[tip: core/build] x86/boot/compressed: Reorganize zero-size section asserts

[tip-bot2 for Kees Cook]

The following commit has been merged into the core/build branch of tip:

Commit-ID:     7cf891a40057f851af74e68bacb01b90bd775b5d
Gitweb:        https://git.kernel.org/tip/7cf891a40057f851af74e68bacb01b90bd775b5d
Author:        Kees Cook <keescook@xxxxxxxxxxxx>
AuthorDate:    Fri, 21 Aug 2020 12:43:07 -07:00
Committer:     Ingo Molnar <mingo@xxxxxxxxxx>
CommitterDate: Tue, 01 Sep 2020 10:03:18 +02:00

x86/boot/compressed: Reorganize zero-size section asserts

For readability, move the zero-sized sections to the end after DISCARDS.

Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20200821194310.3089815-27-keescook@xxxxxxxxxxxx
---
 arch/x86/boot/compressed/vmlinux.lds.S | 44 ++++++++++++++-----------
 1 file changed, 26 insertions(+), 18 deletions(-)

diff --git a/arch/x86/boot/compressed/vmlinux.lds.S b/arch/x86/boot/compressed/vmlinux.lds.S
index 3c2ee9a..ca544a1 100644
--- a/arch/x86/boot/compressed/vmlinux.lds.S
+++ b/arch/x86/boot/compressed/vmlinux.lds.S
@@ -42,19 +42,6 @@ SECTIONS
 		*(.rodata.*)
 		_erodata = . ;
 	}
-	.rel.dyn : {
-		*(.rel.*)
-	}
-	.rela.dyn : {
-		*(.rela.*)
-	}
-	.got : {
-		*(.got)
-	}
-	.got.plt : {
-		*(.got.plt)
-	}
-
 	.data :	{
 		_data = . ;
 		*(.data)
@@ -85,13 +72,34 @@ SECTIONS
 	ELF_DETAILS
 
 	DISCARDS
-}
 
-ASSERT(SIZEOF(.got) == 0, "Unexpected GOT entries detected!")
+	.got.plt (INFO) : {
+		*(.got.plt)
+	}
+	ASSERT(SIZEOF(.got.plt) == 0 ||
 #ifdef CONFIG_X86_64
-ASSERT(SIZEOF(.got.plt) == 0 || SIZEOF(.got.plt) == 0x18, "Unexpected GOT/PLT entries detected!")
+	       SIZEOF(.got.plt) == 0x18,
 #else
-ASSERT(SIZEOF(.got.plt) == 0 || SIZEOF(.got.plt) == 0xc, "Unexpected GOT/PLT entries detected!")
+	       SIZEOF(.got.plt) == 0xc,
 #endif
+	       "Unexpected GOT/PLT entries detected!")
+
+	/*
+	 * Sections that should stay zero sized, which is safer to
+	 * explicitly check instead of blindly discarding.
+	 */
+	.got : {
+		*(.got)
+	}
+	ASSERT(SIZEOF(.got) == 0, "Unexpected GOT entries detected!")
+
+	.rel.dyn : {
+		*(.rel.*)
+	}
+	ASSERT(SIZEOF(.rel.dyn) == 0, "Unexpected run-time relocations (.rel) detected!")
 
-ASSERT(SIZEOF(.rel.dyn) == 0 && SIZEOF(.rela.dyn) == 0, "Unexpected run-time relocations detected!")
+	.rela.dyn : {
+		*(.rela.*)
+	}
+	ASSERT(SIZEOF(.rela.dyn) == 0, "Unexpected run-time relocations (.rela) detected!")
+}