Commit graph

237 commits

Author SHA1 Message Date
Ovidiu Panait
fbf9c154a6 board_f: Make clear_bss generic
clear_bss is already used by 3 arches (x86, arc, xtensa), so make it generic
and provide a weak nop stub for it. This also removes arch-specific ifdef
duplications around clear_bss.

Signed-off-by: Ovidiu Panait <ovpanait@gmail.com>
2020-02-13 10:10:50 -05:00
Ovidiu Panait
016e4ae7ef common/board_f.c: Remove arch-specific checks for cpucheck
This removes the arch-specific checks for "checkcpu" function from the init
sequence. Make "checkcpu" generic and provide a weak nop stub instead.

Signed-off-by: Ovidiu Panait <ovpanait@gmail.com>
2020-01-30 13:30:35 -05:00
Simon Glass
db41d65a97 common: Move hang() to the same header as panic()
At present panic() is in the vsprintf.h header file. That does not seem
like an obvious choice for hang(), even though it relates to panic(). So
let's put hang() in its own header.

Signed-off-by: Simon Glass <sjg@chromium.org>
[trini: Migrate a few more files]
Signed-off-by: Tom Rini <trini@konsulko.com>
2020-01-17 17:53:40 -05:00
Simon Glass
d96c26040e common: Move clock functions into a new file
These three clock functions don't use driver model and should be migrated.
In the meantime, create a new file to hold them.

Signed-off-by: Simon Glass <sjg@chromium.org>
2020-01-17 13:27:29 -05:00
Simon Glass
67c4e9f815 common: Move board_get_usable_ram_top() out of common.h
Move this function into init.h which seems to be designed for this sort
of thing. Also update the header to declare struct global_data so that it
can be included without global_data.h being needed.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Tom Rini <trini@konsulko.com>
2019-12-02 18:25:04 -05:00
Simon Glass
30c7c43473 common: Move checkcpu() out of common.h
This function belongs in cpu_func.h so move it over.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Tom Rini <trini@konsulko.com>
2019-12-02 18:23:14 -05:00
Simon Glass
b03e0510d7 common: Move serial functions out of common.h
These functions belong in serial.h so move them over.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Tom Rini <trini@konsulko.com>
2019-12-02 18:23:11 -05:00
Simon Glass
ac9cd4805c bootstage: Correct relocation algorithm
At present bootstage relocation assumes that it is possible to point back
to memory available before relocation, so it does not relocate the
strings. However this is not the case on some platforms, such as x86 which
uses the cache as RAM and loses access to this when the cache is enabled.

Move the relocation step to before U-Boot relocates, expand the allocated
region to include space for the strings and relocate the strings at the
same time as the bootstage records.

This ensures that bootstage data can remain accessible from TPL through
SPL to U-Boot before/after relocation.

Signed-off-by: Simon Glass <sjg@chromium.org>
2019-10-27 10:56:51 -06:00
Simon Glass
5074a8a3c0 bloblist: Reserve an aligned base
Make sure that the bloblist starts on an aligned boundary. This protects
against one of the early allocating causing the alignment to be lost.

Signed-off-by: Simon Glass <sjg@chromium.org>
2019-10-27 10:56:51 -06:00
Stephen Warren
5e0404ff85 board_f: fix noncached reservation calculation
The current code in reserve_noncached() has two issues:

1) The first update of gd->start_addr_sp always rounds down to a section
start. However, the equivalent calculation in cache.c:noncached_init()
always first rounds up to a section start, then subtracts a section size.
These two calculations differ if the initial value is already rounded to
section alignment.

2) The second update of gd->start_addr_sp subtracts exactly
CONFIG_SYS_NONCACHED_MEMORY, whereas the equivalent calculation in
cache.c:noncached_init() rounds the noncached size up to section
alignment before subtracting it. The two calculations differ if the
noncached region size is not a multiple of the MMU section size.

In practice, one/both of those issues causes a practical problem on
Jetson TX1; U-Boot triggers a synchronous abort during initialization,
likely due to overlapping use of some memory region.

This change fixes both these issues by duplicating the exact calculations
from noncached_init() into reserve_noncached().

