system/memory: use ldn_he_p/stn_he_p

Using direct pointer dereferencing can allow for unaligned accesses,
which was seen during execution with sanitizers enabled.

Cc: qemu-stable@nongnu.org
Reviewed-by: Chris Rauer <crauer@google.com>
Reviewed-by: Peter Foley <pefoley@google.com>
Signed-off-by: Patrick Venture <venture@google.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Message-ID: <20231116163633.276671-1-venture@google.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
(cherry picked from commit 2b8fe81)
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>

softmmu/memory.c

@@ -1326,22 +1326,7 @@ static uint64_t memory_region_ram_device_read(void *opaque,
                                               hwaddr addr, unsigned size)
 {
     MemoryRegion *mr = opaque;
-    uint64_t data = (uint64_t)~0;
-
-    switch (size) {
-    case 1:
-        data = *(uint8_t *)(mr->ram_block->host + addr);
-        break;
-    case 2:
-        data = *(uint16_t *)(mr->ram_block->host + addr);
-        break;
-    case 4:
-        data = *(uint32_t *)(mr->ram_block->host + addr);
-        break;
-    case 8:
-        data = *(uint64_t *)(mr->ram_block->host + addr);
-        break;
-    }
+    uint64_t data = ldn_he_p(mr->ram_block->host + addr, size);
 
     trace_memory_region_ram_device_read(get_cpu_index(), mr, addr, data, size);
 
@@ -1355,20 +1340,7 @@ static void memory_region_ram_device_write(void *opaque, hwaddr addr,
 
     trace_memory_region_ram_device_write(get_cpu_index(), mr, addr, data, size);
 
-    switch (size) {
-    case 1:
-        *(uint8_t *)(mr->ram_block->host + addr) = (uint8_t)data;
-        break;
-    case 2:
-        *(uint16_t *)(mr->ram_block->host + addr) = (uint16_t)data;
-        break;
-    case 4:
-        *(uint32_t *)(mr->ram_block->host + addr) = (uint32_t)data;
-        break;
-    case 8:
-        *(uint64_t *)(mr->ram_block->host + addr) = data;
-        break;
-    }
+    stn_he_p(mr->ram_block->host + addr, size, data);
 }
 
 static const MemoryRegionOps ram_device_mem_ops = {