Adding upstream version 6.1.76.upstream/6.1.76

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 160 insertions, 0 deletions

diff --git a/arch/arm64/include/asm/archrandom.h b/arch/arm64/include/asm/archrandom.h
new file mode 100644
index 000000000..109e2a445
--- /dev/null
+++ b/arch/arm64/include/asm/archrandom.h
@@ -0,0 +1,160 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _ASM_ARCHRANDOM_H
+#define _ASM_ARCHRANDOM_H
+
+#include <linux/arm-smccc.h>
+#include <linux/bug.h>
+#include <linux/kernel.h>
+#include <asm/cpufeature.h>
+
+#define ARM_SMCCC_TRNG_MIN_VERSION	0x10000UL
+
+extern bool smccc_trng_available;
+
+static inline bool __init smccc_probe_trng(void)
+{
+	struct arm_smccc_res res;
+
+	arm_smccc_1_1_invoke(ARM_SMCCC_TRNG_VERSION, &res);
+	if ((s32)res.a0 < 0)
+		return false;
+
+	return res.a0 >= ARM_SMCCC_TRNG_MIN_VERSION;
+}
+
+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 __arm64_rndrrs(unsigned long *v)
+{
+	bool ok;
+
+	/*
+	 * Reads of RNDRRS set PSTATE.NZCV to 0b0000 on success,
+	 * and set PSTATE.NZCV to 0b0100 otherwise.
+	 */
+	asm volatile(
+		__mrs_s("%0", SYS_RNDRRS_EL0) "\n"
+	"	cset %w1, ne\n"
+	: "=r" (*v), "=r" (ok)
+	:
+	: "cc");
+
+	return ok;
+}
+
+static inline size_t __must_check arch_get_random_longs(unsigned long *v, size_t max_longs)
+{
+	/*
+	 * 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 (max_longs && cpus_have_const_cap(ARM64_HAS_RNG) && __arm64_rndr(v))
+		return 1;
+	return 0;
+}
+
+static inline size_t __must_check arch_get_random_seed_longs(unsigned long *v, size_t max_longs)
+{
+	if (!max_longs)
+		return 0;
+
+	/*
+	 * We prefer the SMCCC call, since its semantics (return actual
+	 * hardware backed entropy) is closer to the idea behind this
+	 * function here than what even the RNDRSS register provides
+	 * (the output of a pseudo RNG freshly seeded by a TRNG).
+	 */
+	if (smccc_trng_available) {
+		struct arm_smccc_res res;
+
+		max_longs = min_t(size_t, 3, max_longs);
+		arm_smccc_1_1_invoke(ARM_SMCCC_TRNG_RND64, max_longs * 64, &res);
+		if ((int)res.a0 >= 0) {
+			switch (max_longs) {
+			case 3:
+				*v++ = res.a1;
+				fallthrough;
+			case 2:
+				*v++ = res.a2;
+				fallthrough;
+			case 1:
+				*v++ = res.a3;
+				break;
+			}
+			return max_longs;
+		}
+	}
+
+	/*
+	 * RNDRRS is not backed by an entropy source but by a DRBG that is
+	 * reseeded after each invocation. This is not a 100% fit but good
+	 * enough to implement this API if no other entropy source exists.
+	 */
+	if (cpus_have_const_cap(ARM64_HAS_RNG) && __arm64_rndrrs(v))
+		return 1;
+
+	return 0;
+}
+
+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_EL1_RNDR_SHIFT) & 0xf;
+}
+
+static inline size_t __init __must_check
+arch_get_random_seed_longs_early(unsigned long *v, size_t max_longs)
+{
+	WARN_ON(system_state != SYSTEM_BOOTING);
+
+	if (!max_longs)
+		return 0;
+
+	if (smccc_trng_available) {
+		struct arm_smccc_res res;
+
+		max_longs = min_t(size_t, 3, max_longs);
+		arm_smccc_1_1_invoke(ARM_SMCCC_TRNG_RND64, max_longs * 64, &res);
+		if ((int)res.a0 >= 0) {
+			switch (max_longs) {
+			case 3:
+				*v++ = res.a1;
+				fallthrough;
+			case 2:
+				*v++ = res.a2;
+				fallthrough;
+			case 1:
+				*v++ = res.a3;
+				break;
+			}
+			return max_longs;
+		}
+	}
+
+	if (__early_cpu_has_rndr() && __arm64_rndr(v))
+		return 1;
+
+	return 0;
+}
+#define arch_get_random_seed_longs_early arch_get_random_seed_longs_early
+
+#endif /* _ASM_ARCHRANDOM_H */