[PATCH v4 3/5] remoteproc: Add elf helpers to access elf64 and elf32 fields

[Clement Leger]

elf32 and elf64 mainly differ by their types. In order to avoid
copy/pasting the whole loader code, generate static inline functions
which will access values according to the elf class. It allows to
keep a common loader basis.
In order to accommodate both elf types sizes, the maximum size for a
elf header member is chosen using the maximum value of the field for
both elf class.

Signed-off-by: Clement Leger <cleger@xxxxxxxxx>
---
 drivers/remoteproc/remoteproc_elf_helpers.h | 95 +++++++++++++++++++++++++++++
 1 file changed, 95 insertions(+)
 create mode 100644 drivers/remoteproc/remoteproc_elf_helpers.h

diff --git a/drivers/remoteproc/remoteproc_elf_helpers.h b/drivers/remoteproc/remoteproc_elf_helpers.h
new file mode 100644
index 000000000000..a29c17aaedb7
--- /dev/null
+++ b/drivers/remoteproc/remoteproc_elf_helpers.h
@@ -0,0 +1,95 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Remote processor elf helpers defines
+ *
+ * Copyright (C) 2020 Kalray, Inc.
+ */
+
+#ifndef REMOTEPROC_ELF_LOADER_H
+#define REMOTEPROC_ELF_LOADER_H
+
+#include <linux/elf.h>
+#include <linux/types.h>
+
+/**
+ * fw_elf_get_class - Get elf class
+ * @fw: the ELF firmware image
+ *
+ * Note that we use and elf32_hdr to access the class since the start of the
+ * struct is the same for both elf class
+ *
+ * Return: elf class of the firmware
+ */
+static inline u8 fw_elf_get_class(const struct firmware *fw)
+{
+	struct elf32_hdr *ehdr = (struct elf32_hdr *)fw->data;
+
+	return ehdr->e_ident[EI_CLASS];
+}
+
+static inline void elf_hdr_init_ident(struct elf32_hdr *hdr, u8 class)
+{
+	memcpy(hdr->e_ident, ELFMAG, SELFMAG);
+	hdr->e_ident[EI_CLASS] = class;
+	hdr->e_ident[EI_DATA] = ELFDATA2LSB;
+	hdr->e_ident[EI_VERSION] = EV_CURRENT;
+	hdr->e_ident[EI_OSABI] = ELFOSABI_NONE;
+}
+
+/* Generate getter and setter for a specific elf struct/field */
+#define ELF_GEN_FIELD_GET_SET(__s, __field, __type) \
+static inline __type elf_##__s##_get_##__field(u8 class, const void *arg) \
+{ \
+	if (class == ELFCLASS32) \
+		return (__type) ((const struct elf32_##__s *) arg)->__field; \
+	else \
+		return (__type) ((const struct elf64_##__s *) arg)->__field; \
+} \
+static inline void elf_##__s##_set_##__field(u8 class, void *arg, __type value) \
+{ \
+	if (class == ELFCLASS32) \
+		((struct elf32_##__s *) arg)->__field = (__type) value; \
+	else \
+		((struct elf64_##__s *) arg)->__field = (__type) value; \
+}
+
+ELF_GEN_FIELD_GET_SET(hdr, e_entry, u64)
+ELF_GEN_FIELD_GET_SET(hdr, e_phnum, u16)
+ELF_GEN_FIELD_GET_SET(hdr, e_shnum, u16)
+ELF_GEN_FIELD_GET_SET(hdr, e_phoff, u64)
+ELF_GEN_FIELD_GET_SET(hdr, e_shoff, u64)
+ELF_GEN_FIELD_GET_SET(hdr, e_shstrndx, u16)
+ELF_GEN_FIELD_GET_SET(hdr, e_machine, u16)
+ELF_GEN_FIELD_GET_SET(hdr, e_type, u16)
+ELF_GEN_FIELD_GET_SET(hdr, e_version, u32)
+ELF_GEN_FIELD_GET_SET(hdr, e_ehsize, u32)
+ELF_GEN_FIELD_GET_SET(hdr, e_phentsize, u16)
+
+ELF_GEN_FIELD_GET_SET(phdr, p_paddr, u64)
+ELF_GEN_FIELD_GET_SET(phdr, p_vaddr, u64)
+ELF_GEN_FIELD_GET_SET(phdr, p_filesz, u64)
+ELF_GEN_FIELD_GET_SET(phdr, p_memsz, u64)
+ELF_GEN_FIELD_GET_SET(phdr, p_type, u32)
+ELF_GEN_FIELD_GET_SET(phdr, p_offset, u64)
+ELF_GEN_FIELD_GET_SET(phdr, p_flags, u32)
+ELF_GEN_FIELD_GET_SET(phdr, p_align, u64)
+
+ELF_GEN_FIELD_GET_SET(shdr, sh_size, u64)
+ELF_GEN_FIELD_GET_SET(shdr, sh_offset, u64)
+ELF_GEN_FIELD_GET_SET(shdr, sh_name, u32)
+ELF_GEN_FIELD_GET_SET(shdr, sh_addr, u64)
+
+#define ELF_STRUCT_SIZE(__s) \
+static inline unsigned long elf_size_of_##__s(u8 class) \
+{ \
+	if (class == ELFCLASS32)\
+		return sizeof(struct elf32_##__s); \
+	else \
+		return sizeof(struct elf64_##__s); \
+}
+
+ELF_STRUCT_SIZE(shdr)
+ELF_STRUCT_SIZE(phdr)
+ELF_STRUCT_SIZE(hdr)
+
+#endif /* REMOTEPROC_ELF_LOADER_H */
-- 
2.15.0.276.g89ea799