From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:33059) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aszTG-0007z0-36 for qemu-devel@nongnu.org; Wed, 20 Apr 2016 17:15:39 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1aszTE-0004YL-St for qemu-devel@nongnu.org; Wed, 20 Apr 2016 17:15:37 -0400 Received: from mail-lb0-x234.google.com ([2a00:1450:4010:c04::234]:33596) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aszTE-0004Xt-Ee for qemu-devel@nongnu.org; Wed, 20 Apr 2016 17:15:36 -0400 Received: by mail-lb0-x234.google.com with SMTP id u8so16480383lbk.0 for ; Wed, 20 Apr 2016 14:15:36 -0700 (PDT) From: Sergey Fedorov Date: Thu, 21 Apr 2016 00:15:15 +0300 Message-Id: <1461186921-14977-5-git-send-email-sergey.fedorov@linaro.org> In-Reply-To: <1461186921-14977-1-git-send-email-sergey.fedorov@linaro.org> References: <1461186921-14977-1-git-send-email-sergey.fedorov@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Subject: [Qemu-devel] [PATCH v4 04/10] tcg: Init TB's direct jumps before making it visible List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: =?UTF-8?q?Alex=20Benn=C3=A9e?= , Sergey Fedorov , Paolo Bonzini , Peter Crosthwaite , Richard Henderson , Sergey Fedorov From: Sergey Fedorov Initialize TB's direct jump list data fields and reset the jumps before tb_link_page() puts it into the physical hash table and the physical page list. So TB is completely initialized before it becomes visible. This is pure rearrangement of code to a more suitable place, though it could be a preparation for relaxing the locking scheme in future. Signed-off-by: Sergey Fedorov Signed-off-by: Sergey Fedorov Reviewed-by: Alex Bennée --- Changes in v4: * Added comment on TB stuff synchronization * Expanded commit message Changes in v2: * Tweaked a comment translate-all.c | 32 +++++++++++++++++++------------- 1 file changed, 19 insertions(+), 13 deletions(-) diff --git a/translate-all.c b/translate-all.c index 7ac7916f2792..85b2b95b8afe 100644 --- a/translate-all.c +++ b/translate-all.c @@ -1133,19 +1133,6 @@ static void tb_link_page(TranslationBlock *tb, tb_page_addr_t phys_pc, tb->page_addr[1] = -1; } - assert(((uintptr_t)tb & 3) == 0); - tb->jmp_list_first = (uintptr_t)tb | 2; - tb->jmp_list_next[0] = (uintptr_t)NULL; - tb->jmp_list_next[1] = (uintptr_t)NULL; - - /* init original jump addresses */ - if (tb->jmp_reset_offset[0] != TB_JMP_RESET_OFFSET_INVALID) { - tb_reset_jump(tb, 0); - } - if (tb->jmp_reset_offset[1] != TB_JMP_RESET_OFFSET_INVALID) { - tb_reset_jump(tb, 1); - } - #ifdef DEBUG_TB_CHECK tb_page_check(); #endif @@ -1254,12 +1241,31 @@ TranslationBlock *tb_gen_code(CPUState *cpu, ROUND_UP((uintptr_t)gen_code_buf + gen_code_size + search_size, CODE_GEN_ALIGN); + /* init jump list */ + assert(((uintptr_t)tb & 3) == 0); + tb->jmp_list_first = (uintptr_t)tb | 2; + tb->jmp_list_next[0] = (uintptr_t)NULL; + tb->jmp_list_next[1] = (uintptr_t)NULL; + + /* init original jump addresses wich has been set during tcg_gen_code() */ + if (tb->jmp_reset_offset[0] != TB_JMP_RESET_OFFSET_INVALID) { + tb_reset_jump(tb, 0); + } + if (tb->jmp_reset_offset[1] != TB_JMP_RESET_OFFSET_INVALID) { + tb_reset_jump(tb, 1); + } + /* check next page if needed */ virt_page2 = (pc + tb->size - 1) & TARGET_PAGE_MASK; phys_page2 = -1; if ((pc & TARGET_PAGE_MASK) != virt_page2) { phys_page2 = get_page_addr_code(env, virt_page2); } + /* As long as consistency of the TB stuff is provided by tb_lock in user + * mode and is implicit in single-threaded softmmu emulation, no explicit + * memory barrier is required before tb_link_page() makes the TB visible + * through the physical hash table and physical page list. + */ tb_link_page(tb, phys_pc, phys_page2); return tb; } -- 2.8.1