rtc stuff

4 files changed, 113 insertions, 20 deletions

diff --git a/src/efi/mod.rs b/src/efi/mod.rs
index b6bea0e..c4f4750 100644
--- a/src/efi/mod.rs
+++ b/src/efi/mod.rs
@@ -7,6 +7,7 @@ use crate::efi::configtable::ConfigurationTable;
 use crate::efi::loadedimage::EFI_LOADED_IMAGE_PROTOCOL_GUID;
 use crate::efi::memmap::*;
 use crate::efi::runtimeservices::RuntimeServices;
+use crate::efi::runtimeservices::GetTime;
 use crate::efi::MemoryType::*;
 use crate::efi::{loadedimage::*, memorytype::*, systemtable::*};
 use crate::PeImage;
@@ -37,7 +38,7 @@ pub mod memmap;
 pub mod memorytype;
 pub mod peloader;
 pub mod rng;
-mod runtimeservices;
+pub mod runtimeservices;
 mod simpletext;
 pub mod status;
 mod systemtable;
@@ -117,6 +118,7 @@ pub const EFI_MEMORY_ATTRIBUTES_TABLE_GUID: Guid = guid!(
 );
 
 const EFI_RT_SUPPORTED_GET_TIME: u32 = 0x0001;
+const EFI_RT_SUPPORTED_SET_TIME: u32 = 0x0002;
 const EFI_RT_SUPPORTED_GET_VARIABLE: u32 = 0x0010;
 const EFI_RT_SUPPORTED_GET_NEXT_VARIABLE_NAME: u32 = 0x0020;
 const EFI_RT_SUPPORTED_RESET_SYSTEM: u32 = 0x0400;
@@ -132,6 +134,7 @@ static RT_PROPERTIES_TABLE: RtPropertiesTable = RtPropertiesTable {
     version: 1,
     length: core::mem::size_of::<RtPropertiesTable>() as _,
     supported_mask: EFI_RT_SUPPORTED_GET_TIME
+        | EFI_RT_SUPPORTED_SET_TIME
         | EFI_RT_SUPPORTED_GET_VARIABLE
         | EFI_RT_SUPPORTED_GET_NEXT_VARIABLE_NAME
         | EFI_RT_SUPPORTED_RESET_SYSTEM,
@@ -201,7 +204,7 @@ pub struct EfiContext {
     configtable_db: Spinlock<BTreeMap<Guid, ConfigurationTable>>,
 
     _bs: Pin<Box<BootServices>>,
-    _rt: &'static RuntimeServices,
+    rt: Spinlock<&'static mut RuntimeServices>,
     sys_table: Spinlock<&'static mut SystemTable>,
 }
 
@@ -232,7 +235,7 @@ pub fn init() -> Result<&'static EfiContext, ()> {
             rtsdata: h,
             configtable_db: Spinlock::new(BTreeMap::new()),
             _bs: bs,
-            _rt: rt,
+            rt: Spinlock::new(rt),
             sys_table: Spinlock::new(st),
         }))
     });
@@ -285,4 +288,8 @@ impl EfiContext {
             randomized,
         )
     }
+
+    pub fn set_rtc_override(&self, f: GetTime) {
+        self.rt.lock().get_time = f;
+    }
 }
diff --git a/src/efi/runtimeservices.rs b/src/efi/runtimeservices.rs
index 8aa438e..80294fa 100644
--- a/src/efi/runtimeservices.rs
+++ b/src/efi/runtimeservices.rs
@@ -7,23 +7,24 @@ use crate::efi::{memorytype::*, status::*, tableheader::*};
 use crate::efi::{Bool, Char16, Guid, PhysicalAddress};
 use crate::psci;
 
+#[derive(Debug)]
 #[repr(C)]
-struct Time {
-    year: u16,
-    month: u8,
-    date: u8,
-    hour: u8,
-    minute: u8,
-    second: u8,
-    pad1: u8,
-    nanosecond: u32,
-    timezone: u16,
-    daylight: u8,
-    pad2: u8,
+pub struct Time {
+    pub year: u16,
+    pub month: u8,
+    pub day: u8,
+    pub hour: u8,
+    pub minute: u8,
+    pub second: u8,
+    pub pad1: u8,
+    pub nanosecond: u32,
+    pub timezone: u16,
+    pub daylight: u8,
+    pub pad2: u8,
 }
 
 #[repr(C)]
-struct TimeCapabilities {
+pub struct TimeCapabilities {
     resolution: u32,
     accuracy: u32,
     sets_to_zero: Bool,
@@ -46,7 +47,7 @@ struct CapsuleHeader {
     capsule_image_size: u32,
 }
 
-type GetTime = extern "C" fn(_time: *mut Time, _capabilities: *mut TimeCapabilities) -> Status;
+pub(super) type GetTime = extern "C" fn(_time: *mut Time, _capabilities: *mut TimeCapabilities) -> Status;
 
 type SetTime = extern "C" fn(_time: *const Time) -> Status;
 
