[U-Boot] [PATCH 1/1] x86: detect unsupported relocation types

[Hannes Schmelzer]

On 10/13/18 3:30 AM, Heinrich Schuchardt wrote:
> Currently we support only relocations of type ELF64_R_TYPE or ELF32_R_TYPE.
> We should be warned if other relocation types appear in the relocation
> sections.
>
> This type of message has helped to identify code overwriting a relocation
> section before relocation and incorrect parsing of relocation tables.
>
> Signed-off-by: Heinrich Schuchardt <xypron.glpk at gmx.de>
> ---
>   arch/x86/lib/relocate.c | 18 ++++++++++++++++++
>   1 file changed, 18 insertions(+)
>
> diff --git a/arch/x86/lib/relocate.c b/arch/x86/lib/relocate.c
> index ed10755d9c..01e619d20b 100644
> --- a/arch/x86/lib/relocate.c
> +++ b/arch/x86/lib/relocate.c
> @@ -53,6 +53,15 @@ static void do_elf_reloc_fixups64(unsigned int text_base, uintptr_t size,
>   	Elf64_Addr *offset_ptr_ram;
>   
>   	do {
> +		unsigned long long type = ELF64_R_TYPE(re_src->r_info);
> +
> +		if (type != R_X86_64_RELATIVE) {
> +			printf("%s: unsupported relocation type 0x%llx "
> +			       "at %p, ",__func__, type, re_src);
> +			printf("offset = 0x%llx\n", re_src->r_offset);
> +			continue;
> +		}
> +
>   		/* Get the location from the relocation entry */
>   		offset_ptr_rom = (Elf64_Addr *)(uintptr_t)re_src->r_offset;
>   
> @@ -91,6 +100,15 @@ static void do_elf_reloc_fixups32(unsigned int text_base, uintptr_t size,
>   	Elf32_Addr *offset_ptr_ram;
>   
>   	do {
> +		unsigned int type = ELF32_R_TYPE(re_src->r_info);
> +
> +		if (type != R_386_RELATIVE) {
> +			printf("%s: unsupported relocation type 0x%x "
> +			       "at %p, ",__func__, type, re_src);
> +			printf("offset = 0x%x\n", re_src->r_offset);
> +			continue;
> +		}
> +
>   		/* Get the location from the relocation entry */
>   		offset_ptr_rom = (Elf32_Addr *)(uintptr_t)re_src->r_offset;
>   
Hi Heinrich,
i just merged recent u-boot master into my devbranch and ran it on my board:

--
U-Boot 2018.11-rc2-00728-g85a448b (Oct 23 2018 - 10:50:53 +0200)

CPU: x86, vendor AMD, device 5a2h
DRAM:  119.6 MiB
do_elf_reloc_fixups32: unsupported relocation type 0x1 at 0204d3d0, 
offset = 0x2000087
do_elf_reloc_fixups32: unsupported relocation type 0x2 at 0204d3d8, 
offset = 0x2000091
Bus 0: OK
---

now i get such relocation warnings, can you help me in this how to deal 
with that?

I'm starting u-boot as a payload from coreboot.

thanks!

cheers,
Hannes