From: Thiago Jung Bauermann <bauerman@xxxxxxxxxxxxxxxxxx>
The IMA kexec buffer allows the currently running kernel to pass
the measurement list via a kexec segment to the kernel that will be
kexec'd.
This is the architecture-specific part of setting up the IMA kexec
buffer for the next kernel. It will be used in the next patch.
Changelog v5:
- New patch in this version. This code was previously in the kexec buffer
handover patch series.
Changelog relative to kexec handover patches v5:
- Moved code to arch/powerpc/kernel/ima_kexec.c.
- Renamed functions and struct members to variations of ima_kexec_buffer
instead of variations of kexec_handover_buffer.
- Use a single property /chosen/linux,ima-kexec-buffer containing
the buffer address and length, instead of
/chosen/linux,kexec-handover-buffer-{start,end}.
- Use #address-cells and #size-cells to write the DT property.
- Use size_t instead of unsigned long for size arguments.
- Use CONFIG_IMA_KEXEC to build this code only when necessary.
Signed-off-by: Thiago Jung Bauermann <bauerman at linux.vnet.ibm.com>
---
arch/powerpc/include/asm/ima.h | 16 ++++++
arch/powerpc/include/asm/kexec.h | 15 +++++-
arch/powerpc/kernel/ima_kexec.c | 91 ++++++++++++++++++++++++++++++++++
arch/powerpc/kernel/kexec_elf_64.c | 2 +-
arch/powerpc/kernel/machine_kexec_64.c | 12 +++--
5 files changed, 130 insertions(+), 6 deletions(-)
diff --git a/arch/powerpc/include/asm/ima.h b/arch/powerpc/include/asm/ima.h
index d5a72dd..2313bdf 100644
--- a/arch/powerpc/include/asm/ima.h
+++ b/arch/powerpc/include/asm/ima.h
@@ -1,6 +1,8 @@
#ifndef _ASM_POWERPC_IMA_H
#define _ASM_POWERPC_IMA_H
+struct kimage;
+
int ima_get_kexec_buffer(void **addr, size_t *size);
int ima_free_kexec_buffer(void);
@@ -10,4 +12,18 @@ void remove_ima_buffer(void *fdt, int chosen_node);
static inline void remove_ima_buffer(void *fdt, int chosen_node) {}
#endif
+#ifdef CONFIG_IMA_KEXEC
+int arch_ima_add_kexec_buffer(struct kimage *image, unsigned long load_addr,
+ size_t size);
+
+int setup_ima_buffer(const struct kimage *image, void *fdt, int chosen_node);
+#else
+static inline int setup_ima_buffer(const struct kimage *image, void *fdt,
+ int chosen_node)
+{
+ remove_ima_buffer(fdt, chosen_node);
+ return 0;
+}
+#endif /* CONFIG_IMA_KEXEC */
+
#endif /* _ASM_POWERPC_IMA_H */
diff --git a/arch/powerpc/include/asm/kexec.h b/arch/powerpc/include/asm/kexec.h
index 5dda514..8848eab 100644
--- a/arch/powerpc/include/asm/kexec.h
+++ b/arch/powerpc/include/asm/kexec.h
@@ -92,12 +92,23 @@ static inline bool kdump_in_progress(void)
}
#ifdef CONFIG_KEXEC_FILE
+
+#ifdef CONFIG_IMA_KEXEC
+#define ARCH_HAS_KIMAGE_ARCH
+
+struct kimage_arch {
+ phys_addr_t ima_buffer_addr;
+ size_t ima_buffer_size;
+};
+#endif
+
int setup_purgatory(struct kimage *image, const void *slave_code,
const void *fdt, unsigned long kernel_load_addr,
unsigned long fdt_load_addr, unsigned long stack_top,
int debug);
-int setup_new_fdt(void *fdt, unsigned long initrd_load_addr,
- unsigned long initrd_len, const char *cmdline);
+int setup_new_fdt(const struct kimage *image, void *fdt,
+ unsigned long initrd_load_addr, unsigned long initrd_len,
+ const char *cmdline);
bool find_debug_console(const void *fdt);
int delete_fdt_mem_rsv(void *fdt, unsigned long start, unsigned long size);
#endif /* CONFIG_KEXEC_FILE */
diff --git a/arch/powerpc/kernel/ima_kexec.c b/arch/powerpc/kernel/ima_kexec.c
index 36e5a5d..5ea42c9 100644
--- a/arch/powerpc/kernel/ima_kexec.c
+++ b/arch/powerpc/kernel/ima_kexec.c
@@ -130,3 +130,94 @@ void remove_ima_buffer(void *fdt, int chosen_node)
if (!ret)
pr_debug("Removed old IMA buffer reservation.\n");
}
+
+#ifdef CONFIG_IMA_KEXEC
+/**
+ * arch_ima_add_kexec_buffer - do arch-specific steps to add the IMA buffer
+ *
+ * Architectures should use this function to pass on the IMA buffer
+ * information to the next kernel.
+ *
+ * Return: 0 on success, negative errno on error.
