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-rw-r--r--arch/arm64/include/asm/fpsimdmacros.h17
1 files changed, 15 insertions, 2 deletions
diff --git a/arch/arm64/include/asm/fpsimdmacros.h b/arch/arm64/include/asm/fpsimdmacros.h
index 768414d55e64..007618b8188c 100644
--- a/arch/arm64/include/asm/fpsimdmacros.h
+++ b/arch/arm64/include/asm/fpsimdmacros.h
@@ -40,6 +40,19 @@
str w\tmpnr, [\state, #16 * 2 + 4]
.endm
+.macro fpsimd_restore_fpcr state, tmp
+ /*
+ * Writes to fpcr may be self-synchronising, so avoid restoring
+ * the register if it hasn't changed.
+ */
+ mrs \tmp, fpcr
+ cmp \tmp, \state
+ b.eq 9999f
+ msr fpcr, \state
+9999:
+.endm
+
+/* Clobbers \state */
.macro fpsimd_restore state, tmpnr
ldp q0, q1, [\state, #16 * 0]
ldp q2, q3, [\state, #16 * 2]
@@ -60,7 +73,7 @@
ldr w\tmpnr, [\state, #16 * 2]
msr fpsr, x\tmpnr
ldr w\tmpnr, [\state, #16 * 2 + 4]
- msr fpcr, x\tmpnr
+ fpsimd_restore_fpcr x\tmpnr, \state
.endm
.altmacro
@@ -84,7 +97,7 @@
.macro fpsimd_restore_partial state, tmpnr1, tmpnr2
ldp w\tmpnr1, w\tmpnr2, [\state]
msr fpsr, x\tmpnr1
- msr fpcr, x\tmpnr2
+ fpsimd_restore_fpcr x\tmpnr2, x\tmpnr1
adr x\tmpnr1, 0f
ldr w\tmpnr2, [\state, #8]
add \state, \state, x\tmpnr2, lsl #4
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