Refactor IMA buffer related functions to make them reusable for carrying
TPM logs across kexec.

Signed-off-by: Stefan Berger <stef...@linux.ibm.com>
Cc: Rob Herring <robh...@kernel.org>
Cc: Frank Rowand <frowand.l...@gmail.com>
Cc: Mimi Zohar <zo...@linux.ibm.com>
Reviewed-by: Mimi Zohar <zo...@linux.ibm.com>
Reviewed-by: Rob Herring <r...@kernel.org>
Tested-by: Nageswara R Sastry <rnsas...@linux.ibm.com>
Tested-by: Coiby Xu <c...@redhat.com>

---
v6:
 - Add __init to get_kexec_buffer as suggested by Jonathan

v5:
 - Rebased on Jonathan McDowell's commit "b69a2afd5afc x86/kexec: Carry
   forward IMA measurement log on kexec"
v4:
 - Move debug output into setup_buffer()
---
 drivers/of/kexec.c | 126 ++++++++++++++++++++++++++-------------------
 1 file changed, 74 insertions(+), 52 deletions(-)

diff --git a/drivers/of/kexec.c b/drivers/of/kexec.c
index 548dd5b1b5c1..15a82b574f36 100644
--- a/drivers/of/kexec.c
+++ b/drivers/of/kexec.c
@@ -117,45 +117,57 @@ static int do_get_kexec_buffer(const void *prop, int len, 
unsigned long *addr,
 }
 
 #ifdef CONFIG_HAVE_IMA_KEXEC
-/**
- * ima_get_kexec_buffer - get IMA buffer from the previous kernel
- * @addr:      On successful return, set to point to the buffer contents.
- * @size:      On successful return, set to the buffer size.
- *
- * Return: 0 on success, negative errno on error.
- */
-int __init ima_get_kexec_buffer(void **addr, size_t *size)
+static int __init get_kexec_buffer(const char *name, unsigned long *addr,
+                                  size_t *size)
 {
        int ret, len;
-       unsigned long tmp_addr;
        unsigned long start_pfn, end_pfn;
-       size_t tmp_size;
        const void *prop;
 
-       prop = of_get_property(of_chosen, "linux,ima-kexec-buffer", &len);
+       prop = of_get_property(of_chosen, name, &len);
        if (!prop)
                return -ENOENT;
 
-       ret = do_get_kexec_buffer(prop, len, &tmp_addr, &tmp_size);
+       ret = do_get_kexec_buffer(prop, len, addr, size);
        if (ret)
                return ret;
 
-       /* Do some sanity on the returned size for the ima-kexec buffer */
-       if (!tmp_size)
+       /* Do some sanity on the returned size for the kexec buffer */
+       if (!*size)
                return -ENOENT;
 
        /*
         * Calculate the PFNs for the buffer and ensure
         * they are with in addressable memory.
         */
-       start_pfn = PHYS_PFN(tmp_addr);
-       end_pfn = PHYS_PFN(tmp_addr + tmp_size - 1);
+       start_pfn = PHYS_PFN(*addr);
+       end_pfn = PHYS_PFN(*addr + *size - 1);
        if (!page_is_ram(start_pfn) || !page_is_ram(end_pfn)) {
-               pr_warn("IMA buffer at 0x%lx, size = 0x%zx beyond memory\n",
-                       tmp_addr, tmp_size);
+               pr_warn("%s buffer at 0x%lx, size = 0x%zx beyond memory\n",
+                       name, *addr, *size);
                return -EINVAL;
        }
 
+       return 0;
+}
+
+/**
+ * ima_get_kexec_buffer - get IMA buffer from the previous kernel
+ * @addr:      On successful return, set to point to the buffer contents.
+ * @size:      On successful return, set to the buffer size.
+ *
+ * Return: 0 on success, negative errno on error.
+ */
+int __init ima_get_kexec_buffer(void **addr, size_t *size)
+{
+       int ret;
+       unsigned long tmp_addr;
+       size_t tmp_size;
+
+       ret = get_kexec_buffer("linux,ima-kexec-buffer", &tmp_addr, &tmp_size);
+       if (ret)
+               return ret;
+
        *addr = __va(tmp_addr);
        *size = tmp_size;
 
