From 811842e14234dc44b89ba2987f761f961ed10101 Mon Sep 17 00:00:00 2001
From: guillaume didier <guillaume.didier@inria.fr>
Date: Fri, 3 Apr 2020 11:24:54 +0200
Subject: [PATCH] Add abstraction over mmap

---
 cache_utils/src/calibration.rs |  8 ------
 cache_utils/src/lib.rs         |  2 ++
 cache_utils/src/main.rs        | 13 +++++-----
 cache_utils/src/mmap.rs        | 45 ++++++++++++++++++++++++++++++++++
 4 files changed, 54 insertions(+), 14 deletions(-)
 create mode 100644 cache_utils/src/mmap.rs

diff --git a/cache_utils/src/calibration.rs b/cache_utils/src/calibration.rs
index bd19543..36d6b56 100644
--- a/cache_utils/src/calibration.rs
+++ b/cache_utils/src/calibration.rs
@@ -151,14 +151,6 @@ const CFLUSH_BUCKET_NUMBER: usize = 500;
 
 const CFLUSH_NUM_ITER: u32 = 1 << 11;
 
-/* TODO Code cleanup :
-  - change type back to a slice OK
-  - change return type to return thresholds per cache line ?
-  - change iteration to be per cache line OK
-  - take the cache line size as a parameter OK
-  - parametrize 4k vs 2M ? Or just use the slice length ? OK
-*/
-
 pub fn calibrate_flush(
     array: &[u8],
     cache_line_size: usize,
diff --git a/cache_utils/src/lib.rs b/cache_utils/src/lib.rs
index deefef3..a715c1a 100644
--- a/cache_utils/src/lib.rs
+++ b/cache_utils/src/lib.rs
@@ -12,6 +12,8 @@ assert_cfg!(
 
 pub mod cache_info;
 pub mod calibration;
+#[cfg(feature = "std")]
+pub mod mmap;
 pub mod prefetcher;
 
 use core::arch::x86_64 as arch_x86;
diff --git a/cache_utils/src/main.rs b/cache_utils/src/main.rs
index dfdf770..ae65634 100644
--- a/cache_utils/src/main.rs
+++ b/cache_utils/src/main.rs
@@ -14,8 +14,7 @@ use nix::sched::{sched_getaffinity, sched_setaffinity, CpuSet};
 use nix::unistd::Pid;
 use nix::Error::Sys;
 
-use nix::sys::mman;
-use static_assertions::_core::ptr::{null_mut, slice_from_raw_parts};
+use cache_utils::mmap::MMappedMemory;
 
 /* from linux kernel headers.
 #define HUGETLB_FLAG_ENCODE_SHIFT       26
@@ -35,7 +34,7 @@ struct Page {
 }
 */
 pub fn main() {
-    let m: &[u8] = unsafe {
+    /*let array: &[u8] = unsafe {
         let p: *mut u8 = mman::mmap(
             null_mut(),
             SIZE,
@@ -55,7 +54,9 @@ pub fn main() {
         offset: off_t*/
 
         &*slice_from_raw_parts(p, SIZE)
-    };
+    };*/
+    let m = unsafe { MMappedMemory::new(SIZE) };
+    let array = m.slice();
     /*
         let p = Box::new(Page { mem: [0; 4096] });
 
@@ -71,8 +72,8 @@ pub fn main() {
 
             match sched_setaffinity(Pid::from_raw(0), &core) {
                 Ok(()) => {
-                    calibrate_flush(m, 64, Verbosity::NoOutput);
-                    calibrate_flush(m, 64, Verbosity::Thresholds);
+                    calibrate_flush(array, 64, Verbosity::NoOutput);
+                    calibrate_flush(array, 64, Verbosity::Thresholds);
                     sched_setaffinity(Pid::from_raw(0), &old).unwrap();
                     println!("Iteration {}...ok ", i);
                     eprintln!("Iteration {}...ok ", i);
diff --git a/cache_utils/src/mmap.rs b/cache_utils/src/mmap.rs
new file mode 100644
index 0000000..f02662f
--- /dev/null
+++ b/cache_utils/src/mmap.rs
@@ -0,0 +1,45 @@
+#![cfg(feature = "std")]
+
+use core::ptr::null_mut;
+use core::slice::{from_raw_parts, from_raw_parts_mut};
+use nix::sys::mman;
+
+/* from linux kernel headers.
+#define HUGETLB_FLAG_ENCODE_SHIFT       26
+#define HUGETLB_FLAG_ENCODE_MASK        0x3f
+
+#define HUGETLB_FLAG_ENCODE_64KB        (16 << HUGETLB_FLAG_ENCODE_SHIFT)
+#define HUGETLB_FLAG_ENCODE_512KB       (19 << HUGETLB_FLAG_ENCODE_SHIFT)
+#define HUGETLB_FLAG_ENCODE_1MB         (20 << HUGETLB_FLAG_ENCODE_SHIFT)
+#define HUGETLB_FLAG_ENCODE_2MB         (21 << HUGETLB_FLAG_ENCODE_SHIFT)
+*/
+
+pub struct MMappedMemory {
+    pointer: *mut u8,
+    size: usize,
+}
+
+impl MMappedMemory {
+    pub unsafe fn new(size: usize) -> MMappedMemory {
+        let p: *mut u8 = mman::mmap(
+            null_mut(),
+            size,
+            mman::ProtFlags::PROT_READ | mman::ProtFlags::PROT_WRITE,
+            mman::MapFlags::MAP_PRIVATE
+                | mman::MapFlags::MAP_ANONYMOUS
+                | mman::MapFlags::MAP_HUGETLB,
+            -1,
+            0,
+        )
+        .unwrap() as *mut u8;
+        MMappedMemory { pointer: p, size }
+    }
+
+    pub fn slice(&self) -> &[u8] {
+        unsafe { from_raw_parts(self.pointer, self.size) }
+    }
+
+    pub fn slice_mut(&self) -> &mut [u8] {
+        unsafe { from_raw_parts_mut(self.pointer, self.size) }
+    }
+}