switch-l4t-atf/include/common/asm_macros_common.S
Masahiro Yamada fed18b3aec asm_macros: set the default assembly code alignment to 4 byte
Assembly routines are usually defined by using "func" and "endfunc":

    func foo
      ...
    endfunc foo

Currently, the "func" macro does not specify ".align" directive
by default.  It causes unaligned instruction under some circumstances.

As far as I tested, this problem happens for GCC 5 or older.  It did
not happen for GCC 6 or newer.  Taking into account that GCC 4.x / 5.x
is still used, make sure that assembly code is at least 4 byte aligned.

[ How to reproduce the problem ]

For example, use GCC 5.3 downloaded from Linaro:
http://releases.linaro.org/components/toolchain/binaries/5.3-2016.05/
aarch64-linux-gnu/gcc-linaro-5.3.1-2016.05-x86_64_aarch64-linux-gnu.tar.xz

Expand mbedtls-2.4.2 to the current directory.

Try the following:

  $ git log --oneline -1
  77544ef Merge pull request #1071 from jeenu-arm/syntax-fix
  $ aarch64-linux-gnu-gcc --version | head -1
  aarch64-linux-gnu-gcc (Linaro GCC 5.3-2016.05) 5.3.1 20160412
  $ make CROSS_COMPILE=aarch64-linux-gnu- PLAT=uniphier \
    TRUSTED_BOARD_BOOT=1 MBEDTLS_DIR=mbedtls-2.4.2
    ( snip build log )
  $ aarch64-linux-gnu-nm build/uniphier/release/bl1/bl1.elf | grep handler
  00000000800088f4 T bl1_fwu_smc_handler
  00000000800084c8 T bl1_smc_handler
  000000008000a6e0 t _panic_handler
  000000008000a8e0 W plat_error_handler
  000000008000a8e8 W plat_panic_handler
  000000008000a8d8 W plat_reset_handler
  000000008000a39f T reset_handler
  000000008000a367 t smc_handler
  000000008000a2ef t smc_handler64

You will notice "smc_handler64", "reset_handler", etc. are not properly
aligned.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2017-08-31 18:45:19 +09:00

110 lines
3.0 KiB
ArmAsm

/*
* Copyright (c) 2013-2017, ARM Limited and Contributors. All rights reserved.
*
* SPDX-License-Identifier: BSD-3-Clause
*/
#ifndef __ASM_MACROS_COMMON_S__
#define __ASM_MACROS_COMMON_S__
/*
* This macro is used to create a function label and place the
* code into a separate text section based on the function name
* to enable elimination of unused code during linking. It also adds
* basic debug information to enable call stack printing most of the
* time. The optional _align parameter can be used to force a
* non-standard alignment (indicated in powers of 2). The default is
* _align=2 because both Aarch32 and Aarch64 instructions must be
* word aligned. Do *not* try to use a raw .align directive. Since func
* switches to a new section, this would not have the desired effect.
*/
.macro func _name, _align=2
/*
* Add Call Frame Information entry in the .debug_frame section for
* debugger consumption. This enables callstack printing in debuggers.
* This does not use any space in the final loaded binary, only in the
* ELF file.
* Note that a function manipulating the CFA pointer location (i.e. the
* x29 frame pointer on AArch64) should declare it using the
* appropriate .cfi* directives, or be prepared to have a degraded
* debugging experience.
*/
.cfi_sections .debug_frame
.section .text.\_name, "ax"
.type \_name, %function
.func \_name
/*
* .cfi_startproc and .cfi_endproc are needed to output entries in
* .debug_frame
*/
.cfi_startproc
.align \_align
\_name:
.endm
/*
* This macro is used to mark the end of a function.
*/
.macro endfunc _name
.endfunc
.cfi_endproc
.size \_name, . - \_name
.endm
/*
* Theses macros are used to create function labels for deprecated
* APIs. If ERROR_DEPRECATED is non zero, the callers of these APIs
* will fail to link and cause build failure.
*/
#if ERROR_DEPRECATED
.macro func_deprecated _name
func deprecated\_name
.endm
.macro endfunc_deprecated _name
endfunc deprecated\_name
.endm
#else
.macro func_deprecated _name
func \_name
.endm
.macro endfunc_deprecated _name
endfunc \_name
.endm
#endif
/*
* Helper assembler macro to count trailing zeros. The output is
* populated in the `TZ_COUNT` symbol.
*/
.macro count_tz _value, _tz_count
.if \_value
count_tz "(\_value >> 1)", "(\_tz_count + 1)"
.else
.equ TZ_COUNT, (\_tz_count - 1)
.endif
.endm
/*
* This macro declares an array of 1 or more stacks, properly
* aligned and in the requested section
*/
#define DEFAULT_STACK_ALIGN (1 << 6) /* In case the caller doesnt provide alignment */
.macro declare_stack _name, _section, _size, _count, _align=DEFAULT_STACK_ALIGN
count_tz \_align, 0
.if (\_align - (1 << TZ_COUNT))
.error "Incorrect stack alignment specified (Must be a power of 2)."
.endif
.if ((\_size & ((1 << TZ_COUNT) - 1)) <> 0)
.error "Stack size not correctly aligned"
.endif
.section \_section, "aw", %nobits
.align TZ_COUNT
\_name:
.space ((\_count) * (\_size)), 0
.endm
#endif /* __ASM_MACROS_COMMON_S__ */