[PATCH 11/12] target/s390x: Use set/clear_helper_retaddr in mem_helper.c

[Richard Henderson]

Avoid a race condition with munmap in another thread.
For access_memset and access_memmove, manage the value
within the helper.  For uses of access_{get,set}_byte,
manage the value across the for loops.

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 target/s390x/tcg/mem_helper.c | 43 ++++++++++++++++++++++++++++++-----
 1 file changed, 37 insertions(+), 6 deletions(-)

diff --git a/target/s390x/tcg/mem_helper.c b/target/s390x/tcg/mem_helper.c
index 331a35b2e5..0e12dae2aa 100644
--- a/target/s390x/tcg/mem_helper.c
+++ b/target/s390x/tcg/mem_helper.c
@@ -238,14 +238,14 @@ static void do_access_memset(CPUS390XState *env, vaddr 
vaddr, char *haddr,
 static void access_memset(CPUS390XState *env, S390Access *desta,
                           uint8_t byte, uintptr_t ra)
 {
-
+    set_helper_retaddr(ra);
     do_access_memset(env, desta->vaddr1, desta->haddr1, byte, desta->size1,
                      desta->mmu_idx, ra);
-    if (likely(!desta->size2)) {
-        return;
+    if (unlikely(desta->size2)) {
+        do_access_memset(env, desta->vaddr2, desta->haddr2, byte,
+                         desta->size2, desta->mmu_idx, ra);
     }
-    do_access_memset(env, desta->vaddr2, desta->haddr2, byte, desta->size2,
-                     desta->mmu_idx, ra);
+    clear_helper_retaddr();
 }
 
 static uint8_t access_get_byte(CPUS390XState *env, S390Access *access,
@@ -366,6 +366,8 @@ static uint32_t do_helper_nc(CPUS390XState *env, uint32_t 
l, uint64_t dest,
     access_prepare(&srca1, env, src, l, MMU_DATA_LOAD, mmu_idx, ra);
     access_prepare(&srca2, env, dest, l, MMU_DATA_LOAD, mmu_idx, ra);
     access_prepare(&desta, env, dest, l, MMU_DATA_STORE, mmu_idx, ra);
+    set_helper_retaddr(ra);
+
     for (i = 0; i < l; i++) {
         const uint8_t x = access_get_byte(env, &srca1, i, ra) &
                           access_get_byte(env, &srca2, i, ra);
@@ -373,6 +375,8 @@ static uint32_t do_helper_nc(CPUS390XState *env, uint32_t 
l, uint64_t dest,
         c |= x;
         access_set_byte(env, &desta, i, x, ra);
     }
+
+    clear_helper_retaddr();
     return c != 0;
 }
 
@@ -407,6 +411,7 @@ static uint32_t do_helper_xc(CPUS390XState *env, uint32_t 
l, uint64_t dest,
         return 0;
     }
 
+    set_helper_retaddr(ra);
     for (i = 0; i < l; i++) {
         const uint8_t x = access_get_byte(env, &srca1, i, ra) ^
                           access_get_byte(env, &srca2, i, ra);
@@ -414,6 +419,7 @@ static uint32_t do_helper_xc(CPUS390XState *env, uint32_t 
l, uint64_t dest,
         c |= x;
         access_set_byte(env, &desta, i, x, ra);
     }
+    clear_helper_retaddr();
     return c != 0;
 }
 
@@ -441,6 +447,8 @@ static uint32_t do_helper_oc(CPUS390XState *env, uint32_t 
l, uint64_t dest,
     access_prepare(&srca1, env, src, l, MMU_DATA_LOAD, mmu_idx, ra);
     access_prepare(&srca2, env, dest, l, MMU_DATA_LOAD, mmu_idx, ra);
     access_prepare(&desta, env, dest, l, MMU_DATA_STORE, mmu_idx, ra);
+    set_helper_retaddr(ra);
+
     for (i = 0; i < l; i++) {
         const uint8_t x = access_get_byte(env, &srca1, i, ra) |
                           access_get_byte(env, &srca2, i, ra);
@@ -448,6 +456,8 @@ static uint32_t do_helper_oc(CPUS390XState *env, uint32_t 
l, uint64_t dest,
         c |= x;
         access_set_byte(env, &desta, i, x, ra);
     }
+
+    clear_helper_retaddr();
     return c != 0;
 }
 
@@ -484,11 +494,13 @@ static uint32_t do_helper_mvc(CPUS390XState *env, 
uint32_t l, uint64_t dest,
     } else if (!is_destructive_overlap(env, dest, src, l)) {
         access_memmove(env, &desta, &srca, ra);
     } else {
+        set_helper_retaddr(ra);
         for (i = 0; i < l; i++) {
             uint8_t byte = access_get_byte(env, &srca, i, ra);
 
             access_set_byte(env, &desta, i, byte, ra);
         }
+        clear_helper_retaddr();
     }
 
     return env->cc_op;
@@ -514,10 +526,12 @@ void HELPER(mvcrl)(CPUS390XState *env, uint64_t l, 
uint64_t dest, uint64_t src)
     access_prepare(&srca, env, src, l, MMU_DATA_LOAD, mmu_idx, ra);
     access_prepare(&desta, env, dest, l, MMU_DATA_STORE, mmu_idx, ra);
 