However, this fix assumes that gd->start_addr_sp on entry to
reserve_noncached() exactly matches mem_malloc_start on entry to
noncached_init(). I haven't traced the code to see whether it absolutely
guarantees this in all (or indeed any!) cases. Consequently, I added some
comments in the hope that this condition will continue to be true.

Fixes: 5f7adb5b1c ("board_f: reserve noncached space below malloc area")
Cc: Vikas Manocha <vikas.manocha@st.com>
Signed-off-by: Stephen Warren <swarren@nvidia.com>
2019-08-30 14:17:11 -04:00
Vikas Manocha
5f7adb5b1c board_f: reserve noncached space below malloc area
Noncached area at present is being initialized to random space after malloc
area. It works in most the cases as it goes to stack area & stack is not
overwriting it being far from it.

Signed-off-by: Vikas Manocha <vikas.manocha@st.com>
2019-08-26 11:46:20 -04:00
Simon Glass
f3998fdc4d env: Rename environment.h to env_internal.h
This file contains lots of internal details about the environment. Most
code can include env.h instead, calling the functions there as needed.

Rename this file and add a comment at the top to indicate its internal
nature.

Signed-off-by: Simon Glass <sjg@chromium.org>
Acked-by: Joe Hershberger <joe.hershberger@ni.com>
Reviewed-by: Simon Goldschmidt <simon.k.r.goldschmidt@gmail.com>
[trini: Fixup apalis-tk1.c]
Signed-off-by: Tom Rini <trini@konsulko.com>
2019-08-11 19:27:31 -04:00
Simon Glass
4bfd1f5d62 env: Move env_init() to env.h
Move env_init() over to the new header file.

Signed-off-by: Simon Glass <sjg@chromium.org>
Acked-by: Joe Hershberger <joe.hershberger@ni.com>
2019-08-11 16:43:41 -04:00
Simon Glass
9fe657daa7 common: Remove video_setmem()
This function is no-longer defined in U-Boot. Drop the declaration from
common.h

Signed-off-by: Simon Glass <sjg@chromium.org>
2019-08-11 16:43:41 -04:00
Simon Glass
3c1ecde402 common: Move lcd_setmem() to lcd.h
This function relates to lcd.h and is about to become obsolete with the
driver-model conversion. Move it out of common.h

Signed-off-by: Simon Glass <sjg@chromium.org>
2019-08-11 16:43:41 -04:00
Heinrich Schuchardt
7ea3357957 trace: trace buffer may exceed 2GiB
Correct the debug output for the trace buffer size to accommodate trace
buffers exceeding 2GiB.

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Reviewed-by: Simon Glass <sjg@chromium.org>
2019-07-10 16:52:58 -06:00
Heinrich Schuchardt
7ef8e9b09a trace: undefined reference to `trace_early_init'
Compiling with TRACE but without TRACE_EARLY results in an error
aarch64-linux-gnu-ld.bfd:
common/built-in.o:(.rodata.init_sequence_f+0x10):
undefined reference to `trace_early_init'

trace_early_init() should not be called if CONFIG_TRACE_EARLY is not
defined.

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Reviewed-by: Simon Glass <sjg@chromium.org>
2019-07-10 16:52:58 -06:00
Trevor Woerner
1001502545 CONFIG_SPL_SYS_[DI]CACHE_OFF: add
While converting CONFIG_SYS_[DI]CACHE_OFF to Kconfig, there are instances
where these configuration items are conditional on SPL. This commit adds SPL
variants of these configuration items, uses CONFIG_IS_ENABLED(), and updates
the configurations as required.

Acked-by: Alexey Brodkin <abrodkin@synopsys.com>
Signed-off-by: Trevor Woerner <trevor@toganlabs.com>
[trini: Make the default depend on the setting for full U-Boot, update
more zynq hardware]
Signed-off-by: Tom Rini <trini@konsulko.com>
2019-05-18 08:15:35 -04:00
Simon Glass
001d1885f0 sandbox: Improve debugging in initcall_run_list()
At present if one of the initcalls fails on sandbox the address printing
is not help, e.g.:

  initcall sequence 0000557678967c80 failed at call 00005576709dfe1f (err=-96)

This is because U-Boot gets relocated high into memory and the relocation
offset (gd->reloc_off) does not work correctly for sandbox.

