[Qemu-devel] [PATCH 02/11] target/hppa: fix TLB handling for page 0

[Sven Schnelle <svens@stackframe.org>]

Assume the following sequence:

pitlbe r0(sr0,r0)
iitlba r4,(sr0,r0)
ldil L%3000000,r5
iitlbp r5,(sr0,r0)

This will purge the whole TLB and add an entry for page 0. However
the current TLB implementation in helper_iitlba() will store to
the last empty TLB entry, while helper_iitlbp() will write to the
first empty entry. That is because an empty entry will match address
0 in helper_iitlba()

Signed-off-by: Sven Schnelle <svens@stackframe.org>
---
 target/hppa/mem_helper.c | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/target/hppa/mem_helper.c b/target/hppa/mem_helper.c
index aecf3075f6..f30824f4e1 100644
--- a/target/hppa/mem_helper.c
+++ b/target/hppa/mem_helper.c
@@ -238,15 +238,17 @@ void HELPER(itlba)(CPUHPPAState *env, target_ulong addr, target_ureg reg)
 {
     hppa_tlb_entry *empty = NULL;
     int i;
-
     /* Zap any old entries covering ADDR; notice empty entries on the way.  */
     for (i = 0; i < ARRAY_SIZE(env->tlb); ++i) {
         hppa_tlb_entry *ent = &env->tlb[i];
-        if (!ent->entry_valid) {
-            empty = ent;
-        } else if (ent->va_b <= addr && addr <= ent->va_e) {
-            hppa_flush_tlb_ent(env, ent);
-            empty = ent;
+        if (ent->va_b <= addr && addr <= ent->va_e) {
+            if (ent->entry_valid) {
+                hppa_flush_tlb_ent(env, ent);
+            }
+
+            if (!empty) {
+                empty = ent;
+            }
         }
     }
 
-- 
2.20.1