[U-Boot] [BUG ] efiloader: incorrect creation of *.efi file

[Alexander Graf]

> Am 19.01.2019 um 17:40 schrieb Heinrich Schuchardt <xypron.glpk at gmx.de>:
> 
>> On 1/19/19 12:55 PM, Heinrich Schuchardt wrote:
>>> On 1/19/19 11:21 AM, Heinrich Schuchardt wrote:
>>> Hello Alex,
>>> 
>>> bootefi hello fails since  5be444d14b380b210b246aa73dd5a111e4b1f80d
>>> efi_loader: consistent build flags for EFI applications
>>> 
>>> The problem is caused by incorrect entry point information in the EFI
>>> binary:
>>> 
>>> Actual positions in EFI file:
>>> 0x178 hw_memcmp.constprop.0
>>> 0x1a8 efi_main
>>> 
>>> Header information in EFI file
>>> (using https://github.com/xypron/efi_analyzer):
>>> 
>>> BaseOfCode=0x148
>>> AddressOfEntryPoint=0x148
>>> 
>>> So AddressOfEntryPoint is not pointing to efi_main().
>> 
>> In arch/arm/lib/crt0_aarch64_efi.S we define AddressOfEntryPoint to
>> point to _start. _start() calls _relocate().
>> 
>> We already do a relocation in efi_load_pe(). I cannot understand why the
>> code should be relocated twice.
>> 
>> Best regards
>> 
>> Heinrich
>> 
> 
> Though I still do not understand why we call relocation twice the real
> bug seems to stem form a call to a non-existent memcpy() function.
> 
> See address 0x74 of the disassembly.

Ah, yes. You must not use -Os for the efi binary, otherwise it pulls it back in. I guess I should've put a comment there...

Alex

> 
> https://gcc.gnu.org/onlinedocs/gcc/Standards.html teaches:
> "GCC requires the freestanding environment provide memcpy, memmove,
> memset and memcmp."
> 
>        struct efi_simple_text_output_protocol *con_out = systable->con_out;
>  60:   f940203b        ldr     x27, [x1, #64]
>        u16 rev[] = L"0.0.0";
>  64:   aa1303e0        mov     x0, x19
>        struct efi_boot_services *boottime = systable->boottime;
>  68:   f940303a        ldr     x26, [x1, #96]
>        u16 rev[] = L"0.0.0";
>  6c:   90000001        adrp    x1, 0 <hw_memcmp.constprop.0>
>  70:   91000021        add     x1, x1, #0x0
>  74:   94000000        bl      0 <memcpy>
> 
>        /* UEFI requires CR LF */
>        con_out->output_string(con_out, L"Hello, world!\r\n");
>  78:   f9400762        ldr     x2, [x27, #8]
>  7c:   90000001        adrp    x1, 0 <hw_memcmp.constprop.0>
>  80:   aa1b03e0        mov     x0, x27
>  84:   91000021        add     x1, x1, #0x0
>  88:   d63f0040        blr     x2
> 
> 
> Regards
> 
> Heinrich