linux-kernel - [PATCH 1/2] MIPS: Watch: Avoid duplication of bits in mips_install_watch

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Date:   Tue, 2 Jan 2018 11:31:21 +0000
From:   Matt Redfearn <matt.redfearn@...s.com>
To:     <ralf@...ux-mips.org>
CC:     <linux-mips@...ux-mips.org>, <linux-kernel@...r.kernel.org>,
        Matt Redfearn <matt.redfearn@...s.com>
Subject: [PATCH 1/2] MIPS: Watch: Avoid duplication of bits in mips_install_watch_registers.

Currently the bits to be set in the watchhi register in addition to that
requested by the user is defined inline for each register. To avoid
this, define the bits once and or that in for each register.

Signed-off-by: Matt Redfearn <matt.redfearn@...s.com>
---

 arch/mips/kernel/watch.c | 17 +++++++----------
 1 file changed, 7 insertions(+), 10 deletions(-)

diff --git a/arch/mips/kernel/watch.c b/arch/mips/kernel/watch.c
index 19fcab7348b1..329d2209521d 100644
--- a/arch/mips/kernel/watch.c
+++ b/arch/mips/kernel/watch.c
@@ -18,27 +18,24 @@
 void mips_install_watch_registers(struct task_struct *t)
 {
 	struct mips3264_watch_reg_state *watches = &t->thread.watch.mips3264;
+	unsigned int watchhi = MIPS_WATCHHI_G |		/* Trap all ASIDs */
+			       MIPS_WATCHHI_IRW;	/* Clear result bits */
+
 	switch (current_cpu_data.watch_reg_use_cnt) {
 	default:
 		BUG();
 	case 4:
 		write_c0_watchlo3(watches->watchlo[3]);
-		/* Write 1 to the I, R, and W bits to clear them, and
-		   1 to G so all ASIDs are trapped. */
-		write_c0_watchhi3(MIPS_WATCHHI_G | MIPS_WATCHHI_IRW |
-				  watches->watchhi[3]);
+		write_c0_watchhi3(watchhi | watches->watchhi[3]);
 	case 3:
 		write_c0_watchlo2(watches->watchlo[2]);
-		write_c0_watchhi2(MIPS_WATCHHI_G | MIPS_WATCHHI_IRW |
-				  watches->watchhi[2]);
+		write_c0_watchhi2(watchhi | watches->watchhi[2]);
 	case 2:
 		write_c0_watchlo1(watches->watchlo[1]);
-		write_c0_watchhi1(MIPS_WATCHHI_G | MIPS_WATCHHI_IRW |
-				  watches->watchhi[1]);
+		write_c0_watchhi1(watchhi | watches->watchhi[1]);
 	case 1:
 		write_c0_watchlo0(watches->watchlo[0]);
-		write_c0_watchhi0(MIPS_WATCHHI_G | MIPS_WATCHHI_IRW |
-				  watches->watchhi[0]);
+		write_c0_watchhi0(watchhi | watches->watchhi[0]);
 	}
 }
 
-- 
2.7.4