From 06fbe81b5909847aa13f9c86c2b6f9bbc5c2795b Mon Sep 17 00:00:00 2001 From: Christophe Leroy Date: Mon, 11 Mar 2019 08:30:33 +0000 Subject: powerpc/8xx: Add Kernel Userspace Execution Prevention This patch adds Kernel Userspace Execution Prevention on the 8xx. When a page is Executable, it is set Executable for Key 0 and NX for Key 1. Up to now, the User group is defined with Key 0 for both User and Supervisor. By changing the group to Key 0 for User and Key 1 for Supervisor, this patch prevents the Kernel from being able to execute user code. Signed-off-by: Christophe Leroy Signed-off-by: Michael Ellerman --- arch/powerpc/mm/8xx_mmu.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) (limited to 'arch/powerpc/mm') diff --git a/arch/powerpc/mm/8xx_mmu.c b/arch/powerpc/mm/8xx_mmu.c index fe1f6443d57f..e257a0c9bd08 100644 --- a/arch/powerpc/mm/8xx_mmu.c +++ b/arch/powerpc/mm/8xx_mmu.c @@ -213,3 +213,15 @@ void flush_instruction_cache(void) mtspr(SPRN_IC_CST, IDC_INVALL); isync(); } + +#ifdef CONFIG_PPC_KUEP +void __init setup_kuep(bool disabled) +{ + if (disabled) + return; + + pr_info("Activating Kernel Userspace Execution Prevention\n"); + + mtspr(SPRN_MI_AP, MI_APG_KUEP); +} +#endif -- cgit v1.2.3