[RFC v2 7/8] MIPS: add kexec ELF loading support
Antony Pavlov
antonynpavlov at gmail.com
Mon Dec 5 01:40:32 PST 2016
Signed-off-by: Antony Pavlov <antonynpavlov at gmail.com>
Signed-off-by: Peter Mamonov <pmamonov at gmail.com>
---
arch/mips/include/asm/elf.h | 8 +-
arch/mips/lib/Makefile | 3 +
arch/mips/lib/kexec-mips.c | 171 ++++++++++++++++++++++++++++++++++++++++
arch/mips/lib/relocate_kernel.S | 97 +++++++++++++++++++++++
4 files changed, 278 insertions(+), 1 deletion(-)
diff --git a/arch/mips/include/asm/elf.h b/arch/mips/include/asm/elf.h
index b8b8219..bf974f5 100644
--- a/arch/mips/include/asm/elf.h
+++ b/arch/mips/include/asm/elf.h
@@ -17,12 +17,18 @@
#ifndef ELF_ARCH
+/* Legal values for e_machine (architecture). */
+
+#define EM_MIPS 8 /* MIPS R3000 big-endian */
+#define EM_MIPS_RS4_BE 10 /* MIPS R4000 big-endian */
+
#ifdef CONFIG_32BIT
/*
* This is used to ensure we don't load something for the wrong architecture.
*/
-#define elf_check_arch(hdr) \
+#define elf_check_arch(x) ((x)->e_machine == EM_MIPS)
+
/*
* These are used to set parameters in the core dumps.
*/
diff --git a/arch/mips/lib/Makefile b/arch/mips/lib/Makefile
index d25d096..8dc4989 100644
--- a/arch/mips/lib/Makefile
+++ b/arch/mips/lib/Makefile
@@ -18,4 +18,7 @@ obj-$(CONFIG_CPU_MIPS64) += c-r4k.o
obj-$(CONFIG_CMD_MIPS_CPUINFO) += cpuinfo.o
obj-$(CONFIG_CMD_BOOTM) += bootm.o
+obj-$(CONFIG_KEXEC) += kexec-mips.o
+obj-$(CONFIG_KEXEC) += relocate_kernel.o
+
pbl-y += ashldi3.o
diff --git a/arch/mips/lib/kexec-mips.c b/arch/mips/lib/kexec-mips.c
new file mode 100644
index 0000000..bf2a84b
--- /dev/null
+++ b/arch/mips/lib/kexec-mips.c
@@ -0,0 +1,171 @@
+/*
+ * kexec-mips.c - kexec for mips
+ * Copyright (C) 2007 Francesco Chiechi, Alessandro Rubini
+ * Copyright (C) 2007 Tvblob s.r.l.
+ *
+ * derived from ../ppc/kexec-mips.c
+ * Copyright (C) 2004, 2005 Albert Herranz
+ *
+ * This source code is licensed under the GNU General Public License,
+ * Version 2. See the file COPYING for more details.
