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-rw-r--r--arch/s390/purgatory/purgatory.c33
1 files changed, 33 insertions, 0 deletions
diff --git a/arch/s390/purgatory/purgatory.c b/arch/s390/purgatory/purgatory.c
new file mode 100644
index 000000000..030efda05
--- /dev/null
+++ b/arch/s390/purgatory/purgatory.c
@@ -0,0 +1,33 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Purgatory code running between two kernels.
+ *
+ * Copyright IBM Corp. 2018
+ *
+ * Author(s): Philipp Rudo <prudo@linux.vnet.ibm.com>
+ */
+
+#include <linux/kexec.h>
+#include <linux/string.h>
+#include <crypto/sha2.h>
+#include <asm/purgatory.h>
+
+int verify_sha256_digest(void)
+{
+ struct kexec_sha_region *ptr, *end;
+ u8 digest[SHA256_DIGEST_SIZE];
+ struct sha256_state sctx;
+
+ sha256_init(&sctx);
+ end = purgatory_sha_regions + ARRAY_SIZE(purgatory_sha_regions);
+
+ for (ptr = purgatory_sha_regions; ptr < end; ptr++)
+ sha256_update(&sctx, (uint8_t *)(ptr->start), ptr->len);
+
+ sha256_final(&sctx, digest);
+
+ if (memcmp(digest, purgatory_sha256_digest, sizeof(digest)))
+ return 1;
+
+ return 0;
+}