powerpc: Fix bug causing FP registers corruption on UP + preempt

[powerpc.git] / arch / powerpc / kernel / process.c

diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index 8f85dab..105d560 100644 (file)
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -46,9 +46,9 @@
 #include <asm/processor.h>
 #include <asm/mmu.h>
 #include <asm/prom.h>
+#include <asm/machdep.h>
 #ifdef CONFIG_PPC64
 #include <asm/firmware.h>
-#include <asm/plpar_wrappers.h>
 #include <asm/time.h>
 #endif
 
@@ -201,27 +201,35 @@ int dump_spe(struct pt_regs *regs, elf_vrregset_t *evrregs)
 }
 #endif /* CONFIG_SPE */
 
-static void set_dabr_spr(unsigned long val)
+/*
+ * If we are doing lazy switching of CPU state (FP, altivec or SPE),
+ * and the current task has some state, discard it.
+ */
+static inline void discard_lazy_cpu_state(void)
 {
-       mtspr(SPRN_DABR, val);
+#ifndef CONFIG_SMP
+       preempt_disable();
+       if (last_task_used_math == current)
+               last_task_used_math = NULL;
+#ifdef CONFIG_ALTIVEC
+       if (last_task_used_altivec == current)
+               last_task_used_altivec = NULL;
+#endif /* CONFIG_ALTIVEC */
+#ifdef CONFIG_SPE
+       if (last_task_used_spe == current)
+               last_task_used_spe = NULL;
+#endif
+       preempt_enable();
+#endif /* CONFIG_SMP */
 }
 
 int set_dabr(unsigned long dabr)
 {
-       int ret = 0;
+       if (ppc_md.set_dabr)
+               return ppc_md.set_dabr(dabr);
 
-#ifdef CONFIG_PPC64
-       if (firmware_has_feature(FW_FEATURE_XDABR)) {
-               /* We want to catch accesses from kernel and userspace */
-               unsigned long flags = H_DABRX_KERNEL|H_DABRX_USER;
-               ret = plpar_set_xdabr(dabr, flags);
-       } else if (firmware_has_feature(FW_FEATURE_DABR)) {
-               ret = plpar_set_dabr(dabr);
-       } else
-#endif
-               set_dabr_spr(dabr);
-
-       return ret;
+       mtspr(SPRN_DABR, dabr);
+       return 0;
 }
 
 #ifdef CONFIG_PPC64
@@ -448,19 +456,7 @@ void show_regs(struct pt_regs * regs)
 void exit_thread(void)
 {
        kprobe_flush_task(current);
-
-#ifndef CONFIG_SMP
-       if (last_task_used_math == current)
-               last_task_used_math = NULL;
-#ifdef CONFIG_ALTIVEC
-       if (last_task_used_altivec == current)
-               last_task_used_altivec = NULL;
-#endif /* CONFIG_ALTIVEC */
-#ifdef CONFIG_SPE
-       if (last_task_used_spe == current)
-               last_task_used_spe = NULL;
-#endif
-#endif /* CONFIG_SMP */
+       discard_lazy_cpu_state();
 }
 
 void flush_thread(void)
@@ -471,20 +467,8 @@ void flush_thread(void)
        if (t->flags & _TIF_ABI_PENDING)
                t->flags ^= (_TIF_ABI_PENDING | _TIF_32BIT);
 #endif
-       kprobe_flush_task(current);
 
-#ifndef CONFIG_SMP
-       if (last_task_used_math == current)
-               last_task_used_math = NULL;
-#ifdef CONFIG_ALTIVEC
-       if (last_task_used_altivec == current)
-               last_task_used_altivec = NULL;
-#endif /* CONFIG_ALTIVEC */
-#ifdef CONFIG_SPE
-       if (last_task_used_spe == current)
-               last_task_used_spe = NULL;
-#endif
-#endif /* CONFIG_SMP */
+       discard_lazy_cpu_state();
 
 #ifdef CONFIG_PPC64    /* for now */
        if (current->thread.dabr) {
@@ -566,12 +550,10 @@ int copy_thread(int nr, unsigned long clone_flags, unsigned long usp,
 #ifdef CONFIG_PPC64
        if (cpu_has_feature(CPU_FTR_SLB)) {
                unsigned long sp_vsid = get_kernel_vsid(sp);
+               unsigned long llp = mmu_psize_defs[mmu_linear_psize].sllp;
 
                sp_vsid <<= SLB_VSID_SHIFT;
-               sp_vsid |= SLB_VSID_KERNEL;
-               if (cpu_has_feature(CPU_FTR_16M_PAGE))
-                       sp_vsid |= SLB_VSID_L;
-
+               sp_vsid |= SLB_VSID_KERNEL | llp;
                p->thread.ksp_vsid = sp_vsid;
        }
 
@@ -652,18 +634,7 @@ void start_thread(struct pt_regs *regs, unsigned long start, unsigned long sp)
        }
 #endif
 
-#ifndef CONFIG_SMP
-       if (last_task_used_math == current)
-               last_task_used_math = NULL;
-#ifdef CONFIG_ALTIVEC
-       if (last_task_used_altivec == current)
-               last_task_used_altivec = NULL;
-#endif
-#ifdef CONFIG_SPE
-       if (last_task_used_spe == current)
-               last_task_used_spe = NULL;
-#endif
-#endif /* CONFIG_SMP */
+       discard_lazy_cpu_state();
        memset(current->thread.fpr, 0, sizeof(current->thread.fpr));
        current->thread.fpscr.val = 0;
 #ifdef CONFIG_ALTIVEC