powerpc/signal32: Reorder user reads in restore_tm_user_regs()

In restore_tm_user_regs(), regroup the reads from 'sr' and the ones
from 'tm_sr' together in order to allow two block user accesses
in following patch.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/7c518b9a4c8e5ae9a3bfb647bc8b20bf820233af.1616151715.git.christophe.leroy@csgroup.eu

diff --git a/arch/powerpc/kernel/signal_32.c b/arch/powerpc/kernel/signal_32.c
index e2b1d2a..088c838 100644 (file)
--- a/arch/powerpc/kernel/signal_32.c
+++ b/arch/powerpc/kernel/signal_32.c
@@ -607,8 +607,7 @@ static long restore_tm_user_regs(struct pt_regs *regs,
         * TFHAR is restored from the checkpointed NIP; TEXASR and TFIAR
         * were set by the signal delivery.
         */
-       err = restore_general_regs(regs, tm_sr);
-       err |= restore_general_regs(&current->thread.ckpt_regs, sr);
+       err = restore_general_regs(&current->thread.ckpt_regs, sr);
 
        err |= __get_user(current->thread.tm_tfhar, &sr->mc_gregs[PT_NIP]);
 
@@ -624,9 +623,6 @@ static long restore_tm_user_regs(struct pt_regs *regs,
        if (msr & MSR_VEC) {
                /* restore altivec registers from the stack */
                if (__copy_from_user(&current->thread.ckvr_state, &sr->mc_vregs,
-                                    sizeof(sr->mc_vregs)) ||
-                   __copy_from_user(&current->thread.vr_state,
-                                    &tm_sr->mc_vregs,
                                     sizeof(sr->mc_vregs)))
                        return 1;
                current->thread.used_vr = true;
@@ -639,9 +635,7 @@ static long restore_tm_user_regs(struct pt_regs *regs,
 
        /* Always get VRSAVE back */
        if (__get_user(current->thread.ckvrsave,
-                      (u32 __user *)&sr->mc_vregs[32]) ||
-           __get_user(current->thread.vrsave,
-                      (u32 __user *)&tm_sr->mc_vregs[32]))
+                      (u32 __user *)&sr->mc_vregs[32]))
                return 1;
        if (cpu_has_feature(CPU_FTR_ALTIVEC))
                mtspr(SPRN_VRSAVE, current->thread.ckvrsave);
@@ -649,8 +643,7 @@ static long restore_tm_user_regs(struct pt_regs *regs,
 
        regs->msr &= ~(MSR_FP | MSR_FE0 | MSR_FE1);
 
-       if (copy_fpr_from_user(current, &sr->mc_fregs) ||
-           copy_ckfpr_from_user(current, &tm_sr->mc_fregs))
+       if (copy_fpr_from_user(current, &sr->mc_fregs))
                return 1;
 
 #ifdef CONFIG_VSX
@@ -660,8 +653,7 @@ static long restore_tm_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_vsx_from_user(current, &tm_sr->mc_vsregs) ||
-                   copy_ckvsx_from_user(current, &sr->mc_vsregs))
+               if (copy_ckvsx_from_user(current, &sr->mc_vsregs))
                        return 1;
                current->thread.used_vsr = true;
        } else if (current->thread.used_vsr)
@@ -690,6 +682,39 @@ static long restore_tm_user_regs(struct pt_regs *regs,
                return 1;
 #endif /* CONFIG_SPE */
 
+       err = restore_general_regs(regs, tm_sr);
+       if (err)
+               return 1;
+
+#ifdef CONFIG_ALTIVEC
+       /* restore altivec registers from the stack */
+       if (msr & MSR_VEC)
+               if (__copy_from_user(&current->thread.vr_state,
+                                    &tm_sr->mc_vregs,
+                                    sizeof(sr->mc_vregs)))
+                       return 1;
+
+       /* Always get VRSAVE back */
+       if (__get_user(current->thread.vrsave,
+                      (u32 __user *)&tm_sr->mc_vregs[32]))
+               return 1;
+#endif /* CONFIG_ALTIVEC */
+
+       if (copy_ckfpr_from_user(current, &tm_sr->mc_fregs))
+               return 1;
+
+#ifdef CONFIG_VSX
+       if (msr & MSR_VSX) {
+               /*
+                * Restore altivec registers from the stack to a local
+                * buffer, then write this out to the thread_struct
+                */
+               if (copy_vsx_from_user(current, &tm_sr->mc_vsregs))
+                       return 1;
+               current->thread.used_vsr = true;
+       }
+#endif /* CONFIG_VSX */
+
        /* Get the top half of the MSR from the user context */
        if (__get_user(msr_hi, &tm_sr->mc_gregs[PT_MSR]))
                return 1;