[libc-commits] [libc] [libc][SysMMan] implement mincore (PR #73704)

Schrodinger ZHU Yifan via libc-commits libc-commits at lists.llvm.org
Tue Nov 28 14:00:44 PST 2023


https://github.com/SchrodingerZhu updated https://github.com/llvm/llvm-project/pull/73704

>From 64ff01e3882aabec212ac1133bcc47b9d0f3372e Mon Sep 17 00:00:00 2001
From: Schrodinger ZHU Yifan <yifanzhu at rochester.edu>
Date: Tue, 28 Nov 2023 16:57:01 -0500
Subject: [PATCH] [libc][SysMMan] implement mincore

---
 libc/config/linux/aarch64/entrypoints.txt     |  1 +
 libc/config/linux/riscv/entrypoints.txt       |  1 +
 libc/config/linux/x86_64/entrypoints.txt      |  1 +
 libc/spec/linux.td                            | 15 ++-
 libc/spec/spec.td                             |  2 +
 libc/src/sys/mman/CMakeLists.txt              |  7 ++
 libc/src/sys/mman/linux/CMakeLists.txt        | 13 +++
 libc/src/sys/mman/linux/mincore.cpp           | 28 ++++++
 libc/src/sys/mman/mincore.h                   | 20 ++++
 libc/test/src/sys/mman/linux/CMakeLists.txt   | 16 +++
 libc/test/src/sys/mman/linux/mincore_test.cpp | 98 +++++++++++++++++++
 11 files changed, 201 insertions(+), 1 deletion(-)
 create mode 100644 libc/src/sys/mman/linux/mincore.cpp
 create mode 100644 libc/src/sys/mman/mincore.h
 create mode 100644 libc/test/src/sys/mman/linux/mincore_test.cpp

diff --git a/libc/config/linux/aarch64/entrypoints.txt b/libc/config/linux/aarch64/entrypoints.txt
index 284feb7b99096ec..941c1e04ea20b6f 100644
--- a/libc/config/linux/aarch64/entrypoints.txt
+++ b/libc/config/linux/aarch64/entrypoints.txt
@@ -136,6 +136,7 @@ set(TARGET_LIBC_ENTRYPOINTS
     libc.src.sys.mman.mprotect
     libc.src.sys.mman.munmap
     libc.src.sys.mman.posix_madvise
+    libc.src.sys.mman.mincore
 
     # sys/random.h entrypoints
     libc.src.sys.random.getrandom
diff --git a/libc/config/linux/riscv/entrypoints.txt b/libc/config/linux/riscv/entrypoints.txt
index a5f0c91e32d0810..5849dd68cc03263 100644
--- a/libc/config/linux/riscv/entrypoints.txt
+++ b/libc/config/linux/riscv/entrypoints.txt
@@ -142,6 +142,7 @@ set(TARGET_LIBC_ENTRYPOINTS
     libc.src.sys.mman.mprotect
     libc.src.sys.mman.munmap
     libc.src.sys.mman.posix_madvise
+    libc.src.sys.mman.mincore
 
     # sys/random.h entrypoints
     libc.src.sys.random.getrandom
diff --git a/libc/config/linux/x86_64/entrypoints.txt b/libc/config/linux/x86_64/entrypoints.txt
index 63aa7473115a08e..dbac381a64e87be 100644
--- a/libc/config/linux/x86_64/entrypoints.txt
+++ b/libc/config/linux/x86_64/entrypoints.txt
@@ -142,6 +142,7 @@ set(TARGET_LIBC_ENTRYPOINTS
     libc.src.sys.mman.mprotect
     libc.src.sys.mman.munmap
     libc.src.sys.mman.posix_madvise
+    libc.src.sys.mman.mincore
 
     # sys/random.h entrypoints
     libc.src.sys.random.getrandom
diff --git a/libc/spec/linux.td b/libc/spec/linux.td
index ba5f99c12ecd116..eab0a987b920cd9 100644
--- a/libc/spec/linux.td
+++ b/libc/spec/linux.td
@@ -76,7 +76,20 @@ def Linux : StandardSpec<"Linux"> {
 
   HeaderSpec SysMMan = HeaderSpec<
       "sys/mman.h",
-      [Macro<"MAP_ANONYMOUS">]
+      [Macro<"MAP_ANONYMOUS">],
+      [], // Types
+      [], // Enumerations
+      [
+        FunctionSpec<
+            "mincore",
+            RetValSpec<IntType>,
+            [
+              ArgSpec<VoidPtr>,
+              ArgSpec<SizeTType>,
+              ArgSpec<UnsignedCharPtr>,
+            ]
+        >,
+      ]  // Functions
   >;
 
 
diff --git a/libc/spec/spec.td b/libc/spec/spec.td
index b0d5511a4f087ee..3df3fc30f5e2b58 100644
--- a/libc/spec/spec.td
+++ b/libc/spec/spec.td
@@ -49,6 +49,7 @@ def FloatType : NamedType<"float">;
 def DoubleType : NamedType<"double">;
 def LongDoubleType : NamedType<"long double">;
 def CharType : NamedType<"char">;
+def UnsignedCharType : NamedType<"unsigned char">;
 
