From 481135982d42836f73f197cd92c43c4216aef856 Mon Sep 17 00:00:00 2001 From: Sebastian Andrzej Siewior Date: Tue, 26 Mar 2019 18:31:29 +0100 Subject: [PATCH 186/198] powerpc/stackprotector: work around stack-guard init from atomic 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 | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/arch/powerpc/include/asm/stackprotector.h b/arch/powerpc/include/asm/stackprotector.h index 283c34647856..4727f40052dd 100644 --- a/arch/powerpc/include/asm/stackprotector.h +++ b/arch/powerpc/include/asm/stackprotector.h @@ -19,8 +19,13 @@ */ static __always_inline void boot_init_stack_canary(void) { - unsigned long canary = get_random_canary(); + unsigned long canary; +#ifndef CONFIG_PREEMPT_RT + canary = get_random_canary(); +#else + canary = ((unsigned long)&canary) & CANARY_MASK; +#endif current->stack_canary = canary; #ifdef CONFIG_PPC64 get_paca()->canary = canary; -- 2.44.0