linux-kernel - [PATCH 1/2] x86: vdso: Remove ifdeffery around page setup variants

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20240910-x86-vdso-ifdef-v1-1-877c9df9b081@linutronix.de>
Date: Tue, 10 Sep 2024 12:11:35 +0200
From: Thomas Weißschuh <thomas.weissschuh@...utronix.de>
To: Andy Lutomirski <luto@...nel.org>, Ingo Molnar <mingo@...hat.com>, 
 Borislav Petkov <bp@...en8.de>, Dave Hansen <dave.hansen@...ux.intel.com>, 
 x86@...nel.org, "H. Peter Anvin" <hpa@...or.com>, 
 Eric Biederman <ebiederm@...ssion.com>, Kees Cook <kees@...nel.org>, 
 Thomas Gleixner <tglx@...utronix.de>
Cc: linux-kernel@...r.kernel.org, linux-mm@...ck.org, 
 Thomas Weißschuh <thomas.weissschuh@...utronix.de>
Subject: [PATCH 1/2] x86: vdso: Remove ifdeffery around page setup variants

Replace the open-coded ifdefs in C sources files with IS_ENABLED().
This makes the code easier to read and enables the compiler to typecheck
also the disabled parts, before optimizing them away.
To make this work, also remove the ifdefs from declarations of used
variables.

Signed-off-by: Thomas Weißschuh <thomas.weissschuh@...utronix.de>
---
 arch/x86/entry/vdso/vma.c   | 31 ++++++++++++-------------------
 arch/x86/include/asm/elf.h  |  4 ----
 arch/x86/include/asm/vdso.h |  8 --------
 3 files changed, 12 insertions(+), 31 deletions(-)

diff --git a/arch/x86/entry/vdso/vma.c b/arch/x86/entry/vdso/vma.c
index 6d83ceb7f1ba..9059b9d96393 100644
--- a/arch/x86/entry/vdso/vma.c
+++ b/arch/x86/entry/vdso/vma.c
@@ -300,7 +300,6 @@ int map_vdso_once(const struct vdso_image *image, unsigned long addr)
 	return map_vdso(image, addr);
 }
 
-#if defined(CONFIG_X86_32) || defined(CONFIG_IA32_EMULATION)
 static int load_vdso32(void)
 {
 	if (vdso32_enabled != 1)  /* Other values all mean "disabled" */
@@ -308,39 +307,33 @@ static int load_vdso32(void)
 
 	return map_vdso(&vdso_image_32, 0);
 }
-#endif
 
-#ifdef CONFIG_X86_64
 int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
 {
-	if (!vdso64_enabled)
-		return 0;
+	if (IS_ENABLED(CONFIG_X86_64)) {
+		if (!vdso64_enabled)
+			return 0;
+
+		return map_vdso(&vdso_image_64, 0);
+	}
 
-	return map_vdso(&vdso_image_64, 0);
+	return load_vdso32();
 }
 
 #ifdef CONFIG_COMPAT
 int compat_arch_setup_additional_pages(struct linux_binprm *bprm,
 				       int uses_interp, bool x32)
 {
-#ifdef CONFIG_X86_X32_ABI
-	if (x32) {
+	if (IS_ENABLED(CONFIG_X86_X32_ABI) && x32) {
 		if (!vdso64_enabled)
 			return 0;
 		return map_vdso(&vdso_image_x32, 0);
 	}
-#endif
-#ifdef CONFIG_IA32_EMULATION
-	return load_vdso32();
-#else
+
+	if (IS_ENABLED(CONFIG_IA32_EMULATION))
+		return load_vdso32();
+
 	return 0;
-#endif
-}
-#endif
-#else
-int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
-{
-	return load_vdso32();
 }
 #endif
 
diff --git a/arch/x86/include/asm/elf.h b/arch/x86/include/asm/elf.h
index 1fb83d47711f..d5a5dadc1cbe 100644
--- a/arch/x86/include/asm/elf.h
+++ b/arch/x86/include/asm/elf.h
@@ -75,12 +75,8 @@ typedef struct user_i387_struct elf_fpregset_t;
 
 #include <asm/vdso.h>
 
-#ifdef CONFIG_X86_64
 extern unsigned int vdso64_enabled;
-#endif
-#if defined(CONFIG_X86_32) || defined(CONFIG_IA32_EMULATION)
 extern unsigned int vdso32_enabled;
-#endif
 
 /*
  * This is used to ensure we don't load something for the wrong architecture.
diff --git a/arch/x86/include/asm/vdso.h b/arch/x86/include/asm/vdso.h
index d7f6592b74a9..3f45bcc60b4d 100644
--- a/arch/x86/include/asm/vdso.h
+++ b/arch/x86/include/asm/vdso.h
@@ -33,17 +33,9 @@ struct vdso_image {
 	long sym_vdso32_rt_sigreturn_landing_pad;
 };
 
-#ifdef CONFIG_X86_64
 extern const struct vdso_image vdso_image_64;
-#endif
-
-#ifdef CONFIG_X86_X32_ABI
 extern const struct vdso_image vdso_image_x32;
-#endif
-
-#if defined CONFIG_X86_32 || defined CONFIG_COMPAT
 extern const struct vdso_image vdso_image_32;
-#endif
 
 extern int __init init_vdso_image(const struct vdso_image *image);
 

-- 
2.46.0