accel/tcg: Remove TARGET_PAGE_DATA_SIZE

This macro is used by only one target, and even then under
unusual conditions -- AArch64 with mmap's PROT_MTE flag.

Since page size for aarch64-linux-user is variable, the
per-page data size is also variable.
Since page_reset_target_data via target_munmap does not
have ready access to CPUState, simply pass in the size
from the first allocation and remember that.

Reviewed-by: Pierrick Bouvier <pierrick.bouvier@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

accel/tcg/user-exec.c

@@ -870,7 +870,6 @@ tb_page_addr_t get_page_addr_code_hostp(CPUArchState *env, vaddr addr,
     return addr;
 }
 
-#ifdef TARGET_PAGE_DATA_SIZE
 /*
  * Allocate chunks of target data together.  For the only current user,
  * if we allocate one hunk per page, we have overhead of 40/128 or 40%.
@@ -886,10 +885,16 @@ typedef struct TargetPageDataNode {
 } TargetPageDataNode;
 
 static IntervalTreeRoot targetdata_root;
+static size_t target_page_data_size;
 
 void page_reset_target_data(vaddr start, vaddr last)
 {
     IntervalTreeNode *n, *next;
+    size_t size = target_page_data_size;
+
+    if (likely(size == 0)) {
+        return;
+    }
 
     assert_memory_lock();
 
@@ -920,17 +925,22 @@ void page_reset_target_data(vaddr start, vaddr last)
         n_last = MIN(last, n->last);
         p_len = (n_last + 1 - n_start) >> TARGET_PAGE_BITS;
 
-        memset(t->data + p_ofs * TARGET_PAGE_DATA_SIZE, 0,
-               p_len * TARGET_PAGE_DATA_SIZE);
+        memset(t->data + p_ofs * size, 0, p_len * size);
     }
 }
 
-void *page_get_target_data(vaddr address)
+void *page_get_target_data(vaddr address, size_t size)
 {
     IntervalTreeNode *n;
     TargetPageDataNode *t;
     vaddr page, region, p_ofs;
 
+    /* Remember the size from the first call, and it should be constant. */
+    if (unlikely(target_page_data_size != size)) {
+        assert(target_page_data_size == 0);
+        target_page_data_size = size;
+    }
+
     page = address & TARGET_PAGE_MASK;
     region = address & TBD_MASK;
 
@@ -945,8 +955,7 @@ void *page_get_target_data(vaddr address)
         mmap_lock();
         n = interval_tree_iter_first(&targetdata_root, page, page);
         if (!n) {
-            t = g_malloc0(sizeof(TargetPageDataNode)
-                          + TPD_PAGES * TARGET_PAGE_DATA_SIZE);
+            t = g_malloc0(sizeof(TargetPageDataNode) + TPD_PAGES * size);
             n = &t->itree;
             n->start = region;
             n->last = region | ~TBD_MASK;
@@ -957,11 +966,8 @@ void *page_get_target_data(vaddr address)
 
     t = container_of(n, TargetPageDataNode, itree);
     p_ofs = (page - region) >> TARGET_PAGE_BITS;
-    return t->data + p_ofs * TARGET_PAGE_DATA_SIZE;
+    return t->data + p_ofs * size;
 }
-#else
-void page_reset_target_data(vaddr start, vaddr last) { }
-#endif /* TARGET_PAGE_DATA_SIZE */
 
 /* The system-mode versions of these helpers are in cputlb.c.  */
 

include/user/page-protection.h

@@ -73,18 +73,20 @@ bool page_check_range_empty(vaddr start, vaddr last);
 vaddr page_find_range_empty(vaddr min, vaddr max, vaddr len, vaddr align);
 
 /**
- * page_get_target_data(address)
+ * page_get_target_data
  * @address: guest virtual address
+ * @size: per-page size
  *
- * Return TARGET_PAGE_DATA_SIZE bytes of out-of-band data to associate
+ * Return @size bytes of out-of-band data to associate
  * with the guest page at @address, allocating it if necessary.  The
  * caller should already have verified that the address is valid.
+ * The value of @size must be the same for every call.
  *
  * The memory will be freed when the guest page is deallocated,
  * e.g. with the munmap system call.
  */
 __attribute__((returns_nonnull))
-void *page_get_target_data(vaddr address);
+void *page_get_target_data(vaddr address, size_t size);
 
 typedef int (*walk_memory_regions_fn)(void *, vaddr, vaddr, int);
 int walk_memory_regions(void *, walk_memory_regions_fn);

target/arm/cpu.h

@@ -3213,8 +3213,4 @@ extern const uint64_t pred_esz_masks[5];
 #define LOG2_TAG_GRANULE 4
 #define TAG_GRANULE      (1 << LOG2_TAG_GRANULE)
 
-#ifdef CONFIG_USER_ONLY
-#define TARGET_PAGE_DATA_SIZE (TARGET_PAGE_SIZE >> (LOG2_TAG_GRANULE + 1))
-#endif /* CONFIG_USER_ONLY */
-
 #endif

target/arm/tcg/mte_helper.c

@@ -37,7 +37,6 @@
 #include "qemu/guest-random.h"
 #include "mte_helper.h"
 
-
 static int choose_nonexcluded_tag(int tag, int offset, uint16_t exclude)
 {
     if (exclude == 0xffff) {
@@ -63,6 +62,7 @@ uint8_t *allocation_tag_mem_probe(CPUARMState *env, int ptr_mmu_idx,
                                   bool probe, uintptr_t ra)
 {
 #ifdef CONFIG_USER_ONLY
+    const size_t page_data_size = TARGET_PAGE_SIZE >> (LOG2_TAG_GRANULE + 1);
     uint64_t clean_ptr = useronly_clean_ptr(ptr);
     int flags = page_get_flags(clean_ptr);
     uint8_t *tags;
@@ -83,7 +83,7 @@ uint8_t *allocation_tag_mem_probe(CPUARMState *env, int ptr_mmu_idx,
         return NULL;
     }
 
-    tags = page_get_target_data(clean_ptr);
+    tags = page_get_target_data(clean_ptr, page_data_size);
 
     index = extract32(ptr, LOG2_TAG_GRANULE + 1,
                       TARGET_PAGE_BITS - LOG2_TAG_GRANULE - 1);