new file mode 100644
@@ -0,0 +1,11 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _ASM_POWERPC_KUP_H_
+#define _ASM_POWERPC_KUP_H_
+
+#ifndef __ASSEMBLY__
+
+void setup_kup(void);
+
+#endif /* !__ASSEMBLY__ */
+
+#endif /* _ASM_POWERPC_KUP_H_ */
@@ -68,6 +68,7 @@
#include <asm/cputhreads.h>
#include <asm/hw_irq.h>
#include <asm/feature-fixups.h>
+#include <asm/kup.h>
#include "setup.h"
@@ -331,6 +332,12 @@ void __init early_setup(unsigned long dt_ptr)
*/
configure_exceptions();
+ /*
+ * Configure Kernel Userspace Protection. This needs to happen before
+ * feature fixups for platforms that implement this using features.
+ */
+ setup_kup();
+
/* Apply all the dynamic patching */
apply_feature_fixups();
setup_feature_keys();
@@ -24,6 +24,11 @@
#include <linux/string.h>
#include <asm/pgalloc.h>
#include <asm/pgtable.h>
+#include <asm/kup.h>
+
+void __init setup_kup(void)
+{
+}
static void pgd_ctor(void *addr)
{
@@ -45,6 +45,7 @@
#include <asm/tlb.h>
#include <asm/sections.h>
#include <asm/hugetlb.h>
+#include <asm/kup.h>
#include "mmu_decl.h"
@@ -182,6 +183,8 @@ void __init MMU_init(void)
btext_unmap();
#endif
+ setup_kup();
+
/* Shortly after that, the entire linear mapping will be available */
memblock_set_current_limit(lowmem_end_addr);
}
This patch adds a skeleton for Kernel Userspace Protection functionnalities like Kernel Userspace Access Protection and Kernel Userspace Execution Prevention The subsequent implementation of KUAP for radix makes use of a MMU feature in order to patch out assembly when KUAP is disabled or unsupported. This won't work unless there's an entry point for KUP support before the feature magic happens, so for PPC64 setup_kup() is called early in setup. On PPC32, feature_fixup is done too early to allow the same. Suggested-by: Russell Currey <ruscur@russell.cc> Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> --- arch/powerpc/include/asm/kup.h | 11 +++++++++++ arch/powerpc/kernel/setup_64.c | 7 +++++++ arch/powerpc/mm/init-common.c | 5 +++++ arch/powerpc/mm/init_32.c | 3 +++ 4 files changed, 26 insertions(+) create mode 100644 arch/powerpc/include/asm/kup.h