powerpc: Clean up copy_to/from_user for vsx and fpr

This merges and cleans up some of the ugly copy/to from user code
which is required for the new fpr and vsx layout in the thread_struct.

Also fixes some hard coded buffer sizes and removes a redundant
fpr_flush_to_thread.

Signed-off-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>

3 files changed, 96 insertions, 66 deletions

diff --git a/arch/powerpc/kernel/signal.h b/arch/powerpc/kernel/signal.h
index 77efb3d5465a..28f4b9f5fe5e 100644
--- a/arch/powerpc/kernel/signal.h
+++ b/arch/powerpc/kernel/signal.h
@@ -24,6 +24,16 @@ extern int handle_rt_signal32(unsigned long sig, struct k_sigaction *ka,
                               siginfo_t *info, sigset_t *oldset,
                               struct pt_regs *regs);
 
+extern unsigned long copy_fpr_to_user(void __user *to,
+                                      struct task_struct *task);
+extern unsigned long copy_fpr_from_user(struct task_struct *task,
+                                        void __user *from);
+#ifdef CONFIG_VSX
+extern unsigned long copy_vsx_to_user(void __user *to,
+                                      struct task_struct *task);
+extern unsigned long copy_vsx_from_user(struct task_struct *task,
+                                        void __user *from);
+#endif
 
 #ifdef CONFIG_PPC64
 
diff --git a/arch/powerpc/kernel/signal_32.c b/arch/powerpc/kernel/signal_32.c
index 349d3487d920..9991e2a58bf4 100644
--- a/arch/powerpc/kernel/signal_32.c
+++ b/arch/powerpc/kernel/signal_32.c
@@ -328,6 +328,75 @@ struct rt_sigframe {
         int                     abigap[56];
 };
 
+#ifdef CONFIG_VSX
+unsigned long copy_fpr_to_user(void __user *to,
+                               struct task_struct *task)
+{
+        double buf[ELF_NFPREG];
+        int i;
+
+        /* save FPR copy to local buffer then write to the thread_struct */
+        for (i = 0; i < (ELF_NFPREG - 1) ; i++)
+                buf[i] = task->thread.TS_FPR(i);
+        memcpy(&buf[i], &task->thread.fpscr, sizeof(double));
+        return __copy_to_user(to, buf, ELF_NFPREG * sizeof(double));
+}
+
+unsigned long copy_fpr_from_user(struct task_struct *task,
+                                 void __user *from)
+{
+        double buf[ELF_NFPREG];
+        int i;
+
+        if (__copy_from_user(buf, from, ELF_NFPREG * sizeof(double)))
+                return 1;
+        for (i = 0; i < (ELF_NFPREG - 1) ; i++)
+                task->thread.TS_FPR(i) = buf[i];
+        memcpy(&task->thread.fpscr, &buf[i], sizeof(double));
+
+        return 0;
+}
+
+unsigned long copy_vsx_to_user(void __user *to,
+                               struct task_struct *task)
+{
+        double buf[ELF_NVSRHALFREG];
+        int i;
+
+        /* save FPR copy to local buffer then write to the thread_struct */
+        for (i = 0; i < ELF_NVSRHALFREG; i++)
+                buf[i] = task->thread.fpr[i][TS_VSRLOWOFFSET];
+        return __copy_to_user(to, buf, ELF_NVSRHALFREG * sizeof(double));
+}
+
+unsigned long copy_vsx_from_user(struct task_struct *task,
+                                 void __user *from)
+{
+        double buf[ELF_NVSRHALFREG];
+        int i;
+
+        if (__copy_from_user(buf, from, ELF_NVSRHALFREG * sizeof(double)))
+                return 1;
+        for (i = 0; i < ELF_NVSRHALFREG ; i++)
+                task->thread.fpr[i][TS_VSRLOWOFFSET] = buf[i];
+        return 0;
+}
+#else
+inline unsigned long copy_fpr_to_user(void __user *to,
+                                      struct task_struct *task)
+{
+        return __copy_to_user(to, task->thread.fpr,
+                              ELF_NFPREG * sizeof(double));
+}
+
+inline unsigned long copy_fpr_from_user(struct task_struct *task,
+                                        void __user *from)
+{
+        return __copy_from_user(task->thread.fpr, from,
+                              ELF_NFPREG * sizeof(double));
+}
+#endif
+
 /*
  * Save the current user registers on the user stack.
  * We only save the altivec/spe registers if the process has used
@@ -337,10 +406,6 @@ static int save_user_regs(struct pt_regs *regs, struct mcontext __user *frame,
                 int sigret)
 {
         unsigned long msr = regs->msr;
-#ifdef CONFIG_VSX
-        double buf[32];
-        int i;
-#endif
 
