Flash operations support (#172)

This PR adds support for the flash commands as described in
(https://sourceware.org/gdb/current/onlinedocs/gdb.html/Packets.html#Packets).

I had to change the memory map in the armv4t example providing a real
memory map, otherwise GDB would not load a real .elf file. It doesn't
have to be a real memory map, but you need at least a region marked a
flash containing the address of the elf sections to be loaded. (eg:
.vector_table, .text etc..)

Author: eulerdisk

README.md

@@ -93,6 +93,7 @@ Of course, most use-cases will want to support additional debugging features as
     - Configure tracepoints and actions to perform when hit
     - Select and interrogate collected trace frames
    - _Note:_ Feature support is not exhaustive, and many feature haven't been implemented yet.
+-   Flash operations (`load`)
 
 _Note:_ GDB features are implemented on an as-needed basis by `gdbstub`'s contributors. If there's a missing GDB feature that you'd like `gdbstub` to implement, please file an issue and/or open a PR!
 

examples/armv4t/gdb/flash.rs

@@ -0,0 +1,21 @@
+use crate::emu::Emu;
+use gdbstub::target;
+use gdbstub::target::TargetResult;
+use log::info;
+
+impl target::ext::flash::Flash for Emu {
+    fn flash_erase(&mut self, start_addr: u32, length: u32) -> TargetResult<(), Self> {
+        info!("flash_erase start_addr: {start_addr:08x}, length: {length:08x}");
+        Ok(())
+    }
+
+    fn flash_write(&mut self, start_addr: u32, _data: &[u8]) -> TargetResult<(), Self> {
+        info!("flash_write start_addr: {start_addr:08x}");
+        Ok(())
+    }
+
+    fn flash_done(&mut self) -> TargetResult<(), Self> {
+        info!("flash_done");
+        Ok(())
+    }
+}

examples/armv4t/gdb/memory_map.rs

@@ -10,14 +10,23 @@ impl target::ext::memory_map::MemoryMap for Emu {
         length: usize,
         buf: &mut [u8],
     ) -> TargetResult<usize, Self> {
-        // Sample memory map, with RAM coverying the whole
-        // memory space.
+        // Sample memory map, modeled on part of STM32F446 memory map.
+        // A real memory map is necessary to test the flash commands.
         let memory_map = r#"<?xml version="1.0"?>
 <!DOCTYPE memory-map
     PUBLIC "+//IDN gnu.org//DTD GDB Memory Map V1.0//EN"
             "http://sourceware.org/gdb/gdb-memory-map.dtd">
 <memory-map>
-    <memory type="ram" start="0x0" length="0x100000000"/>
+    <memory type="ram" start="0x20000000" length="0x20000"/>
+    <memory type="flash" start="0x08000000" length="0x10000">
+        <property name="blocksize">0x4000</property>
+    </memory>
+    <memory type="flash" start="0x08010000" length="0x10000">
+        <property name="blocksize">0x10000</property>
+    </memory>
+    <memory type="flash" start="0x08020000" length="0x60000">
+        <property name="blocksize">0x20000</property>
+    </memory>
 </memory-map>"#
             .trim()
             .as_bytes();

examples/armv4t/gdb/mod.rs

@@ -19,6 +19,7 @@ mod breakpoints;
 mod catch_syscalls;
 mod exec_file;
 mod extended_mode;
+mod flash;
 mod host_io;
 mod libraries;
 mod lldb_register_info_override;
@@ -169,6 +170,11 @@ impl Target for Emu {
     ) -> Option<target::ext::tracepoints::TracepointsOps<'_, Self>> {
         Some(self)
     }
+
+    #[inline(always)]
+    fn support_flash_operations(&mut self) -> Option<target::ext::flash::FlashOps<'_, Self>> {
+        Some(self)
+    }
 }
 
 impl SingleThreadBase for Emu {

src/protocol/commands.rs

@@ -302,6 +302,12 @@ commands! {
         "qXfer:memory-map:read" => _qXfer_memory_map::qXferMemoryMapRead<'a>,
     }
 
