linux-kernel - [PATCH 4.4 14/35] MIPS: DEC: Avoid la pseudo-instruction in delay slots

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Message-Id: <20170316142907.649228774@linuxfoundation.org>
Date:   Thu, 16 Mar 2017 23:29:33 +0900
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Ralf Baechle <ralf@...ux-mips.org>
Subject: [PATCH 4.4 14/35] MIPS: DEC: Avoid la pseudo-instruction in delay slots

4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Ralf Baechle <ralf@...ux-mips.org>

commit 3021773c7c3e75e20b693931a19362681e744ea9 upstream.

When expanding the la or dla pseudo-instruction in a delay slot the GNU
assembler will complain should the pseudo-instruction expand to multiple
actual instructions, since only the first of them will be in the delay
slot leading to the pseudo-instruction being only partially executed if
the branch is taken. Use of PTR_LA in the dec int-handler.S leads to
such warnings:

  arch/mips/dec/int-handler.S: Assembler messages:
  arch/mips/dec/int-handler.S:149: Warning: macro instruction expanded into multiple instructions in a branch delay slot
  arch/mips/dec/int-handler.S:198: Warning: macro instruction expanded into multiple instructions in a branch delay slot

Avoid this by open coding the PTR_LA macros.

Signed-off-by: Ralf Baechle <ralf@...ux-mips.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 arch/mips/dec/int-handler.S |   40 ++++++++++++++++++++++++++++++++++++++--
 1 file changed, 38 insertions(+), 2 deletions(-)

--- a/arch/mips/dec/int-handler.S
+++ b/arch/mips/dec/int-handler.S
@@ -146,7 +146,25 @@
 		/*
 		 * Find irq with highest priority
 		 */
-		 PTR_LA	t1,cpu_mask_nr_tbl
+		# open coded PTR_LA t1, cpu_mask_nr_tbl
+#if (_MIPS_SZPTR == 32)
+		# open coded la t1, cpu_mask_nr_tbl
+		lui	t1, %hi(cpu_mask_nr_tbl)
+		addiu	t1, %lo(cpu_mask_nr_tbl)
+
+#endif
+#if (_MIPS_SZPTR == 64)
+		# open coded dla t1, cpu_mask_nr_tbl
+		.set	push
+		.set	noat
+		lui	t1, %highest(cpu_mask_nr_tbl)
+		lui	AT, %hi(cpu_mask_nr_tbl)
+		daddiu	t1, t1, %higher(cpu_mask_nr_tbl)
+		daddiu	AT, AT, %lo(cpu_mask_nr_tbl)
+		dsll	t1, 32
+		daddu	t1, t1, AT
+		.set	pop
+#endif
 1:		lw	t2,(t1)
 		nop
 		and	t2,t0
@@ -195,7 +213,25 @@
 		/*
 		 * Find irq with highest priority
 		 */
-		 PTR_LA	t1,asic_mask_nr_tbl
+		# open coded PTR_LA t1,asic_mask_nr_tbl
+#if (_MIPS_SZPTR == 32)
+		# open coded la t1, asic_mask_nr_tbl
+		lui	t1, %hi(asic_mask_nr_tbl)
+		addiu	t1, %lo(asic_mask_nr_tbl)
+
+#endif
+#if (_MIPS_SZPTR == 64)
+		# open coded dla t1, asic_mask_nr_tbl
+		.set	push
+		.set	noat
+		lui	t1, %highest(asic_mask_nr_tbl)
+		lui	AT, %hi(asic_mask_nr_tbl)
+		daddiu	t1, t1, %higher(asic_mask_nr_tbl)
+		daddiu	AT, AT, %lo(asic_mask_nr_tbl)
+		dsll	t1, 32
+		daddu	t1, t1, AT
+		.set	pop
+#endif
 2:		lw	t2,(t1)
 		nop
 		and	t2,t0