[PATCH v2 11/15] arm: riscv: efi: Export _start symbol from crt0_*_efi stubs

[Heinrich Schuchardt]

On 3/15/25 23:18, Sam Edwards wrote:
> While the _start label is only intended for use locally to populate the
> (hand-written) PE header, the linker script includes ENTRY(_start) which
> designates it as the entry point in the output ELF, resulting in linker
> warnings under some linkers (e.g. LLVM's lld) due to _start not being a
> globally-visible symbol. Since  ELF is only an intermediary build
> format, and the aforementioned PE header correctly points to _start, the
> ENTRY(_start) directive could easily be removed to silence this warning.
>
> However, since some developers who are debugging EFI by analyzing the
> intermediary ELF may appreciate having correct entry-point information,
> this patch instead promotes the _start labels to global symbols,
> silencing the linker warning and making the intermediary ELF reflect the
> true entry point.
>
> This patch doesn't affect the final output binaries in any way.
>
> Signed-off-by: Sam Edwards <CFSworks at gmail.com>

Reviewed-by: Heinrich Schuchardt <xypron.glpk at gmx.de>

> ---
>   arch/arm/lib/crt0_aarch64_efi.S | 1 +
>   arch/arm/lib/crt0_arm_efi.S     | 1 +
>   arch/riscv/lib/crt0_riscv_efi.S | 1 +
>   3 files changed, 3 insertions(+)
>
> diff --git a/arch/arm/lib/crt0_aarch64_efi.S b/arch/arm/lib/crt0_aarch64_efi.S
> index e21b54fdbcb..003d5f83041 100644
> --- a/arch/arm/lib/crt0_aarch64_efi.S
> +++ b/arch/arm/lib/crt0_aarch64_efi.S
> @@ -144,6 +144,7 @@ section_table:
>   		 IMAGE_SCN_CNT_INITIALIZED_DATA)
>
>   	.align		12
> +	.globl		_start
>   _start:
>   	stp		x29, x30, [sp, #-32]!
>   	mov		x29, sp
> diff --git a/arch/arm/lib/crt0_arm_efi.S b/arch/arm/lib/crt0_arm_efi.S
> index 235b3a0c48f..593ee1e194a 100644
> --- a/arch/arm/lib/crt0_arm_efi.S
> +++ b/arch/arm/lib/crt0_arm_efi.S
> @@ -143,6 +143,7 @@ section_table:
>   		 IMAGE_SCN_CNT_INITIALIZED_DATA)
>
>   	.align		12
> +	.globl		_start
>   _start:
>   	stmfd		sp!, {r0-r2, lr}
>
> diff --git a/arch/riscv/lib/crt0_riscv_efi.S b/arch/riscv/lib/crt0_riscv_efi.S
> index 9eacbe4a859..f170e4b26d6 100644
> --- a/arch/riscv/lib/crt0_riscv_efi.S
> +++ b/arch/riscv/lib/crt0_riscv_efi.S
> @@ -179,6 +179,7 @@ section_table:
>   		 IMAGE_SCN_CNT_INITIALIZED_DATA)
>
>   	.align		12
> +	.globl		_start
>   _start:
>   	addi		sp, sp, -(SIZE_LONG * 3)
>   	SAVE_LONG(a0, 0)