[PATCH v4 5/5] arm64: Add IMA kexec buffer to DTB

[Lakshmi Ramasubramanian <nramas@linux.microsoft.com>]

The address and size of the current kernel's IMA measurement log
need to be added to the device tree's IMA kexec buffer node for
the log to be carried over to the next kernel on the kexec call.

Add the IMA measurement log buffer properties to the device tree for
ARM64. Update CONFIG_KEXEC_FILE to select CONFIG_HAVE_IMA_KEXEC to
indicate that the IMA measurement log information is present in
the device tree.

Co-developed-by: Prakhar Srivastava <prsriva@linux.microsoft.com>
Signed-off-by: Prakhar Srivastava <prsriva@linux.microsoft.com>
Signed-off-by: Lakshmi Ramasubramanian <nramas@linux.microsoft.com>
---
 arch/arm64/Kconfig                     |  1 +
 arch/arm64/kernel/machine_kexec_file.c | 11 +++++++++++
 2 files changed, 12 insertions(+)

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 6d232837cbee..9f03c8245e5b 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -1077,6 +1077,7 @@ config KEXEC
 config KEXEC_FILE
 	bool "kexec file based system call"
 	select KEXEC_CORE
+	select HAVE_IMA_KEXEC
 	help
 	  This is new version of kexec system call. This system call is
 	  file based and takes file descriptors as system call argument
diff --git a/arch/arm64/kernel/machine_kexec_file.c b/arch/arm64/kernel/machine_kexec_file.c
index 4c54723e7a04..8488f8e87d1a 100644
--- a/arch/arm64/kernel/machine_kexec_file.c
+++ b/arch/arm64/kernel/machine_kexec_file.c
@@ -153,6 +153,17 @@ static int setup_dtb(struct kimage *image,
 				FDT_PROP_KASLR_SEED);
 	}
 
+	/* add ima-kexec-buffer */
+	if (image->arch.ima_buffer_size > 0) {
+
+		ret = fdt_appendprop_addrrange(dtb, 0, off,
+				FDT_PROP_IMA_KEXEC_BUFFER,
+				image->arch.ima_buffer_addr,
+				image->arch.ima_buffer_size);
+		if (ret)
+			return (ret == -FDT_ERR_NOSPACE ? -ENOMEM : -EINVAL);
+	}
+
 	/* add rng-seed */
 	if (rng_is_initialized()) {
 		void *rng_seed;
-- 
2.28.0