7 files changed, 35 insertions, 22 deletions

diff --git a/arch/x86/kernel/cpu/amd_64.c b/arch/x86/kernel/cpu/amd_64.c
index 7c36fb8a28d4..d1692b2a41ff 100644
--- a/arch/x86/kernel/cpu/amd_64.c
+++ b/arch/x86/kernel/cpu/amd_64.c
@@ -115,6 +115,8 @@ static void __cpuinit early_init_amd(struct cpuinfo_x86 *c)
         /* c->x86_power is 8000_0007 edx. Bit 8 is constant TSC */
         if (c->x86_power & (1<<8))
                 set_cpu_cap(c, X86_FEATURE_CONSTANT_TSC);
+
+        set_cpu_cap(c, X86_FEATURE_SYSCALL32);
 }
 
 static void __cpuinit init_amd(struct cpuinfo_x86 *c)
diff --git a/arch/x86/kernel/cpu/common_64.c b/arch/x86/kernel/cpu/common_64.c
index 15419cd3c5a4..736f50fa433d 100644
--- a/arch/x86/kernel/cpu/common_64.c
+++ b/arch/x86/kernel/cpu/common_64.c
@@ -317,9 +317,6 @@ static void __cpuinit early_identify_cpu(struct cpuinfo_x86 *c)
                 c->x86_phys_bits = eax & 0xff;
         }
 
-        /* Assume all 64-bit CPUs support 32-bit syscall */
-        set_cpu_cap(c, X86_FEATURE_SYSCALL32);
-
         if (c->x86_vendor != X86_VENDOR_UNKNOWN &&
             cpu_devs[c->x86_vendor]->c_early_init)
                 cpu_devs[c->x86_vendor]->c_early_init(c);
diff --git a/arch/x86/vdso/Makefile b/arch/x86/vdso/Makefile
index b7ad9f89d21f..4d6ef0a336d6 100644
--- a/arch/x86/vdso/Makefile
+++ b/arch/x86/vdso/Makefile
@@ -62,7 +62,7 @@ $(obj)/%-syms.lds: $(obj)/%.so.dbg FORCE
 # Build multiple 32-bit vDSO images to choose from at boot time.
 #
 obj-$(VDSO32-y)                 += vdso32-syms.lds
-vdso32.so-$(CONFIG_X86_32)      += int80
+vdso32.so-$(VDSO32-y)           += int80
 vdso32.so-$(CONFIG_COMPAT)      += syscall
 vdso32.so-$(VDSO32-y)           += sysenter
 
diff --git a/arch/x86/vdso/vdso32-setup.c b/arch/x86/vdso/vdso32-setup.c
index 0bce5429a515..513f330c5832 100644
--- a/arch/x86/vdso/vdso32-setup.c
+++ b/arch/x86/vdso/vdso32-setup.c
@@ -193,17 +193,12 @@ static __init void relocate_vdso(Elf32_Ehdr *ehdr)
         }
 }
 
-/*
- * These symbols are defined by vdso32.S to mark the bounds
- * of the ELF DSO images included therein.
- */
-extern const char vdso32_default_start, vdso32_default_end;
-extern const char vdso32_sysenter_start, vdso32_sysenter_end;
 static struct page *vdso32_pages[1];
 
 #ifdef CONFIG_X86_64
 
 #define vdso32_sysenter()       (boot_cpu_has(X86_FEATURE_SYSENTER32))
+#define vdso32_syscall()        (boot_cpu_has(X86_FEATURE_SYSCALL32))
 
 /* May not be __init: called during resume */
 void syscall32_cpu_init(void)
@@ -226,6 +221,7 @@ static inline void map_compat_vdso(int map)
 #else  /* CONFIG_X86_32 */
 
 #define vdso32_sysenter()       (boot_cpu_has(X86_FEATURE_SEP))
+#define vdso32_syscall()        (0)
 
 void enable_sep_cpu(void)
 {
@@ -296,12 +292,15 @@ int __init sysenter_setup(void)
         gate_vma_init();
 #endif
 
