===================================================================
@@ -145,6 +145,11 @@ END_FTR_SECTION_IFSET(CPU_FTR_VSX)
beq 1f
PPC_LL r4,_MSR-STACK_FRAME_OVERHEAD(r5)
li r3,MSR_FP|MSR_FE0|MSR_FE1
+#ifdef CONFIG_VSX
+BEGIN_FTR_SECTION
+ oris r3,r3,MSR_VSX@h
+END_FTR_SECTION_IFSET(CPU_FTR_VSX)
+#endif
andc r4,r4,r3 /* disable FP for previous task */
PPC_STL r4,_MSR-STACK_FRAME_OVERHEAD(r5)
1:
===================================================================
@@ -495,7 +495,15 @@ _GLOBAL(giveup_altivec)
stvx vr0,r4,r3
beq 1f
ld r4,_MSR-STACK_FRAME_OVERHEAD(r5)
+#ifdef CONFIG_VSX
+BEGIN_FTR_SECTION
+ lis r3,(MSR_VEC|MSR_VSX)@h
+FTR_SECTION_ELSE
+ lis r3,MSR_VEC@h
+ALT_FTR_SECTION_END_IFSET(CPU_FTR_VSX)
+#else
lis r3,MSR_VEC@h
+#endif
andc r4,r4,r3 /* disable FP for previous task */
std r4,_MSR-STACK_FRAME_OVERHEAD(r5)
1:
When we call giveup_fpu, we need to need to turn off VSX in current. If we don't, on return to current it may execute a VSX instruction (before the next FP), and not have it's register state refreshed correctly from the thread_struct. Ditto for altivec. This caused a bug where an unaligned lfs or stfs (which calls giveup_fpu so it can use the FPRs) to return to userspace with FP off but VSX on. Then if a VSX instruction is executed, before another FP instruction, it will proceed without another exception and hence have the incorrect register state for VSX registers 0-31. lfs unaligned <- alignment exception turns FP off but leaves VSX on VSX instruction <- no exception since VSX on, hence we get the wrong VSX register values for VSX registers 0-31 (overlapping the FPRs) Signed-off-by: Michael Neuling <mikey@neuling.org> --- arch/powerpc/kernel/fpu.S | 5 +++++ arch/powerpc/kernel/misc_64.S | 8 ++++++++ 2 files changed, 13 insertions(+)