[PATCH 1/1] sandbox: add symbol _init for RISC-V compilation

[Heinrich Schuchardt]

On 5/18/21 11:36 PM, Jim Wilson wrote:
> On Tue, May 18, 2021 at 2:32 PM Jim Wilson <jimw at sifive.com
> <mailto:jimw at sifive.com>> wrote:
>
>     On Tue, May 18, 2021 at 1:58 PM Heinrich Schuchardt
>     <xypron.glpk at gmx.de <mailto:xypron.glpk at gmx.de>> wrote:
>
>         I am compiling the sandbox_defconfig target of upstream U-Boot
>         with GCC
>         11. Please, indicate what "legacy user code" you are referring to.
>
>
>     I have no idea what that is.  I'm not a uboot developer.
>
>
> By "user code" I mean that it isn't toolchain code, as the toolchain
> doesn't use init.
>
> Jim

This seems to be the culprit:

common/board_f.c:269:
#elif defined(CONFIG_SANDBOX) || defined(CONFIG_EFI_APP)
         gd->mon_len = (ulong)&_end - (ulong)_init;

gd->mon_len is used here:

common/board_f.c:344
gd->ram_top = board_get_usable_ram_top(gd->mon_len);

@Simon:
We don't relocate the sandbox code into the mmap'ed memory.
Why should we use a nonzero value of gd->mon_len on the sandbox?

When compiling the sandbox on x86_64 u-boot.map has:

.init           0x0000000000031000       0x17
  *(SORT_NONE(.init))
  .init          0x0000000000031000       0x12
/usr/lib/gcc/x86_64-linux-gnu/11/../../../x86_64-linux-gnu/crti.o
                 0x0000000000031000                _init
  .init          0x0000000000031012        0x5
/usr/lib/gcc/x86_64-linux-gnu/11/../../../x86_64-linux-gnu/crtn.o

This relates to
https://github.com/gcc-mirror/gcc/blob/master/libgcc/config/i386/crti.S

This file defines symbols _init and _fini.

For aarch64 we have:

https://github.com/gcc-mirror/gcc/blob/master/libgcc/config/aarch64/crti.S
This file contains symbols _init and _fini, too.

For RISC-V we have:

https://github.com/gcc-mirror/gcc/blob/master/libgcc/config/riscv/crti.S

It contains only a comment
/* crti.S is empty because .init_array/.fini_array are used exclusively. */

Symbols _init and _fini don't exist on RISC-V.

As the usage of _init is deprecated in GCC we should not use it in any
U-Boot configuration, neither for SANDBOX nor for EFI_APP.

Best regards

Heinrich