 // TODO: Add compatibility layer to use C23 type _Float128 if possible.
 def Float128Type : NamedType<"__float128">;
@@ -109,6 +110,7 @@ def IntPtr : PtrType<IntType>;
 def RestrictedIntPtr : RestrictedPtrType<IntType>;
 def FloatPtr : PtrType<FloatType>;
 def DoublePtr : PtrType<DoubleType>;
+def UnsignedCharPtr : PtrType<UnsignedCharType>;
 
 def SigHandlerT : NamedType<"__sighandler_t">;
 
diff --git a/libc/src/sys/mman/CMakeLists.txt b/libc/src/sys/mman/CMakeLists.txt
index e336bfd5d6dbc6e..2d17429a26b457b 100644
--- a/libc/src/sys/mman/CMakeLists.txt
+++ b/libc/src/sys/mman/CMakeLists.txt
@@ -36,3 +36,10 @@ add_entrypoint_object(
   DEPENDS
     .${LIBC_TARGET_OS}.posix_madvise
 )
+
+add_entrypoint_object(
+  mincore
+  ALIAS
+  DEPENDS
+    .${LIBC_TARGET_OS}.mincore
+)
diff --git a/libc/src/sys/mman/linux/CMakeLists.txt b/libc/src/sys/mman/linux/CMakeLists.txt
index 163e7dead8887ab..ce0cda7f2227708 100644
--- a/libc/src/sys/mman/linux/CMakeLists.txt
+++ b/libc/src/sys/mman/linux/CMakeLists.txt
@@ -61,3 +61,16 @@ add_entrypoint_object(
     libc.include.sys_syscall
     libc.src.__support.OSUtil.osutil
 )
+
+add_entrypoint_object(
+  mincore
+  SRCS
+    mincore.cpp
+  HDRS
+    ../mincore.h
+  DEPENDS
+    libc.include.sys_mman
+    libc.include.sys_syscall
+    libc.src.__support.OSUtil.osutil
+    libc.src.errno.errno
+)
diff --git a/libc/src/sys/mman/linux/mincore.cpp b/libc/src/sys/mman/linux/mincore.cpp
new file mode 100644
index 000000000000000..8220c69ef2cb77c
--- /dev/null
+++ b/libc/src/sys/mman/linux/mincore.cpp
@@ -0,0 +1,28 @@
+//===---------- Linux implementation of the mincore function --------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "src/sys/mman/mincore.h"
+
+#include "src/__support/OSUtil/syscall.h" // For internal syscall function.
+
+#include "src/errno/libc_errno.h"
+#include <sys/syscall.h> // For syscall numbers.
+
+namespace LIBC_NAMESPACE {
+
+LLVM_LIBC_FUNCTION(int, mincore, (void *addr, size_t len, unsigned char *vec)) {
+  long ret = syscall_impl(SYS_mincore, reinterpret_cast<long>(addr), len,
+                          reinterpret_cast<long>(vec));
+  if (ret < 0) {
+    libc_errno = static_cast<int>(-ret);
+    return -1;
+  }
+  return 0;
+}
+
+} // namespace LIBC_NAMESPACE
diff --git a/libc/src/sys/mman/mincore.h b/libc/src/sys/mman/mincore.h
new file mode 100644
index 000000000000000..403afaeb6af970c
--- /dev/null
+++ b/libc/src/sys/mman/mincore.h
@@ -0,0 +1,20 @@
+//===-- Implementation header for mincore function --------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIBC_SRC_SYS_MMAN_MINCORE_H
+#define LLVM_LIBC_SRC_SYS_MMAN_MINCORE_H
+
+#include <sys/mman.h> // For size_t
+
+namespace LIBC_NAMESPACE {
+
+int mincore(void *addr, size_t len, unsigned char *vec);
+
+} // namespace LIBC_NAMESPACE
+
+#endif // LLVM_LIBC_SRC_SYS_MMAN_MINCORE_H
diff --git a/libc/test/src/sys/mman/linux/CMakeLists.txt b/libc/test/src/sys/mman/linux/CMakeLists.txt
index 66743be175fed1d..5402ae030b345c6 100644
--- a/libc/test/src/sys/mman/linux/CMakeLists.txt
+++ b/libc/test/src/sys/mman/linux/CMakeLists.txt
@@ -62,3 +62,19 @@ add_libc_unittest(
     libc.src.sys.mman.posix_madvise
     libc.test.UnitTest.ErrnoSetterMatcher
 )
+
+add_libc_unittest(
+  mincore_test
+  SUITE
+    libc_sys_mman_unittests
+  SRCS
+    mincore_test.cpp
+  DEPENDS
+    libc.include.sys_mman
+    libc.src.errno.errno
+    libc.src.sys.mman.mmap
+    libc.src.sys.mman.munmap
+    libc.src.sys.mman.madvise
+    libc.src.sys.mman.mincore
+    libc.test.UnitTest.ErrnoSetterMatcher
+)
diff --git a/libc/test/src/sys/mman/linux/mincore_test.cpp b/libc/test/src/sys/mman/linux/mincore_test.cpp
