[U-Boot] [PATCH 0/2] rockchip: make_fit_atf.py Eliminate pyelftools dependency

[U-Boot] [PATCH 0/2] rockchip: make_fit_atf.py Eliminate pyelftools dependency

[Chris Webb]

Building for rockchip, make_fit_atf.py depends on pyelftools, a non-bundled
python module that is not used elsewhere in building u-boot or the kernel.

We only use pyelftools to pull out PT_LOAD segments. ELF is very simple, so
doing this manually is easy and spares users the extra dependency. In fact,
a straightforward implementation shrinks make_fit_aft.py rather than adding
complexity.

Andy Yan's patch

  https://gitlab.denx.de/u-boot/custodians/u-boot-rockchip/commit/619f002db864ef8caa30863bde62df5c651a7312

is a prerequisite for this. (The new code does not erroneously count
GNU_STACK sections and therefore without the above patch, the loadables in
the conf section will always be one short, even where GNU_STACK is present.)

I have tested this script with python 2 and 3 against all bl31 elf files at

  https://github.com/rockchip-linux/rkbin/tree/master/bin/rk33

as well as an rk3399 bl31.elf built locally from the master branch of

  https://github.com/ARM-software/arm-trusted-firmware

to which my toolchain added the extra GNU_STACK segment.

In each case, identical *.bin files were produced compared to the pyelftools
implementation, and a correct .its configuration (without off-by-one error)
was emitted, with and without dtbs supplied to the script.

[U-Boot] [PATCH 1/2] rockchip: make_fit_atf.py: Eliminate pyelftools dependency

[Chris Webb]

make_fit_aft.py depends on the non-standard library pyelftools to pull
out PT_LOAD segments from ELF files. However, this is as easy to do
manually, without imposing the extra dependency on users.

Structures in the ELF file are unpacked into variables named to exactly
match the ELF spec to ensure the destructuring code is reasonably
self-documenting.

Signed-off-by: Chris Webb <chris@arachsys.com>
---
 arch/arm/mach-rockchip/make_fit_atf.py | 74 +++++++++++---------------
 1 file changed, 31 insertions(+), 43 deletions(-)

diff --git a/arch/arm/mach-rockchip/make_fit_atf.py b/arch/arm/mach-rockchip/make_fit_atf.py
index db0ae96ca8..4b0acb8105 100755
--- a/arch/arm/mach-rockchip/make_fit_atf.py
+++ b/arch/arm/mach-rockchip/make_fit_atf.py
@@ -13,16 +13,7 @@ import os
 import sys
 import getopt
 import logging
-
-# pip install pyelftools
-from elftools.elf.elffile import ELFFile
-
-ELF_SEG_P_TYPE = 'p_type'
-ELF_SEG_P_PADDR = 'p_paddr'
-ELF_SEG_P_VADDR = 'p_vaddr'
-ELF_SEG_P_OFFSET = 'p_offset'
-ELF_SEG_P_FILESZ = 'p_filesz'
-ELF_SEG_P_MEMSZ = 'p_memsz'
+import struct
 
 DT_HEADER = """
 /*
@@ -118,33 +109,19 @@ def append_conf_node(file, dtbs, segments):
     file.write('\n')
 
 def generate_atf_fit_dts_uboot(fit_file, uboot_file_name):
-    num_load_seg = 0
-    p_paddr = 0xFFFFFFFF
-    with open(uboot_file_name, 'rb') as uboot_file:
-        uboot = ELFFile(uboot_file)
-        for i in range(uboot.num_segments()):
-            seg = uboot.get_segment(i)
-            if seg.__getitem__(ELF_SEG_P_TYPE) == 'PT_LOAD':
-                p_paddr = seg.__getitem__(ELF_SEG_P_PADDR)
-                num_load_seg = num_load_seg + 1
-
-    assert (p_paddr != 0xFFFFFFFF and num_load_seg == 1)
-
+    segments = unpack_elf(uboot_file_name)
+    if len(segments) != 1:
+        raise ValueError("Invalid u-boot ELF image '%s'" % uboot_file_name)
+    entry, p_paddr, data = segments[0]
     fit_file.write(DT_UBOOT % p_paddr)
 
 def generate_atf_fit_dts_bl31(fit_file, bl31_file_name, dtbs_file_name):
-    with open(bl31_file_name, 'rb') as bl31_file:
-        bl31 = ELFFile(bl31_file)
-        elf_entry = bl31.header['e_entry']
-        segments = bl31.num_segments()
-        for i in range(segments):
-            seg = bl31.get_segment(i)
-            if seg.__getitem__(ELF_SEG_P_TYPE) == 'PT_LOAD':
-                paddr = seg.__getitem__(ELF_SEG_P_PADDR)
-                append_bl31_node(fit_file, i + 1, paddr, elf_entry)
+    segments = unpack_elf(bl31_file_name)
+    for i, (entry, paddr, data) in enumerate(segments):
+        append_bl31_node(fit_file, i + 1, paddr, entry)
     append_fdt_node(fit_file, dtbs_file_name)
     fit_file.write(DT_IMAGES_NODE_END)
-    append_conf_node(fit_file, dtbs_file_name, segments)
+    append_conf_node(fit_file, dtbs_file_name, len(segments))
 
 def generate_atf_fit_dts(fit_file_name, bl31_file_name, uboot_file_name, dtbs_file_name):
     # Generate FIT script for ATF image.
@@ -162,17 +139,28 @@ def generate_atf_fit_dts(fit_file_name, bl31_file_name, uboot_file_name, dtbs_fi
         fit_file.close()
 