@@ -188,72 +200,82 @@ int __init ima_free_kexec_buffer(void)
 }
 #endif
 
-/**
- * remove_ima_buffer - remove the IMA buffer property and reservation from @fdt
- *
- * @fdt: Flattened Device Tree to update
- * @chosen_node: Offset to the chosen node in the device tree
- *
- * The IMA measurement buffer is of no use to a subsequent kernel, so we always
- * remove it from the device tree.
- */
-static void remove_ima_buffer(void *fdt, int chosen_node)
+static int remove_buffer(void *fdt, int chosen_node, const char *name)
 {
        int ret, len;
        unsigned long addr;
        size_t size;
        const void *prop;
 
-       if (!IS_ENABLED(CONFIG_HAVE_IMA_KEXEC))
-               return;
-
-       prop = fdt_getprop(fdt, chosen_node, "linux,ima-kexec-buffer", &len);
+       prop = fdt_getprop(fdt, chosen_node, name, &len);
        if (!prop)
-               return;
+               return -ENOENT;
 
        ret = do_get_kexec_buffer(prop, len, &addr, &size);
-       fdt_delprop(fdt, chosen_node, "linux,ima-kexec-buffer");
+       fdt_delprop(fdt, chosen_node, name);
        if (ret)
-               return;
+               return ret;
 
        ret = fdt_find_and_del_mem_rsv(fdt, addr, size);
        if (!ret)
-               pr_debug("Removed old IMA buffer reservation.\n");
+               pr_debug("Remove old %s buffer reserveration", name);
+       return ret;
 }
 
-#ifdef CONFIG_IMA_KEXEC
 /**
- * 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.
+ * remove_ima_buffer - remove the IMA buffer property and reservation from @fdt
  *
- * Return: 0 on success, or negative errno on error.
+ * @fdt: Flattened Device Tree to update
+ * @chosen_node: Offset to the chosen node in the device tree
+ *
+ * The IMA measurement buffer is of no use to a subsequent kernel, so we always
+ * remove it from the device tree.
  */
-static int setup_ima_buffer(const struct kimage *image, void *fdt,
-                           int chosen_node)
+static void remove_ima_buffer(void *fdt, int chosen_node)
+{
+       if (!IS_ENABLED(CONFIG_HAVE_IMA_KEXEC))
+               return;
+
+       remove_buffer(fdt, chosen_node, "linux,ima-kexec-buffer");
+}
+
+#ifdef CONFIG_IMA_KEXEC
+static int setup_buffer(void *fdt, int chosen_node, const char *name,
+                       phys_addr_t addr, size_t size)
 {
        int ret;
 
-       if (!image->ima_buffer_size)
+       if (!size)
                return 0;
 
        ret = fdt_appendprop_addrrange(fdt, 0, chosen_node,
-                                      "linux,ima-kexec-buffer",
-                                      image->ima_buffer_addr,
-                                      image->ima_buffer_size);
+                                      name, addr, size);
        if (ret < 0)
                return -EINVAL;
 
-       ret = fdt_add_mem_rsv(fdt, image->ima_buffer_addr,
-                             image->ima_buffer_size);
+       ret = fdt_add_mem_rsv(fdt, addr, size);
        if (ret)
                return -EINVAL;
 
-       pr_debug("IMA buffer at 0x%pa, size = 0x%zx\n",
-                &image->ima_buffer_addr, image->ima_buffer_size);
+       pr_debug("%s at 0x%pa, size = 0x%zx\n", name, &addr, size);
 
        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.
+ */
+static int setup_ima_buffer(const struct kimage *image, void *fdt,
+                           int chosen_node)
+{
+       return setup_buffer(fdt, chosen_node, "linux,ima-kexec-buffer",
+                           image->ima_buffer_addr, image->ima_buffer_size);
 }
 #else /* CONFIG_IMA_KEXEC */
 static inline int setup_ima_buffer(const struct kimage *image, void *fdt,
-- 
2.35.1


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