csky: ELF and module probe

This patch adds ELF definition and module relocate codes.

Signed-off-by: Guo Ren <ren_guo@c-sky.com>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>

1 files changed, 92 insertions, 0 deletions

diff --git a/arch/csky/kernel/module.c b/arch/csky/kernel/module.c
new file mode 100644
index 000000000000..65abab0c7a47
--- /dev/null
+++ b/arch/csky/kernel/module.c
@@ -0,0 +1,92 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (C) 2018 Hangzhou C-SKY Microsystems co.,ltd.
+
+#include <linux/moduleloader.h>
+#include <linux/elf.h>
+#include <linux/mm.h>
+#include <linux/vmalloc.h>
+#include <linux/slab.h>
+#include <linux/fs.h>
+#include <linux/string.h>
+#include <linux/kernel.h>
+#include <linux/spinlock.h>
+#include <asm/pgtable.h>
+
+#if defined(__CSKYABIV2__)
+#define IS_BSR32(hi16, lo16)		(((hi16) & 0xFC00) == 0xE000)
+#define IS_JSRI32(hi16, lo16)		((hi16) == 0xEAE0)
+
+#define CHANGE_JSRI_TO_LRW(addr) do {					\
+	*(uint16_t *)(addr) = (*(uint16_t *)(addr) & 0xFF9F) | 0x001a;	\
+	*((uint16_t *)(addr) + 1) = *((uint16_t *)(addr) + 1) & 0xFFFF;	\
+} while (0)
+
+#define SET_JSR32_R26(addr) do {		\
+	*(uint16_t *)(addr) = 0xE8Fa;		\
+	*((uint16_t *)(addr) + 1) = 0x0000;	\
+} while (0)
+#endif
+
+int apply_relocate_add(Elf32_Shdr *sechdrs, const char *strtab,
+		unsigned int symindex, unsigned int relsec, struct module *me)
+{
+	unsigned int i;
+	Elf32_Rela	*rel = (void *) sechdrs[relsec].sh_addr;
+	Elf32_Sym	*sym;
+	uint32_t	*location;
+	short		*temp;
+#if defined(__CSKYABIV2__)
+	uint16_t	*location_tmp;
+#endif
+
+	for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
+		/* This is where to make the change */
+		location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
+							+ rel[i].r_offset;
+		sym = (Elf32_Sym *)sechdrs[symindex].sh_addr
+						+ ELF32_R_SYM(rel[i].r_info);
+
+		switch (ELF32_R_TYPE(rel[i].r_info)) {
+		case R_CSKY_32:
+			/* We add the value into the location given */
+			*location = rel[i].r_addend + sym->st_value;
+			break;
+		case R_CSKY_PC32:
+			/* Add the value, subtract its postition */
+			*location = rel[i].r_addend + sym->st_value
+							- (uint32_t)location;
+			break;
+		case R_CSKY_PCRELJSR_IMM11BY2:
+			break;
+		case R_CSKY_PCRELJSR_IMM26BY2:
+#if defined(__CSKYABIV2__)
+			location_tmp = (uint16_t *)location;
+			if (IS_BSR32(*location_tmp, *(location_tmp + 1)))
+				break;
+
+			if (IS_JSRI32(*location_tmp, *(location_tmp + 1))) {
+				/* jsri 0x...  --> lrw r26, 0x... */
+				CHANGE_JSRI_TO_LRW(location);
+				/* lsli r0, r0 --> jsr r26 */
+				SET_JSR32_R26(location + 1);
+			}
+#endif
+			break;
+		case R_CSKY_ADDR_HI16:
+			temp = ((short  *)location) + 1;
+			*temp = (short)
+				((rel[i].r_addend + sym->st_value) >> 16);
+			break;
+		case R_CSKY_ADDR_LO16:
+			temp = ((short  *)location) + 1;
+			*temp = (short)
+				((rel[i].r_addend + sym->st_value) & 0xffff);
+			break;
+		default:
+			pr_err("module %s: Unknown relocation: %u\n",
+				me->name, ELF32_R_TYPE(rel[i].r_info));
+			return -ENOEXEC;
+		}
+	}
+	return 0;
+}