Add support for finding the base address of the text region (at least on
Linux) and use that to set the relocation offset. This makes the output
better:

  initcall sequence 0000560775957c80 failed at call 0000000000048134 (err=-96)

Then you use can use grep to see which init call failed, e.g.:

   $ grep 0000000000048134 u-boot.map
   stdio_add_devices

Of course another option is to run it with a debugger such as gdb:

   $ gdb u-boot
   ...
   (gdb) br initcall.h:41
   Breakpoint 1 at 0x4db9d: initcall.h:41. (2 locations)

Note that two locations are reported, since this function is used in both
board_init_f() and board_init_r().

   (gdb) r
   Starting program: /tmp/b/sandbox/u-boot
   [Thread debugging using libthread_db enabled]
   Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".

   U-Boot 2018.09-00264-ge0c2ba9814-dirty (Sep 22 2018 - 12:21:46 -0600)

   DRAM:  128 MiB
   MMC:

Breakpoint 1, initcall_run_list (init_sequence=0x5555559619e0 <init_sequence_f>)
    at /scratch/sglass/cosarm/src/third_party/u-boot/files/include/initcall.h:41
41				printf("initcall sequence %p failed at call %p (err=%d)\n",
   (gdb) print *init_fnc_ptr
   $1 = (const init_fnc_t) 0x55555559c114 <stdio_add_devices>
   (gdb)

Signed-off-by: Simon Glass <sjg@chromium.org>
2019-04-23 20:26:43 -06:00
Tom Rini
9450ab2ba8 Merge branch 'master' of git://git.denx.de/u-boot-spi
- Various MTD fixes from Boris
- Zap various unused / legacy paths.
- pxa3xx NAND update from Miquel

Signed-off-by: Tom Rini <trini@konsulko.com>
2018-12-05 15:06:24 -05:00
Jagan Teki
35f9d9bdd0 spi: Zap CONFIG_HARD_SPI
In legacy CONFIG_HARD_SPI initalizing spi_init code, which
was removed during dm conversion cleanup.

So remove the dead instances of CONFIG_HARD_SPI, and related
code.

Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>
2018-11-27 21:06:53 +05:30
Jagan Teki
fe82ca8f71 spi: Remove used spi_init
spi_init used in some areas in tree, but the respective
drivers will remove in future patches.

So remove the same instances.

Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>
2018-11-27 21:06:53 +05:30
Simon Glass
b0edea3c27 spl: Add support for passing handoff info to U-Boot proper
There is some basic informaton that SPL normally wants to pass through to
U-Boot, such as the SDRAM size and bank information.

Mkae use of the new bloblist structure for this. Add a new 'handoff' blob
which is set up in SPL and passed to U-Boot proper. Also adda  test for
sandbox_spl that checks that this works correctly and a new 'sb' command
to show the information passed from SPL.

Reviewed-by: Tom Rini <trini@konsulko.com>
Signed-off-by: Simon Glass <sjg@chromium.org>
2018-11-26 08:25:37 -05:00
Simon Glass
f0293d33b7 bloblist: Locate bloblist in U-Boot
Add support for locating a bloblist in U-Boot that has been set up by SPL.
It is copied into RAM during relocation.

Reviewed-by: Tom Rini <trini@konsulko.com>
Signed-off-by: Simon Glass <sjg@chromium.org>
2018-11-26 08:25:32 -05:00
Prasanthi Chellakumar
1473f6ac88 arm: at91: wdt: Convert watchdog driver to dm/dt
Convert the Watchdog driver for AT91SAM9x processors to support
the driver model and device tree. Changes "CONFIG_AT91SAM9_WATCHDOG"
to new "CONFIG_WDT_AT91" Kconfig option.

Signed-off-by: Prasanthi Chellakumar <prasanthi.chellakumar@microchip.com>
2018-11-16 13:34:34 -05:00
Bin Meng
ecfe66330d dm: cpu: Fix print_cpuinfo() output
It was observed that current output of print_cpuinfo() on QEMU
x86 targets does not have an ending '\n', neither have a leading
'CPU:' any more. However it used to have these before.

It turns out commit c0434407b5 introduced a unified DM version
of print_cpuinfo() that exposed such issue on QEMU x86.

