Merge branch 'for-next/rng' into for-next/core

* for-next/rng: (2 commits)
  arm64: Use v8.5-RNG entropy for KASLR seed
  ...

5 files changed, 84 insertions, 2 deletions

diff --git a/arch/arm64/include/asm/archrandom.h b/arch/arm64/include/asm/archrandom.h
new file mode 100644
index 000000000000..3fe02da70004
--- /dev/null
+++ b/arch/arm64/include/asm/archrandom.h
@@ -0,0 +1,75 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _ASM_ARCHRANDOM_H
+#define _ASM_ARCHRANDOM_H
+
+#ifdef CONFIG_ARCH_RANDOM
+
+#include <linux/random.h>
+#include <asm/cpufeature.h>
+
+static inline bool __arm64_rndr(unsigned long *v)
+{
+	bool ok;
+
+	/*
+	 * Reads of RNDR set PSTATE.NZCV to 0b0000 on success,
+	 * and set PSTATE.NZCV to 0b0100 otherwise.
+	 */
+	asm volatile(
+		__mrs_s("%0", SYS_RNDR_EL0) "\n"
+	"	cset %w1, ne\n"
+	: "=r" (*v), "=r" (ok)
+	:
+	: "cc");
+
+	return ok;
+}
+
+static inline bool __must_check arch_get_random_long(unsigned long *v)
+{
+	return false;
+}
+
+static inline bool __must_check arch_get_random_int(unsigned int *v)
+{
+	return false;
+}
+
+static inline bool __must_check arch_get_random_seed_long(unsigned long *v)
+{
+	/*
+	 * Only support the generic interface after we have detected
+	 * the system wide capability, avoiding complexity with the
+	 * cpufeature code and with potential scheduling between CPUs
+	 * with and without the feature.
+	 */
+	if (!cpus_have_const_cap(ARM64_HAS_RNG))
+		return false;
+
+	return __arm64_rndr(v);
+}
+
+
+static inline bool __must_check arch_get_random_seed_int(unsigned int *v)
+{
+	unsigned long val;
+	bool ok = arch_get_random_seed_long(&val);
+
+	*v = val;
+	return ok;
+}
+
+static inline bool __init __early_cpu_has_rndr(void)
+{
+	/* Open code as we run prior to the first call to cpufeature. */
+	unsigned long ftr = read_sysreg_s(SYS_ID_AA64ISAR0_EL1);
+	return (ftr >> ID_AA64ISAR0_RNDR_SHIFT) & 0xf;
+}
+
+#else
+
+static inline bool __arm64_rndr(unsigned long *v) { return false; }
+static inline bool __init __early_cpu_has_rndr(void) { return false; }
+
+#endif /* CONFIG_ARCH_RANDOM */
+#endif /* _ASM_ARCHRANDOM_H */
diff --git a/arch/arm64/include/asm/cpucaps.h b/arch/arm64/include/asm/cpucaps.h
index a61c33611e39..865e0253fc1e 100644
--- a/arch/arm64/include/asm/cpucaps.h
+++ b/arch/arm64/include/asm/cpucaps.h
@@ -57,7 +57,8 @@
 #define ARM64_WORKAROUND_1542419		47
 #define ARM64_WORKAROUND_SPECULATIVE_AT_NVHE	48
 #define ARM64_HAS_E0PD				49
+#define ARM64_HAS_RNG				50
 
-#define ARM64_NCAPS				50
+#define ARM64_NCAPS				51
 
 #endif /* __ASM_CPUCAPS_H */
diff --git a/arch/arm64/include/asm/hwcap.h b/arch/arm64/include/asm/hwcap.h
index fcb390ea29ea..0f00265248b5 100644
--- a/arch/arm64/include/asm/hwcap.h
+++ b/arch/arm64/include/asm/hwcap.h
@@ -91,8 +91,9 @@
 #define KERNEL_HWCAP_SVEF64MM		__khwcap2_feature(SVEF64MM)
 #define KERNEL_HWCAP_SVEBF16		__khwcap2_feature(SVEBF16)
 #define KERNEL_HWCAP_I8MM		__khwcap2_feature(I8MM)
-#define KERNEL_HWCAP_DGH		__khwcap2_feature(DGH)
 #define KERNEL_HWCAP_BF16		__khwcap2_feature(BF16)
+#define KERNEL_HWCAP_DGH		__khwcap2_feature(DGH)
+#define KERNEL_HWCAP_RNG		__khwcap2_feature(RNG)
 
 /*
  * This yields a mask that user programs can use to figure out what
diff --git a/arch/arm64/include/asm/sysreg.h b/arch/arm64/include/asm/sysreg.h
index a2d3271b64bd..b91570ff9db1 100644
--- a/arch/arm64/include/asm/sysreg.h
+++ b/arch/arm64/include/asm/sysreg.h
@@ -366,6 +366,9 @@
 #define SYS_CTR_EL0			sys_reg(3, 3, 0, 0, 1)
 #define SYS_DCZID_EL0			sys_reg(3, 3, 0, 0, 7)
 
+#define SYS_RNDR_EL0			sys_reg(3, 3, 2, 4, 0)
+#define SYS_RNDRRS_EL0			sys_reg(3, 3, 2, 4, 1)
+
 #define SYS_PMCR_EL0			sys_reg(3, 3, 9, 12, 0)
 #define SYS_PMCNTENSET_EL0		sys_reg(3, 3, 9, 12, 1)
 #define SYS_PMCNTENCLR_EL0		sys_reg(3, 3, 9, 12, 2)
@@ -552,6 +555,7 @@
 #define MAIR_ATTRIDX(attr, idx)		((attr) << ((idx) * 8))
 
 /* id_aa64isar0 */
+#define ID_AA64ISAR0_RNDR_SHIFT		60
 #define ID_AA64ISAR0_TS_SHIFT		52
 #define ID_AA64ISAR0_FHM_SHIFT		48
 #define ID_AA64ISAR0_DP_SHIFT		44
diff --git a/arch/arm64/include/uapi/asm/hwcap.h b/arch/arm64/include/uapi/asm/hwcap.h
index e6dad5924703..7752d93bb50f 100644
--- a/arch/arm64/include/uapi/asm/hwcap.h
+++ b/arch/arm64/include/uapi/asm/hwcap.h
@@ -72,5 +72,6 @@
 #define HWCAP2_I8MM		(1 << 13)
 #define HWCAP2_BF16		(1 << 14)
 #define HWCAP2_DGH		(1 << 15)
+#define HWCAP2_RNG		(1 << 16)
 
 #endif /* _UAPI__ASM_HWCAP_H */