linux-kernel - [RFC PATCH PoC 10/11] x86/boot: Revert "Reject absolute references in .head.text"

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Message-ID: <20250423110948.1103030-23-ardb+git@google.com>
Date: Wed, 23 Apr 2025 13:09:59 +0200
From: Ard Biesheuvel <ardb+git@...gle.com>
To: linux-kernel@...r.kernel.org
Cc: x86@...nel.org, mingo@...nel.org, Ard Biesheuvel <ardb@...nel.org>
Subject: [RFC PATCH PoC 10/11] x86/boot: Revert "Reject absolute references in .head.text"

From: Ard Biesheuvel <ardb@...nel.org>

This reverts commit faf0ed487415f76fe4acf7980ce360901f5e1698.

The startup code is checked directly for the absence of absolute symbol
references, so checking the .head.text section in the relocs tool is no
longer needed.

Signed-off-by: Ard Biesheuvel <ardb@...nel.org>
---
 arch/x86/tools/relocs.c | 8 +-------
 1 file changed, 1 insertion(+), 7 deletions(-)

diff --git a/arch/x86/tools/relocs.c b/arch/x86/tools/relocs.c
index 5778bc498415..e5a2b9a912d1 100644
--- a/arch/x86/tools/relocs.c
+++ b/arch/x86/tools/relocs.c
@@ -740,10 +740,10 @@ static void walk_relocs(int (*process)(struct section *sec, Elf_Rel *rel,
 static int do_reloc64(struct section *sec, Elf_Rel *rel, ElfW(Sym) *sym,
 		      const char *symname)
 {
-	int headtext = !strcmp(sec_name(sec->shdr.sh_info), ".head.text");
 	unsigned r_type = ELF64_R_TYPE(rel->r_info);
 	ElfW(Addr) offset = rel->r_offset;
 	int shn_abs = (sym->st_shndx == SHN_ABS) && !is_reloc(S_REL, symname);
+
 	if (sym->st_shndx == SHN_UNDEF)
 		return 0;
 
@@ -783,12 +783,6 @@ static int do_reloc64(struct section *sec, Elf_Rel *rel, ElfW(Sym) *sym,
 			break;
 		}
 
-		if (headtext) {
-			die("Absolute reference to symbol '%s' not permitted in .head.text\n",
-			    symname);
-			break;
-		}
-
 		/*
 		 * Relocation offsets for 64 bit kernels are output
 		 * as 32 bits and sign extended back to 64 bits when
-- 
2.49.0.805.g082f7c87e0-goog