         /* Make sure floating point registers are stored in regs */
         flush_fp_to_thread(current);
@@ -370,14 +435,9 @@ static int save_user_regs(struct pt_regs *regs, struct mcontext __user *frame,
         if (__put_user(current->thread.vrsave, (u32 __user *)&frame->mc_vregs[32]))
                 return 1;
 #endif /* CONFIG_ALTIVEC */
-#ifdef CONFIG_VSX
-        /* save FPR copy to local buffer then write to the thread_struct */
-        flush_fp_to_thread(current);
-        for (i = 0; i < 32 ; i++)
-                buf[i] = current->thread.TS_FPR(i);
-        memcpy(&buf[i], &current->thread.fpscr, sizeof(double));
-        if (__copy_to_user(&frame->mc_fregs, buf, ELF_NFPREG * sizeof(double)))
+        if (copy_fpr_to_user(&frame->mc_fregs, current))
                 return 1;
+#ifdef CONFIG_VSX
         /*
          * Copy VSR 0-31 upper half from thread_struct to local
          * buffer, then write that to userspace.  Also set MSR_VSX in
@@ -386,18 +446,10 @@ static int save_user_regs(struct pt_regs *regs, struct mcontext __user *frame,
          */
         if (current->thread.used_vsr) {
                 flush_vsx_to_thread(current);
-                for (i = 0; i < 32 ; i++)
-                        buf[i] = current->thread.fpr[i][TS_VSRLOWOFFSET];
-                if (__copy_to_user(&frame->mc_vsregs, buf,
-                                   ELF_NVSRHALFREG  * sizeof(double)))
+                if (copy_vsx_to_user(&frame->mc_vsregs, current))
                         return 1;
                 msr |= MSR_VSX;
         }
-#else
-        /* save floating-point registers */
-        if (__copy_to_user(&frame->mc_fregs, current->thread.fpr,
-                    ELF_NFPREG * sizeof(double)))
-                return 1;
 #endif /* CONFIG_VSX */
 #ifdef CONFIG_SPE
         /* save spe registers */
@@ -442,7 +494,6 @@ static long restore_user_regs(struct pt_regs *regs,
         unsigned int save_r2 = 0;
         unsigned long msr;
 #ifdef CONFIG_VSX
-        double buf[32];
         int i;
 #endif
 
@@ -490,13 +541,10 @@ static long restore_user_regs(struct pt_regs *regs,
         if (__get_user(current->thread.vrsave, (u32 __user *)&sr->mc_vregs[32]))
                 return 1;
 #endif /* CONFIG_ALTIVEC */
+        if (copy_fpr_from_user(current, &sr->mc_fregs))
+                return 1;
 
 #ifdef CONFIG_VSX
-        if (__copy_from_user(buf, &sr->mc_fregs,sizeof(sr->mc_fregs)))
-                return 1;
-        for (i = 0; i < 32 ; i++)
-                current->thread.TS_FPR(i) = buf[i];
-        memcpy(&current->thread.fpscr, &buf[i], sizeof(double));
         /*
          * Force the process to reload the VSX registers from
          * current->thread when it next does VSX instruction.
@@ -507,18 +555,11 @@ static long restore_user_regs(struct pt_regs *regs,
                  * Restore altivec registers from the stack to a local
                  * buffer, then write this out to the thread_struct
                  */
-                if (__copy_from_user(buf, &sr->mc_vsregs,
-                                     sizeof(sr->mc_vsregs)))
+                if (copy_vsx_from_user(current, &sr->mc_vsregs))
                         return 1;
-                for (i = 0; i < 32 ; i++)
-                        current->thread.fpr[i][TS_VSRLOWOFFSET] = buf[i];
         } else if (current->thread.used_vsr)
                 for (i = 0; i < 32 ; i++)
                         current->thread.fpr[i][TS_VSRLOWOFFSET] = 0;
-#else
-        if (__copy_from_user(current->thread.fpr, &sr->mc_fregs,
-                             sizeof(sr->mc_fregs)))
-                return 1;
 #endif /* CONFIG_VSX */
         /*
          * force the process to reload the FP registers from
diff --git a/arch/powerpc/kernel/signal_64.c b/arch/powerpc/kernel/signal_64.c
index 8214e57aab67..93ebfb6944b6 100644
--- a/arch/powerpc/kernel/signal_64.c
+++ b/arch/powerpc/kernel/signal_64.c
@@ -89,10 +89,6 @@ static long setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs,
 #endif
         unsigned long msr = regs->msr;
         long err = 0;
-#ifdef CONFIG_VSX
-        double buf[FP_REGS_SIZE];
-        int i;
-#endif
 
         flush_fp_to_thread(current);
 
