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[Qemu-devel] [PATCH v5 04/10] tcg: Init TB's direct jumps before making
From: |
Sergey Fedorov |
Subject: |
[Qemu-devel] [PATCH v5 04/10] tcg: Init TB's direct jumps before making it visible |
Date: |
Fri, 29 Apr 2016 00:33:49 +0300 |
From: Sergey Fedorov <address@hidden>
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 <address@hidden>
Signed-off-by: Sergey Fedorov <address@hidden>
Reviewed-by: Alex Bennée <address@hidden>
---
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 4a58af43a430..1dc1a73c1d55 100644
--- a/translate-all.c
+++ b/translate-all.c
@@ -1134,19 +1134,6 @@ 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
@@ -1255,12 +1242,31 @@ 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
- [Qemu-devel] [PATCH v5 00/10] tcg: Direct block chaining clean-up, Sergey Fedorov, 2016/04/28
- [Qemu-devel] [PATCH v5 05/10] tcg: Clarify thread safety check in tb_add_jump(), Sergey Fedorov, 2016/04/28
- [Qemu-devel] [PATCH v5 06/10] tcg: Rename tb_jmp_remove() to tb_remove_from_jmp_list(), Sergey Fedorov, 2016/04/28
- [Qemu-devel] [PATCH v5 02/10] tcg: Use uintptr_t type for jmp_list_{next|first} fields of TB, Sergey Fedorov, 2016/04/28
- [Qemu-devel] [PATCH v5 03/10] tcg: Rearrange tb_link_page() to avoid forward declaration, Sergey Fedorov, 2016/04/28
- [Qemu-devel] [PATCH v5 01/10] tcg: Clean up direct block chaining data fields, Sergey Fedorov, 2016/04/28
- [Qemu-devel] [PATCH v5 08/10] tcg: Clean up tb_jmp_unlink(), Sergey Fedorov, 2016/04/28
- [Qemu-devel] [PATCH v5 04/10] tcg: Init TB's direct jumps before making it visible,
Sergey Fedorov <=
- [Qemu-devel] [PATCH v5 09/10] tcg: Clean up direct block chaining safety checks, Sergey Fedorov, 2016/04/28
- [Qemu-devel] [PATCH v5 10/10] tcg: Allow goto_tb to any target PC in user mode, Sergey Fedorov, 2016/04/28
- [Qemu-devel] [PATCH v5 07/10] tcg: Extract removing of jumps to TB from tb_phys_invalidate(), Sergey Fedorov, 2016/04/28
- Re: [Qemu-devel] [PATCH v5 00/10] tcg: Direct block chaining clean-up, Richard Henderson, 2016/04/29