From 26a029d407be480d791972afb5975cf62c9360a6 Mon Sep 17 00:00:00 2001
From: Daniel Baumann <daniel.baumann@progress-linux.org>
Date: Fri, 19 Apr 2024 02:47:55 +0200
Subject: Adding upstream version 124.0.1.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
---
 mfbt/TaggedAnonymousMemory.cpp | 83 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 83 insertions(+)
 create mode 100644 mfbt/TaggedAnonymousMemory.cpp

(limited to 'mfbt/TaggedAnonymousMemory.cpp')

diff --git a/mfbt/TaggedAnonymousMemory.cpp b/mfbt/TaggedAnonymousMemory.cpp
new file mode 100644
index 0000000000..382b9cef7a
--- /dev/null
+++ b/mfbt/TaggedAnonymousMemory.cpp
@@ -0,0 +1,83 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifdef XP_LINUX
+
+#  include "mozilla/TaggedAnonymousMemory.h"
+
+#  include <sys/types.h>
+#  include <sys/mman.h>
+#  include <sys/prctl.h>
+#  include <sys/syscall.h>
+#  include <unistd.h>
+
+#  include "mozilla/Assertions.h"
+
+// These constants are copied from <sys/prctl.h>, because the headers
+// used for building may not have them even though the running kernel
+// supports them.
+#  ifndef PR_SET_VMA
+#    define PR_SET_VMA 0x53564d41
+#  endif
+#  ifndef PR_SET_VMA_ANON_NAME
+#    define PR_SET_VMA_ANON_NAME 0
+#  endif
+
+namespace mozilla {
+
+// Returns 0 for success and -1 (with errno) for error.
+static int TagAnonymousMemoryAligned(const void* aPtr, size_t aLength,
+                                     const char* aTag) {
+  return prctl(PR_SET_VMA, PR_SET_VMA_ANON_NAME,
+               reinterpret_cast<unsigned long>(aPtr), aLength,
+               reinterpret_cast<unsigned long>(aTag));
+}
+
+// On some architectures, it's possible for the page size to be larger
+// than the PAGE_SIZE we were compiled with.  This computes the
+// equivalent of PAGE_MASK.
+static uintptr_t GetPageMask() {
+  static uintptr_t mask = 0;
+
+  if (mask == 0) {
+    uintptr_t pageSize = sysconf(_SC_PAGESIZE);
+    mask = ~(pageSize - 1);
+    MOZ_ASSERT((pageSize & (pageSize - 1)) == 0,
+               "Page size must be a power of 2!");
+  }
+  return mask;
+}
+
+}  // namespace mozilla
+
+void MozTagAnonymousMemory(const void* aPtr, size_t aLength, const char* aTag) {
+  // The kernel will round up the end of the range to the next page
+  // boundary if it's not aligned (comments indicate this behavior is
+  // based on that of madvise), but it will reject the request if the
+  // start is not aligned.  We therefore round down the start address
+  // and adjust the length accordingly.
+  uintptr_t addr = reinterpret_cast<uintptr_t>(aPtr);
+  uintptr_t end = addr + aLength;
+  uintptr_t addrRounded = addr & mozilla::GetPageMask();
+  const void* ptrRounded = reinterpret_cast<const void*>(addrRounded);
+
+  // Ignore the return value. TagAnonymousMemoryAligned will harmlessly fail on
+  // kernels without CONFIG_ANON_VMA_NAME.
+  mozilla::TagAnonymousMemoryAligned(ptrRounded, end - addrRounded, aTag);
+}
+
+void* MozTaggedAnonymousMmap(void* aAddr, size_t aLength, int aProt, int aFlags,
+                             int aFd, off_t aOffset, const char* aTag) {
+  void* mapped = mmap(aAddr, aLength, aProt, aFlags, aFd, aOffset);
+  if ((aFlags & MAP_ANONYMOUS) == MAP_ANONYMOUS && mapped != MAP_FAILED) {
+    // Ignore the return value. TagAnonymousMemoryAligned will harmlessly fail
+    // on kernels without CONFIG_ANON_VMA_NAME.
+    mozilla::TagAnonymousMemoryAligned(mapped, aLength, aTag);
+  }
+  return mapped;
+}
+
+#endif  // XP_LINUX
-- 
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