From 150ed4d2ff2f53395737e8627186756d1775ad09 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 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(+) Index: linux-6.1.96-rt35/arch/powerpc/include/asm/stackprotector.h =================================================================== --- linux-6.1.96-rt35.orig/arch/powerpc/include/asm/stackprotector.h +++ linux-6.1.96-rt35/arch/powerpc/include/asm/stackprotector.h @@ -24,7 +24,11 @@ static __always_inline void boot_init_st 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;