Thread (49 messages) flat view 49 messages, 2 authors, 2020-07-07
STALE2230d

Revision v5 of 2 in this series.

Revisions (2)
  1. v5 current
  2. v6 [diff vs current]

[PATCH v5 14/26] powerpc/book3s64/kuep: Add MMU_FTR_KUEP

From: Aneesh Kumar K.V <hidden>
Date: 2020-06-19 15:17:00
Subsystem: linux for powerpc (32-bit and 64-bit), the rest · Maintainers: Madhavan Srinivasan, Linus Torvalds

This will be used to enable/disable Kernel Userspace Execution
Prevention (KUEP).

Signed-off-by: Aneesh Kumar K.V <redacted>
---
 arch/powerpc/include/asm/mmu.h           | 5 +++++
 arch/powerpc/mm/book3s64/radix_pgtable.c | 4 +++-
 2 files changed, 8 insertions(+), 1 deletion(-)
diff --git a/arch/powerpc/include/asm/mmu.h b/arch/powerpc/include/asm/mmu.h
index 72966d3d8f64..94435f85e3bc 100644
--- a/arch/powerpc/include/asm/mmu.h
+++ b/arch/powerpc/include/asm/mmu.h
@@ -24,6 +24,7 @@
 /* Radix page table supported and enabled */
 #define MMU_FTR_TYPE_RADIX		ASM_CONST(0x00000040)
 #define MMU_FTR_PKEY			ASM_CONST(0x00000080)
+#define MMU_FTR_KUEP			ASM_CONST(0x00000100)
 
 /*
  * Individual features below.
@@ -181,6 +182,10 @@ enum {
 #ifdef CONFIG_PPC_MEM_KEYS
 	MMU_FTR_PKEY |
 #endif
+#ifdef CONFIG_PPC_KUEP
+	MMU_FTR_KUEP |
+#endif /* CONFIG_PPC_KUAP */
+
 		0,
 };
 
diff --git a/arch/powerpc/mm/book3s64/radix_pgtable.c b/arch/powerpc/mm/book3s64/radix_pgtable.c
index 8acb96de0e48..04fd749c6339 100644
--- a/arch/powerpc/mm/book3s64/radix_pgtable.c
+++ b/arch/powerpc/mm/book3s64/radix_pgtable.c
@@ -520,8 +520,10 @@ void setup_kuep(bool disabled)
 	if (disabled || !early_radix_enabled())
 		return;
 
-	if (smp_processor_id() == boot_cpuid)
+	if (smp_processor_id() == boot_cpuid) {
 		pr_info("Activating Kernel Userspace Execution Prevention\n");
+		cur_cpu_spec->mmu_features |= MMU_FTR_KUEP;
+	}
 
 	/*
 	 * Radix always uses key0 of the IAMR to determine if an access is
-- 
2.26.2
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