Configure the number of pages in the board

This permits to have portable apps.

boards/nordic/nrf52840_dongle_opensk/src/main.rs

@@ -66,7 +66,8 @@ static mut PROCESSES: [Option<&'static dyn kernel::procs::ProcessType>; NUM_PROC
 
 static mut STORAGE_LOCATIONS: [kernel::StorageLocation; 1] = [kernel::StorageLocation {
     address: 0xC0000,
-    size: 0x40000,
+    size: 0x14000, // NUM_PAGES = 20
+    unallocated_size: 0x40000, // MPU limitation
     storage_type: kernel::StorageType::STORE,
 }];
 

boards/nordic/nrf52840_mdk_dfu/src/main.rs

@@ -60,7 +60,8 @@ static mut PROCESSES: [Option<&'static dyn kernel::procs::ProcessType>; NUM_PROC
 
 static mut STORAGE_LOCATIONS: [kernel::StorageLocation; 1] = [kernel::StorageLocation {
     address: 0xC0000,
-    size: 0x40000,
+    size: 0x14000, // NUM_PAGES = 20
+    unallocated_size: 0x40000, // MPU limitation
     storage_type: kernel::StorageType::STORE,
 }];
 

boards/nordic/nrf52840dk_opensk/src/main.rs

@@ -130,7 +130,8 @@ static mut PROCESSES: [Option<&'static dyn kernel::procs::ProcessType>; NUM_PROC
 
 static mut STORAGE_LOCATIONS: [kernel::StorageLocation; 1] = [kernel::StorageLocation {
     address: 0xC0000,
-    size: 0x40000,
+    size: 0x14000, // NUM_PAGES = 20
+    unallocated_size: 0x40000, // MPU limitation
     storage_type: kernel::StorageType::STORE,
 }];
 

deploy.py

@@ -94,7 +94,7 @@
             app_ldscript="nrf52840_layout.ld",
             app_address=0x40000,
             storage_address=0xC0000,
-            storage_size=0x40000,
+            storage_size=0x14000,
             pyocd_target="nrf52840",
             openocd_board="nordic_nrf52840_dongle.cfg",
             openocd_options=[],
@@ -113,7 +113,7 @@
             app_ldscript="nrf52840_layout.ld",
             app_address=0x40000,
             storage_address=0xC0000,
-            storage_size=0x40000,
+            storage_size=0x14000,
             pyocd_target="nrf52840",
             openocd_board="nordic_nrf52840_dongle.cfg",
             openocd_options=[],
@@ -132,7 +132,7 @@
             app_ldscript="nrf52840_layout.ld",
             app_address=0x40000,
             storage_address=0xC0000,
-            storage_size=0x40000,
+            storage_size=0x14000,
             pyocd_target="nrf52840",
             openocd_board="nordic_nrf52840_dongle.cfg",
             openocd_options=[],
@@ -151,7 +151,7 @@
             app_ldscript="nrf52840_layout.ld",
             app_address=0x40000,
             storage_address=0xC0000,
-            storage_size=0x40000,
+            storage_size=0x14000,
             pyocd_target="nrf52840",
             openocd_board="nordic_nrf52840_dongle.cfg",
             openocd_options=[],

examples/erase_storage.rs

@@ -37,10 +37,10 @@ fn is_page_erased(storage: &dyn Storage, page: usize) -> bool {
 
 fn main() {
     led::get(1).flex_unwrap().on().flex_unwrap(); // red on dongle
-    const NUM_PAGES: usize = 20; // should be at least ctap::storage::NUM_PAGES
-    let mut storage = new_storage(NUM_PAGES);
-    writeln!(Console::new(), "Erase {} pages of storage:", NUM_PAGES).unwrap();
-    for page in 0..NUM_PAGES {
+    let mut storage = new_storage().unwrap();
+    let num_pages = storage.num_pages();
+    writeln!(Console::new(), "Erase {} pages of storage:", num_pages).unwrap();
+    for page in 0..num_pages {
         write!(Console::new(), "- Page {} ", page).unwrap();
         if is_page_erased(&storage, page) {
             writeln!(Console::new(), "skipped (was already erased).").unwrap();

examples/store_latency.rs

@@ -26,7 +26,7 @@ use libtock_drivers::console::Console;
 use libtock_drivers::timer::{self, Duration, Timer, Timestamp};
 use persistent_store::Store;
 
