This is going to be useful in the next patch when rolling up the locking on the slow path into the TB patching.
Signed-off-by: Alex Bennée <alex.ben...@linaro.org> --- cpu-exec.c | 59 +++++++++++++++++++++++++++++++++++++---------------------- 1 file changed, 37 insertions(+), 22 deletions(-) diff --git a/cpu-exec.c b/cpu-exec.c index dd0bd50..59c2ec5 100644 --- a/cpu-exec.c +++ b/cpu-exec.c @@ -278,6 +278,40 @@ static TranslationBlock *tb_find_physical(CPUState *cpu, return qht_lookup(&tcg_ctx.tb_ctx.htable, tb_cmp, &desc, h); } +/* + * Patch the last TB with a jump to the current TB. + * + * Modification of the TB has to be protected with tb_lock. + */ +static inline void maybe_patch_last_tb(CPUState *cpu, + TranslationBlock *tb, + TranslationBlock **last_tb, + int tb_exit) +{ + if (cpu->tb_flushed) { + /* Ensure that no TB jump will be modified as the + * translation buffer has been flushed. + */ + *last_tb = NULL; + cpu->tb_flushed = false; + } +#ifndef CONFIG_USER_ONLY + /* We don't take care of direct jumps when address mapping changes in + * system emulation. So it's not safe to make a direct jump to a TB + * spanning two pages because the mapping for the second page can change. + */ + if (tb->page_addr[1] != -1) { + *last_tb = NULL; + } +#endif + /* See if we can patch the calling TB. */ + if (*last_tb && !qemu_loglevel_mask(CPU_LOG_TB_NOCHAIN)) { + tb_lock(); + tb_add_jump(*last_tb, tb_exit, tb); + tb_unlock(); + } +} + static TranslationBlock *tb_find_slow(CPUState *cpu, target_ulong pc, target_ulong cs_base, @@ -336,28 +370,9 @@ static inline TranslationBlock *tb_find_fast(CPUState *cpu, tb->flags != flags)) { tb = tb_find_slow(cpu, pc, cs_base, flags); } - if (cpu->tb_flushed) { - /* Ensure that no TB jump will be modified as the - * translation buffer has been flushed. - */ - *last_tb = NULL; - cpu->tb_flushed = false; - } -#ifndef CONFIG_USER_ONLY - /* We don't take care of direct jumps when address mapping changes in - * system emulation. So it's not safe to make a direct jump to a TB - * spanning two pages because the mapping for the second page can change. - */ - if (tb->page_addr[1] != -1) { - *last_tb = NULL; - } -#endif - /* See if we can patch the calling TB. */ - if (*last_tb && !qemu_loglevel_mask(CPU_LOG_TB_NOCHAIN)) { - tb_lock(); - tb_add_jump(*last_tb, tb_exit, tb); - tb_unlock(); - } + + maybe_patch_last_tb(cpu, tb, last_tb, tb_exit); + return tb; } -- 2.7.4