powerpc: Remove PT_NOTE workaround

In preparation for moving NOTES into RO_DATA, remove the PT_NOTE
workaround since the kernel requires at least gcc 4.6 now.

Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Michael Ellerman <mpe@ellerman.id.au>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: linux-alpha@vger.kernel.org
Cc: linux-arch@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-c6x-dev@linux-c6x.org
Cc: linux-ia64@vger.kernel.org
Cc: linux-s390@vger.kernel.org
Cc: linuxppc-dev@lists.ozlabs.org
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Rick Edgecombe <rick.p.edgecombe@intel.com>
Cc: Segher Boessenkool <segher@kernel.crashing.org>
Cc: Will Deacon <will@kernel.org>
Cc: x86@kernel.org
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Link: https://lkml.kernel.org/r/20191029211351.13243-3-keescook@chromium.org

diff --git a/arch/powerpc/kernel/vmlinux.lds.S b/arch/powerpc/kernel/vmlinux.lds.S
index 81e6726547898cbb0a7c272c9dab272b62d23667..a3c8492b2b194496dbc3045505d18ecc4917f542 100644 (file)
--- a/arch/powerpc/kernel/vmlinux.lds.S
+++ b/arch/powerpc/kernel/vmlinux.lds.S
@@ -20,20 +20,6 @@ ENTRY(_stext)
 PHDRS {
        kernel PT_LOAD FLAGS(7); /* RWX */
        note PT_NOTE FLAGS(0);
-       dummy PT_NOTE FLAGS(0);
-
-       /* binutils < 2.18 has a bug that makes it misbehave when taking an
-          ELF file with all segments at load address 0 as input.  This
-          happens when running "strip" on vmlinux, because of the AT() magic
-          in this linker script.  People using GCC >= 4.2 won't run into
-          this problem, because the "build-id" support will put some data
-          into the "notes" segment (at a non-zero load address).
-
-          To work around this, we force some data into both the "dummy"
-          segment and the kernel segment, so the dummy segment will get a
-          non-zero load address.  It's not enough to always create the
-          "notes" segment, since if nothing gets assigned to it, its load
-          address will be zero.  */
 }
 
 #ifdef CONFIG_PPC64
@@ -178,14 +164,8 @@ SECTIONS
        EXCEPTION_TABLE(0)
 
        NOTES :kernel :note
-
-       /* The dummy segment contents for the bug workaround mentioned above
-          near PHDRS.  */
-       .dummy : AT(ADDR(.dummy) - LOAD_OFFSET) {
-               LONG(0)
-               LONG(0)
-               LONG(0)
-       } :kernel :dummy
+       /* Restore program header away from PT_NOTE. */
+       .dummy : { *(.dummy) } :kernel
 
 /*
  * Init sections discarded at runtime