ppc: Fix various compile errors resulting from ptrace.c merge

This introduces flush_{fp,altivec,spe}_to_thread and fixes a
branch-too-far error in linking.

Signed-off-by: Paul Mackerras <paulus@samba.org>

2 files changed, 98 insertions, 37 deletions

diff --git a/arch/ppc/kernel/entry.S b/arch/ppc/kernel/entry.S
index 03d4886869f3..68fc61221776 100644
--- a/arch/ppc/kernel/entry.S
+++ b/arch/ppc/kernel/entry.S
@@ -633,7 +633,8 @@ sigreturn_exit:
         rlwinm  r12,r1,0,0,18   /* current_thread_info() */
         lwz     r9,TI_FLAGS(r12)
         andi.   r0,r9,_TIF_SYSCALL_T_OR_A
-        bnel-   do_syscall_trace_leave
+        beq+    ret_from_except_full
+        bl      do_syscall_trace_leave
         /* fall through */
 
         .globl  ret_from_except_full
diff --git a/arch/ppc/kernel/process.c b/arch/ppc/kernel/process.c
index 0870e5553453..6d60c40598e7 100644
--- a/arch/ppc/kernel/process.c
+++ b/arch/ppc/kernel/process.c
@@ -152,18 +152,66 @@ int check_stack(struct task_struct *tsk)
 }
 #endif /* defined(CHECK_STACK) */
 
-#ifdef CONFIG_ALTIVEC
-int
-dump_altivec(struct pt_regs *regs, elf_vrregset_t *vrregs)
+/*
+ * Make sure the floating-point register state in the
+ * the thread_struct is up to date for task tsk.
+ */
+void flush_fp_to_thread(struct task_struct *tsk)
 {
-        if (regs->msr & MSR_VEC)
-                giveup_altivec(current);
-        memcpy(vrregs, &current->thread.vr[0], sizeof(*vrregs));
+        if (tsk->thread.regs) {
+                /*
+                 * We need to disable preemption here because if we didn't,
+                 * another process could get scheduled after the regs->msr
+                 * test but before we have finished saving the FP registers
+                 * to the thread_struct.  That process could take over the
+                 * FPU, and then when we get scheduled again we would store
+                 * bogus values for the remaining FP registers.
+                 */
+                preempt_disable();
+                if (tsk->thread.regs->msr & MSR_FP) {
+#ifdef CONFIG_SMP
+                        /*
+                         * This should only ever be called for current or
+                         * for a stopped child process.  Since we save away
+                         * the FP register state on context switch on SMP,
+                         * there is something wrong if a stopped child appears
+                         * to still have its FP state in the CPU registers.
+                         */
+                        BUG_ON(tsk != current);
+#endif
+                        giveup_fpu(current);
+                }
+                preempt_enable();
+        }
+}
+
+void enable_kernel_fp(void)
+{
+        WARN_ON(preemptible());
+
+#ifdef CONFIG_SMP
+        if (current->thread.regs && (current->thread.regs->msr & MSR_FP))
+                giveup_fpu(current);
+        else
+                giveup_fpu(NULL);       /* just enables FP for kernel */
+#else
+        giveup_fpu(last_task_used_math);
+#endif /* CONFIG_SMP */
+}
+EXPORT_SYMBOL(enable_kernel_fp);
+
+int dump_task_fpu(struct task_struct *tsk, elf_fpregset_t *fpregs)
+{
+        preempt_disable();
+        if (tsk->thread.regs && (tsk->thread.regs->msr & MSR_FP))
+                giveup_fpu(tsk);
+        preempt_enable();
+        memcpy(fpregs, &tsk->thread.fpr[0], sizeof(*fpregs));
         return 1;
 }
 
-void
-enable_kernel_altivec(void)
+#ifdef CONFIG_ALTIVEC
+void enable_kernel_altivec(void)
 {
         WARN_ON(preemptible());
 
@@ -177,19 +225,35 @@ enable_kernel_altivec(void)
 #endif /* __SMP __ */
 }
 EXPORT_SYMBOL(enable_kernel_altivec);
-#endif /* CONFIG_ALTIVEC */
 
-#ifdef CONFIG_SPE
-int
-dump_spe(struct pt_regs *regs, elf_vrregset_t *evrregs)
+/*
+ * Make sure the VMX/Altivec register state in the
+ * the thread_struct is up to date for task tsk.
+ */
+void flush_altivec_to_thread(struct task_struct *tsk)
 {
-        if (regs->msr & MSR_SPE)
-                giveup_spe(current);
-        /* We copy u32 evr[32] + u64 acc + u32 spefscr -> 35 */
-        memcpy(evrregs, &current->thread.evr[0], sizeof(u32) * 35);
+        if (tsk->thread.regs) {
+                preempt_disable();
+                if (tsk->thread.regs->msr & MSR_VEC) {
+#ifdef CONFIG_SMP
+                        BUG_ON(tsk != current);
+#endif
+                        giveup_altivec(current);
+                }
+                preempt_enable();
+        }
+}
+
+int dump_altivec(struct pt_regs *regs, elf_vrregset_t *vrregs)
+{
+        if (regs->msr & MSR_VEC)
+                giveup_altivec(current);
+        memcpy(vrregs, &current->thread.vr[0], sizeof(*vrregs));
         return 1;
 }
+#endif /* CONFIG_ALTIVEC */
 
+#ifdef CONFIG_SPE
 void
 enable_kernel_spe(void)
 {
@@ -205,34 +269,30 @@ enable_kernel_spe(void)
 #endif /* __SMP __ */
 }
 EXPORT_SYMBOL(enable_kernel_spe);
-#endif /* CONFIG_SPE */
 
-void
-enable_kernel_fp(void)
+void flush_spe_to_thread(struct task_struct *tsk)
 {
-        WARN_ON(preemptible());
-
+        if (tsk->thread.regs) {
+                preempt_disable();
+                if (tsk->thread.regs->msr & MSR_SPE) {
 #ifdef CONFIG_SMP
-        if (current->thread.regs && (current->thread.regs->msr & MSR_FP))
-                giveup_fpu(current);
-        else
-                giveup_fpu(NULL);       /* just enables FP for kernel */
-#else
-        giveup_fpu(last_task_used_math);
-#endif /* CONFIG_SMP */
+                        BUG_ON(tsk != current);
+#endif
+                        giveup_spe(current);
+                }
+                preempt_enable();
+        }
 }
-EXPORT_SYMBOL(enable_kernel_fp);
 
-int
-dump_task_fpu(struct task_struct *tsk, elf_fpregset_t *fpregs)
+int dump_spe(struct pt_regs *regs, elf_vrregset_t *evrregs)
 {
-        preempt_disable();
-        if (tsk->thread.regs && (tsk->thread.regs->msr & MSR_FP))
-                giveup_fpu(tsk);
-        preempt_enable();
-        memcpy(fpregs, &tsk->thread.fpr[0], sizeof(*fpregs));
+        if (regs->msr & MSR_SPE)
+                giveup_spe(current);
+        /* We copy u32 evr[32] + u64 acc + u32 spefscr -> 35 */
+        memcpy(evrregs, &current->thread.evr[0], sizeof(u32) * 35);
         return 1;
 }
+#endif /* CONFIG_SPE */
 
 struct task_struct *__switch_to(struct task_struct *prev,
         struct task_struct *new)