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From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
To: LKML <linux-kernel@vger.kernel.org>,
	linux-rt-users <linux-rt-users@vger.kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>,
	Steven Rostedt <rostedt@goodmis.org>
Subject: [PATCH 2/4] powerpc/stackprotector: work around stack-guard init from atomic
Date: Wed, 27 Mar 2019 19:33:08 +0100	[thread overview]
Message-ID: <20190327183310.1015-2-bigeasy@linutronix.de> (raw)
In-Reply-To: <20190327183310.1015-1-bigeasy@linutronix.de>

This is invoked from the secondary CPU in atomic context. On x86 we use
tsc instead. On Power we XOR it against mftb() so lets use stack address
as the initial value.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---
 arch/powerpc/include/asm/stackprotector.h | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/arch/powerpc/include/asm/stackprotector.h b/arch/powerpc/include/asm/stackprotector.h
index 1c8460e235838..e764eb4b6c284 100644
--- a/arch/powerpc/include/asm/stackprotector.h
+++ b/arch/powerpc/include/asm/stackprotector.h
@@ -24,7 +24,11 @@ static __always_inline void boot_init_stack_canary(void)
 	unsigned long canary;
 
 	/* Try to get a semi random initial value. */
+#ifdef CONFIG_PREEMPT_RT_FULL
+	canary = (unsigned long)&canary;
+#else
 	canary = get_random_canary();
+#endif
 	canary ^= mftb();
 	canary ^= LINUX_VERSION_CODE;
 	canary &= CANARY_MASK;
-- 
2.20.1


  reply	other threads:[~2019-03-27 18:33 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-03-20 17:15 [ANNOUNCE] v5.0.3-rt1 Sebastian Andrzej Siewior
2019-03-22 18:52 ` Julien Grall
2019-03-25  8:13   ` John Ogness
2019-03-25 10:18     ` Julien Grall
2019-03-25 10:34       ` John Ogness
2019-03-26 10:26         ` Julien Grall
2019-03-26 16:04           ` John Ogness
2019-03-27 18:33 ` [PATCH 1/4] printk: An all-in-one commit to fix build failures Sebastian Andrzej Siewior
2019-03-27 18:33   ` Sebastian Andrzej Siewior [this message]
2019-05-10 21:46     ` [PATCH 2/4] powerpc/stackprotector: work around stack-guard init from atomic Steven Rostedt
2019-03-27 18:33   ` [PATCH 3/4] powerpc/pseries/iommu: Use a locallock instead local_irq_save() Sebastian Andrzej Siewior
2019-03-27 18:33   ` [PATCH 4/4] powerpc: reshuffle TIF bits Sebastian Andrzej Siewior

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