Add updated linker scripts, custom linker script and relocation code …

…at app startup

cargo-ledger/src/setup.rs

@@ -39,4 +39,32 @@ pub fn install_targets() {
             println!("* {target} already installed");
         }
     }
+
+    // Install link_wrap.sh script needed for relocation into proper location
+    let target_host = std::str::from_utf8(
+        Command::new("rustup")
+            .arg("default")
+            .output()
+            .expect("failed to call rustup")
+            .stdout
+            .as_slice(),
+    )
+    .unwrap();
+
+    let start = target_host.find('-')? + 1;
+    let end = target_host.find(' ').unwrap() + start;
+    println!(
+        " Output folder for custom link script {}",
+        &target_host[start..end]
+    );
+
+    let outfilepath =
+        sysroot.join(&target_host[start..end]).join("link_wrap.sh");
+    let target_url = target_files_url.join("link_wrap.sh");
+    let cmd = Command::new("curl")
+        .arg(target_url)
+        .arg("-o")
+        .arg(outfilepath)
+        .output()
+        .expect("failed to execute 'curl'");
 }

ledger_device_sdk/link.ld

@@ -1,43 +1,110 @@
+PHDRS
+{
+  flash0 PT_LOAD ;
+  data   PT_LOAD ;
+  flash2 PT_LOAD ;
+  sram PT_LOAD ;
+
+  headers PT_PHDR PHDRS ;
+}
+
 SECTIONS
 {
+  /* Code, read only, no relocations needed. */
   .text :
   {
     _text = .;
+    /* Here begins flash. This symbol is used by the ideompotent `pic`
+       function as the lower bound of addressed to relocate. */
     _nvram_start = .;
 
     *(.boot*)
     *(.text*)
-    *(.rodata*) 
+    /* .rodata is moved out so we can update it */
 
     . = ALIGN(PAGE_SIZE);
     _etext = .;
-  } > FLASH
+  } > FLASH :flash0
 
-  .nvm_data : ALIGN(PAGE_SIZE)
+  /* Relocations, read only, no relocations aginst the relocations themselves
+     needed! */
+  _reloc_size = SIZEOF(.rel.rodata) + SIZEOF(.rel.data) + SIZEOF(.rel.nvm_data);
+  .rel_flash : ALIGN(PAGE_SIZE)
   {
+    _relocs = .;
+
+    . += _reloc_size;
+    . = ALIGN(PAGE_SIZE);
+
+    _erelocs = .;
+
+    . = ALIGN(PAGE_SIZE);
+
+    /* After this section we have mutable flash. Must be a multiple of PAGE_SIZE from _nvram_start. */
     _nvram_data = .;
-    *(.nvm_data*)
+  } > FLASH :flash0
+
+  /* Immutable globals, read only during app running proper, but
+     relocations are needed. (So not read-only completely.) */
+  .rodata : ALIGN(PAGE_SIZE)
+  {
+    /* Moved here from .text so we can permantly apply relocations to it with
+       nvm_write() */
     . = ALIGN(PAGE_SIZE);
-    _envram_data = .;
-    _install_parameters = .;
-    _nvram_end = .;
-  } > FLASH 
+    _rodata = .;
+    _rodata_src = .;
+    *(.rodata*)
+    . = ALIGN(PAGE_SIZE);
+    _erodata = .;
+  } > FLASH :flash0
+  _rodata_len = _erodata - _rodata;
 
+  /* Mutable Globals, writable, relocations are needed. */
   .data : ALIGN(4)
   {
     _data = .;
     *(vtable)
     *(.data*)
+    . = ALIGN(PAGE_SIZE);
     _edata = .;
-  } > SRAM
+  } > SRAM AT> FLASH :data =0xa4a4
+  _data_len = SIZEOF(.data);
 
   ASSERT( (_edata - _data) <= 0, ".data section must be empty" )
 
+  /* Persistent data, read and written during app running proper,
+     relocations are also needed. */
+  .nvm_data : ALIGN(PAGE_SIZE)
+  {
+    *(.nvm_data*)
+
+    /* Store _nvram value during link_pass and use this to detect movement of
+       _nvram as compared to the previous app execution, and redo the relocations
+       if necessary */
+    . = ALIGN(4);
+    _nvram_prev_run = .;
+    LONG(ABSOLUTE(_nvram_start))
+
+    . = ALIGN(PAGE_SIZE);
+
+    /* After this section we no longer have Flash memory at all. */
+
+    /* This symbol is used by the mutable portion of flash calculations. */
+    _envram_data = .;
+    _install_parameters = .;
+    /* This symbol is used by the ideompotent `pic` function as the upper
+       bound of addressed to relocate. */
+    _nvram_end = .;
+  } > FLASH :flash2
+
+  _sidata_src = LOADADDR(.data);
+
   .bss :
   {
     _bss = .;
     *(.bss*)
     _ebss = .;
+    _bss_len = ABSOLUTE(_ebss) - ABSOLUTE(_bss);
 
     . = ALIGN(4);
     app_stack_canary = .;
@@ -46,7 +113,7 @@ SECTIONS
     . = _stack_validation + STACK_SIZE;
     _stack = ABSOLUTE(END_STACK) - STACK_SIZE;
     _estack = ABSOLUTE(END_STACK);
-  } > SRAM
+  } > SRAM :sram
 