@@ -118,7 +119,7 @@ type QueryVariableInfo = extern "C" fn(
 #[repr(C)]
 pub struct RuntimeServices {
     hdr: TableHeader,
-    get_time: GetTime,
+    pub get_time: GetTime,
     set_time: SetTime,
     get_wakeup_time: GetWakeupTime,
     set_wakeup_time: SetWakeupTime,
diff --git a/src/main.rs b/src/main.rs
index 9999166..12ff4b5 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -25,6 +25,7 @@ mod idmap;
 mod initrd;
 mod pagealloc;
 mod paging;
+mod pl031;
 mod psci;
 mod rng;
 
@@ -44,9 +45,9 @@ use crate::efi::FileLoader;
 use crate::efi::{guid, Guid};
 use crate::paging::Attributes;
 use crate::MemoryType::EfiBootServicesData;
+use crate::MemoryType::EfiMemoryMappedIO;
 use crate::MemoryType::EfiRuntimeServicesCode;
 use crate::MemoryType::EfiRuntimeServicesData;
-use crate::MemoryType::EfiMemoryMappedIO;
 
 #[macro_use]
 extern crate bitflags;
@@ -166,7 +167,9 @@ extern "C" fn efilite_main(base: *mut u8, mapped: usize, used: isize, avail: usi
         pl031_node.reg().map(|mut r| {
             let b = r.nth(0)?.starting_address;
             let s = unsafe { slice::from_raw_parts(b as *const u8, EFI_PAGE_MASK + 1) };
-            efi::memmap::declare_runtime_region(s, EfiMemoryMappedIO).ok()
+            efi::memmap::declare_runtime_region(s, EfiMemoryMappedIO).ok();
+            pl031::init(b as usize);
+            Some(efi.set_rtc_override(pl031::get_time))
         });
     } else {
         debug!("ACPI tables unavailable: {}\n", tbl.err().unwrap());
diff --git a/src/pl031.rs b/src/pl031.rs
new file mode 100644
index 0000000..83429d2
--- /dev/null
+++ b/src/pl031.rs
@@ -0,0 +1,82 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright 2023 Google LLC
+// Author: Ard Biesheuvel <ardb@google.com>
+
+use crate::efi::runtimeservices::{Time, TimeCapabilities};
+use crate::efi::status::Status;
+use crate::efi::status::Status::EFI_SUCCESS;
+
+use core::mem::MaybeUninit;
+use mmio::{Allow, VolBox};
+
+//const EFI_TIME_ADJUST_DAYLIGHT: u8 = 0x1;
+//const EFI_TIME_IN_DAYLIGHT: u8 = 0x2;
+
+const EFI_UNSPECIFIED_TIMEZONE: u16 = 0x07ff;
+
+#[link_section = ".rtrodata"]
+static mut _RTC: MaybeUninit<VolBox<u32, Allow, Allow>> = MaybeUninit::uninit();
+
+fn time_from_ts(ts: u32) -> Time {
+    let secs = ts % 86400;
+
+    let h = secs / 3600;
+    let m = (secs / 60) % 60;
+    let s = secs % 60;
+
+    /* algorithm taken from drivers/rtc/lib.c in Linux */
+    let (century, day_of_century) = {
+        let d = ts / 86400 + 719468;
+        let t = 4 * d + 3;
+
+        (t / 146097, t % 146097 / 4)
+    };
+
+    let (year_of_century, day_of_year) = {
+        let t = 2939745u64 * (4 * day_of_century as u64 + 3);
+
+        (t >> 32, (t & u32::MAX as u64) as u32 / 2939745 / 4)
+    };
+
+    let (day, year, month) = {
+        let t = 2141 * day_of_year + 132377;
+        let y = 100 * century + year_of_century as u32;
+        let m = t >> 16;
+        let d = (t & u16::MAX as u32) / 2141;
+        if m > 12 {
+            (d + 1, y + 1, m - 11)
+        } else {
+            (d + 1, y, m + 1)
+        }
+    };
+
+    Time {
+        year: year as u16,
+        month: month as u8,
+        day: day as u8,
+        hour: h as u8,
+        minute: m as u8,
+        second: s as u8,
+        pad1: 0,
+        nanosecond: 0,
+        timezone: EFI_UNSPECIFIED_TIMEZONE,
+        daylight: 0,
+        pad2: 0,
+    }
+}
+
+pub extern "C" fn get_time(time: *mut Time, _capabilities: *mut TimeCapabilities) -> Status {
+    let rtc = unsafe { _RTC.assume_init_ref() };
+    let t = time_from_ts(rtc.read());
+
+    unsafe {
+        *time = t;
+    }
+    EFI_SUCCESS
+}
+
+pub fn init(base: usize) {
+    let rtc = unsafe { _RTC.write(VolBox::<u32, Allow, Allow>::new(base as *mut u32)) };
+
+    log::trace!("{:?}\n", time_from_ts(rtc.read()));
+}