-libtock_core::stack_size! {0x800}
+libtock_core::stack_size! {0x2000}
 
 fn timestamp(timer: &Timer) -> Timestamp<f64> {
     Timestamp::<f64>::from_clock_value(timer.get_current_clock().ok().unwrap())
@@ -40,20 +40,35 @@ fn measure<T>(timer: &Timer, operation: impl FnOnce() -> T) -> (T, Duration<f64>
 }
 
 // Only use one store at a time.
-unsafe fn boot_store(num_pages: usize, erase: bool) -> Store<Storage> {
-    let mut storage = new_storage(num_pages);
+unsafe fn boot_store(erase: bool) -> Store<Storage> {
+    use persistent_store::Storage;
+    let mut storage = new_storage().unwrap();
+    let num_pages = storage.num_pages();
     if erase {
         for page in 0..num_pages {
-            use persistent_store::Storage;
             storage.erase_page(page).unwrap();
         }
     }
     Store::new(storage).ok().unwrap()
 }
 
+#[derive(Debug)]
+struct StorageConfig {
+    page_size: usize,
+    num_pages: usize,
+}
+
+fn storage_config() -> StorageConfig {
+    use persistent_store::Storage;
+    let storage = new_storage().unwrap();
+    StorageConfig {
+        page_size: storage.page_size(),
+        num_pages: storage.num_pages(),
+    }
+}
+
 #[derive(Default)]
 struct Stat {
-    num_pages: usize,
     key_increment: usize,
     entry_length: usize, // words
     boot_ms: f64,
@@ -69,7 +84,6 @@ fn compute_latency(
     word_length: usize,
 ) -> Stat {
     let mut stat = Stat {
-        num_pages,
         key_increment,
         entry_length: word_length,
         ..Default::default()
@@ -78,12 +92,12 @@ fn compute_latency(
     let mut console = Console::new();
     writeln!(
         console,
-        "\nLatency for num_pages={} key_increment={} word_length={}.",
-        num_pages, key_increment, word_length
+        "\nLatency for key_increment={} word_length={}.",
+        key_increment, word_length
     )
     .unwrap();
 
-    let mut store = unsafe { boot_store(num_pages, true) };
+    let mut store = unsafe { boot_store(true) };
     let total_capacity = store.capacity().unwrap().total();
     assert_eq!(store.capacity().unwrap().used(), 0);
     assert_eq!(store.lifetime().unwrap().used(), 0);
@@ -121,7 +135,7 @@ fn compute_latency(
     );
 
     // Measure latency of boot.
-    let (mut store, time) = measure(&timer, || unsafe { boot_store(num_pages, false) });
+    let (mut store, time) = measure(&timer, || unsafe { boot_store(false) });
     writeln!(console, "Boot: {:.1}ms.", time.ms()).unwrap();
     stat.boot_ms = time.ms();
 
@@ -150,19 +164,17 @@ fn compute_latency(
 fn main() {
     let mut with_callback = timer::with_callback(|_, _| {});
     let timer = with_callback.init().ok().unwrap();
+    let config = storage_config();
     let mut stats = Vec::new();
 
-    writeln!(Console::new(), "\nRunning 4 tests...").unwrap();
-    // Those non-overwritten 50 words entries simulate credentials.
-    stats.push(compute_latency(&timer, 3, 1, 50));
-    stats.push(compute_latency(&timer, 20, 1, 50));
-    // Those overwritten 1 word entries simulate counters.
-    stats.push(compute_latency(&timer, 3, 0, 1));
-    stats.push(compute_latency(&timer, 20, 0, 1));
+    writeln!(Console::new(), "\nRunning 2 tests...").unwrap();
+    // Simulate a store full of credentials (of 50 words).
+    stats.push(compute_latency(&timer, config.num_pages, 1, 50));
+    // Simulate a store full of increments of a single counter.
+    stats.push(compute_latency(&timer, config.num_pages, 0, 1));
     writeln!(Console::new(), "\nDone.\n").unwrap();
 
     const HEADERS: &[&str] = &[
-        "Pages",
         "Overwrite",
         "Length",
         "Boot",
@@ -173,7 +185,6 @@ fn main() {
     let mut matrix = vec![HEADERS.iter().map(|x| x.to_string()).collect()];
     for stat in stats {
         matrix.push(vec![
-            format!("{}", stat.num_pages),
             if stat.key_increment == 0 { "yes" } else { "no" }.to_string(),
             format!("{} words", stat.entry_length),
             format!("{:.1} ms", stat.boot_ms),
@@ -182,14 +193,15 @@ fn main() {
             format!("{:.1} ms", stat.remove_ms),
         ]);
     }
+    writeln!(Console::new(), "Copy to examples/store_latency.rs:\n").unwrap();
+    writeln!(Console::new(), "{:?}", config).unwrap();
     write_matrix(matrix);
 
