[U-Boot] [PATCH 5/5] riscv: efi: Generate Microsoft PE format complaint images

[Heinrich Schuchardt]

On 09/26/2018 08:03 AM, Bin Meng wrote:
> Per Microsoft PE Format documentation [1], PointerToSymbolTable and
> NumberOfSymbols should be zero for an image in the COFF file header.
> Currently the COFF file header is hardcoded on RISC-V and these two
> members are not zero.
> 
> This updates the hardcoded structure to clear these two members, as
> well as setting the flag IMAGE_FILE_LOCAL_SYMS_STRIPPED so that we
> can generate compliant *.efi images.
> 
> [1] https://docs.microsoft.com/zh-cn/windows/desktop/Debug/pe-format
> 
> Signed-off-by: Bin Meng <bmeng.cn at gmail.com>
> ---
> 
>  arch/riscv/lib/crt0_riscv_efi.S | 7 ++++---
>  1 file changed, 4 insertions(+), 3 deletions(-)
> 
> diff --git a/arch/riscv/lib/crt0_riscv_efi.S b/arch/riscv/lib/crt0_riscv_efi.S
> index 18f61f5..6d61b3a 100644
> --- a/arch/riscv/lib/crt0_riscv_efi.S
> +++ b/arch/riscv/lib/crt0_riscv_efi.S
> @@ -41,13 +41,14 @@ coff_header:
>  	.short	2				/* nr_sections */
>  	.long	0				/* TimeDateStamp */
>  	.long	0				/* PointerToSymbolTable */
> -	.long	1				/* NumberOfSymbols */
> +	.long	0				/* NumberOfSymbols */
>  	.short	section_table - optional_header	/* SizeOfOptionalHeader */
>  	/*
>  	 * Characteristics: IMAGE_FILE_DEBUG_STRIPPED |
> -	 * IMAGE_FILE_EXECUTABLE_IMAGE | IMAGE_FILE_LINE_NUMS_STRIPPED
> +	 * IMAGE_FILE_EXECUTABLE_IMAGE | IMAGE_FILE_LINE_NUMS_STRIPPED |
> +	 * IMAGE_FILE_LOCAL_SYMS_STRIPPED
>  	 */

Thanks for your patch.

I think your code misses to set IMAGE_FILE_32BIT_MACHINE in dependence
of the bitness of the system.

I would prefer if these constants were defined in asm-generic/pe.h:

#define IMAGE_FILE_RELOCS_STRIPPED		0x0001
#define IMAGE_FILE_EXECUTABLE_IMAGE		0x0002
#define IMAGE_FILE_LINE_NUMS_STRIPPED		0x0004
#define IMAGE_FILE_LOCAL_SYMS_STRIPPED		0x0008
#define IMAGE_FILE_AGGRESSIVE_WS_TRIM 		0x0010
#define IMAGE_FILE_LARGE_ADDRESS_AWARE		0x0020
/* Reserved					0x0040 */
#define IMAGE_FILE_BYTES_REVERSED_LO		0x0080
#define IMAGE_FILE_32BIT_MACHINE		0x0100
#define IMAGE_FILE_DEBUG_STRIPPED		0x0200
#define IMAGE_FILE_REMOVABLE_RUN_FROM_SWAP	0x0400
#define IMAGE_FILE_NET_RUN_FROM_SWAP		0x0800
#define IMAGE_FILE_SYSTEM			0x1000
#define IMAGE_FILE_DLL				0x2000
#define IMAGE_FILE_UP_SYSTEM_ONLY		0x4000
#define IMAGE_FILE_BYTES_REVERSED_HI		0x8000

These values of "characteristics" I found in the wild:

Windows: memtest.efi: Characteristics 0x22
Windows: bootmgfw.efi: Characteristics 0x2022
GRUB: bootx64.efi: Characteristics 0x20e
EDK2:
Characteristics 0x10e
Characteristics 0x2022
Characteristics 0x2102
Characteristics 0x2e

Best regards

Heinrich

> -	.short	0x206
> +	.short	0x20e
>  optional_header:
>  	.short	0x20b				/* PE32+ format */
>  	.byte	0x02				/* MajorLinkerVersion */
>