Merge git://git.infradead.org/mtd-2.6

[karo-tx-linux.git] / arch / powerpc / kernel / signal_32.c

diff --git a/arch/powerpc/kernel/signal_32.c b/arch/powerpc/kernel/signal_32.c
index 9991e2a58bf41fb6e561ba122b917a45f03a93d6..3e80aa32b8b09e1daf432cb7e112d9a04be7ce4a 100644 (file)
--- a/arch/powerpc/kernel/signal_32.c
+++ b/arch/powerpc/kernel/signal_32.c
@@ -67,6 +67,13 @@
 #define mcontext       mcontext32
 #define ucontext       ucontext32
 
+/*
+ * Userspace code may pass a ucontext which doesn't include VSX added
+ * at the end.  We need to check for this case.
+ */
+#define UCONTEXTSIZEWITHOUTVSX \
+               (sizeof(struct ucontext) - sizeof(elf_vsrreghalf_t32))
+
 /*
  * Returning 0 means we return to userspace via
  * ret_from_except and thus restore all user
@@ -445,7 +452,7 @@ static int save_user_regs(struct pt_regs *regs, struct mcontext __user *frame,
         * contains valid data
         */
        if (current->thread.used_vsr) {
-               flush_vsx_to_thread(current);
+               __giveup_vsx(current);
                if (copy_vsx_to_user(&frame->mc_vsregs, current))
                        return 1;
                msr |= MSR_VSX;
@@ -930,12 +937,42 @@ long sys_swapcontext(struct ucontext __user *old_ctx,
 {
        unsigned char tmp;
 
+#ifdef CONFIG_PPC64
+       unsigned long new_msr = 0;
+
+       if (new_ctx &&
+           __get_user(new_msr, &new_ctx->uc_mcontext.mc_gregs[PT_MSR]))
+               return -EFAULT;
+       /*
+        * Check that the context is not smaller than the original
+        * size (with VMX but without VSX)
+        */
+       if (ctx_size < UCONTEXTSIZEWITHOUTVSX)
+               return -EINVAL;
+       /*
+        * If the new context state sets the MSR VSX bits but
+        * it doesn't provide VSX state.
+        */
+       if ((ctx_size < sizeof(struct ucontext)) &&
+           (new_msr & MSR_VSX))
+               return -EINVAL;
+#ifdef CONFIG_VSX
+       /*
+        * If userspace doesn't provide enough room for VSX data,
+        * but current thread has used VSX, we don't have anywhere
+        * to store the full context back into.
+        */
+       if ((ctx_size < sizeof(struct ucontext)) &&
+           (current->thread.used_vsr && old_ctx))
+               return -EINVAL;
+#endif
+#else
        /* Context size is for future use. Right now, we only make sure
         * we are passed something we understand
         */
        if (ctx_size < sizeof(struct ucontext))
                return -EINVAL;
-
+#endif
        if (old_ctx != NULL) {
                struct mcontext __user *mctx;