On Wed, 20 Dec 2023 at 22:26, Rebecca Cran <rebe...@bsdio.com> wrote: > > Reviewed-by: Rebecca Cran <rebe...@bsdio.com> >
Merged as #5183 Thanks all > > On 12/20/2023 12:31 PM, Jake Garver wrote: > > In the R_AARCH64_ADR_GOT_PAGE case on AARCH64, we may encounter an ADR > > instead of an ADRP when the toolchain is working around Cortex-A53 > > erratum #843419. If that's the case, be sure to calculate the offset > > appropriately. > > > > This resolves an issue experienced when building a StandaloneMm image > > with stack protection enabled on GCC compiled with > > "--enable-fix-cortex-a53-843419". This scenario sometimes generates an > > ADR with a R_AARCH64_ADR_GOT_PAGE relocation. > > > > In this scenario, the following code is being generated by the > > toolchain: > > > > # Load to set the stack canary > > 2ffc: 10028020 adr x0, 8000 <mErrorString+0x1bc> > > 3008: f940d400 ldr x0, [x0, #424] > > > > # Load to check the stack canary > > 30cc: b0000020 adrp x0, 8000 <mErrorString+0x1bc> > > 30d0: f940d400 ldr x0, [x0, #424] > > > > GenFw rewrote that to: > > > > # Load to set the stack canary > > 2ffc: 10000480 adr x0, 0x308c > > 3008: 912ec000 add x0, x0, #0xbb0 > > > > # Load to check the stack canary > > 30cc: f0000460 adrp x0, 0x92000 > > 30d0: 912ec000 add x0, x0, #0xbb0 > > > > Note that we're now setting the stack canary from the wrong address, > > resulting in an erroneous stack fault. > > > > After this fix, the offset will be calculated correctly for an ADR and > > the stack canary is set correctly. > > > > Signed-off-by: Jake Garver <j...@nvidia.com> > > --- > > > > Notes: > > v2: Implement approach proposed by Ard Biesheuvel. > > - title changed to: Correct offset when relocating an ADR > > v1: Original title: Change opcode when converting ADR to ADRP > > > > BaseTools/Source/C/GenFw/Elf64Convert.c | 22 +++++++++++++++++++++- > > 1 file changed, 21 insertions(+), 1 deletion(-) > > > > diff --git a/BaseTools/Source/C/GenFw/Elf64Convert.c > > b/BaseTools/Source/C/GenFw/Elf64Convert.c > > index 9911db65af..9d04fc612e 100644 > > --- a/BaseTools/Source/C/GenFw/Elf64Convert.c > > +++ b/BaseTools/Source/C/GenFw/Elf64Convert.c > > @@ -1562,7 +1562,27 @@ WriteSections64 ( > > // subsequent LDR instruction (covered by a > > R_AARCH64_LD64_GOT_LO12_NC > > // relocation) into an ADD instruction - this is handled > > above. > > // > > - Offset = (Sym->st_value - (Rel->r_offset & ~0xfff)) >> 12; > > + // In order to handle Cortex-A53 erratum #843419, the GCC > > toolchain > > + // may convert an ADRP instruction at the end of a page (0xffc > > + // offset) into an ADR instruction. If so, be sure to > > calculate the > > + // offset for an ADR instead of ADRP. > > + // > > + if ((*(UINT32 *)Targ & BIT31) == 0) { > > + // > > + // Calculate the offset for an ADR. > > + // > > + Offset = (Sym->st_value & ~0xfff) - Rel->r_offset; > > + if (Offset < -0x100000 || Offset > 0xfffff) { > > + Error (NULL, 0, 3000, "Invalid", "WriteSections64(): %s > > due to its size (> 1 MB), unable to relocate ADR.", > > + mInImageName); > > + break; > > + } > > + } else { > > + // > > + // Calculate the offset for an ADRP. > > + // > > + Offset = (Sym->st_value - (Rel->r_offset & ~0xfff)) >> 12; > > + } > > > > *(UINT32 *)Targ &= 0x9000001f; > > *(UINT32 *)Targ |= ((Offset & 0x1ffffc) << (5 - 2)) | > > ((Offset & 0x3) << 29); > > > > > > > -=-=-=-=-=-=-=-=-=-=-=- Groups.io Links: You receive all messages sent to this group. View/Reply Online (#112806): https://edk2.groups.io/g/devel/message/112806 Mute This Topic: https://groups.io/mt/103287393/21656 Group Owner: devel+ow...@edk2.groups.io Unsubscribe: https://edk2.groups.io/g/devel/unsub [arch...@mail-archive.com] -=-=-=-=-=-=-=-=-=-=-=-