+ */
+
+#include <linux/stddef.h>
+#include <stdio.h>
+#include <errno.h>
+#include <string.h>
+#include <asm/io.h>
+#include <asm/addrspace.h>
+#include <memory.h>
+#include <elf.h>
+#include "../../../lib/kexec/kexec.h"
+
+static int elf_mips_probe(const char *buf, off_t len)
+{
+ struct mem_ehdr ehdr;
+ int result;
+
+ result = build_elf_exec_info(buf, len, &ehdr, 0);
+ if (result < 0) {
+ goto out;
+ }
+
+ /* Verify the architecuture specific bits */
+ if (ehdr.e_machine != EM_MIPS) {
+ /* for a different architecture */
+ printf("Not for this architecture.\n");
+ result = -1;
+ goto out;
+ }
+ result = 0;
+
+ out:
+ free_elf_info(&ehdr);
+
+ return result;
+}
+
+static int elf_mips_load(const char *buf, off_t len, struct kexec_info *info)
+{
+ struct mem_ehdr ehdr;
+ int result;
+ size_t i;
+
+ result = build_elf_exec_info(buf, len, &ehdr, 0);
+ if (result < 0) {
+ printf("ELF exec parse failed\n");
+ goto out;
+ }
+
+ /* Read in the PT_LOAD segments and remove CKSEG0 mask from address */
+ for (i = 0; i < ehdr.e_phnum; i++) {
+ struct mem_phdr *phdr;
+ phdr = &ehdr.e_phdr[i];
+ if (phdr->p_type == PT_LOAD) {
+ phdr->p_paddr = virt_to_phys((void *)phdr->p_paddr);
+ }
+ }
+
+ /* Load the ELF data */
+ result = elf_exec_load(&ehdr, info);
+ if (result < 0) {
+ printf("ELF exec load failed\n");
+ goto out;
+ }
+
+ info->entry = (void *)virt_to_phys((void *)ehdr.e_entry);
+
+out:
+ return result;
+}
+
+struct kexec_file_type kexec_file_type[] = {
+ {"elf-mips", elf_mips_probe, elf_mips_load },
+};
+int kexec_file_types = sizeof(kexec_file_type) / sizeof(kexec_file_type[0]);
+
+/*
+ * add_segment() should convert base to a physical address on mips,
+ * while the default is just to work with base as is */
+void add_segment(struct kexec_info *info, const void *buf, size_t bufsz,
+ unsigned long base, size_t memsz)
+{
+ add_segment_phys_virt(info, buf, bufsz,
+ virt_to_phys((void *)base), memsz, 1);
+}
+
+/* relocator parameters */
+extern unsigned long relocate_new_kernel;
+extern unsigned long relocate_new_kernel_size;
+extern unsigned long kexec_start_address;
+extern unsigned long kexec_segments;
+extern unsigned long kexec_nr_segments;
+
+unsigned long reboot_code_buffer;
+
+long kexec_load(void *entry, unsigned long nr_segments,
+ struct kexec_segment *segments, unsigned long flags)
+{
+ int i;
+ struct resource *elf;
+ resource_size_t start;
+ LIST_HEAD(elf_segments);
+
+ for (i = 0; i < nr_segments; i++) {
+ resource_size_t mem = (resource_size_t)segments[i].mem;
+
+ elf = create_resource("elf segment",
+ mem, mem + segments[i].memsz - 1);
+
+ list_add_used_region(&elf->sibling, &elf_segments);
+ }
+
+ if (check_room_for_elf(&elf_segments)) {
+ printf("ELF can't be loaded!\n");
+ return 0;
+ }
+
+ start = dcheck_res(&elf_segments);
+
+ /* relocate_new_kernel() copy by register (4 or 8 bytes)
+ so start address must be aligned to 4/8 */
+ start = (start + 15) & 0xfffffff0;
+
+ for (i = 0; i < nr_segments; i++) {
+ segments[i].mem = (void *)(phys_to_virt((unsigned long)segments[i].mem));
+ memcpy(phys_to_virt(start), segments[i].buf, segments[i].bufsz);
+ request_sdram_region("kexec relocatable segment",
+ (unsigned long)phys_to_virt(start),
