> From: Paolo Bonzini [mailto:pbonz...@redhat.com] > On 07/11/2014 11:32, Pavel Dovgalyuk wrote: > > This patch is required for deterministic replay to generate an exception > > by trying executing an instruction without changing icount. > > It adds new flag to TB for disabling icount while translating it. > > > > Signed-off-by: Pavel Dovgalyuk <pavel.dovga...@ispras.ru> > > --- > > cpu-exec.c | 6 +++--- > > include/exec/exec-all.h | 7 ++++--- > > translate-all.c | 22 ++++++++++++++++++++-- > > 3 files changed, 27 insertions(+), 8 deletions(-) > > > > diff --git a/cpu-exec.c b/cpu-exec.c > > index 011f51f..e7206ac 100644 > > --- a/cpu-exec.c > > +++ b/cpu-exec.c > > @@ -198,7 +198,7 @@ static inline tcg_target_ulong cpu_tb_exec(CPUState > > *cpu, uint8_t > *tb_ptr) > > /* Execute the code without caching the generated code. An interpreter > > could be used if available. */ > > static void cpu_exec_nocache(CPUArchState *env, int max_cycles, > > - TranslationBlock *orig_tb) > > + TranslationBlock *orig_tb, bool ignore_icount) > > { > > CPUState *cpu = ENV_GET_CPU(env); > > TranslationBlock *tb; > > @@ -214,7 +214,7 @@ static void cpu_exec_nocache(CPUArchState *env, int > > max_cycles, > > /* tb_gen_code can flush our orig_tb, invalidate it now */ > > tb_phys_invalidate(orig_tb, -1); > > tb = tb_gen_code(cpu, pc, cs_base, flags, > > - max_cycles); > > + max_cycles | (ignore_icount ? CF_IGNORE_ICOUNT : 0)); > > cpu->current_tb = tb; > > /* execute the generated code */ > > trace_exec_tb_nocache(tb, tb->pc); > > @@ -516,7 +516,7 @@ int cpu_exec(CPUArchState *env) > > } else { > > if (insns_left > 0) { > > /* Execute remaining instructions. */ > > - cpu_exec_nocache(env, insns_left, tb); > > + cpu_exec_nocache(env, insns_left, tb, > > false); > > align_clocks(&sc, cpu); > > } > > cpu->exception_index = EXCP_INTERRUPT; > > diff --git a/include/exec/exec-all.h b/include/exec/exec-all.h > > index 1d17f75..052e8ef 100644 > > --- a/include/exec/exec-all.h > > +++ b/include/exec/exec-all.h > > @@ -142,9 +142,10 @@ struct TranslationBlock { > > uint64_t flags; /* flags defining in which context the code was > > generated */ > > uint16_t size; /* size of target code for this block (1 <= > > size <= TARGET_PAGE_SIZE) */ > > - uint16_t cflags; /* compile flags */ > > -#define CF_COUNT_MASK 0x7fff > > -#define CF_LAST_IO 0x8000 /* Last insn may be an IO access. */ > > + uint32_t cflags; /* compile flags */ > > +#define CF_COUNT_MASK 0x7fff > > +#define CF_LAST_IO 0x8000 /* Last insn may be an IO access. */ > > +#define CF_IGNORE_ICOUNT 0x10000 /* Do not generate icount code */ > > > > void *tc_ptr; /* pointer to the translated code */ > > /* next matching tb for physical address. */ > > diff --git a/translate-all.c b/translate-all.c > > index 7177b71..182ea7d 100644 > > --- a/translate-all.c > > +++ b/translate-all.c > > @@ -207,6 +207,7 @@ static int cpu_restore_state_from_tb(CPUState *cpu, > > TranslationBlock > *tb, > > TCGContext *s = &tcg_ctx; > > int j; > > uintptr_t tc_ptr; > > + int old_icount = use_icount; > > #ifdef CONFIG_PROFILER > > int64_t ti; > > #endif > > @@ -218,6 +219,10 @@ static int cpu_restore_state_from_tb(CPUState *cpu, > > TranslationBlock > *tb, > > > > gen_intermediate_code_pc(env, tb); > > > > + if (tb->cflags & CF_IGNORE_ICOUNT) { > > Would it be possible to instead have a CF_USE_ICOUNT tbflag, and check > it when applicable instead of use_icount? It seems cleaner, because it > would avoid playing with global variables, but perhaps it's hard to do it.
Using context-specific flag is better than using global variable like use_icount. But I could not test such changes because they will affect all of the platforms (and will be also hard to implement for i386). Pavel Dovgalyuk
