From: Peter Zijlstra <peterz@infradead.org>
Date: Tue, 8 Mar 2022 15:30:43 +0000 (+0100)
Subject: x86/ibt: Dont generate ENDBR in .discard.text
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=2b6ff7dea670a4623fae1d2349806fc7f8e305d1;p=linux.git

x86/ibt: Dont generate ENDBR in .discard.text

Having ENDBR in discarded sections can easily lead to relocations into
discarded sections which the linkers aren't really fond of. Objtool
also shouldn't generate them, but why tempt fate.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Link: https://lore.kernel.org/r/20220308154319.054842742@infradead.org
---

diff --git a/arch/x86/include/asm/setup.h b/arch/x86/include/asm/setup.h
index a12458a7a8d4a..896e48d45828c 100644
--- a/arch/x86/include/asm/setup.h
+++ b/arch/x86/include/asm/setup.h
@@ -8,6 +8,7 @@
 
 #include <linux/linkage.h>
 #include <asm/page_types.h>
+#include <asm/ibt.h>
 
 #ifdef __i386__
 
@@ -119,7 +120,7 @@ void *extend_brk(size_t size, size_t align);
  * executable.)
  */
 #define RESERVE_BRK(name,sz)						\
-	static void __section(".discard.text") __used notrace		\
+	static void __section(".discard.text") __noendbr __used notrace	\
 	__brk_reservation_fn_##name##__(void) {				\
 		asm volatile (						\
 			".pushsection .brk_reservation,\"aw\",@nobits;" \