search for: __cfi_check

...The dynamic linker needs to make the read-only VMA briefly writable in order for it to have the same VM flags with the RELRO VMA so that they can be merged. Specifically VM_ACCOUNT is set when a VMA is made writable. 2. The cross-DSO CFI implementation in Android dynamic linker currently assumes __cfi_check is at a lower address than all CFI targets, so CFI check fails when RELRO is moved to below text section. After I added support for CFI targets below __cfi_check, I don't see CFI failures anymore. One drawback that comes with this change is that the number of LOAD segments increases by one for...

...mic linker needs to make the read-only VMA briefly writable in order for it to have the same VM flags with the RELRO VMA so that they can be merged. Specifically VM_ACCOUNT is set when a VMA is made writable. >> 2. The cross-DSO CFI implementation in Android dynamic linker currently assumes __cfi_check is at a lower address than all CFI targets, so CFI check fails when RELRO is moved to below text section. After I added support for CFI targets below __cfi_check, I don't see CFI failures anymore. >> One drawback that comes with this change is that the number of LOAD segments increases by...

The problem as I recall was that we do not want jumptable sections to appear before __cfi_check, so we gave these jump tables a name so that the bfd default linker script would sort them after __cfi_check. This is the relevant part of the default linker script: .text : { [...] *(.text.hot .text.hot.*) *(.text .stub .text.* .gnu.linkonce.t.*) } So I guess the idea...

Taking out that line breaks some LowerTypeTest tests, need to investigate. Runtime compiler-rt all passed. > On May 1, 2018, at 3:11 PM, Peter Collingbourne <peter at pcc.me.uk> wrote: > > The problem as I recall was that we do not want jumptable sections to appear before __cfi_check, so we gave these jump tables a name so that the bfd default linker script would sort them after __cfi_check. This is the relevant part of the default linker script: > > .text : > { > [...] > *(.text.hot .text.hot.*) > *(.text .stub .text.* .gnu.linkonce...

Jump table sections already have this prefix: ".text..L.cfi.jumptable.”, without forcing the name with setSection(). Is that good enough? > On May 1, 2018, at 1:16 PM, Peter Collingbourne <peter at pcc.me.uk> wrote: > > I think we just need to change the section name for non-MachO object formats because "__TEXT,__text,regular,pure_instructions" is the default text

...iefly >> writable in order for it to have the same VM flags with the RELRO VMA so >> that they can be merged. Specifically VM_ACCOUNT is set when a VMA is made >> writable. >> >> 2. The cross-DSO CFI implementation in Android dynamic linker >> currently assumes __cfi_check is at a lower address than all CFI targets, >> so CFI check fails when RELRO is moved to below text section. After I added >> support for CFI targets below __cfi_check, I don't see CFI failures anymore. >> >> One drawback that comes with this change is that the number of...