-    // Results on nrf52840dk_opensk:
-    // Pages  Overwrite    Length      Boot  Compaction   Insert  Remove
-    //     3         no  50 words    5.3 ms    141.9 ms   8.0 ms  3.3 ms
-    //    20         no  50 words   18.7 ms    148.6 ms   21.0 ms 9.8 ms
-    //     3        yes   1 words   37.8 ms    100.2 ms   11.3 ms 5.5 ms
-    //    20        yes   1 words  336.5 ms    100.3 ms   11.5 ms 5.6 ms
+    // Results for nrf52840dk_opensk:
+    // StorageConfig { page_size: 4096, num_pages: 20 }
+    // Overwrite    Length      Boot  Compaction   Insert  Remove
+    //        no  50 words   16.2 ms    143.8 ms  18.3 ms  8.4 ms
+    //       yes   1 words  303.8 ms     97.9 ms   9.7 ms  4.7 ms
 }
 
 fn align(x: &str, n: usize) {

patches/tock/01-persistent-storage.patch

@@ -349,7 +349,7 @@ index 348c746a5..5465c95f4 100644
      }
  }
 diff --git a/kernel/src/process.rs b/kernel/src/process.rs
-index c52754be3..ae6a58341 100644
+index c52754be3..26a7c47d3 100644
 --- a/kernel/src/process.rs
 +++ b/kernel/src/process.rs
 @@ -359,6 +359,15 @@ pub trait ProcessType {
@@ -415,7 +415,7 @@ index c52754be3..ae6a58341 100644
 +                .mpu()
 +                .allocate_region(
 +                    storage_location.address as *const u8,
-+                    storage_location.size,
++                    storage_location.unallocated_size,
 +                    storage_location.size,
 +                    mpu::Permissions::ReadOnly,
 +                    &mut mpu_config,
@@ -439,23 +439,24 @@ index c52754be3..ae6a58341 100644
          // memory space just for kernel and grant state. We need to make
          // sure we allocate enough memory just for that.
 diff --git a/kernel/src/sched.rs b/kernel/src/sched.rs
-index 10626a2e1..8844bc6c3 100644
+index 10626a2e1..61401b04a 100644
 --- a/kernel/src/sched.rs
 +++ b/kernel/src/sched.rs
-@@ -118,6 +118,12 @@ pub enum SchedulingDecision {
+@@ -118,6 +118,13 @@ pub enum SchedulingDecision {
      TrySleep,
  }
 
 +/// Represents a storage location in flash.
 +pub struct StorageLocation {
 +    pub address: usize,
 +    pub size: usize,
++    pub unallocated_size: usize,
 +}
 +
  /// Main object for the kernel. Each board will need to create one.
  pub struct Kernel {
      /// How many "to-do" items exist at any given time. These include
-@@ -127,6 +133,9 @@ pub struct Kernel {
+@@ -127,6 +134,9 @@ pub struct Kernel {
      /// This holds a pointer to the static array of Process pointers.
      processes: &'static [Option<&'static dyn process::ProcessType>],
 
@@ -465,7 +466,7 @@ index 10626a2e1..8844bc6c3 100644
      /// A counter which keeps track of how many process identifiers have been
      /// created. This is used to create new unique identifiers for processes.
      process_identifier_max: Cell<usize>,
-@@ -170,9 +179,17 @@ pub enum StoppedExecutingReason {
+@@ -170,9 +180,17 @@ pub enum StoppedExecutingReason {
 
  impl Kernel {
      pub fn new(processes: &'static [Option<&'static dyn process::ProcessType>]) -> Kernel {
@@ -483,7 +484,7 @@ index 10626a2e1..8844bc6c3 100644
              process_identifier_max: Cell::new(0),
              grant_counter: Cell::new(0),
              grants_finalized: Cell::new(false),
-@@ -900,4 +917,8 @@ impl Kernel {
+@@ -900,4 +918,8 @@ impl Kernel {
 
          (return_reason, time_executed_us)
      }

patches/tock/06-upgrade-partitions.patch

@@ -31,10 +31,10 @@ index 5465c95f4..e596648f7 100644
      }
  }
 diff --git a/kernel/src/sched.rs b/kernel/src/sched.rs
-index 031159500..0cbfea929 100644
+index 61401b04a..e9a58c018 100644
 --- a/kernel/src/sched.rs
 +++ b/kernel/src/sched.rs
-@@ -118,10 +118,19 @@ pub enum SchedulingDecision {
+@@ -118,11 +118,20 @@ pub enum SchedulingDecision {
      TrySleep,
  }
 
