linux-kernel - [PATCH 02/15] MIPS: traps: Make sure secondary cores have a sane ebase register

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Date:	Wed, 3 Feb 2016 03:15:22 +0000
From:	Paul Burton <paul.burton@...tec.com>
To:	<linux-mips@...ux-mips.org>, Ralf Baechle <ralf@...ux-mips.org>
CC:	Markos Chandras <markos.chandras@...tec.com>,
	Paul Burton <paul.burton@...tec.com>,
	Leonid Yegoshin <Leonid.Yegoshin@...tec.com>,
	"Maciej W. Rozycki" <macro@...ux-mips.org>,
	<linux-kernel@...r.kernel.org>,
	James Hogan <james.hogan@...tec.com>,
	Petri Gynther <pgynther@...gle.com>
Subject: [PATCH 02/15] MIPS: traps: Make sure secondary cores have a sane ebase register

From: Markos Chandras <markos.chandras@...tec.com>

We shouldn't trust that the secondary cores will have a sane ebase register
(either from the bootloader or during the hardware design phase) so use the
ebase address as calculated by the boot CPU.

Signed-off-by: Markos Chandras <markos.chandras@...tec.com>
Signed-off-by: Paul Burton <paul.burton@...tec.com>
---

 arch/mips/kernel/traps.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/arch/mips/kernel/traps.c b/arch/mips/kernel/traps.c
index bafcb7a..1fb5f8a 100644
--- a/arch/mips/kernel/traps.c
+++ b/arch/mips/kernel/traps.c
@@ -2125,6 +2125,13 @@ void per_cpu_trap_init(bool is_boot_cpu)
 	 *  o read IntCtl.IPFDC to determine the fast debug channel interrupt
 	 */
 	if (cpu_has_mips_r2_r6) {
+		/*
+		 * We shouldn't trust a secondary core has a sane EBASE register
+		 * so use the one calculated by the boot CPU.
+		 */
+		if (!is_boot_cpu)
+			write_c0_ebase(ebase);
+
 		cp0_compare_irq_shift = CAUSEB_TI - CAUSEB_IP;
 		cp0_compare_irq = (read_c0_intctl() >> INTCTLB_IPTI) & 7;
 		cp0_perfcount_irq = (read_c0_intctl() >> INTCTLB_IPPCI) & 7;
-- 
2.7.0