 def generate_atf_binary(bl31_file_name):
-    with open(bl31_file_name, 'rb') as bl31_file:
-        bl31 = ELFFile(bl31_file)
-
-        num = bl31.num_segments()
-        for i in range(num):
-            seg = bl31.get_segment(i)
-            if seg.__getitem__(ELF_SEG_P_TYPE) == 'PT_LOAD':
-                paddr = seg.__getitem__(ELF_SEG_P_PADDR)
-                file_name = 'bl31_0x%08x.bin' % paddr
-                with open(file_name, "wb") as atf:
-                    atf.write(seg.data())
+    for entry, paddr, data in unpack_elf(bl31_file_name):
+        file_name = 'bl31_0x%08x.bin' % paddr
+        with open(file_name, "wb") as atf:
+            atf.write(data)
+
+def unpack_elf(filename):
+    with open(filename, 'rb') as file:
+        elf = file.read()
+    if elf[0:7] != b'\x7fELF\x02\x01\x01' or elf[18:20] != b'\xb7\x00':
+        raise ValueError("Invalid arm64 ELF file '%s'" % filename)
+
+    e_entry, e_phoff = struct.unpack_from('<2Q', elf, 0x18)
+    e_phentsize, e_phnum = struct.unpack_from('<2H', elf, 0x36)
+    segments = []
+
+    for offset in range(e_phoff, e_phoff + e_phnum*e_phentsize, e_phentsize):
+        p_type, p_flags, p_offset = struct.unpack_from('<LLQ', elf, offset)
+        if p_type == 1: # PT_LOAD
+            p_paddr, p_filesz = struct.unpack_from('<2Q', elf, offset + 0x18)
+            p_data = elf[p_offset:p_offset + p_filesz]
+            segments.append((e_entry, p_paddr, p_data))
+    return segments
 
 def main():
     uboot_elf = "./u-boot"

[U-Boot] [PATCH 2/2] rockchip: Remove obsolete references to pyelftools

[Chris Webb]

make_fit_atf.py no longer requires pyelftools, and nothing else in the
tree requires it either, so remove references to installing it from the
documentation and travis configuration.

Signed-off-by: Chris Webb <chris@arachsys.com>
---
 .travis.yml                      | 1 -
 board/rockchip/evb_rk3399/README | 6 ------
 board/synopsys/hsdk/README       | 7 -------
 doc/README.rockchip              | 4 ----
 4 files changed, 18 deletions(-)

diff --git a/.travis.yml b/.travis.yml
index 6662ca126a..e4e7e653f6 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -50,7 +50,6 @@ install:
  - . /tmp/venv/bin/activate
  - pip install pytest==2.8.7
  - pip install python-subunit
- - pip install pyelftools
  - grub-mkimage -o ~/grub_x86.efi -O i386-efi normal  echo lsefimmap lsefi lsefisystab efinet tftp minicmd
  - grub-mkimage -o ~/grub_x64.efi -O x86_64-efi normal  echo lsefimmap lsefi lsefisystab efinet tftp minicmd
  - mkdir ~/grub2-arm
diff --git a/board/rockchip/evb_rk3399/README b/board/rockchip/evb_rk3399/README
index 6469821987..ea3258cf37 100644
--- a/board/rockchip/evb_rk3399/README
+++ b/board/rockchip/evb_rk3399/README
@@ -35,12 +35,6 @@ Get the Source and prebuild binary
   > git clone https://github.com/rockchip-linux/rkbin.git
   > git clone https://github.com/rockchip-linux/rkdeveloptool.git
 
-Get some prerequisites
-======================
-
-You need the Python elftools.elf.elffile library for make_fit_atf.py to work:
-
-  > sudo apt-get install python-pyelftools
 
 Compile ATF
 ===========
diff --git a/board/synopsys/hsdk/README b/board/synopsys/hsdk/README
index 9155f17c6e..6e7f9a6c3e 100644
--- a/board/synopsys/hsdk/README
+++ b/board/synopsys/hsdk/README
@@ -82,13 +82,6 @@ Useful notes on bulding and using of U-Boot on ARC HS Development Kit (AKA HSDK)
       be put on the first FAT partition of micro SD-card to be inserted in the
       HSDK board.
 
-      Note that Python3 script is used for generation of a header, thus
-      to get that done it's required to have Python3 with "pyelftools" installed.
-
-      "pyelftools" could be installed with help of "pip" even w/o root rights:
-      ------------------------->8----------------------
-      python3 -m pip install --user pyelftools
-      ------------------------->8----------------------
 
    EXECUTING U-BOOT
 
diff --git a/doc/README.rockchip b/doc/README.rockchip
index 02e2497b15..8ccbb87264 100644
--- a/doc/README.rockchip
+++ b/doc/README.rockchip
@@ -123,10 +123,6 @@ For example:
 
    Option 2: Package the image with SPL:
 
-   - We need the Python elftools.elf.elffile library for make_fit_atf.py to work
-
-     => sudo apt-get install python-pyelftools
-
    - Export cross compiler path for aarch64
 
    - Compile ATF

[U-Boot] [PATCH 2/2] rockchip: Remove obsolete references to pyelftools

[Chris Webb]

Oops, sorry; I'm an idiot. The synopsys board does indeed still use
pyelftools, and therefore while these are correct:

>  board/rockchip/evb_rk3399/README | 6 ------
>  doc/README.rockchip              | 4 ----

these removals are incorrect:

>  .travis.yml                      | 1 -
>  board/synopsys/hsdk/README       | 7 -------

Please disregard this second tidy-up patch for now.