From 6ebe002aae6beb7d1b527670eaf898fc11606ccc Mon Sep 17 00:00:00 2001 From: Sebastian Andrzej Siewior Date: Tue, 26 Mar 2019 18:31:29 +0100 Subject: [PATCH 48/64] powerpc/stackprotector: work around stack-guard init from atomic Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.1/older/patches-6.1.82-rt27.tar.xz 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. Cc: stable-rt@vger.kernel.org Signed-off-by: Sebastian Andrzej Siewior Signed-off-by: Thomas Gleixner --- 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 1c8460e23583..b1653c160bab 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 + canary = (unsigned long)&canary; +#else canary = get_random_canary(); +#endif canary ^= mftb(); canary ^= LINUX_VERSION_CODE; canary &= CANARY_MASK; -- 2.44.0