+    set_helper_retaddr(ra);
     for (i = l - 1; i >= 0; i--) {
         uint8_t byte = access_get_byte(env, &srca, i, ra);
         access_set_byte(env, &desta, i, byte, ra);
     }
+    clear_helper_retaddr();
 }
 
 /* move inverse  */
@@ -534,11 +548,13 @@ void HELPER(mvcin)(CPUS390XState *env, uint32_t l, 
uint64_t dest, uint64_t src)
     src = wrap_address(env, src - l + 1);
     access_prepare(&srca, env, src, l, MMU_DATA_LOAD, mmu_idx, ra);
     access_prepare(&desta, env, dest, l, MMU_DATA_STORE, mmu_idx, ra);
+
+    set_helper_retaddr(ra);
     for (i = 0; i < l; i++) {
         const uint8_t x = access_get_byte(env, &srca, l - i - 1, ra);
-
         access_set_byte(env, &desta, i, x, ra);
     }
+    clear_helper_retaddr();
 }
 
 /* move numerics  */
@@ -555,12 +571,15 @@ void HELPER(mvn)(CPUS390XState *env, uint32_t l, uint64_t 
dest, uint64_t src)
     access_prepare(&srca1, env, src, l, MMU_DATA_LOAD, mmu_idx, ra);
     access_prepare(&srca2, env, dest, l, MMU_DATA_LOAD, mmu_idx, ra);
     access_prepare(&desta, env, dest, l, MMU_DATA_STORE, mmu_idx, ra);
+
+    set_helper_retaddr(ra);
     for (i = 0; i < l; i++) {
         const uint8_t x = (access_get_byte(env, &srca1, i, ra) & 0x0f) |
                           (access_get_byte(env, &srca2, i, ra) & 0xf0);
 
         access_set_byte(env, &desta, i, x, ra);
     }
+    clear_helper_retaddr();
 }
 
 /* move with offset  */
@@ -580,6 +599,8 @@ void HELPER(mvo)(CPUS390XState *env, uint32_t l, uint64_t 
dest, uint64_t src)
 
     /* Handle rightmost byte */
     byte_dest = cpu_ldub_data_ra(env, dest + len_dest - 1, ra);
+
+    set_helper_retaddr(ra);
     byte_src = access_get_byte(env, &srca, len_src - 1, ra);
     byte_dest = (byte_dest & 0x0f) | (byte_src << 4);
     access_set_byte(env, &desta, len_dest - 1, byte_dest, ra);
@@ -595,6 +616,7 @@ void HELPER(mvo)(CPUS390XState *env, uint32_t l, uint64_t 
dest, uint64_t src)
         byte_dest |= byte_src << 4;
         access_set_byte(env, &desta, i, byte_dest, ra);
     }
+    clear_helper_retaddr();
 }
 
 /* move zones  */
@@ -611,12 +633,15 @@ void HELPER(mvz)(CPUS390XState *env, uint32_t l, uint64_t 
dest, uint64_t src)
     access_prepare(&srca1, env, src, l, MMU_DATA_LOAD, mmu_idx, ra);
     access_prepare(&srca2, env, dest, l, MMU_DATA_LOAD, mmu_idx, ra);
     access_prepare(&desta, env, dest, l, MMU_DATA_STORE, mmu_idx, ra);
+
+    set_helper_retaddr(ra);
     for (i = 0; i < l; i++) {
         const uint8_t x = (access_get_byte(env, &srca1, i, ra) & 0xf0) |
                           (access_get_byte(env, &srca2, i, ra) & 0x0f);
 
         access_set_byte(env, &desta, i, x, ra);
     }
+    clear_helper_retaddr();
 }
 
 /* compare unsigned byte arrays */
@@ -961,15 +986,19 @@ uint32_t HELPER(mvst)(CPUS390XState *env, uint32_t r1, 
uint32_t r2)
      */
     access_prepare(&srca, env, s, len, MMU_DATA_LOAD, mmu_idx, ra);
     access_prepare(&desta, env, d, len, MMU_DATA_STORE, mmu_idx, ra);
+
+    set_helper_retaddr(ra);
     for (i = 0; i < len; i++) {
         const uint8_t v = access_get_byte(env, &srca, i, ra);
 
         access_set_byte(env, &desta, i, v, ra);
         if (v == c) {
+            clear_helper_retaddr();
             set_address_zero(env, r1, d + i);
             return 1;
         }
     }
+    clear_helper_retaddr();
     set_address_zero(env, r1, d + len);
     set_address_zero(env, r2, s + len);
     return 3;
@@ -1060,6 +1089,7 @@ static inline uint32_t do_mvcl(CPUS390XState *env,
         *dest = wrap_address(env, *dest + len);
     } else {
         access_prepare(&desta, env, *dest, len, MMU_DATA_STORE, mmu_idx, ra);
+        set_helper_retaddr(ra);
 
         /* The remaining length selects the padding byte. */
         for (i = 0; i < len; (*destlen)--, i++) {
@@ -1069,6 +1099,7 @@ static inline uint32_t do_mvcl(CPUS390XState *env,
                 access_set_byte(env, &desta, i, pad >> 8, ra);
             }
         }
+        clear_helper_retaddr();
         *dest = wrap_address(env, *dest + len);
     }
 
-- 
2.43.0