On Mon, 7 Dec 2020 at 19:08, dann frazier <dann.frazier@xxxxxxxxxxxxx> wrote:
>
> On Mon, Dec 7, 2020 at 10:50 AM Ard Biesheuvel <ardb@xxxxxxxxxx> wrote:
> >
> > On Mon, 7 Dec 2020 at 18:26, dann frazier <dann.frazier@xxxxxxxxxxxxx> wrote:
> > >
> > > This reverts commit c042dd600f4e89b6e7bdffa00aea4d1d3c1e9686.
> > >
> > > This caused the build to emit ADR_PREL_PG_HI21 relocations in the sha{1,2}_ce
> > > modules. This relocation type is not supported by the linux-4.4.y kernel
> > > module loader when CONFIG_ARM64_ERRATUM_843419=y, which we have enabled, so
> > > these modules now fail to load:
> > >
> > > [ 37.866250] module sha1_ce: unsupported RELA relocation: 275
> > >
> > > This issue does not exist with the backport to 4.9+. Bisection shows that
> > > this is due to those kernels also having a backport of
> > > commit 41c066f ("arm64: assembler: make adr_l work in modules under KASLR")
> >
> > Hi Dann,
> >
> > Would it be an option to backport 41c066f as well?
>
> Hi Ard,
>
> That was attempted before, but caused a build failure which would
> still happen today:
> https://www.spinics.net/lists/stable/msg179709.html
> Specifically, head.S still has a 3 argument usage of adr_l. I'm not
> sure how to safely fix that up myself.
>
Given that the original reason for reverting the backport of 41c066f
no longer holds (as there are other users of adr_l in v4.4 now), I
think the best solution is to backport it again, but with the hunk
below folded in. (This just replaces the macro invocation with its
output when called with the 3 arguments in question, so the generated
code is identical)
--- a/arch/arm64/kernel/head.S
+++ b/arch/arm64/kernel/head.S
@@ -424,7 +424,8 @@ __mmap_switched:
str xzr, [x6], #8 // Clear BSS
b 1b
2:
- adr_l sp, initial_sp, x4
+ adrp x4, initial_sp
+ add sp, x4, :lo12:initial_sp
str_l x21, __fdt_pointer, x5 // Save FDT pointer
str_l x24, memstart_addr, x6 // Save PHYS_OFFSET
mov x29, #0