+ */
+int arch_ima_add_kexec_buffer(struct kimage *image, unsigned long load_addr,
+ size_t size)
+{
+ image->arch.ima_buffer_addr = load_addr;
+ image->arch.ima_buffer_size = size;
+
+ return 0;
+}
+
+static int write_number(void *p, u64 value, int cells)
+{
+ if (cells == 1) {
+ u32 tmp;
+
+ if (value > U32_MAX)
+ return -EINVAL;
+
+ tmp = cpu_to_be32(value);
+ memcpy(p, &tmp, sizeof(tmp));
+ } else if (cells == 2) {
+ u64 tmp;
+
+ tmp = cpu_to_be64(value);
+ memcpy(p, &tmp, sizeof(tmp));
+ } else
+ return -EINVAL;
+
+ return 0;
+}
+
+/**
+ * setup_ima_buffer - add IMA buffer information to the fdt
+ * @image: kexec image being loaded.
+ * @fdt: Flattened device tree for the next kernel.
+ * @chosen_node: Offset to the chosen node.
+ *
+ * Return: 0 on success, or negative errno on error.
+ */
+int setup_ima_buffer(const struct kimage *image, void *fdt, int chosen_node)
+{
+ int ret, addr_cells, size_cells, entry_size;
+ u8 value[16];
+
+ remove_ima_buffer(fdt, chosen_node);
+ if (!image->arch.ima_buffer_size)
+ return 0;
+
+ ret = get_addr_size_cells(&addr_cells, &size_cells);
+ if (ret)
+ return ret;
+
+ entry_size = 4 * (addr_cells + size_cells);
+
+ if (entry_size > sizeof(value))
+ return -EINVAL;
+
+ ret = write_number(value, image->arch.ima_buffer_addr, addr_cells);
+ if (ret)
+ return ret;
+
+ ret = write_number(value + 4 * addr_cells, image->arch.ima_buffer_size,
+ size_cells);
+ if (ret)
+ return ret;
+
+ ret = fdt_setprop(fdt, chosen_node, "linux,ima-kexec-buffer", value,
+ entry_size);
+ if (ret < 0)
+ return -EINVAL;
+
+ ret = fdt_add_mem_rsv(fdt, image->arch.ima_buffer_addr,
+ image->arch.ima_buffer_size);
+ if (ret)
+ return -EINVAL;
+
+ pr_debug("IMA buffer at 0x%llx, size = 0x%zx\n",
+ image->arch.ima_buffer_addr, image->arch.ima_buffer_size);
+
+ return 0;
+}
+#endif /* CONFIG_IMA_KEXEC */
diff --git a/arch/powerpc/kernel/kexec_elf_64.c b/arch/powerpc/kernel/kexec_elf_64.c
index c612436..db68bee 100644
--- a/arch/powerpc/kernel/kexec_elf_64.c
+++ b/arch/powerpc/kernel/kexec_elf_64.c
@@ -208,7 +208,7 @@ void *elf64_load(struct kimage *image, char *kernel_buf,
goto out;
}
- ret = setup_new_fdt(fdt, initrd_load_addr, initrd_len, cmdline);
+ ret = setup_new_fdt(image, fdt, initrd_load_addr, initrd_len, cmdline);
if (ret)
goto out;
diff --git a/arch/powerpc/kernel/machine_kexec_64.c b/arch/powerpc/kernel/machine_kexec_64.c
index c2e0b18..86322f7 100644
--- a/arch/powerpc/kernel/machine_kexec_64.c
+++ b/arch/powerpc/kernel/machine_kexec_64.c
@@ -660,6 +660,7 @@ int setup_purgatory(struct kimage *image, const void *slave_code,
/**
* setup_new_fdt() - modify /chosen and memory reservations for the next kernel
+ * @image: kexec image being loaded.
* @fdt: Flattened device tree for the next kernel.
* @initrd_load_addr: Address where the next initrd will be loaded.
* @initrd_len: Size of the next initrd, or 0 if there will be none.
@@ -668,8 +669,9 @@ int setup_purgatory(struct kimage *image, const void *slave_code,
*
* Return: 0 on success, or negative errno on error.
*/
-int setup_new_fdt(void *fdt, unsigned long initrd_load_addr,
- unsigned long initrd_len, const char *cmdline)
+int setup_new_fdt(const struct kimage *image, void *fdt,
+ unsigned long initrd_load_addr, unsigned long initrd_len,
+ const char *cmdline)
{
int ret, chosen_node;
const void *prop;
@@ -779,7 +781,11 @@ int setup_new_fdt(void *fdt, unsigned long initrd_load_addr,
}
}
- remove_ima_buffer(fdt, chosen_node);
+ ret = setup_ima_buffer(image, fdt, chosen_node);
+ if (ret) {
+ pr_err("Error setting up the new device tree.\n");
+ return ret;
+ }
ret = fdt_setprop(fdt, chosen_node, "linux,booted-from-kexec", NULL, 0);
if (ret) {
--
2.1.0
