powerpc/64s: Simplify POWER9 DD1 idle workaround code

The idle workaround does not need to load PACATOC, and it does not
need to be called within a nested function that requires LR to be
saved.

Load the PACATOC at entry to the idle wakeup. It does not matter which
PACA this comes from, so it's okay to call before the workaround. Then
apply the workaround to get the right PACA.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

arch/powerpc/include/asm/feature-fixups.h

@@ -66,6 +66,9 @@ label##5:							\
 #define END_FTR_SECTION(msk, val)		\
 	END_FTR_SECTION_NESTED(msk, val, 97)
 
+#define END_FTR_SECTION_NESTED_IFSET(msk, label)	\
+	END_FTR_SECTION_NESTED((msk), (msk), label)
+
 #define END_FTR_SECTION_IFSET(msk)	END_FTR_SECTION((msk), (msk))
 #define END_FTR_SECTION_IFCLR(msk)	END_FTR_SECTION((msk), 0)
 

arch/powerpc/kernel/idle_book3s.S

@@ -411,7 +411,6 @@ power9_dd1_recover_paca:
 	/* Load paca->thread_sibling_pacas[i] into r13 */
 	ldx	r13, r4, r5
 	SET_PACA(r13)
-	ld	r2, PACATOC(r13)
 	/*
 	 * Indicate that we have lost NVGPR state
 	 * which needs to be restored from the stack.
@@ -451,7 +450,12 @@ pnv_powersave_wakeup_mce:
  */
 .global pnv_powersave_wakeup
 pnv_powersave_wakeup:
+	ld	r2, PACATOC(r13)
+
 BEGIN_FTR_SECTION
+BEGIN_FTR_SECTION_NESTED(70)
+	bl	power9_dd1_recover_paca
+END_FTR_SECTION_NESTED_IFSET(CPU_FTR_POWER9_DD1, 70)
 	bl	pnv_restore_hyp_resource_arch300
 FTR_SECTION_ELSE
 	bl	pnv_restore_hyp_resource_arch207
@@ -488,14 +492,6 @@ pnv_restore_hyp_resource_arch300:
 	 * POWER ISA 3. Use PSSCR to determine if we
 	 * are waking up from deep idle state
 	 */
-BEGIN_FTR_SECTION
-	mflr 	r6
-	bl	power9_dd1_recover_paca
-	mtlr	r6
-FTR_SECTION_ELSE
-	ld	r2, PACATOC(r13)
-ALT_FTR_SECTION_END_IFSET(CPU_FTR_POWER9_DD1)
-
 	LOAD_REG_ADDRBASE(r5,pnv_first_deep_stop_state)
 	ld	r4,ADDROFF(pnv_first_deep_stop_state)(r5)
 
@@ -516,8 +512,6 @@ pnv_restore_hyp_resource_arch207:
 	 * POWER ISA 2.07 or less.
 	 * Check if we slept with sleep or winkle.
 	 */
-	ld	r2,PACATOC(r13);
-
 	lbz	r4,PACA_THREAD_IDLE_STATE(r13)
 	cmpwi	cr2,r4,PNV_THREAD_NAP
 	bgt	cr2,pnv_wakeup_tb_loss	/* Either sleep or Winkle */