Fixes: c0434407b5 ("board_f: Use static print_cpuinfo if CONFIG_CPU is active")
Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
2018-11-14 09:16:27 -08:00
Mario Six
5d6c61ac40 board_f: Use static print_cpuinfo if CONFIG_CPU is active
When the DM CPU drivers are active, printing information about a CPU
should be delegated to a matching driver.

Hence, add a static print_cpuinfo that implements this delegation when
DM CPU drivers are active.

Reviewed-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Mario Six <mario.six@gdsys.cc>
Changed condition to CONFIG_IS_ENABLED(CPU):
Signed-off-by: Simon Glass <sjg@chromium.org>
2018-11-14 09:16:27 -08:00
Bin Meng
5764ea2df4 Revert "board_f: Use static print_cpuinfo if CONFIG_CPU is active"
This reverts commit c0434407b5.

It turns out commit c0434407b5 broke some boards which have DM CPU
driver with CONFIG_DISPLAY_CPUINFO option on. These boards just fail
to boot when print_cpuinfo() is called during boot.

Fixes are already sent to ML and in u-boot-dm/next, however since
we are getting close to the v2018.11 release, it's safer we revert
the original commit.

This commit should be reverted after v2018.11 release.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Acked-by: Peng Fan <peng.fan@nxp.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
2018-11-07 12:13:35 -05:00
Mario Six
c0434407b5 board_f: Use static print_cpuinfo if CONFIG_CPU is active
When the DM CPU drivers are active, printing information about a CPU
should be delegated to a matching driver.

Hence, add a static print_cpuinfo that implements this delegation when
DM CPU drivers are active.

Reviewed-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Mario Six <mario.six@gdsys.cc>
Changed condition to CONFIG_IS_ENABLED(CPU):
Signed-off-by: Simon Glass <sjg@chromium.org>
2018-09-18 08:12:16 -06:00
Mario Six
138181a550 common: board_f: Sort includes
Includes should be sorted.

Reviewed-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Mario Six <mario.six@gdsys.cc>
2018-09-18 00:01:18 -06:00
Mario Six
23471aed5c board_f: Add reset status printing
To print the reset status during boot, add a method print_resetinfo to
board_f, which is called in init_sequence_f[], that gets the reset
information from the sysreset driver (assuming there is only one seems
reasonable), and prints it.

Reviewed-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Mario Six <mario.six@gdsys.cc>
2018-09-18 00:01:18 -06:00
Siva Durga Prasad Paladugu
1473b12ad0 lib: fdtdec: Update ram_base to store ram start adddress
This patch updates the ram_base to store the start address of
the first bank DRAM and the use this ram_base to calculate ram_top
properly. This patch fixes the erroneous calculation of ram_top
incase of non zero ram start address.

Signed-off-by: Siva Durga Prasad Paladugu <siva.durga.paladugu@xilinx.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Reviewed-by: Tom Rini <trini@konsulko.com>
2018-07-19 10:49:56 +02:00
Alexey Brodkin
ff2b2ba845 board_f: Only reserve memory for U-Boot if we're going to relocate
In case of no relocation we'll just waste some space at the very end
of usable memory area. If target device has very limited amount of memory
(for example 256 kB) this loss will be pretty inconvenient.

Signed-off-by: Alexey Brodkin <abrodkin@synopsys.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Cc: Bin Meng <bmeng.cn@gmail.com>
Cc: Heiko Schocher <hs@denx.de>
Cc: York Sun <york.sun@nxp.com>
Cc: Stefan Roese <sr@denx.de>
2018-06-05 20:19:08 -04:00
Tom Rini
83d290c56f SPDX: Convert all of our single license tags to Linux Kernel style
When U-Boot started using SPDX tags we were among the early adopters and
there weren't a lot of other examples to borrow from.  So we picked the
area of the file that usually had a full license text and replaced it
with an appropriate SPDX-License-Identifier: entry.  Since then, the
Linux Kernel has adopted SPDX tags and they place it as the very first
line in a file (except where shebangs are used, then it's second line)
and with slightly different comment styles than us.

In part due to community overlap, in part due to better tag visibility
and in part for other minor reasons, switch over to that style.

This commit changes all instances where we have a single declared
license in the tag as both the before and after are identical in tag
contents.  There's also a few places where I found we did not have a tag
and have introduced one.

