Sync L3 headers in sc-dev

Merge of these CLs from Widevine sc-dev:

modified:   libwvdrmengine/level3/include/clear_cache_function.h
  Add cache flush assembly for arm64 L3 to Android header | http://go/wvgerrit/124828
  Address compilation errors | http://go/wvgerrit/113083

modified:   libwvdrmengine/level3/include/level3_file_system_android.h
  Update Widevine Copyright header for android | http://go/wvgerrit/108084

Bug: 184866351
Test: Header changes for clearing cache is verified by one of the partners on their arm64 target;
https: //b.corp.google.com/issues/175432203#comment13

Change-Id: I0ac8f339f65d02abb3080020fbc715b9c0db85b2

libwvdrmengine/level3/include/clear_cache_function.h

@@ -1,6 +1,8 @@
 #include <errno.h>
 #include <stdio.h>
 #include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
 
 #include <linux/membarrier.h>
 #include <sys/syscall.h>
@@ -71,17 +73,19 @@ void clear_cache_function(void *page, size_t len) {
   // So, instead, we will define USED_BUILTIN_CLEAR_CACHE if both conditions
   // are true, and use "#ifndef  USED_BUILTIN_CLEAR_CACHE" instead of #else.
 #ifdef __has_builtin
-#if __has_builtin(__builtin___clear_cache)
-#pragma message "(info): clear_cache_function is using __builtin___clear_cache."
-#define USED_BUILTIN_CLEAR_CACHE
+#  if __has_builtin(__builtin___clear_cache)
+#    pragma message "(info): clear_cache_function is using __builtin___clear_cache."
+#      define USED_BUILTIN_CLEAR_CACHE
   char *begin = static_cast<char *>(page);
   char *end = begin + len;
   __builtin___clear_cache(begin, end);
+#  endif
 #endif
-#endif
+
 #ifndef USED_BUILTIN_CLEAR_CACHE
-#if __arm__
-#pragma message "(info): clear_cache_function is using arm asm."
+#  if defined(__arm__)
+#    pragma message "(info): clear_cache_function is using arm asm."
+#      define USED_ARM_ASM_CLEAR_CACHE
   // ARM Cache Flush System Call:
   char *begin = static_cast<char *>(page);
   char *end = begin + len;
@@ -97,25 +101,49 @@ void clear_cache_function(void *page, size_t len) {
       :
       : "r"(begin), "r"(end), "r"(syscall)
       : "r0", "r1", "r7");
-#elif __mips__
-#pragma message "(info): clear_cache_function is using mips asm."
+#  elif defined(__aarch64__)
+#    pragma message "(info): clear_cache_function is using arm64 asm."
+#      define USED_ARM_ASM_CLEAR_CACHE
+  uint64_t begin = static_cast<uint64_t>(reinterpret_cast<uintptr_t>(page));
+  uint64_t end = begin + len;
+  register uint64_t ctr_el0;
+  __asm __volatile("mrs %0, ctr_el0" : "=r"(ctr_el0));
+  // register CTR_EL0 [19:16] contains dcache line size
+  const size_t dcache_line_size = 4 << ((ctr_el0 >> 16) & 0xF);
+  register uint64_t addr;
+  for (addr = begin; addr < end; addr += dcache_line_size) {
+    __asm __volatile("dc cvau, %0" ::"r"(addr));
+  }
+  __asm __volatile("dsb ish");
+  //  register CTR_EL0 [3:0] contains icache line size
+  const size_t icache_line_size = 4 << (ctr_el0 & 0xF);
+  for (addr = begin; addr < end; addr += icache_line_size) {
+    __asm __volatile("ic ivau, %0" ::"r"(addr));
+  }
+  __asm __volatile("dsb ish");
+  __asm __volatile("isb sy");
+#  elif __mips__
+#    pragma message "(info): clear_cache_function is using mips asm."
   int result = syscall(__NR_cacheflush, page, len, ICACHE);
   if (result) {
     fprintf(stderr, "cacheflush failed!: errno=%d %s\n", errno,
             strerror(errno));
     exit(-1);  // TODO(fredgc): figure out more graceful error handling.
   }
-#else
-#pragma message "(info): clear_cache_function is not doing anything."
+#  else
+#    pragma message "(info): clear_cache_function is not doing anything."
   // TODO(fredgc): silence warning about unused variables.
-#endif
+#  endif
 #endif
 
 #if defined(__arm__) || defined(__aarch64__)
+#  if !defined(USED_BUILTIN_CLEAR_CACHE) && !defined(USED_ARM_ASM_CLEAR_CACHE)
+#    error "clear cache function unavailable, which is required for ARM."
+#  endif
 #  pragma message "(info): inserting membarrier_function calls."
   membarrier_function(MEMBARRIER_CMD_REGISTER_PRIVATE_EXPEDITED_SYNC_CORE);
   membarrier_function(MEMBARRIER_CMD_PRIVATE_EXPEDITED_SYNC_CORE);
 #endif  // defined(__arm__) || defined(__aarch64__)
 }
 
-}  // namespace wvoec3
+}  // namespace wvoec3

libwvdrmengine/level3/include/level3_file_system_android.h

@@ -1,6 +1,6 @@
 // Copyright 2018 Google LLC. All Rights Reserved. This file and proprietary
-// source code may only be used and distributed under the Widevine Master
-// License Agreement.
+// source code may only be used and distributed under the Widevine License
+// Agreement.
 
 /*********************************************************************
  * level3_file_system_android.h