Merge branch 'x86-smap-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 SMAP fixes from Ingo Molnar:
 "Fixes for Intel SMAP support, to fix SIGSEGVs during bootup"

* 'x86-smap-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  Introduce [compat_]save_altstack_ex() to unbreak x86 SMAP
  x86, smap: Handle csum_partial_copy_*_user()

4 files changed, 31 insertions, 11 deletions

diff --git a/arch/x86/ia32/ia32_signal.c b/arch/x86/ia32/ia32_signal.c
index bccfca68430e..665a730307f2 100644
--- a/arch/x86/ia32/ia32_signal.c
+++ b/arch/x86/ia32/ia32_signal.c
@@ -457,7 +457,7 @@ int ia32_setup_rt_frame(int sig, struct ksignal *ksig,
                 else
                         put_user_ex(0, &frame->uc.uc_flags);
                 put_user_ex(0, &frame->uc.uc_link);
-                err |= __compat_save_altstack(&frame->uc.uc_stack, regs->sp);
+                compat_save_altstack_ex(&frame->uc.uc_stack, regs->sp);
 
                 if (ksig->ka.sa.sa_flags & SA_RESTORER)
                         restorer = ksig->ka.sa.sa_restorer;
diff --git a/arch/x86/include/asm/checksum_32.h b/arch/x86/include/asm/checksum_32.h
index 46fc474fd819..f50de6951738 100644
--- a/arch/x86/include/asm/checksum_32.h
+++ b/arch/x86/include/asm/checksum_32.h
@@ -49,9 +49,15 @@ static inline __wsum csum_partial_copy_from_user(const void __user *src,
                                                  int len, __wsum sum,
                                                  int *err_ptr)
 {
+        __wsum ret;
+
         might_sleep();
-        return csum_partial_copy_generic((__force void *)src, dst,
-                                         len, sum, err_ptr, NULL);
+        stac();
+        ret = csum_partial_copy_generic((__force void *)src, dst,
+                                        len, sum, err_ptr, NULL);
+        clac();
+
+        return ret;
 }
 
 /*
@@ -176,10 +182,16 @@ static inline __wsum csum_and_copy_to_user(const void *src,
                                            int len, __wsum sum,
                                            int *err_ptr)
 {
+        __wsum ret;
+
         might_sleep();
-        if (access_ok(VERIFY_WRITE, dst, len))
-                return csum_partial_copy_generic(src, (__force void *)dst,
-                                                 len, sum, NULL, err_ptr);
+        if (access_ok(VERIFY_WRITE, dst, len)) {
+                stac();
+                ret = csum_partial_copy_generic(src, (__force void *)dst,
+                                                len, sum, NULL, err_ptr);
+                clac();
+                return ret;
+        }
 
         if (len)
                 *err_ptr = -EFAULT;
diff --git a/arch/x86/kernel/signal.c b/arch/x86/kernel/signal.c
index 6a9acc667d20..9e5de6813e1f 100644
--- a/arch/x86/kernel/signal.c
+++ b/arch/x86/kernel/signal.c
@@ -358,7 +358,7 @@ static int __setup_rt_frame(int sig, struct ksignal *ksig,
                 else
                         put_user_ex(0, &frame->uc.uc_flags);
                 put_user_ex(0, &frame->uc.uc_link);
-                err |= __save_altstack(&frame->uc.uc_stack, regs->sp);
+                save_altstack_ex(&frame->uc.uc_stack, regs->sp);
 
                 /* Set up to return from userspace.  */
                 restorer = VDSO32_SYMBOL(current->mm->context.vdso, rt_sigreturn);
@@ -423,7 +423,7 @@ static int __setup_rt_frame(int sig, struct ksignal *ksig,
                 else
                         put_user_ex(0, &frame->uc.uc_flags);
                 put_user_ex(0, &frame->uc.uc_link);
-                err |= __save_altstack(&frame->uc.uc_stack, regs->sp);
+                save_altstack_ex(&frame->uc.uc_stack, regs->sp);
 
                 /* Set up to return from userspace.  If provided, use a stub
                    already in userspace.  */
@@ -490,7 +490,7 @@ static int x32_setup_rt_frame(struct ksignal *ksig,
                 else
                         put_user_ex(0, &frame->uc.uc_flags);
                 put_user_ex(0, &frame->uc.uc_link);
-                err |= __compat_save_altstack(&frame->uc.uc_stack, regs->sp);
+                compat_save_altstack_ex(&frame->uc.uc_stack, regs->sp);
                 put_user_ex(0, &frame->uc.uc__pad0);
 
                 if (ksig->ka.sa.sa_flags & SA_RESTORER) {
diff --git a/arch/x86/lib/csum-wrappers_64.c b/arch/x86/lib/csum-wrappers_64.c
index 25b7ae8d058a..7609e0e421ec 100644
--- a/arch/x86/lib/csum-wrappers_64.c
+++ b/arch/x86/lib/csum-wrappers_64.c
@@ -6,6 +6,7 @@
  */
 #include <asm/checksum.h>
 #include <linux/module.h>
+#include <asm/smap.h>
 
 /**
  * csum_partial_copy_from_user - Copy and checksum from user space.
@@ -52,8 +53,10 @@ csum_partial_copy_from_user(const void __user *src, void *dst,
                         len -= 2;
                 }
         }
+        stac();
         isum = csum_partial_copy_generic((__force const void *)src,
                                 dst, len, isum, errp, NULL);
+        clac();
         if (unlikely(*errp))
                 goto out_err;
 
@@ -82,6 +85,8 @@ __wsum
 csum_partial_copy_to_user(const void *src, void __user *dst,
                           int len, __wsum isum, int *errp)
 {
+        __wsum ret;
+
         might_sleep();
 
         if (unlikely(!access_ok(VERIFY_WRITE, dst, len))) {
@@ -105,8 +110,11 @@ csum_partial_copy_to_user(const void *src, void __user *dst,
         }
 
         *errp = 0;
-        return csum_partial_copy_generic(src, (void __force *)dst,
-                                         len, isum, NULL, errp);
+        stac();
+        ret = csum_partial_copy_generic(src, (void __force *)dst,
+                                        len, isum, NULL, errp);
+        clac();
+        return ret;
 }
 EXPORT_SYMBOL(csum_partial_copy_to_user);