u-boot.git/arch/mips/include, branch v2017.09

MIPS: Stop building position independent code

2017-07-25T18:44:00+00:00

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 

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 
Cc: Daniel Schwierzeck 
Cc: u-boot@lists.denx.de
Reviewed-by: Daniel Schwierzeck 
Tested-by: Daniel Schwierzeck

mips: Make u-boot-mips.h a private header

2017-06-05T15:02:33+00:00

Rather than including this arch-specific header file in common.h, include
it from within mips's u-boot.h header.

Signed-off-by: Simon Glass 
Reviewed-by: Daniel Schwierzeck

mips: Use common _AC macro now.

2017-01-10T13:19:26+00:00

MIPS no longer needs to have its own version of this macro now.

Fixes: 2a6713b09b8d ("move UL() macro from armv8/mmu.h into common.h")
Signed-off-by: Tom Rini

MIPS: Fix map_physmem for cached mappings

2016-11-30T15:18:19+00:00

map_physmem should return a pointer that can be used by the CPU to
access the given memory - on MIPS simply returning the physical address
as it does prior to this patch doesn't achieve that. Instead return a
pointer to the memory within (c)kseg0, which matches up consistently
with the (c)kseg1 pointer that uncached mappings return via ioremap.

Signed-off-by: Paul Burton

mips: Let cache.h be included from assembly source

2016-11-30T15:13:17+00:00

Add ifdef __ASSEMBLY__ around the function prototype to let cache.h
be included from assembly code.

Signed-off-by: Marek Vasut 
Cc: Daniel Schwierzeck 
Cc: Paul Burton

MIPS: add handling for generic and EJTAG exceptions

2016-11-30T15:12:17+00:00

Add exception handlers for generic and EJTAG exceptions. Most of
the assembly code is imported from Linux kernel and adapted to U-Boot.
The exception vector table will be reserved above the stack before
U-Boot is relocated. The exception handlers will be installed and
activated after relocation in the initr_traps hook function.

Generic exceptions are handled by showing a CPU register dump similar
to Linux kernel. For example:

malta # md 1
00000001:
Ooops:
$ 0   : 00000000 00000000 00000009 00000004
$ 4   : 8ff7e108 00000000 0000003a 00000000
$ 8   : 00000008 00000001 8ff7cd18 00000004
$12   : 00000002 00000000 00000005 0000003a
$16   : 00000004 00000040 00000001 00000001
$20   : 00000000 8fff53c0 00000008 00000004
$24   : ffffffff 8ffdea44
$28   : 90001650 8ff7cd00 00000004 8ffe6818
Hi    : 00000000
Lo    : 00000004
epc   : 8ffe6848 (text bfc28848)
ra    : 8ffe6818 (text bfc28818)
Status: 00000006
Cause : 00000410 (ExcCode 04)
BadVA : 8ff9e928
PrId  : 00019300
 ### ERROR ### Please RESET the board ###

EJTAG exceptions are checked for SDBBP and delegated to the SDBBP handler
if necessary. Otherwise the debug mode will simply be exited. The SDBBP
handler currently prints the contents of registers c0_depc and c0_debug.
This could be extended in the future to handle semi-hosting according to
the MIPS UHI specification.

Signed-off-by: Daniel Schwierzeck 
Reviewed-by: Paul Burton 
Tested-by: Paul Burton

MIPS: add asm-offsets for struct pt_regs

2016-11-30T15:11:46+00:00

Import asm-offsets.c from kernel to generate offset for struct pt_regs
needed by exception handlers.

Signed-off-by: Daniel Schwierzeck

MIPS: fix iand optimize setup of CP0 registers

2016-11-30T15:11:46+00:00

Clear cp0 status while preserving implementation specific bits.
Set bits BEV and ERL as the arch specification requires after
a reset or soft-reset exception.

Extend and fix initialization of watch registers. Check if additional
watch register sets are implemented and initialize them too.

Initialize cp0 count as early as possible to get the most
accurate boot timing.

Signed-off-by: Daniel Schwierzeck

efi: Use asmlinkage for EFIAPI

2016-10-19T07:01:53+00:00

This is required for x86 and is also correct for ARM (since it is empty).

Signed-off-by: Simon Glass 
Reviewed-by: Bin Meng 
Signed-off-by: Alexander Graf

Remove arch/${ARCH}/include/asm/errno.h

2016-09-23T21:56:18+00:00

Unlike Linux, nothing about errno.h is arch-specific in U-Boot.
As you see, all of arch/${ARCH}/include/asm/errno.h is just a
wrapper of .  Actually, U-Boot does not
export headers to user-space, so we just have to care about the
consistency in the U-Boot tree.

Now all of include directives for  are gone.
Deprecate .

Signed-off-by: Masahiro Yamada 
Acked-by: Alexey Brodkin