new file mode 100644
index 000000000000000..729f2909dd9b296
--- /dev/null
+++ b/libc/test/src/sys/mman/linux/mincore_test.cpp
@@ -0,0 +1,98 @@
+//===-- Unittests for mincore ---------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "src/errno/libc_errno.h"
+#include "src/sys/mman/madvise.h"
+#include "src/sys/mman/mincore.h"
+#include "src/sys/mman/mmap.h"
+#include "src/sys/mman/munmap.h"
+#include "test/UnitTest/ErrnoSetterMatcher.h"
+#include "test/UnitTest/LibcTest.h"
+#include "test/UnitTest/Test.h"
+
+#include <linux/param.h> // For EXEC_PAGESIZE
+#include <sys/mman.h>
+
+using LIBC_NAMESPACE::testing::ErrnoSetterMatcher::Fails;
+using LIBC_NAMESPACE::testing::ErrnoSetterMatcher::Succeeds;
+
+TEST(LlvmLibcMincoreTest, UnMappedMemory) {
+  libc_errno = 0;
+  unsigned char vec;
+  int res = LIBC_NAMESPACE::mincore(nullptr, 1, &vec);
+  EXPECT_THAT(res, Fails(ENOMEM, -1));
+}
+
+TEST(LlvmLibcMincoreTest, InvalidVec) {
+  void *addr = LIBC_NAMESPACE::mmap(nullptr, EXEC_PAGESIZE, PROT_READ,
+                                    MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
+  EXPECT_NE(addr, MAP_FAILED);
+  EXPECT_EQ(reinterpret_cast<unsigned long>(addr) % EXEC_PAGESIZE, 0ul);
+  libc_errno = 0;
+  int res = LIBC_NAMESPACE::mincore(addr, 1, nullptr);
+  EXPECT_THAT(res, Fails(EFAULT, -1));
+  EXPECT_THAT(LIBC_NAMESPACE::munmap(addr, EXEC_PAGESIZE), Succeeds());
+}
+
+TEST(LlvmLibcMincoreTest, UnalignedAddr) {
+  void *addr = LIBC_NAMESPACE::mmap(nullptr, EXEC_PAGESIZE, PROT_READ,
+                                    MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
+  EXPECT_NE(addr, MAP_FAILED);
+  EXPECT_EQ(reinterpret_cast<unsigned long>(addr) % EXEC_PAGESIZE, 0ul);
+  libc_errno = 0;
+  int res = LIBC_NAMESPACE::mincore(static_cast<char *>(addr) + 1, 1, nullptr);
+  EXPECT_THAT(res, Fails(EINVAL, -1));
+  EXPECT_THAT(LIBC_NAMESPACE::munmap(addr, EXEC_PAGESIZE), Succeeds());
+}
+
+TEST(LlvmLibcMincoreTest, NoError) {
+  void *addr = LIBC_NAMESPACE::mmap(nullptr, EXEC_PAGESIZE, PROT_READ,
+                                    MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
+  EXPECT_NE(addr, MAP_FAILED);
+  EXPECT_EQ(reinterpret_cast<unsigned long>(addr) % EXEC_PAGESIZE, 0ul);
+  unsigned char vec;
+  libc_errno = 0;
+  int res = LIBC_NAMESPACE::mincore(static_cast<char *>(addr), 1, &vec);
+  EXPECT_THAT(res, Succeeds());
+  EXPECT_THAT(LIBC_NAMESPACE::munmap(addr, EXEC_PAGESIZE), Succeeds());
+}
+
+#if defined(MADV_PAGEOUT)
+TEST(LlvmLibcMincoreTest, PageOut) {
+  unsigned char vec;
+  void *addr =
+      LIBC_NAMESPACE::mmap(nullptr, EXEC_PAGESIZE, PROT_READ | PROT_WRITE,
+                           MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
+  EXPECT_NE(addr, MAP_FAILED);
+  EXPECT_EQ(reinterpret_cast<unsigned long>(addr) % EXEC_PAGESIZE, 0ul);
+
+  // touch the page
+  {
+    static_cast<char *>(addr)[0] = 0;
+    libc_errno = 0;
+    int res = LIBC_NAMESPACE::mincore(static_cast<char *>(addr), 1, &vec);
+    EXPECT_EQ(vec, static_cast<unsigned char>(1));
+    EXPECT_THAT(res, Succeeds());
+  }
+
+  // page out the memory
+  {
+    libc_errno = 0;
+    EXPECT_THAT(LIBC_NAMESPACE::madvise(addr, EXEC_PAGESIZE, MADV_PAGEOUT),
+                Succeeds());
+
+    libc_errno = 0;
+    int res =
+        LIBC_NAMESPACE::mincore(static_cast<char *>(addr), EXEC_PAGESIZE, &vec);
+    EXPECT_EQ(vec, static_cast<unsigned char>(0));
+    EXPECT_THAT(res, Succeeds());
+  }
+
+  EXPECT_THAT(LIBC_NAMESPACE::munmap(addr, EXEC_PAGESIZE), Succeeds());
+}
+#endif



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