[PATCH v13 6/6] arm64: Add IMA log information in kimage used for kexec

[Lakshmi Ramasubramanian]

Address and size of the buffer containing the IMA measurement log need
to be passed from the current kernel to the next kernel on kexec.

Any existing "linux,ima-kexec-buffer" property in the device tree
needs to be removed and its corresponding memory reservation in
the currently running kernel needs to be freed. 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 and memory for the buffer
needs to be reserved for the log to be carried over to the next kernel
on the kexec call.

Add address and size fields to "struct kimage_arch" for ARM64 platform
to hold the address and size of the IMA measurement log buffer. Remove
any existing "linux,ima-kexec-buffer" property in the device tree and
free the corresponding memory reservation in the currently running
kernel. Add "linux,ima-kexec-buffer" property to the device tree and
reserve the memory for storing the IMA log that needs to be passed from
the current kernel to the next one.

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

Co-developed-by: Prakhar Srivastava <prsriva at linux.microsoft.com>
Signed-off-by: Prakhar Srivastava <prsriva at linux.microsoft.com>
Signed-off-by: Lakshmi Ramasubramanian <nramas at linux.microsoft.com>
---
 arch/arm64/Kconfig             | 1 +
 arch/arm64/include/asm/kexec.h | 5 +++++
 2 files changed, 6 insertions(+)

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 1d466addb078..c85d18b1f2fd 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -1094,6 +1094,7 @@ 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/include/asm/kexec.h b/arch/arm64/include/asm/kexec.h
index d24b527e8c00..2bd19ccb6c43 100644
--- a/arch/arm64/include/asm/kexec.h
+++ b/arch/arm64/include/asm/kexec.h
@@ -100,6 +100,11 @@ struct kimage_arch {
 	void *elf_headers;
 	unsigned long elf_headers_mem;
 	unsigned long elf_headers_sz;
+
+#ifdef CONFIG_IMA_KEXEC
+	phys_addr_t ima_buffer_addr;
+	size_t ima_buffer_size;
+#endif
 };
 
 extern const struct kexec_file_ops kexec_image_ops;
-- 
2.29.2