@@ -117,12 +113,9 @@ static long setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs,
         err |= __put_user(0, &sc->v_regs);
 #endif /* CONFIG_ALTIVEC */
         flush_fp_to_thread(current);
+        /* copy fpr regs and fpscr */
+        err |= copy_fpr_to_user(&sc->fp_regs, current);
 #ifdef CONFIG_VSX
-        /* Copy FP to local buffer then write that out */
-        for (i = 0; i < 32 ; i++)
-                buf[i] = current->thread.TS_FPR(i);
-        memcpy(&buf[i], &current->thread.fpscr, sizeof(double));
-        err |= __copy_to_user(&sc->fp_regs, buf, FP_REGS_SIZE);
         /*
          * Copy VSX low doubleword to local buffer for formatting,
          * then out to userspace.  Update v_regs to point after the
@@ -131,17 +124,12 @@ static long setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs,
         if (current->thread.used_vsr) {
                 flush_vsx_to_thread(current);
                 v_regs += ELF_NVRREG;
-                for (i = 0; i < 32 ; i++)
-                        buf[i] = current->thread.fpr[i][TS_VSRLOWOFFSET];
-                err |= __copy_to_user(v_regs, buf, 32 * sizeof(double));
+                err |= copy_vsx_to_user(v_regs, current);
                 /* set MSR_VSX in the MSR value in the frame to
                  * indicate that sc->vs_reg) contains valid data.
                  */
                 msr |= MSR_VSX;
         }
-#else /* CONFIG_VSX */
-        /* copy fpr regs and fpscr */
-        err |= __copy_to_user(&sc->fp_regs, &current->thread.fpr, FP_REGS_SIZE);
 #endif /* CONFIG_VSX */
         err |= __put_user(&sc->gp_regs, &sc->regs);
         WARN_ON(!FULL_REGS(regs));
@@ -165,13 +153,12 @@ static long restore_sigcontext(struct pt_regs *regs, sigset_t *set, int sig,
 #ifdef CONFIG_ALTIVEC
         elf_vrreg_t __user *v_regs;
 #endif
-#ifdef CONFIG_VSX
-        double buf[FP_REGS_SIZE];
-        int i;
-#endif
         unsigned long err = 0;
         unsigned long save_r13 = 0;
         unsigned long msr;
+#ifdef CONFIG_VSX
+        int i;
+#endif
 
         /* If this is not a signal return, we preserve the TLS in r13 */
         if (!sig)
@@ -234,15 +221,9 @@ static long restore_sigcontext(struct pt_regs *regs, sigset_t *set, int sig,
         else
                 current->thread.vrsave = 0;
 #endif /* CONFIG_ALTIVEC */
-#ifdef CONFIG_VSX
         /* restore floating point */
-        err |= __copy_from_user(buf, &sc->fp_regs, FP_REGS_SIZE);
-        if (err)
-                return err;
-        for (i = 0; i < 32 ; i++)
-                current->thread.TS_FPR(i) = buf[i];
-        memcpy(&current->thread.fpscr, &buf[i], sizeof(double));
-
+        err |= copy_fpr_from_user(current, &sc->fp_regs);
+#ifdef CONFIG_VSX
         /*
          * Get additional VSX data. Update v_regs to point after the
          * VMX data.  Copy VSX low doubleword from userspace to local
@@ -250,14 +231,12 @@ static long restore_sigcontext(struct pt_regs *regs, sigset_t *set, int sig,
          */
         v_regs += ELF_NVRREG;
         if ((msr & MSR_VSX) != 0)
-                err |= __copy_from_user(buf, v_regs, 32 * sizeof(double));
+                err |= copy_vsx_from_user(current, v_regs);
         else
-                memset(buf, 0, 32 * sizeof(double));
+                for (i = 0; i < 32 ; i++)
+                        current->thread.fpr[i][TS_VSRLOWOFFSET] = 0;
 
-        for (i = 0; i < 32 ; i++)
-                current->thread.fpr[i][TS_VSRLOWOFFSET] = buf[i];
 #else
-        err |= __copy_from_user(&current->thread.fpr, &sc->fp_regs, FP_REGS_SIZE);
 #endif
         return err;
 }