   .stack_sizes (INFO):
   {

ledger_device_sdk/link_wrap.sh

@@ -0,0 +1,42 @@
+#!/usr/bin/env bash
+
+set -eu
+
+set -x
+
+LD=${LD:-rust-lld}
+# Needed because LLD gets behavior from argv[0]
+LD=${LD/-ld/-lld}
+${LD} "$@" --emit-relocs
+
+echo RUST_LLD DONE
+
+while [ $# -gt 0 -a "$1" != "-o" ];
+do
+	shift;
+done
+OUT="$2"
+
+echo OUT IS $OUT
+
+# the relocations for the constants section are required
+llvm-objcopy --dump-section .rel.rodata=$OUT-rodata-reloc $OUT /dev/null
+# there might not _be_ nonempty .data or .nvm_data sections, so there might be no relocations for it; fail gracefully.
+llvm-objcopy --dump-section .rel.data=$OUT-data-reloc $OUT /dev/null || true
+llvm-objcopy --dump-section .rel.nvm_data=$OUT-nvm-reloc $OUT /dev/null || true
+# Concatenate the relocation sections; this should still write $OUT-relocs even if $OUT-data-reloc doesn't exist.
+cat $OUT-rodata-reloc $OUT-nvm-reloc $OUT-data-reloc > $OUT-relocs || true
+
+reloc_allocated_size="$((0x$(llvm-nm $OUT | grep _reloc_size | cut -d' ' -f1)))"
+reloc_real_size="$(stat -c %s $OUT-relocs)"
+# Check that our relocations _actually_ fit.
+if [ "$reloc_real_size" -gt "$reloc_allocated_size" ]
+then
+	echo "Insufficient size for relocs; This is likely some bug in nanos_sdk's link.ld."
+	echo "Available size: " $reloc_allocated_size " Used size: " $reloc_real_size
+	exit 1
+fi
+
+truncate -s $reloc_allocated_size $OUT-relocs
+# and write the relocs to their section in the flash image.
+llvm-objcopy --update-section .rel_flash=$OUT-relocs $OUT

ledger_device_sdk/nanos.json

@@ -8,19 +8,21 @@
   "executables": true,
   "features": "+strict-align",
   "frame-pointer": "always",
-  "linker": "rust-lld",
+  "linker": "link_wrap.sh",
   "linker-flavor": "ld.lld",
   "llvm-target": "thumbv6m-none-eabi",
   "panic-strategy": "abort",
   "pre-link-args": {
-      "ld.lld": [
-          "-Tnanos_layout.ld",
-          "-Tlink.ld"
-      ],
-      "ld": [
-          "-Tnanos_layout.ld",
-          "-Tlink.ld"
-      ]
+    "ld.lld": [
+      "-Tnanos_layout.ld",
+      "-Tlink.ld",
+      "--emit-relocs"
+    ],
+    "ld": [
+      "-Tnanos_layout.ld",
+      "-Tlink.ld",
+      "--emit-relocs"
+    ]
   },
   "relocation-model": "ropi",
   "singlethread": true,

ledger_device_sdk/nanosplus.json

@@ -6,20 +6,20 @@
   "emit-debug-gdb-scripts": false,
   "executables": true,
   "frame-pointer": "always",
-  "linker": "rust-lld",
+  "linker": "link_wrap.sh",
   "linker-flavor": "ld.lld",
   "llvm-target": "thumbv8m.main-none-eabi",
   "max-atomic-width": 32,
   "panic-strategy": "abort",
   "pre-link-args": {
-      "ld.lld": [
-          "-Tnanosplus_layout.ld",
-          "-Tlink.ld"
-      ],
-      "ld": [
-          "-Tnanosplus_layout.ld",
-          "-Tlink.ld"
-      ]
+    "ld.lld": [
+      "-Tnanosplus_layout.ld",
+      "-Tlink.ld"
+    ],
+    "ld": [
+      "-Tnanosplus_layout.ld",
+      "-Tlink.ld"
+    ]
   },
   "relocation-model": "ropi-rwpi",
   "singlethread": true,

ledger_device_sdk/nanox.json

@@ -7,24 +7,23 @@
   "emit-debug-gdb-scripts": false,
   "executables": true,
   "frame-pointer": "always",
-  "linker": "rust-lld",
+  "linker": "link_wrap.sh",
   "linker-flavor": "ld.lld",
   "llvm-target": "thumbv6m-none-eabi",
   "panic-strategy": "abort",
   "pre-link-args": {
-      "ld.lld": [
-          "-Tnanox_layout.ld",
-          "-Tlink.ld"
-      ],
-      "ld": [
-          "-Tnanox_layout.ld",
-          "-Tlink.ld"
-      ]
+    "ld.lld": [
+      "-Tnanox_layout.ld",
+      "-Tlink.ld"
+    ],
+    "ld": [
+      "-Tnanox_layout.ld",
+      "-Tlink.ld"
+    ]
   },
   "relocation-model": "ropi-rwpi",
   "singlethread": true,
   "target-pointer-width": "32",
   "os": "nanox",
   "target-family": [ "bolos" ]
-
 }