linux-kernel - [PATCH 06/12] x86/compat: Don't build 32-bit vdso if not needed.

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Message-Id: <1434974121-32575-7-git-send-email-brgerst@gmail.com>
Date:	Mon, 22 Jun 2015 07:55:15 -0400
From:	Brian Gerst <brgerst@...il.com>
To:	x86@...nel.org
Cc:	linux-kernel@...r.kernel.org, Ingo Molnar <mingo@...nel.org>,
	"H. Peter Anvin" <hpa@...or.com>,
	Denys Vlasenko <dvlasenk@...hat.com>,
	Andy Lutomirski <luto@...capital.net>
Subject: [PATCH 06/12] x86/compat: Don't build 32-bit vdso if not needed.

Build the 32-bit vdso only for native 32-bit or 32-bit compat is
enabled.  x32 should not force it to build.

Signed-off-by: Brian Gerst <brgerst@...il.com>
---
 arch/x86/entry/vdso/Makefile | 6 +++---
 arch/x86/entry/vdso/vma.c    | 7 +++++--
 arch/x86/include/asm/elf.h   | 2 +-
 3 files changed, 9 insertions(+), 6 deletions(-)

diff --git a/arch/x86/entry/vdso/Makefile b/arch/x86/entry/vdso/Makefile
index e970320..96c0617 100644
--- a/arch/x86/entry/vdso/Makefile
+++ b/arch/x86/entry/vdso/Makefile
@@ -8,7 +8,7 @@ KASAN_SANITIZE := n
 VDSO64-$(CONFIG_X86_64)		:= y
 VDSOX32-$(CONFIG_X86_X32_ABI)	:= y
 VDSO32-$(CONFIG_X86_32)		:= y
-VDSO32-$(CONFIG_COMPAT)		:= y
+VDSO32-$(CONFIG_IA32_EMULATION)	:= y
 
 # files to link into the vdso
 vobjs-y := vdso-note.o vclock_gettime.o vgetcpu.o
@@ -20,7 +20,7 @@ obj-y				+= vma.o
 vdso_img-$(VDSO64-y)		+= 64
 vdso_img-$(VDSOX32-y)		+= x32
 vdso_img-$(VDSO32-y)		+= 32-int80
-vdso_img-$(CONFIG_COMPAT)	+= 32-syscall
+vdso_img-$(CONFIG_IA32_EMULATION)	+= 32-syscall
 vdso_img-$(VDSO32-y)		+= 32-sysenter
 
 obj-$(VDSO32-y)			+= vdso32-setup.o
@@ -126,7 +126,7 @@ $(obj)/vdsox32.so.dbg: $(src)/vdsox32.lds $(vobjx32s) FORCE
 # Build multiple 32-bit vDSO images to choose from at boot time.
 #
 vdso32.so-$(VDSO32-y)		+= int80
-vdso32.so-$(CONFIG_COMPAT)	+= syscall
+vdso32.so-$(CONFIG_IA32_EMULATION)	+= syscall
 vdso32.so-$(VDSO32-y)		+= sysenter
 
 vdso32-images			= $(vdso32.so-y:%=vdso32-%.so)
diff --git a/arch/x86/entry/vdso/vma.c b/arch/x86/entry/vdso/vma.c
index 1c9f750..4345431 100644
--- a/arch/x86/entry/vdso/vma.c
+++ b/arch/x86/entry/vdso/vma.c
@@ -177,7 +177,7 @@ up_fail:
 	return ret;
 }
 
-#if defined(CONFIG_X86_32) || defined(CONFIG_COMPAT)
+#if defined(CONFIG_X86_32) || defined(CONFIG_IA32_EMULATION)
 static int load_vdso32(void)
 {
 	int ret;
@@ -219,8 +219,11 @@ int compat_arch_setup_additional_pages(struct linux_binprm *bprm,
 		return map_vdso(&vdso_image_x32, true);
 	}
 #endif
-
+#ifdef CONFIG_IA32_EMULATION
 	return load_vdso32();
+#else
+	return 0;
+#endif
 }
 #endif
 #else
diff --git a/arch/x86/include/asm/elf.h b/arch/x86/include/asm/elf.h
index 2bf67c0..141c561 100644
--- a/arch/x86/include/asm/elf.h
+++ b/arch/x86/include/asm/elf.h
@@ -78,7 +78,7 @@ typedef struct user_fxsr_struct elf_fpxregset_t;
 #ifdef CONFIG_X86_64
 extern unsigned int vdso64_enabled;
 #endif
-#if defined(CONFIG_X86_32) || defined(CONFIG_COMPAT)
+#if defined(CONFIG_X86_32) || defined(CONFIG_IA32_EMULATION)
 extern unsigned int vdso32_enabled;
 #endif
 
-- 
2.1.0

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