arm64: vmlinux.lds: account for spurious empty .igot.plt sections

Now that we started making the linker warn about orphan sections
(input sections that are not explicitly consumed by an output section),
some configurations produce the following warning:

  aarch64-linux-gnu-ld: warning: orphan section `.igot.plt' from
         `arch/arm64/kernel/head.o' being placed in section `.igot.plt'

It could be any file that triggers this - head.o is simply the first
input file in the link - and the resulting .igot.plt section never
actually appears in vmlinux as it turns out to be empty.

So let's add .igot.plt to our collection of input sections to disregard
unless they are empty.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Cc: Jessica Yu <jeyu@kernel.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Link: https://lore.kernel.org/r/20201028133332.5571-1-ardb@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>

diff --git a/arch/arm64/kernel/vmlinux.lds.S b/arch/arm64/kernel/vmlinux.lds.S
index 6d78c041fdf691b91786c0152534a84d5f46f1a6..1bda604f4c704bd22f810c02fcacd60d720c43e4 100644 (file)
--- a/arch/arm64/kernel/vmlinux.lds.S
+++ b/arch/arm64/kernel/vmlinux.lds.S
@@ -278,7 +278,7 @@ SECTIONS
         * explicitly check instead of blindly discarding.
         */
        .plt : {
-               *(.plt) *(.plt.*) *(.iplt) *(.igot)
+               *(.plt) *(.plt.*) *(.iplt) *(.igot .igot.plt)
        }
        ASSERT(SIZEOF(.plt) == 0, "Unexpected run-time procedure linkages detected!")