x86/fpu/xstate: Define and use 'fpu_user_xstate_size'

[cascardo/linux.git] / arch / x86 / kernel / fpu / signal.c

diff --git a/arch/x86/kernel/fpu/signal.c b/arch/x86/kernel/fpu/signal.c
index c6f2a3c..0d29d4d 100644 (file)
--- a/arch/x86/kernel/fpu/signal.c
+++ b/arch/x86/kernel/fpu/signal.c
@@ -32,7 +32,7 @@ static inline int check_for_xstate(struct fxregs_state __user *buf,
        /* Check for the first magic field and other error scenarios. */
        if (fx_sw->magic1 != FP_XSTATE_MAGIC1 ||
            fx_sw->xstate_size < min_xstate_size ||
-           fx_sw->xstate_size > xstate_size ||
+           fx_sw->xstate_size > fpu_user_xstate_size ||
            fx_sw->xstate_size > fx_sw->extended_size)
                return -1;
 
@@ -89,7 +89,8 @@ static inline int save_xstate_epilog(void __user *buf, int ia32_frame)
        if (!use_xsave())
                return err;
 
-       err |= __put_user(FP_XSTATE_MAGIC2, (__u32 *)(buf + xstate_size));
+       err |= __put_user(FP_XSTATE_MAGIC2,
+                         (__u32 *)(buf + fpu_user_xstate_size));
 
        /*
         * Read the xfeatures which we copied (directly from the cpu or
@@ -126,7 +127,7 @@ static inline int copy_fpregs_to_sigframe(struct xregs_state __user *buf)
        else
                err = copy_fregs_to_user((struct fregs_state __user *) buf);
 
-       if (unlikely(err) && __clear_user(buf, xstate_size))
+       if (unlikely(err) && __clear_user(buf, fpu_user_xstate_size))
                err = -EFAULT;
        return err;
 }
@@ -176,8 +177,19 @@ int copy_fpstate_to_sigframe(void __user *buf, void __user *buf_fx, int size)
                if (ia32_fxstate)
                        copy_fxregs_to_kernel(&tsk->thread.fpu);
        } else {
+               /*
+                * It is a *bug* if kernel uses compacted-format for xsave
+                * area and we copy it out directly to a signal frame. It
+                * should have been handled above by saving the registers
+                * directly.
+                */
+               if (boot_cpu_has(X86_FEATURE_XSAVES)) {
+                       WARN_ONCE(1, "x86/fpu: saving compacted-format xsave area to a signal frame!\n");
+                       return -1;
+               }
+
                fpstate_sanitize_xstate(&tsk->thread.fpu);
-               if (__copy_to_user(buf_fx, xsave, xstate_size))
+               if (__copy_to_user(buf_fx, xsave, fpu_user_xstate_size))
                        return -1;
        }
 
@@ -344,7 +356,8 @@ static int __fpu__restore_sig(void __user *buf, void __user *buf_fx, int size)
 
 static inline int xstate_sigframe_size(void)
 {
-       return use_xsave() ? xstate_size + FP_XSTATE_MAGIC2_SIZE : xstate_size;
+       return use_xsave() ? fpu_user_xstate_size + FP_XSTATE_MAGIC2_SIZE :
+                       fpu_user_xstate_size;
 }
 
 /*
@@ -388,12 +401,12 @@ fpu__alloc_mathframe(unsigned long sp, int ia32_frame,
  */
 void fpu__init_prepare_fx_sw_frame(void)
 {
-       int size = xstate_size + FP_XSTATE_MAGIC2_SIZE;
+       int size = fpu_user_xstate_size + FP_XSTATE_MAGIC2_SIZE;
 
        fx_sw_reserved.magic1 = FP_XSTATE_MAGIC1;
        fx_sw_reserved.extended_size = size;
        fx_sw_reserved.xfeatures = xfeatures_mask;
-       fx_sw_reserved.xstate_size = xstate_size;
+       fx_sw_reserved.xstate_size = fpu_user_xstate_size;
 
        if (config_enabled(CONFIG_IA32_EMULATION) ||
            config_enabled(CONFIG_X86_32)) {