linux-kernel - [PATCH v2 2/3] MIPS: print MAAR configuration during boot

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Date:	Fri, 25 Sep 2015 08:59:37 -0700
From:	Paul Burton <paul.burton@...tec.com>
To:	<linux-mips@...ux-mips.org>
CC:	Paul Burton <paul.burton@...tec.com>,
	"Steven J. Hill" <Steven.Hill@...tec.com>,
	David Hildenbrand <dahi@...ux.vnet.ibm.com>,
	<linux-kernel@...r.kernel.org>, Ralf Baechle <ralf@...ux-mips.org>,
	"Peter Zijlstra (Intel)" <peterz@...radead.org>
Subject: [PATCH v2 2/3] MIPS: print MAAR configuration during boot

Verifying that the MAAR configuration is as expected is useful when
debugging the performance of a system. Print out the memory regions
configured via MAAR along with their attributes.

Signed-off-by: Paul Burton <paul.burton@...tec.com>
---

Changes in v2: None

 arch/mips/mm/init.c | 29 +++++++++++++++++++++++++++++
 1 file changed, 29 insertions(+)

diff --git a/arch/mips/mm/init.c b/arch/mips/mm/init.c
index 074ac54..023c164 100644
--- a/arch/mips/mm/init.c
+++ b/arch/mips/mm/init.c
@@ -291,6 +291,7 @@ unsigned __weak platform_maar_init(unsigned num_pairs)
 static void maar_init(void)
 {
 	unsigned num_maars, used, i;
+	phys_addr_t lower, upper, attr;
 
 	if (!cpu_has_maar)
 		return;
@@ -313,6 +314,34 @@ static void maar_init(void)
 		write_c0_maar(0);
 		back_to_back_c0_hazard();
 	}
+
+	pr_info("MAAR configuration:\n");
+	for (i = 0; i < num_maars; i += 2) {
+		write_c0_maari(i);
+		back_to_back_c0_hazard();
+		upper = read_c0_maar();
+
+		write_c0_maari(i + 1);
+		back_to_back_c0_hazard();
+		lower = read_c0_maar();
+
+		attr = lower & upper;
+		lower = (lower & MIPS_MAAR_ADDR) << 4;
+		upper = ((upper & MIPS_MAAR_ADDR) << 4) | 0xffff;
+
+		pr_info("  [%d]: ", i / 2);
+		if (!(attr & MIPS_MAAR_V)) {
+			pr_cont("disabled\n");
+			continue;
+		}
+
+		pr_cont("%pa-%pa", &lower, &upper);
+
+		if (attr & MIPS_MAAR_S)
+			pr_cont(" speculate");
+
+		pr_cont("\n");
+	}
 }
 
 #ifndef CONFIG_NEED_MULTIPLE_NODES
-- 
2.5.3

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