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// SPDX-License-Identifier: GPL-2.0
/*
* Support for Kernel relocation at boot time
*
* Copyright (C) 2023 Loongson Technology Corporation Limited
*/
#include <linux/elf.h>
#include <linux/kernel.h>
#include <linux/printk.h>
#include <linux/panic_notifier.h>
#include <asm/inst.h>
#include <asm/sections.h>
#include <asm/setup.h>
#define RELOCATED(x) ((void *)((long)x + reloc_offset))
static unsigned long reloc_offset;
static inline void __init relocate_relative(void)
{
Elf64_Rela *rela, *rela_end;
rela = (Elf64_Rela *)&__rela_dyn_begin;
rela_end = (Elf64_Rela *)&__rela_dyn_end;
for ( ; rela < rela_end; rela++) {
Elf64_Addr addr = rela->r_offset;
Elf64_Addr relocated_addr = rela->r_addend;
if (rela->r_info != R_LARCH_RELATIVE)
continue;
if (relocated_addr >= VMLINUX_LOAD_ADDRESS)
relocated_addr = (Elf64_Addr)RELOCATED(relocated_addr);
*(Elf64_Addr *)RELOCATED(addr) = relocated_addr;
}
}
static inline void __init relocate_absolute(void)
{
void *begin, *end;
struct rela_la_abs *p;
begin = &__la_abs_begin;
end = &__la_abs_end;
for (p = begin; (void *)p < end; p++) {
long v = p->symvalue;
uint32_t lu12iw, ori, lu32id, lu52id;
union loongarch_instruction *insn = (void *)p - p->offset;
lu12iw = (v >> 12) & 0xfffff;
ori = v & 0xfff;
lu32id = (v >> 32) & 0xfffff;
lu52id = v >> 52;
insn[0].reg1i20_format.immediate = lu12iw;
insn[1].reg2i12_format.immediate = ori;
insn[2].reg1i20_format.immediate = lu32id;
insn[3].reg2i12_format.immediate = lu52id;
}
}
void __init relocate_kernel(void)
{
reloc_offset = (unsigned long)_text - VMLINUX_LOAD_ADDRESS;
if (reloc_offset)
relocate_relative();
relocate_absolute();
}
/*
* Show relocation information on panic.
*/
static void show_kernel_relocation(const char *level)
{
if (reloc_offset > 0) {
printk(level);
pr_cont("Kernel relocated by 0x%lx\n", reloc_offset);
pr_cont(" .text @ 0x%px\n", _text);
pr_cont(" .data @ 0x%px\n", _sdata);
pr_cont(" .bss @ 0x%px\n", __bss_start);
}
}
static int kernel_location_notifier_fn(struct notifier_block *self,
unsigned long v, void *p)
{
show_kernel_relocation(KERN_EMERG);
return NOTIFY_DONE;
}
static struct notifier_block kernel_location_notifier = {
.notifier_call = kernel_location_notifier_fn
};
static int __init register_kernel_offset_dumper(void)
{
atomic_notifier_chain_register(&panic_notifier_list,
&kernel_location_notifier);
return 0;
}
arch_initcall(register_kernel_offset_dumper);
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