envflags &= ~GUSA_MASK;
ctx->base.pc_next = pc_end;
return max_insns;
ctx->base.num_insns += max_insns - 1;
return;

fail:
qemu_log_mask(LOG_UNIMP, "Unrecognized gUSA sequence %08x-%08x\n",
pc, pc_end);

/* Restart with the EXCLUSIVE bit set, within a TB run via
cpu_exec_step_atomic holding the exclusive lock. */
tcg_gen_insn_start(pc, ctx->envflags);
ctx->envflags |= GUSA_EXCLUSIVE;
gen_save_cpu_state(ctx, false);
gen_helper_exclusive(cpu_env);
Expand All @@ -2254,27 +2236,47 @@ static int decode_gusa(DisasContext *ctx, CPUSH4State *env, int *pmax_insns)
entire region consumed via ctx->base.pc_next so that it's immediately
available in the disassembly dump. */
ctx->base.pc_next = pc_end;
return 1;
ctx->base.num_insns += max_insns - 1;
}
#endif

static void sh4_tr_init_disas_context(DisasContextBase *dcbase, CPUState *cs)
{
DisasContext *ctx = container_of(dcbase, DisasContext, base);
CPUSH4State *env = cs->env_ptr;
uint32_t tbflags;
int bound;

ctx->tbflags = (uint32_t)ctx->base.tb->flags;
ctx->envflags = ctx->base.tb->flags & TB_FLAG_ENVFLAGS_MASK;
ctx->memidx = (ctx->tbflags & (1u << SR_MD)) == 0 ? 1 : 0;
ctx->tbflags = tbflags = ctx->base.tb->flags;
ctx->envflags = tbflags & TB_FLAG_ENVFLAGS_MASK;
ctx->memidx = (tbflags & (1u << SR_MD)) == 0 ? 1 : 0;
/* We don't know if the delayed pc came from a dynamic or static branch,
so assume it is a dynamic branch. */
ctx->delayed_pc = -1; /* use delayed pc from env pointer */
ctx->features = env->features;
ctx->has_movcal = (ctx->tbflags & TB_FLAG_PENDING_MOVCA);
ctx->gbank = ((ctx->tbflags & (1 << SR_MD)) &&
(ctx->tbflags & (1 << SR_RB))) * 0x10;
ctx->fbank = ctx->tbflags & FPSCR_FR ? 0x10 : 0;
ctx->has_movcal = (tbflags & TB_FLAG_PENDING_MOVCA);
ctx->gbank = ((tbflags & (1 << SR_MD)) &&
(tbflags & (1 << SR_RB))) * 0x10;
ctx->fbank = tbflags & FPSCR_FR ? 0x10 : 0;

if (tbflags & GUSA_MASK) {
uint32_t pc = ctx->base.pc_next;
uint32_t pc_end = ctx->base.tb->cs_base;
int backup = sextract32(ctx->tbflags, GUSA_SHIFT, 8);
int max_insns = (pc_end - pc) / 2;

if (pc != pc_end + backup || max_insns < 2) {
/* This is a malformed gUSA region. Don't do anything special,
since the interpreter is likely to get confused. */
ctx->envflags &= ~GUSA_MASK;
} else if (tbflags & GUSA_EXCLUSIVE) {
/* Regardless of single-stepping or the end of the page,
we must complete execution of the gUSA region while
holding the exclusive lock. */
ctx->base.max_insns = max_insns;
return;
}
}

/* Since the ISA is fixed-width, we can bound by the number
of instructions remaining on the page. */
Expand All @@ -2284,14 +2286,6 @@ static void sh4_tr_init_disas_context(DisasContextBase *dcbase, CPUState *cs)

static void sh4_tr_tb_start(DisasContextBase *dcbase, CPUState *cs)
{
#ifdef CONFIG_USER_ONLY
DisasContext *ctx = container_of(dcbase, DisasContext, base);
CPUSH4State *env = cs->env_ptr;

if (ctx->tbflags & GUSA_MASK) {
ctx->base.num_insns = decode_gusa(ctx, env, &ctx->base.max_insns);
}
#endif
}

static void sh4_tr_insn_start(DisasContextBase *dcbase, CPUState *cs)
Expand Down Expand Up @@ -2323,6 +2317,19 @@ static void sh4_tr_translate_insn(DisasContextBase *dcbase, CPUState *cs)
CPUSH4State *env = cs->env_ptr;
DisasContext *ctx = container_of(dcbase, DisasContext, base);

#ifdef CONFIG_USER_ONLY
if (unlikely(ctx->envflags & GUSA_MASK)
&& !(ctx->envflags & GUSA_EXCLUSIVE)) {
/* We're in an gUSA region, and we have not already fallen
back on using an exclusive region. Attempt to parse the
region into a single supported atomic operation. Failure
is handled within the parser by raising an exception to
retry using an exclusive region. */
decode_gusa(ctx, env);
return;
}
#endif

ctx->opcode = cpu_lduw_code(env, ctx->base.pc_next);
decode_opc(ctx);
ctx->base.pc_next += 2;
Expand Down

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