On Mon, Mar 27, 2023 at 12:01 PM Ard Biesheuvel <a...@kernel.org> wrote: > > Implement a CPP macro that can be called from .S files to emit the .note > section carrying the annotation that informs the linker that the object > file is compatible with BTI control flow integrity checks. > > Signed-off-by: Ard Biesheuvel <a...@kernel.org> > --- > MdePkg/Include/AArch64/ProcessorBind.h | 31 ++++++++++++++++++++ > 1 file changed, 31 insertions(+) > > diff --git a/MdePkg/Include/AArch64/ProcessorBind.h > b/MdePkg/Include/AArch64/ProcessorBind.h > index abe2571245c665f3..11814f1ffaef698a 100644 > --- a/MdePkg/Include/AArch64/ProcessorBind.h > +++ b/MdePkg/Include/AArch64/ProcessorBind.h > @@ -186,6 +186,37 @@ typedef INT64 INTN; > #define GCC_ASM_IMPORT(func__) \ > .extern _CONCATENATE (__USER_LABEL_PREFIX__, func__) > > +#if defined(__ARM_FEATURE_BTI_DEFAULT) && __ARM_FEATURE_BTI_DEFAULT == 1 > +#define AARCH64_BTI(__type) \ > + .ifnc __type, ;\ > + bti __type ;\ > + .endif ;\ > + .ifndef .Lgnu_bti_notesize ;\ > + .pushsection .note.gnu.property, "a" ;\ > + .set NT_GNU_PROPERTY_TYPE_0, 0x5 ;\ > + .set GNU_PROPERTY_AARCH64_FEATURE_1_AND, 0xc0000000 ;\ > + .set GNU_PROPERTY_AARCH64_FEATURE_1_BTI, 0x1 ;\ > + .align 3 ;\ > + .long .Lnamesize ;\ > + .long .Lgnu_bti_notesize ;\ > + .long NT_GNU_PROPERTY_TYPE_0 ;\ > +0: .asciz "GNU" ;\ > + .set .Lnamesize, . - 0b ;\ > + .align 3 ;\ > +1: .long GNU_PROPERTY_AARCH64_FEATURE_1_AND ;\ > + .long .Lvalsize ;\ > +2: .long GNU_PROPERTY_AARCH64_FEATURE_1_BTI ;\ > + .set .Lvalsize, . - 2b ;\ > + .align 3 ;\ > + .set .Lgnu_bti_notesize, . - 1b ;\ > + .popsection ;\ > + .endif > +#endif > + > +#endif > + > +#ifndef AARCH64_BTI > +#define AARCH64_BTI(__type) > #endif > > /** > -- > 2.39.2
Patch-set wide comment: is there any chance we could take this opportunity to introduce a global ASM_FUNC (or a more Linux-named ENTRY(FuncName))? It seems to be that the current way is a bit error prone and you end up repeating yourself quite a bit with: ASM_PFX(Foo): AARCH64_BTI(c) <code> having a: ASM_FUNC(Foo) <code> that does proper PFX and BTI expansion internally seems better to me. -- Pedro -=-=-=-=-=-=-=-=-=-=-=- Groups.io Links: You receive all messages sent to this group. View/Reply Online (#101959): https://edk2.groups.io/g/devel/message/101959 Mute This Topic: https://groups.io/mt/97879282/21656 Group Owner: devel+ow...@edk2.groups.io Unsubscribe: https://edk2.groups.io/g/devel/unsub [arch...@mail-archive.com] -=-=-=-=-=-=-=-=-=-=-=-
