powerpc/book3s64/kuap/kuep: Add PPC_PKEY config on book3s64

The config CONFIG_PPC_PKEY is used to select the base support that is
required for PPC_MEM_KEYS, KUAP, and KUEP. Adding this dependency
reduces the code complexity(in terms of #ifdefs) and enables us to
move some of the initialization code to pkeys.c

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20201127044424.40686-4-aneesh.kumar@linux.ibm.com

arch/powerpc/include/asm/book3s/64/kup-radix.h

@@ -16,7 +16,7 @@
 #ifdef CONFIG_PPC_KUAP
 	BEGIN_MMU_FTR_SECTION_NESTED(67)
 	mfspr	\gpr1, SPRN_AMR
-	ld	\gpr2, STACK_REGS_KUAP(r1)
+	ld	\gpr2, STACK_REGS_AMR(r1)
 	cmpd	\gpr1, \gpr2
 	beq	998f
 	isync
@@ -48,7 +48,7 @@
 	bne	\msr_pr_cr, 99f
 	.endif
 	mfspr	\gpr1, SPRN_AMR
-	std	\gpr1, STACK_REGS_KUAP(r1)
+	std	\gpr1, STACK_REGS_AMR(r1)
 	li	\gpr2, (AMR_KUAP_BLOCKED >> AMR_KUAP_SHIFT)
 	sldi	\gpr2, \gpr2, AMR_KUAP_SHIFT
 	cmpd	\use_cr, \gpr1, \gpr2

arch/powerpc/include/asm/book3s/64/mmu.h

@@ -199,7 +199,7 @@ extern int mmu_io_psize;
 void mmu_early_init_devtree(void);
 void hash__early_init_devtree(void);
 void radix__early_init_devtree(void);
-#ifdef CONFIG_PPC_MEM_KEYS
+#ifdef CONFIG_PPC_PKEY
 void pkey_early_init_devtree(void);
 #else
 static inline void pkey_early_init_devtree(void) {}

arch/powerpc/include/asm/ptrace.h

@@ -53,9 +53,14 @@ struct pt_regs
 #ifdef CONFIG_PPC64
 			unsigned long ppr;
 #endif
+			union {
 #ifdef CONFIG_PPC_KUAP
-			unsigned long kuap;
+				unsigned long kuap;
 #endif
+#ifdef CONFIG_PPC_PKEY
+				unsigned long amr;
+#endif
+			};
 		};
 		unsigned long __pad[2];	/* Maintain 16 byte interrupt stack alignment */
 	};

arch/powerpc/kernel/asm-offsets.c

@@ -356,6 +356,9 @@ int main(void)
 	STACK_PT_REGS_OFFSET(_PPR, ppr);
 #endif /* CONFIG_PPC64 */
 
+#ifdef CONFIG_PPC_PKEY
+	STACK_PT_REGS_OFFSET(STACK_REGS_AMR, amr);
+#endif
 #ifdef CONFIG_PPC_KUAP
 	STACK_PT_REGS_OFFSET(STACK_REGS_KUAP, kuap);
 #endif

arch/powerpc/mm/book3s64/Makefile

@@ -17,7 +17,7 @@ endif
 obj-$(CONFIG_TRANSPARENT_HUGEPAGE) += hash_hugepage.o
 obj-$(CONFIG_PPC_SUBPAGE_PROT)	+= subpage_prot.o
 obj-$(CONFIG_SPAPR_TCE_IOMMU)	+= iommu_api.o
-obj-$(CONFIG_PPC_MEM_KEYS)	+= pkeys.o
+obj-$(CONFIG_PPC_PKEY)	+= pkeys.o
 
 # Instrumenting the SLB fault path can lead to duplicate SLB entries
 KCOV_INSTRUMENT_slb.o := n

arch/powerpc/mm/book3s64/pkeys.c

@@ -89,12 +89,14 @@ static int scan_pkey_feature(void)
 		}
 	}
 
+#ifdef CONFIG_PPC_MEM_KEYS
 	/*
 	 * Adjust the upper limit, based on the number of bits supported by
 	 * arch-neutral code.
 	 */
 	pkeys_total = min_t(int, pkeys_total,
 			    ((ARCH_VM_PKEY_FLAGS >> VM_PKEY_SHIFT) + 1));
+#endif
 	return pkeys_total;
 }
 
@@ -102,6 +104,7 @@ void __init pkey_early_init_devtree(void)
 {
 	int pkeys_total, i;
 
+#ifdef CONFIG_PPC_MEM_KEYS
 	/*
 	 * We define PKEY_DISABLE_EXECUTE in addition to the arch-neutral
 	 * generic defines for PKEY_DISABLE_ACCESS and PKEY_DISABLE_WRITE.
@@ -117,7 +120,7 @@ void __init pkey_early_init_devtree(void)
 	BUILD_BUG_ON(__builtin_clzl(ARCH_VM_PKEY_FLAGS >> VM_PKEY_SHIFT) +
 		     __builtin_popcountl(ARCH_VM_PKEY_FLAGS >> VM_PKEY_SHIFT)
 				!= (sizeof(u64) * BITS_PER_BYTE));
-
+#endif
 	/*
 	 * Only P7 and above supports SPRN_AMR update with MSR[PR] = 1
 	 */
@@ -223,14 +226,6 @@ out:
 	return;
 }
 
-void pkey_mm_init(struct mm_struct *mm)
-{
-	if (!mmu_has_feature(MMU_FTR_PKEY))
-		return;
-	mm_pkey_allocation_map(mm) = initial_allocation_mask;
-	mm->context.execute_only_pkey = execute_only_key;
-}
-
 static inline u64 read_amr(void)
 {
 	return mfspr(SPRN_AMR);
@@ -257,6 +252,15 @@ static inline void write_iamr(u64 value)
 	mtspr(SPRN_IAMR, value);
 }
 
+#ifdef CONFIG_PPC_MEM_KEYS
+void pkey_mm_init(struct mm_struct *mm)
+{
+	if (!mmu_has_feature(MMU_FTR_PKEY))
+		return;
+	mm_pkey_allocation_map(mm) = initial_allocation_mask;
+	mm->context.execute_only_pkey = execute_only_key;
+}
+
 static inline void init_amr(int pkey, u8 init_bits)
 {
 	u64 new_amr_bits = (((u64)init_bits & 0x3UL) << pkeyshift(pkey));
@@ -445,3 +449,5 @@ void arch_dup_pkeys(struct mm_struct *oldmm, struct mm_struct *mm)
 	mm_pkey_allocation_map(mm) = mm_pkey_allocation_map(oldmm);
 	mm->context.execute_only_pkey = oldmm->context.execute_only_pkey;
 }
+
+#endif /* CONFIG_PPC_MEM_KEYS */

arch/powerpc/platforms/Kconfig.cputype

@@ -406,6 +406,11 @@ config PPC_KUAP_DEBUG
 	  Add extra debugging for Kernel Userspace Access Protection (KUAP)
 	  If you're unsure, say N.
 
+config PPC_PKEY
+	def_bool y
+	depends on PPC_BOOK3S_64
+	depends on PPC_MEM_KEYS || PPC_KUAP || PPC_KUEP
+
 config ARCH_ENABLE_HUGEPAGE_MIGRATION
 	def_bool y
 	depends on PPC_BOOK3S_64 && HUGETLB_PAGE && MIGRATION