powerpc: Introduce VSX thread_struct and CONFIG_VSX

The layout of the new VSR registers and how they overlap on top of the
legacy FPR and VR registers is:

                   VSR doubleword 0               VSR doubleword 1
          ----------------------------------------------------------------
  VSR[0]  |             FPR[0]            |                              |
          ----------------------------------------------------------------
  VSR[1]  |             FPR[1]            |                              |
          ----------------------------------------------------------------
          |              ...              |                              |
          |              ...              |                              |
          ----------------------------------------------------------------
  VSR[30] |             FPR[30]           |                              |
          ----------------------------------------------------------------
  VSR[31] |             FPR[31]           |                              |
          ----------------------------------------------------------------
  VSR[32] |                             VR[0]                            |
          ----------------------------------------------------------------
  VSR[33] |                             VR[1]                            |
          ----------------------------------------------------------------
          |                              ...                             |
          |                              ...                             |
          ----------------------------------------------------------------
  VSR[62] |                             VR[30]                           |
          ----------------------------------------------------------------
  VSR[63] |                             VR[31]                           |
          ----------------------------------------------------------------

VSX has 64 128bit registers.  The first 32 regs overlap with the FP
registers and hence extend them with and additional 64 bits.  The
second 32 regs overlap with the VMX registers.

This commit introduces the thread_struct changes required to reflect
this register layout.  Ptrace and signals code is updated so that the
floating point registers are correctly accessed from the thread_struct
when CONFIG_VSX is enabled.

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

1 files changed, 45 insertions, 14 deletions

diff --git a/arch/powerpc/kernel/signal_32.c b/arch/powerpc/kernel/signal_32.c
index b057e6852a7d..f7fa395b9fb5 100644
--- a/arch/powerpc/kernel/signal_32.c
+++ b/arch/powerpc/kernel/signal_32.c
@@ -337,14 +337,16 @@ 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);
 
-        /* save general and floating-point registers */
-        if (save_general_regs(regs, frame) ||
-            __copy_to_user(&frame->mc_fregs, current->thread.fpr,
-                    ELF_NFPREG * sizeof(double)))
+        /* save general registers */
+        if (save_general_regs(regs, frame))
                 return 1;
 
 #ifdef CONFIG_ALTIVEC
@@ -368,7 +370,20 @@ 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)))
+                return 1;
+#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 */
         if (current->thread.used_spe) {
@@ -411,6 +426,10 @@ static long restore_user_regs(struct pt_regs *regs,
         long err;
         unsigned int save_r2 = 0;
         unsigned long msr;
+#ifdef CONFIG_VSX
+        double buf[32];
+        int i;
+#endif
 
         /*
          * restore general registers but not including MSR or SOFTE. Also
@@ -438,16 +457,11 @@ static long restore_user_regs(struct pt_regs *regs,
          */
         discard_lazy_cpu_state();
 
-        /* force the process to reload the FP registers from
-           current->thread when it next does FP instructions */
-        regs->msr &= ~(MSR_FP | MSR_FE0 | MSR_FE1);
-        if (__copy_from_user(current->thread.fpr, &sr->mc_fregs,
-                             sizeof(sr->mc_fregs)))
-                return 1;
-
 #ifdef CONFIG_ALTIVEC
-        /* force the process to reload the altivec registers from
-           current->thread when it next does altivec instructions */
+        /*
+         * Force the process to reload the altivec registers from
+         * current->thread when it next does altivec instructions
+         */
         regs->msr &= ~MSR_VEC;
         if (msr & MSR_VEC) {
                 /* restore altivec registers from the stack */
@@ -462,6 +476,23 @@ static long restore_user_regs(struct pt_regs *regs,
                 return 1;
 #endif /* CONFIG_ALTIVEC */
 
+#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));
+#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
+         * current->thread when it next does FP instructions
+         */
+        regs->msr &= ~(MSR_FP | MSR_FE0 | MSR_FE1);
+
 #ifdef CONFIG_SPE
         /* force the process to reload the spe registers from
            current->thread when it next does spe instructions */