On 23 February 2017 at 19:53, Laszlo Ersek <ler...@redhat.com> wrote:
> On 02/23/17 19:30, Ard Biesheuvel wrote:
>> The generated AutoGen.c files mostly contain read-only data, but due to
>> lacking annotations, all of it is emitted into the .data section by the
>> compiler.
>>
>> Given that GUIDs are UEFI's gaffer tape, having writable GUIDs is a
>> security hazard, and this was the main rationale for putting AutoGen.obj
>> in the .text section. However, as it turns out, patchable PCDs are emitted
>> there as well, which can legally be modified at runtime.
>>
>> So update the wildcard pattern to only match g...Guid sections, and move
>> everything else back to .data (Note that this relies on -fdata-sections,
>> without that option, everything is emitted into .data)
>>
>> Contributed-under: TianoCore Contribution Agreement 1.0
>> Signed-off-by: Ard Biesheuvel <ard.biesheu...@linaro.org>
>> ---
>> BaseTools/Scripts/GccBase.lds | 9 ++++++---
>> 1 file changed, 6 insertions(+), 3 deletions(-)
>>
>> diff --git a/BaseTools/Scripts/GccBase.lds b/BaseTools/Scripts/GccBase.lds
>> index 900848747144..41e5c0b4a769 100644
>> --- a/BaseTools/Scripts/GccBase.lds
>> +++ b/BaseTools/Scripts/GccBase.lds
>> @@ -32,11 +32,14 @@ SECTIONS {
>> *(.got .got.*)
>>
>> /*
>> - * The contents of AutoGen.c files are constant from the POV of the
>> program,
>> - * but most of its contents end up in .data or .bss by default since
>> few of
>> + * The contents of AutoGen.c files are mostly constant from the POV of
>> the
>> + * program, but most of it ends up in .data or .bss by default since
>> few of
>> * the variable definitions that get emitted are declared as CONST.
>> + * Unfortunately, we cannot pull it into the .text section entirely,
>> since
>> + * patchable PCDs are also emitted here, but we can at least move all
>> of the
>> + * emitted GUIDs here.
>> */
>> - *:AutoGen.obj(.data .data.* .bss .bss.*)
>> + *:AutoGen.obj(.data.g*Guid)
>> }
>>
>> /*
>>
>
> Do you agree to add:
>
> Fixes: 233bd25b000f92fc4bbe181fa48edcd72808de8e
>
> to the commit message, or to reference that commit in some other form?
>
Yes, that makes sense.
> Either way:
>
> Tested-by: Laszlo Ersek <ler...@redhat.com>
>
> Thank you very much for the quick fix!
No problem.
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