+ (unsigned long)segments[i].bufsz);
+
+ /* relocate_new_kernel() copy by register (4 or 8 bytes)
+ so bufsz must be aligned to 4/8 */
+ segments[i].bufsz = (segments[i].bufsz + 15) & 0xfffffff0;
+ segments[i].buf = phys_to_virt(start);
+ start = start + segments[i].bufsz;
+ }
+
+ start = (start + 15) & 0xfffffff0;
+
+ reboot_code_buffer = start;
+
+ memcpy(phys_to_virt(start), &relocate_new_kernel,
+ relocate_new_kernel_size);
+ request_sdram_region("kexec relocator",
+ (unsigned long)phys_to_virt(start),
+ (unsigned long)relocate_new_kernel_size);
+
+ start = start + relocate_new_kernel_size;
+ start = (start + 15) & 0xfffffff0;
+
+ kexec_start_address = (unsigned long)phys_to_virt((unsigned long)entry);
+ kexec_segments = (unsigned long)phys_to_virt((unsigned long)start);
+ kexec_nr_segments = nr_segments;
+
+ memcpy(phys_to_virt(start), segments, nr_segments * sizeof(*segments));
+ request_sdram_region("kexec control segments",
+ (unsigned long)phys_to_virt(start),
+ (unsigned long)nr_segments * sizeof(*segments));
+
+ return 1;
+}
diff --git a/arch/mips/lib/relocate_kernel.S b/arch/mips/lib/relocate_kernel.S
new file mode 100644
index 0000000..1cd2ee5
--- /dev/null
+++ b/arch/mips/lib/relocate_kernel.S
@@ -0,0 +1,97 @@
+/*
+ * Copyright (C) 2012, 2016 Antony Pavlov <antonynpavlov at gmail.com>
+ *
+ * based on relocate_kernel.S for kexec
+ * Created by <nschichan at corp.free.fr> on Thu Oct 12 17:49:57 2006
+ *
+ * This file is part of barebox.
+ * See file CREDITS for list of people who contributed to this project.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ */
+
+#include <asm/asm.h>
+#include <asm/regdef.h>
+#include <asm/mipsregs.h>
+#include <asm/addrspace.h>
+
+LEAF(relocate_new_kernel)
+ .set push
+ .set reorder
+ PTR_L a0, arg0
+ PTR_L a1, arg1
+ PTR_L a2, arg2
+ PTR_L a3, arg3
+
+ PTR_L s0, kexec_segments
+ PTR_L s1, kexec_nr_segments
+ PTR_L s2, kexec_start_address
+
+process_segment:
+ PTR_L s4, (s0) /* buf */
+ PTR_L s5, SZREG (s0) /* bufsz */
+ PTR_L s6, 2*SZREG (s0) /* mem */
+
+copy_segment:
+ /* copy segment word by word */
+ REG_L s7, (s4)
+ REG_S s7, (s6)
+ PTR_ADD s4, s4, SZREG
+ PTR_ADD s6, s6, SZREG
+ LONG_SUB s5, s5, 1
+ bne s5, zero, copy_segment
+
+ LONG_SUB s1, s1, 1
+ beq s1, zero, done
+
+ PTR_ADD s0, s0, 4*SZREG
+
+ b process_segment
+
+done:
+ /* jump to kexec_start_address */
+ j s2
+ END(relocate_new_kernel)
+
+/* All parameters to new kernel are passed in registers a0-a3.
+ * kexec_args[0..3] are uses to prepare register values.
+ */
+
+kexec_args:
+ EXPORT(kexec_args)
+arg0: PTR 0x0
+arg1: PTR 0x0
+arg2: PTR 0x0
+arg3: PTR 0x0
+ .size kexec_args,PTRSIZE*4
+
+kexec_start_address:
+ EXPORT(kexec_start_address)
+ PTR 0x0
+ .size kexec_start_address, PTRSIZE
+
+kexec_segments:
+ EXPORT(kexec_segments)
+ PTR 0x0
+ .size kexec_segments, PTRSIZE
+
+kexec_nr_segments:
+ EXPORT(kexec_nr_segments)
+ PTR 0x0
+ .size kexec_nr_segments, PTRSIZE
+
+relocate_new_kernel_end:
+
+relocate_new_kernel_size:
+ EXPORT(relocate_new_kernel_size)
+ PTR relocate_new_kernel_end - relocate_new_kernel
+ .size relocate_new_kernel_size, PTRSIZE
+ .set pop
--
2.10.2
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