-        if (!vdso32_sysenter()) {
-                vsyscall = &vdso32_default_start;
-                vsyscall_len = &vdso32_default_end - &vdso32_default_start;
-        } else {
+        if (vdso32_syscall()) {
+                vsyscall = &vdso32_syscall_start;
+                vsyscall_len = &vdso32_syscall_end - &vdso32_syscall_start;
+        } else if (vdso32_sysenter()){
                 vsyscall = &vdso32_sysenter_start;
                 vsyscall_len = &vdso32_sysenter_end - &vdso32_sysenter_start;
+        } else {
+                vsyscall = &vdso32_int80_start;
+                vsyscall_len = &vdso32_int80_end - &vdso32_int80_start;
         }
 
         memcpy(syscall_page, vsyscall, vsyscall_len);
diff --git a/arch/x86/vdso/vdso32.S b/arch/x86/vdso/vdso32.S
index 1e36f72cab86..2ce5f82c333b 100644
--- a/arch/x86/vdso/vdso32.S
+++ b/arch/x86/vdso/vdso32.S
@@ -2,14 +2,17 @@
 
 __INITDATA
 
-        .globl vdso32_default_start, vdso32_default_end
-vdso32_default_start:
-#ifdef CONFIG_X86_32
+        .globl vdso32_int80_start, vdso32_int80_end
+vdso32_int80_start:
         .incbin "arch/x86/vdso/vdso32-int80.so"
-#else
+vdso32_int80_end:
+
+        .globl vdso32_syscall_start, vdso32_syscall_end
+vdso32_syscall_start:
+#ifdef CONFIG_COMPAT
         .incbin "arch/x86/vdso/vdso32-syscall.so"
 #endif
-vdso32_default_end:
+vdso32_syscall_end:
 
         .globl vdso32_sysenter_start, vdso32_sysenter_end
 vdso32_sysenter_start:
diff --git a/arch/x86/xen/setup.c b/arch/x86/xen/setup.c
index 3e11779755c3..e3648e64a637 100644
--- a/arch/x86/xen/setup.c
+++ b/arch/x86/xen/setup.c
@@ -83,12 +83,16 @@ static void xen_idle(void)
 
 /*
  * Set the bit indicating "nosegneg" library variants should be used.
+ * We only need to bother in pure 32-bit mode; compat 32-bit processes
+ * can have un-truncated segments, so wrapping around is allowed.
  */
 static void __init fiddle_vdso(void)
 {
-#if defined(CONFIG_X86_32) || defined(CONFIG_IA32_EMULATION)
-        extern const char vdso32_default_start;
-        u32 *mask = VDSO32_SYMBOL(&vdso32_default_start, NOTE_MASK);
+#ifdef CONFIG_X86_32
+        u32 *mask;
+        mask = VDSO32_SYMBOL(&vdso32_int80_start, NOTE_MASK);
+        *mask |= 1 << VDSO_NOTE_NONEGSEG_BIT;
+        mask = VDSO32_SYMBOL(&vdso32_sysenter_start, NOTE_MASK);
         *mask |= 1 << VDSO_NOTE_NONEGSEG_BIT;
 #endif
 }
diff --git a/include/asm-x86/vdso.h b/include/asm-x86/vdso.h
index 86e085e003d2..8e18fb80f5e6 100644
--- a/include/asm-x86/vdso.h
+++ b/include/asm-x86/vdso.h
@@ -36,4 +36,12 @@ extern const char VDSO32_PRELINK[];
 extern void __user __kernel_sigreturn;
 extern void __user __kernel_rt_sigreturn;
 
+/*
+ * These symbols are defined by vdso32.S to mark the bounds
+ * of the ELF DSO images included therein.
+ */
+extern const char vdso32_int80_start, vdso32_int80_end;
+extern const char vdso32_syscall_start, vdso32_syscall_end;
+extern const char vdso32_sysenter_start, vdso32_sysenter_end;
+
 #endif  /* asm-x86/vdso.h */