Signed-off-by: Tom Rini <trini@konsulko.com>
2018-05-07 09:34:12 -04:00
Alexey Brodkin
264d298fda arc: Introduce a possibility to not relocate U-boot
Disabling relocation might be useful on ARC for 2 reasons:
 a) For advanced debugging with Synopsys proprietary MetaWare debugger
    which is capable of accessing much more specific hardware resources
    compared to gdb. For example it may show contents of L1 and L2 caches,
    internal states of some hardware blocks etc.

    But on the downside MetaWare debugger still cannot work with PIE.
    Even though that limitation could be work-arounded with change of ELF's
    header and stripping down all debug info but with it we won't have
    debug info for source-level debugging which is quite inconvenient.

 b) Some platforms which might benefit from usage of U-Boot basically
    don't have enough RAM to accommodate relocation of U-Boot so we
    keep code in flash and use as much of RAM as possible for more
    interesting things.

Signed-off-by: Alexey Brodkin <abrodkin@synopsys.com>
Cc: Simon Glass <sjg@chromium.org>
Cc: Bin Meng <bmeng.cn@gmail.com>
Cc: Heiko Schocher <hs@denx.de>
Cc: York Sun <york.sun@nxp.com>
Cc: Stefan Roese <sr@denx.de>
2018-03-21 16:21:34 +03:00
Patrick Delaunay
b8aa55cb64 common: move init_helpers.h prototypes in init.h
Merge init_helpers.h in the new file init.h
with only prototypes for init_cache_f_r
used in common/board_f.c

Signed-off-by: Patrick Delaunay <patrick.delaunay@st.com>
2018-03-16 14:56:59 -04:00
Patrick Delaunay
d6f8771239 common: move board_f.c prototypes in init.h
Move prototypes for function used in common/board_f.c
from common.h to init.h
Remove weak for arch_reserve_stacks in prototype
(checkpatch issue)

Signed-off-by: Patrick Delaunay <patrick.delaunay@st.com>
2018-03-16 14:56:00 -04:00
Mario Six
16ef147425 common: board_f: Fix style violations
Fix some style violations in the board_f file.

Reviewed-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Mario Six <mario.six@gdsys.cc>
2018-01-28 09:36:28 -05:00
Tom Rini
a3f77c810b Merge branch 'master' of git://git.denx.de/u-boot-coldfire 2018-01-24 22:08:00 -05:00
Angelo Dureghello
b9153fe308 common/board_f.c: align m68k arch to use CONFIG_DISPLAY_CPUINFO
Change all coldfire arch files to use CONFIG_DISPLAY_CPUINFO.

Signed-off-by: Angelo Dureghello <angelo@sysam.it>
Reviewed-by: Tom Rini <trini@konsulko.com>
---
Changes for v2:
   - update common/Kconfig to add M68K to the default y list
2018-01-23 23:47:02 +01:00
Rajesh Bhagat
1fab98fb90 common: board_f: vid: Add VID specific API to adjust core voltage
Adds a VID specific API in init_sequence_f and spl code flow
namely init_func_vid which is required to adjust core voltage.

VID specific code is required in spl, hence moving flag CONFIG_VID
out of spl flags.

Signed-off-by: Ashish Kumar <Ashish.Kumar@nxp.com>
Signed-off-by: Rajesh Bhagat <rajesh.bhagat@nxp.com>
Reviewed-by: York Sun <york.sun@nxp.com>
2018-01-23 11:20:46 -08:00
Rick Chen
068feb9b86 riscv: Modify generic codes to support RISC-V
Support common commands bdinfo and image format,
also modify common generic flow for RISC-V.