@@ -50,6 +50,7 @@ index 031159500..0cbfea929 100644
  pub struct StorageLocation {
      pub address: usize,
      pub size: usize,
+     pub unallocated_size: usize,
 +    pub storage_type: StorageType,
  }
 

src/ctap/customization.rs

@@ -219,23 +219,10 @@ pub const MAX_RP_IDS_LENGTH: usize = 8;
 ///
 /// - The storage key CREDENTIALS must fit at least this number of credentials.
 ///
-/// This value has implications on the flash lifetime, please see the
-/// documentation for NUM_PAGES below.
-pub const MAX_SUPPORTED_RESIDENT_KEYS: usize = 150;
-
-/// Sets the number of pages used for persistent storage.
-///
-/// The number of pages should be at least 3 and at most what the flash can
-/// hold. There should be no reason to put a small number here, except that the
-/// latency of flash operations is linear in the number of pages. This may
-/// improve in the future. Currently, using 20 pages gives between 20ms and
-/// 240ms per operation. The rule of thumb is between 1ms and 12ms per
-/// additional page.
-///
 /// Limiting the number of resident keys permits to ensure a minimum number of
 /// counter increments.
 /// Let:
-/// - P the number of pages (NUM_PAGES)
+/// - P the number of pages (NUM_PAGES in the board definition)
 /// - K the maximum number of resident keys (MAX_SUPPORTED_RESIDENT_KEYS)
 /// - S the maximum size of a resident key (about 500)
 /// - C the number of erase cycles (10000)
@@ -245,7 +232,7 @@ pub const MAX_SUPPORTED_RESIDENT_KEYS: usize = 150;
 ///
 /// With P=20 and K=150, we have I=2M which is enough for 500 increments per day
 /// for 10 years.
-pub const NUM_PAGES: usize = 20;
+pub const MAX_SUPPORTED_RESIDENT_KEYS: usize = 150;
 
 #[cfg(test)]
 mod test {

src/ctap/storage.rs

@@ -18,7 +18,6 @@ use crate::ctap::client_pin::PIN_AUTH_LENGTH;
 use crate::ctap::customization::{
     DEFAULT_MIN_PIN_LENGTH, DEFAULT_MIN_PIN_LENGTH_RP_IDS, ENFORCE_ALWAYS_UV,
     MAX_LARGE_BLOB_ARRAY_SIZE, MAX_PIN_RETRIES, MAX_RP_IDS_LENGTH, MAX_SUPPORTED_RESIDENT_KEYS,
-    NUM_PAGES,
 };
 use crate::ctap::data_formats::{
     extract_array, extract_text_string, CredentialProtectionPolicy, PublicKeyCredentialSource,
@@ -68,7 +67,7 @@ impl PersistentStore {
     ///
     /// This should be at most one instance of persistent store per program lifetime.
     pub fn new(rng: &mut impl Rng256) -> PersistentStore {
-        let storage = new_storage(NUM_PAGES);
+        let storage = new_storage().ok().unwrap();
         let mut store = PersistentStore {
             store: persistent_store::Store::new(storage).ok().unwrap(),
         };

src/embedded_flash/mod.rs

@@ -28,8 +28,8 @@ mod prod {
 
     pub type Storage = SyscallStorage;
 
-    pub fn new_storage(num_pages: usize) -> Storage {
-        Storage::new(num_pages).unwrap()
+    pub fn new_storage() -> persistent_store::StorageResult<Storage> {
+        Storage::new()
     }
 
     pub type UpgradeLocations = SyscallUpgradeStorage;
@@ -44,17 +44,19 @@ mod test {
 
     pub type Storage = persistent_store::BufferStorage;
 
-    pub fn new_storage(num_pages: usize) -> Storage {
+    pub fn new_storage() -> persistent_store::StorageResult<Storage> {
+        // Use the Nordic configuration.
         const PAGE_SIZE: usize = 0x1000;
-        let store = vec![0xff; num_pages * PAGE_SIZE].into_boxed_slice();
+        const NUM_PAGES: usize = 20;
+        let store = vec![0xff; NUM_PAGES * PAGE_SIZE].into_boxed_slice();
         let options = persistent_store::BufferOptions {
             word_size: 4,
             page_size: PAGE_SIZE,
             max_word_writes: 2,
             max_page_erases: 10000,
             strict_mode: true,
         };
-        Storage::new(store, options)
+        Ok(Storage::new(store, options))
     }
 
     pub type UpgradeLocations = BufferUpgradeStorage;