Follow @Openwall on Twitter for new release announcements and other news
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date: Fri, 23 Nov 2018 01:04:15 +1100
From: Russell Currey <ruscur@...sell.cc>
To: linuxppc-dev@...ts.ozlabs.org
Cc: mpe@...erman.id.au,
	benh@...nel.crashing.org,
	kernel-hardening@...ts.openwall.com,
	christophe.leroy@....fr,
	Russell Currey <ruscur@...sell.cc>
Subject: [PATCH 3/4] powerpc/mm/radix: Use KUEP API for Radix MMU

Execution protection already exists on radix, this just refactors
the radix init to provide the KUEP setup function instead.

Thus, the only functional change is that it can now be disabled.

Signed-off-by: Russell Currey <ruscur@...sell.cc>
---
 arch/powerpc/mm/pgtable-radix.c        | 9 ++++++---
 arch/powerpc/platforms/Kconfig.cputype | 1 +
 2 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/arch/powerpc/mm/pgtable-radix.c b/arch/powerpc/mm/pgtable-radix.c
index 931156069a81..f08a459b4255 100644
--- a/arch/powerpc/mm/pgtable-radix.c
+++ b/arch/powerpc/mm/pgtable-radix.c
@@ -535,8 +535,13 @@ static void radix_init_amor(void)
 	mtspr(SPRN_AMOR, (3ul << 62));
 }
 
-static void radix_init_iamr(void)
+void setup_kuep(bool disabled)
 {
+	if (disabled)
+		return;
+
+	pr_warn("Activating Kernel Userspace Execution Prevention\n");
+
 	/*
 	 * Radix always uses key0 of the IAMR to determine if an access is
 	 * allowed. We set bit 0 (IBM bit 1) of key0, to prevent instruction
@@ -605,7 +610,6 @@ void __init radix__early_init_mmu(void)
 
 	memblock_set_current_limit(MEMBLOCK_ALLOC_ANYWHERE);
 
-	radix_init_iamr();
 	radix_init_pgtable();
 	/* Switch to the guard PID before turning on MMU */
 	radix__switch_mmu_context(NULL, &init_mm);
@@ -627,7 +631,6 @@ void radix__early_init_mmu_secondary(void)
 		      __pa(partition_tb) | (PATB_SIZE_SHIFT - 12));
 		radix_init_amor();
 	}
-	radix_init_iamr();
 
 	radix__switch_mmu_context(NULL, &init_mm);
 	if (cpu_has_feature(CPU_FTR_HVMODE))
diff --git a/arch/powerpc/platforms/Kconfig.cputype b/arch/powerpc/platforms/Kconfig.cputype
index a20669a9ec13..e6831d0ec159 100644
--- a/arch/powerpc/platforms/Kconfig.cputype
+++ b/arch/powerpc/platforms/Kconfig.cputype
@@ -334,6 +334,7 @@ config PPC_RADIX_MMU
 	bool "Radix MMU Support"
 	depends on PPC_BOOK3S_64
 	select ARCH_HAS_GIGANTIC_PAGE if (MEMORY_ISOLATION && COMPACTION) || CMA
+	select PPC_HAVE_KUEP
 	default y
 	help
 	  Enable support for the Power ISA 3.0 Radix style MMU. Currently this
-- 
2.19.1

Powered by blists - more mailing lists

Confused about mailing lists and their use? Read about mailing lists on Wikipedia and check out these guidelines on proper formatting of your messages.