+    flash_operations use 'a {
+        "vFlashErase" => _vFlashErase::vFlashErase<'a>,
+        "vFlashWrite" => _vFlashWrite::vFlashWrite<'a>,
+        "vFlashDone" => _vFlashDone::vFlashDone,
+    }
+
     auxv use 'a {
         "qXfer:auxv:read" => _qXfer_auxv_read::qXferAuxvRead<'a>,
     }

src/protocol/commands/_vFlashDone.rs

@@ -0,0 +1,11 @@
+use super::prelude::*;
+
+#[derive(Debug)]
+pub struct vFlashDone;
+
+impl<'a> ParseCommand<'a> for vFlashDone {
+    #[inline(always)]
+    fn from_packet(_buf: PacketBuf<'a>) -> Option<Self> {
+        Some(vFlashDone)
+    }
+}

src/protocol/commands/_vFlashErase.rs

@@ -0,0 +1,76 @@
+use super::prelude::*;
+
+#[derive(Debug)]
+pub struct vFlashErase<'a> {
+    pub addr: &'a [u8],
+    pub length: &'a [u8],
+}
+
+impl<'a> ParseCommand<'a> for vFlashErase<'a> {
+    #[inline(always)]
+    fn from_packet(buf: PacketBuf<'a>) -> Option<Self> {
+        let body = buf.into_body();
+
+        let mut body = body.splitn_mut(3, |&b| b == b',' || b == b':');
+        let _first_colon = body.next()?;
+        let addr = decode_hex_buf(body.next()?).ok()?;
+        let length = decode_hex_buf(body.next()?)
+            .ok()
+            .filter(|l| !l.is_empty())?;
+        Some(Self { addr, length })
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    macro_rules! test_buf {
+        ($bufname:ident, $body:literal) => {
+            let mut test = $body.to_vec();
+            let mut buf = PacketBuf::new_with_raw_body(&mut test).unwrap();
+            if !buf.strip_prefix(b"vFlashErase") {
+                panic!("invalid test");
+            }
+            let $bufname = buf;
+        };
+    }
+
+    #[test]
+    fn valid_vFlashErase() {
+        test_buf!(buf, b"vFlashErase:08000000,00004000");
+
+        let pkt = vFlashErase::from_packet(buf).unwrap();
+
+        assert_eq!(pkt.addr, [0x08, 0, 0, 0]);
+        assert_eq!(pkt.length, [0, 0, 0x40, 0]);
+    }
+
+    #[test]
+    fn invalid_vFlashErase_wrong_address() {
+        test_buf!(buf, b"vFlashErase:abcdefg:00004000");
+
+        assert!(vFlashErase::from_packet(buf).is_none());
+    }
+
+    #[test]
+    fn invalid_vFlashErase_wrong_length() {
+        test_buf!(buf, b"vFlashErase:08000000:abcdefg");
+
+        assert!(vFlashErase::from_packet(buf).is_none());
+    }
+
+    #[test]
+    fn invalid_vFlashErase_missing_address() {
+        test_buf!(buf, b"vFlashErase:");
+
+        assert!(vFlashErase::from_packet(buf).is_none());
+    }
+
+    #[test]
+    fn invalid_vFlashErase_missing_length() {
+        test_buf!(buf, b"vFlashErase:08000000:");
+
+        assert!(vFlashErase::from_packet(buf).is_none());
+    }
+}

