[PATCH 3/3] powerpc: re-initialise lazy FPU/VEC counters on every fault

[Nicholas Piggin]

When a FP/VEC/VSX unavailable fault loads registers and enables the
facility in the MSR, re-set the lazy restore counters to 1 rather
than incrementing them so every fault gets the same number of
restores before the next fault.

This probably shouldn't be a practical change because if a lazy counter
was non-zero then it should have been restored and would not cause a
fault when userspace tries to access it. However the code and comment
implies otherwise so that's misleading and unnecessary.

Signed-off-by: Nicholas Piggin <npiggin at gmail.com>
---
 arch/powerpc/kernel/fpu.S    | 4 +---
 arch/powerpc/kernel/vector.S | 4 +---
 2 files changed, 2 insertions(+), 6 deletions(-)

diff --git a/arch/powerpc/kernel/fpu.S b/arch/powerpc/kernel/fpu.S
index cac22cb97a8c..4ae39db70044 100644
--- a/arch/powerpc/kernel/fpu.S
+++ b/arch/powerpc/kernel/fpu.S
@@ -107,9 +107,7 @@ END_FTR_SECTION_IFSET(CPU_FTR_VSX)
 	or	r12,r12,r4
 	std	r12,_MSR(r1)
 #endif
-	/* Don't care if r4 overflows, this is desired behaviour */
-	lbz	r4,THREAD_LOAD_FP(r5)
-	addi	r4,r4,1
+	li	r4,1
 	stb	r4,THREAD_LOAD_FP(r5)
 	addi	r10,r5,THREAD_FPSTATE
 	lfd	fr0,FPSTATE_FPSCR(r10)
diff --git a/arch/powerpc/kernel/vector.S b/arch/powerpc/kernel/vector.S
index efc5b52f95d2..801dc28fdcca 100644
--- a/arch/powerpc/kernel/vector.S
+++ b/arch/powerpc/kernel/vector.S
@@ -76,9 +76,7 @@ _GLOBAL(load_up_altivec)
 	oris	r12,r12,MSR_VEC at h
 	std	r12,_MSR(r1)
 #endif
-	/* Don't care if r4 overflows, this is desired behaviour */
-	lbz	r4,THREAD_LOAD_VEC(r5)
-	addi	r4,r4,1
+	li	r4,1
 	stb	r4,THREAD_LOAD_VEC(r5)
 	addi	r6,r5,THREAD_VRSTATE
 	li	r4,1
-- 
2.23.0