Signed-off-by: Rick Chen <rick@andestech.com>
Signed-off-by: Rick Chen <rickchen36@gmail.com>
Signed-off-by: Greentime Hu <green.hu@gmail.com>
Reviewed-by: Tom Rini <trini@konsulko.com>
2018-01-12 08:05:12 -05:00
Simon Glass
af1bc0cf46 log: Plumb logging into the init sequence
Set up logging both before and after relocation.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
2017-12-07 15:17:00 -05:00
Simon Glass
c5404b64fb Drop the log buffer
This does not appear to be used by any boards. Before introducing a new
log system, remove this old one.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
2017-12-07 15:17:00 -05:00
Simon Glass
5ee94b4f40 board_f: Drop the timer after relocation
Once U-Boot relocates itself the existing driver-model timer (if any) is
no-longer valid until the device is reinitialised. Any use of the device
may cause a crash. To handle this, set the timer to NULL after relocation.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
2017-09-16 14:57:44 +08:00
Thomas Petazzoni
c1ee8936bf common/board_f.c: remove CONFIG_SYS_GENERIC_GLOBAL_DATA
CONFIG_SYS_GENERIC_GLOBAL_DATA is no longer used by any board or
platform, so support for it can be dropped.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Reviewed-by: Vladimir Zapolskiy <vz@mleia.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
2017-08-20 09:54:32 -04:00
Simon Glass
bfebc8c965 env: Rename getenv_hex(), getenv_yesno(), getenv_ulong()
We are now using an env_ prefix for environment functions. Rename these
for consistency. Also add function comments in common.h.

Suggested-by: Wolfgang Denk <wd@denx.de>
Signed-off-by: Simon Glass <sjg@chromium.org>
2017-08-16 08:30:32 -04:00
Siva Durga Prasad Paladugu
60873f736e common: board_f: Make reserve_mmu a weak function
Make reserve_mmu a weak so that it provides an option
to customize this routine as per platform need

Signed-off-by: Siva Durga Prasad Paladugu <sivadur@xilinx.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
2017-08-02 09:11:52 +02:00
Andy Yan
f1896c45cb spl: make SPL and normal u-boot stage use independent SYS_MALLOC_F_LEN
Some platforms have very limited SRAM to run SPL code, so there may
not be the same amount space for a malloc pool before relocation in
the SPL stage as the normal U-Boot stage.

Make SPL and (the full) U-Boot stage use independent SYS_MALLOC_F_LEN,
so the size of pre-relocation malloc pool can be configured memory
space independently.

Signed-off-by: Andy Yan <andy.yan@rock-chips.com>
Reviewed-by: Tom Rini <trini@konsulko.com>
Acked-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>
Reviewed-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>
[fixed up commit-message:]
Signed-off-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>
2017-07-27 14:59:03 +02:00
Paul Burton
703ec9ddf9 MIPS: Stop building position independent code
U-Boot has up until now built with -fpic for the MIPS architecture,
producing position independent code which uses indirection through a
global offset table, making relocation fairly straightforward as it
simply involves patching up GOT entries.

Using -fpic does however have some downsides. The biggest of these is
that generated code is bloated in various ways. For example, function
calls are indirected through the GOT & the t9 register:

  8f998064   lw     t9,-32668(gp)
  0320f809   jalr   t9

Without -fpic the call is simply:

  0f803f01   jal    be00fc04 <puts>

This is more compact & faster (due to the lack of the load & the
dependency the jump has on its result). It is also easier to read &
debug because the disassembly shows what function is being called,
rather than just an offset from gp which would then have to be looked up
in the ELF to discover the target function.

Another disadvantage of -fpic is that each function begins with a
sequence to calculate the value of the gp register, for example:

  3c1c0004   lui    gp,0x4
  279c3384   addiu  gp,gp,13188
  0399e021   addu   gp,gp,t9

Without using -fpic this sequence no longer appears at the start of each
function, reducing code size considerably.

This patch switches U-Boot from building with -fpic to building with
-fno-pic, in order to gain the benefits described above. The cost of
this is an extra step during the build process to extract relocation
data from the ELF & write it into a new .rel section in a compact
format, plus the added complexity of dealing with multiple types of
relocation rather than the single type that applied to the GOT. The
benefit is smaller, cleaner, more debuggable code. The relocate_code()
function is reimplemented in C to handle the new relocation scheme,
which also makes it easier to read & debug.

Taking maltael_defconfig as an example the size of u-boot.bin built
using the Codescape MIPS 2016.05-06 toolchain (gcc 4.9.2, binutils
2.24.90) shrinks from 254KiB to 224KiB.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: Daniel Schwierzeck <daniel.schwierzeck@gmail.com>
Cc: u-boot@lists.denx.de
Reviewed-by: Daniel Schwierzeck <daniel.schwierzeck@gmail.com>
Tested-by: Daniel Schwierzeck <daniel.schwierzeck@gmail.com>
2017-07-25 20:44:00 +02:00