src/protocol/commands/_vFlashWrite.rs

@@ -0,0 +1,77 @@
+use super::prelude::*;
+use crate::protocol::common::hex::decode_bin_buf;
+
+#[derive(Debug)]
+pub struct vFlashWrite<'a> {
+    pub addr: &'a [u8],
+    pub val: &'a [u8],
+}
+
+impl<'a> ParseCommand<'a> for vFlashWrite<'a> {
+    #[inline(always)]
+    fn from_packet(buf: PacketBuf<'a>) -> Option<Self> {
+        let body = buf.into_body();
+
+        let mut body = body.splitn_mut(3, |&b| b == b':');
+        let _first_colon = body.next()?;
+        let addr = decode_hex_buf(body.next()?)
+            .ok()
+            .filter(|a| !a.is_empty())?;
+        let val = decode_bin_buf(body.next()?)?;
+
+        Some(vFlashWrite { addr, val })
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    macro_rules! test_buf {
+        ($bufname:ident, $body:literal) => {
+            let mut test = $body.to_vec();
+            let mut buf = PacketBuf::new_with_raw_body(&mut test).unwrap();
+            if !buf.strip_prefix(b"vFlashWrite") {
+                panic!("invalid test");
+            }
+            let $bufname = buf;
+        };
+    }
+
+    #[test]
+    fn valid_vFlashWrite() {
+        test_buf!(
+            buf,
+            b"vFlashWrite:08000000:\x00\x01\x02\x03\x04\x05\x06\x07\x08\x09\x0A"
+        );
+
+        let pkt = vFlashWrite::from_packet(buf).unwrap();
+
+        assert_eq!(pkt.addr, [0x08, 0, 0, 0]);
+        assert_eq!(pkt.val, [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10]);
+    }
+
+    #[test]
+    fn invalid_vFlashWrite_wrong_address() {
+        test_buf!(
+            buf,
+            b"vFlashWrite:abcdefg:\x00\x01\x02\x03\x04\x05\x06\x07\x08\x09\x0A"
+        );
+
+        assert!(vFlashWrite::from_packet(buf).is_none())
+    }
+
+    #[test]
+    fn invalid_vFlashWrite_missing_data() {
+        test_buf!(buf, b"vFlashWrite:abcdefg:");
+
+        assert!(vFlashWrite::from_packet(buf).is_none())
+    }
+
+    #[test]
+    fn invalid_vFlashWrite_missing_address() {
+        test_buf!(buf, b"vFlashWrite:");
+
+        assert!(vFlashWrite::from_packet(buf).is_none())
+    }
+}

src/stub/core_impl.rs

@@ -30,6 +30,7 @@ mod breakpoints;
 mod catch_syscalls;
 mod exec_file;
 mod extended_mode;
+mod flash;
 mod host_io;
 mod libraries;
 mod lldb_register_info;
@@ -213,6 +214,7 @@ impl<T: Target, C: Connection> GdbStubImpl<T, C> {
             Command::ReverseCont(cmd) => self.handle_reverse_cont(res, target, cmd),
             Command::ReverseStep(cmd) => self.handle_reverse_step(res, target, cmd),
             Command::MemoryMap(cmd) => self.handle_memory_map(res, target, cmd),
+            Command::FlashOperations(cmd) => self.handle_flash_operations(res, target, cmd),
             Command::HostIo(cmd) => self.handle_host_io(res, target, cmd),
             Command::ExecFile(cmd) => self.handle_exec_file(res, target, cmd),
             Command::Auxv(cmd) => self.handle_auxv(res, target, cmd),

src/stub/core_impl/flash.rs

@@ -0,0 +1,42 @@
+use super::prelude::*;
+use crate::arch::Arch;
+use crate::protocol::commands::ext::FlashOperations;
+
+impl<T: Target, C: Connection> GdbStubImpl<T, C> {
+    pub(crate) fn handle_flash_operations(
+        &mut self,
+        _res: &mut ResponseWriter<'_, C>,
+        target: &mut T,
+        command: FlashOperations<'_>,
+    ) -> Result<HandlerStatus, Error<T::Error, C::Error>> {
+        let ops = match target.support_flash_operations() {
+            Some(ops) => ops,
+            None => return Ok(HandlerStatus::Handled),
+        };
+        let handler_status = match command {
+            FlashOperations::vFlashErase(cmd) => {
+                let addr = <T::Arch as Arch>::Usize::from_be_bytes(cmd.addr)
+                    .ok_or(Error::TargetMismatch)?;
+
+                let length = <T::Arch as Arch>::Usize::from_be_bytes(cmd.length)
+                    .ok_or(Error::TargetMismatch)?;
+
+                ops.flash_erase(addr, length).handle_error()?;
+                HandlerStatus::NeedsOk
+            }
+            FlashOperations::vFlashWrite(cmd) => {
+                let addr = <T::Arch as Arch>::Usize::from_be_bytes(cmd.addr)
+                    .ok_or(Error::TargetMismatch)?;
+
+                ops.flash_write(addr, cmd.val).handle_error()?;
+                HandlerStatus::NeedsOk
+            }
+            FlashOperations::vFlashDone(_) => {
+                ops.flash_done().handle_error()?;
+                HandlerStatus::NeedsOk
+            }
+        };
+
+        Ok(handler_status)
+    }
+}