[PATCH 5/9] target/loongarch: Add common function get_tlb_random_index()

[Bibo Mao]

With software PTW system, tlb index is calculated randomly when new
TLB entry is added. For hardware PTW, it is the same logic to add
new TLB entry.

Here common function get_tlb_random_index() is added to get random
tlb index when adding new TLB entry.

Signed-off-by: Bibo Mao <maob...@loongson.cn>
---
 target/loongarch/tcg/tlb_helper.c | 39 +++++++++++++++++++------------
 1 file changed, 24 insertions(+), 15 deletions(-)

diff --git a/target/loongarch/tcg/tlb_helper.c 
b/target/loongarch/tcg/tlb_helper.c
index fa216b92fd..67b8f95849 100644
--- a/target/loongarch/tcg/tlb_helper.c
+++ b/target/loongarch/tcg/tlb_helper.c
@@ -390,31 +390,21 @@ void helper_tlbwr(CPULoongArchState *env)
     old->tlb_entry1 = new.tlb_entry1;
 }
 
-void helper_tlbfill(CPULoongArchState *env)
+static int get_tlb_random_index(CPULoongArchState *env, vaddr addr, int ps)
 {
-    uint64_t address, entryhi;
+    vaddr address;
     int index, set, i, stlb_idx;
-    uint16_t pagesize, stlb_ps;
+    uint16_t stlb_ps;
     uint16_t asid, tlb_asid;
     LoongArchTLB *tlb;
     uint8_t tlb_e;
 
-    if (FIELD_EX64(env->CSR_TLBRERA, CSR_TLBRERA, ISTLBR)) {
-        entryhi = env->CSR_TLBREHI;
-        /* Validity of pagesize is checked in helper_ldpte() */
-        pagesize = FIELD_EX64(env->CSR_TLBREHI, CSR_TLBREHI, PS);
-    } else {
-        entryhi = env->CSR_TLBEHI;
-        /* Validity of pagesize is checked in helper_tlbrd() */
-        pagesize = FIELD_EX64(env->CSR_TLBIDX, CSR_TLBIDX, PS);
-    }
-
     /* Validity of stlb_ps is checked in helper_csrwr_stlbps() */
     stlb_ps = FIELD_EX64(env->CSR_STLBPS, CSR_STLBPS, PS);
     asid = FIELD_EX64(env->CSR_ASID, CSR_ASID, ASID);
-    if (pagesize == stlb_ps) {
+    if (ps == stlb_ps) {
         /* Only write into STLB bits [47:13] */
-        address = entryhi & ~MAKE_64BIT_MASK(0, R_CSR_TLBEHI_64_VPPN_SHIFT);
+        address = addr & ~MAKE_64BIT_MASK(0, R_CSR_TLBEHI_64_VPPN_SHIFT);
         set = -1;
         stlb_idx = (address >> (stlb_ps + 1)) & 0xff; /* [0,255] */
         for (i = 0; i < 8; ++i) {
@@ -459,6 +449,25 @@ void helper_tlbfill(CPULoongArchState *env)
         }
     }
 
+    return index;
+}
+
+void helper_tlbfill(CPULoongArchState *env)
+{
+    uint64_t entryhi;
+    int index, pagesize;
+
+    if (FIELD_EX64(env->CSR_TLBRERA, CSR_TLBRERA, ISTLBR)) {
+        entryhi = env->CSR_TLBREHI;
+        /* Validity of pagesize is checked in helper_ldpte() */
+        pagesize = FIELD_EX64(env->CSR_TLBREHI, CSR_TLBREHI, PS);
+    } else {
+        entryhi = env->CSR_TLBEHI;
+        /* Validity of pagesize is checked in helper_tlbrd() */
+        pagesize = FIELD_EX64(env->CSR_TLBIDX, CSR_TLBIDX, PS);
+    }
+
+    index = get_tlb_random_index(env, entryhi, pagesize);
     invalidate_tlb(env, index);
     fill_tlb_entry(env, env->tlb + index);
 }
-- 
2.39.3