[Qemu-devel] [PATCH 24/24] tcg-mips: Enable direct chaining of TBs

[Richard Henderson]

Now that the code_gen_buffer is constrained to not cross 256mb
regions, we are assured that we can use J to reach another TB.

Signed-off-by: Richard Henderson <address@hidden>
---
 include/exec/exec-all.h |  9 ++++-----
 tcg/mips/tcg-target.c   | 11 ++++++++++-
 2 files changed, 14 insertions(+), 6 deletions(-)

diff --git a/include/exec/exec-all.h b/include/exec/exec-all.h
index 444b4d9..6ef90f1 100644
--- a/include/exec/exec-all.h
+++ b/include/exec/exec-all.h
@@ -128,10 +128,9 @@ static inline void tlb_flush(CPUState *cpu, int 
flush_global)
 #define CODE_GEN_AVG_BLOCK_SIZE 64
 #endif
 
-#if defined(__arm__) || defined(_ARCH_PPC) \
-    || defined(__x86_64__) || defined(__i386__) \
-    || defined(__sparc__) || defined(__aarch64__) \
-    || defined(CONFIG_TCG_INTERPRETER)
+#if defined(__arm__) || defined(_ARCH_PPC) || defined(__x86_64__) \
+    || defined(__i386__) || defined(__sparc__) || defined(__aarch64__) \
+    || defined(__mips__) || defined(CONFIG_TCG_INTERPRETER)
 #define USE_DIRECT_JUMP
 #endif
 
@@ -259,7 +258,7 @@ static inline void tb_set_jmp_target1(uintptr_t jmp_addr, 
uintptr_t addr)
     __asm __volatile__ ("swi 0x9f0002" : : "r" (_beg), "r" (_end), "r" (_flg));
 #endif
 }
-#elif defined(__sparc__)
+#elif defined(__sparc__) || defined(__mips__)
 void tb_set_jmp_target1(uintptr_t jmp_addr, uintptr_t addr);
 #else
 #error tb_set_jmp_target1 is missing
diff --git a/tcg/mips/tcg-target.c b/tcg/mips/tcg-target.c
index ad752c4..8855d50 100644
--- a/tcg/mips/tcg-target.c
+++ b/tcg/mips/tcg-target.c
@@ -1354,7 +1354,9 @@ static inline void tcg_out_op(TCGContext *s, TCGOpcode 
opc,
     case INDEX_op_goto_tb:
         if (s->tb_jmp_offset) {
             /* direct jump method */
-            tcg_abort();
+            s->tb_jmp_offset[a0] = tcg_current_code_size(s);
+            /* Avoid clobbering the address during retranslation.  */
+            tcg_out32(s, OPC_J | (*(uint32_t *)s->code_ptr & 0x3ffffff));
         } else {
             /* indirect jump method */
             tcg_out_ld(s, TCG_TYPE_PTR, TCG_TMP0, TCG_REG_ZERO,
@@ -1805,3 +1807,10 @@ static void tcg_target_init(TCGContext *s)
 
     tcg_add_target_add_op_defs(mips_op_defs);
 }
+
+void tb_set_jmp_target1(uintptr_t jmp_addr, uintptr_t addr)
+{
+    uint32_t *ptr = (uint32_t *)jmp_addr;
+    *ptr = deposit32(*ptr, 0, 26, addr >> 2);
+    flush_icache_range(jmp_addr, jmp_addr + 4);
+}
-- 
1.9.0