[PATCH v2] powerpc/vmlinux.lds: Drop binutils < 2.18 workarounds

[Joel Stanley <joel@jms.id.au>]

Segher added some workarounds for binutils < 2.18 and GCC < 4.2. We
now set GCC 4.6 and binutils 2.20 as the minimum, so the workarounds
can be dropped.

This is mostly a revert of c69cccc95fe4 ("powerpc: Fix build bug with
binutils < 2.18 and GCC < 4.2"), except we keep the kernel PHDRS
statement as ppc64_defconfig would fail to link without it:

 powerpc64-linux-ld: .tmp_vmlinux1: Not enough room for program headers, try linking with -N
 powerpc64-linux-ld: final link failed: Bad value

See https://lore.kernel.org/linuxppc-dev/20190321003253.22100-1-joel@jms.id.au/
for the discussion.

Signed-off-by: Joel Stanley <joel@jms.id.au>
---
v2: Fix ppc64_defconfig by keeping kernel PHDRS

Segher, Christophe, I did my best but to summarise your conversation.
Please suggest corrections or additions to the commit message if you
have any.

---
 arch/powerpc/kernel/vmlinux.lds.S | 25 +------------------------
 1 file changed, 1 insertion(+), 24 deletions(-)

diff --git a/arch/powerpc/kernel/vmlinux.lds.S b/arch/powerpc/kernel/vmlinux.lds.S
index 060a1acd7c6d..9ddc7c0dc672 100644
--- a/arch/powerpc/kernel/vmlinux.lds.S
+++ b/arch/powerpc/kernel/vmlinux.lds.S
@@ -19,21 +19,6 @@ ENTRY(_stext)
 
 PHDRS {
 	kernel PT_LOAD FLAGS(7); /* RWX */
-	notes 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
@@ -177,15 +162,7 @@ SECTIONS
 #endif
 	EXCEPTION_TABLE(0)
 
-	NOTES :kernel :notes
-
-	/* 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
+	NOTES
 
 /*
  * Init sections discarded at runtime
-- 
2.20.1