From ace9429bb58fd418f0c81d4c2835699bddf6bde6 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Thu, 11 Apr 2024 10:27:49 +0200 Subject: Adding upstream version 6.6.15. Signed-off-by: Daniel Baumann --- arch/loongarch/kernel/relocate.c | 246 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 246 insertions(+) create mode 100644 arch/loongarch/kernel/relocate.c (limited to 'arch/loongarch/kernel/relocate.c') diff --git a/arch/loongarch/kernel/relocate.c b/arch/loongarch/kernel/relocate.c new file mode 100644 index 0000000000..1acfa704c8 --- /dev/null +++ b/arch/loongarch/kernel/relocate.c @@ -0,0 +1,246 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Support for Kernel relocation at boot time + * + * Copyright (C) 2023 Loongson Technology Corporation Limited + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#define RELOCATED(x) ((void *)((long)x + reloc_offset)) +#define RELOCATED_KASLR(x) ((void *)((long)x + random_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(long random_offset) +{ + void *begin, *end; + struct rela_la_abs *p; + + begin = RELOCATED_KASLR(&__la_abs_begin); + end = RELOCATED_KASLR(&__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->pc; + + 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; + } +} + +#ifdef CONFIG_RANDOMIZE_BASE +static inline __init unsigned long rotate_xor(unsigned long hash, + const void *area, size_t size) +{ + size_t i, diff; + const typeof(hash) *ptr = PTR_ALIGN(area, sizeof(hash)); + + diff = (void *)ptr - area; + if (size < diff + sizeof(hash)) + return hash; + + size = ALIGN_DOWN(size - diff, sizeof(hash)); + + for (i = 0; i < size / sizeof(hash); i++) { + /* Rotate by odd number of bits and XOR. */ + hash = (hash << ((sizeof(hash) * 8) - 7)) | (hash >> 7); + hash ^= ptr[i]; + } + + return hash; +} + +static inline __init unsigned long get_random_boot(void) +{ + unsigned long hash = 0; + unsigned long entropy = random_get_entropy(); + + /* Attempt to create a simple but unpredictable starting entropy. */ + hash = rotate_xor(hash, linux_banner, strlen(linux_banner)); + + /* Add in any runtime entropy we can get */ + hash = rotate_xor(hash, &entropy, sizeof(entropy)); + + return hash; +} + +static int __init nokaslr(char *p) +{ + pr_info("KASLR is disabled.\n"); + + return 0; /* Print a notice and silence the boot warning */ +} +early_param("nokaslr", nokaslr); + +static inline __init bool kaslr_disabled(void) +{ + char *str; + const char *builtin_cmdline = CONFIG_CMDLINE; + + str = strstr(builtin_cmdline, "nokaslr"); + if (str == builtin_cmdline || (str > builtin_cmdline && *(str - 1) == ' ')) + return true; + + str = strstr(boot_command_line, "nokaslr"); + if (str == boot_command_line || (str > boot_command_line && *(str - 1) == ' ')) + return true; + + return false; +} + +/* Choose a new address for the kernel */ +static inline void __init *determine_relocation_address(void) +{ + unsigned long kernel_length; + unsigned long random_offset; + void *destination = _text; + + if (kaslr_disabled()) + return destination; + + kernel_length = (long)_end - (long)_text; + + random_offset = get_random_boot() << 16; + random_offset &= (CONFIG_RANDOMIZE_BASE_MAX_OFFSET - 1); + if (random_offset < kernel_length) + random_offset += ALIGN(kernel_length, 0xffff); + + return RELOCATED_KASLR(destination); +} + +static inline int __init relocation_addr_valid(void *location_new) +{ + if ((unsigned long)location_new & 0x00000ffff) + return 0; /* Inappropriately aligned new location */ + + if ((unsigned long)location_new < (unsigned long)_end) + return 0; /* New location overlaps original kernel */ + + return 1; +} +#endif + +static inline void __init update_reloc_offset(unsigned long *addr, long random_offset) +{ + unsigned long *new_addr = (unsigned long *)RELOCATED_KASLR(addr); + + *new_addr = (unsigned long)reloc_offset; +} + +unsigned long __init relocate_kernel(void) +{ + unsigned long kernel_length; + unsigned long random_offset = 0; + void *location_new = _text; /* Default to original kernel start */ + char *cmdline = early_ioremap(fw_arg1, COMMAND_LINE_SIZE); /* Boot command line is passed in fw_arg1 */ + + strscpy(boot_command_line, cmdline, COMMAND_LINE_SIZE); + +#ifdef CONFIG_RANDOMIZE_BASE + location_new = determine_relocation_address(); + + /* Sanity check relocation address */ + if (relocation_addr_valid(location_new)) + random_offset = (unsigned long)location_new - (unsigned long)(_text); +#endif + reloc_offset = (unsigned long)_text - VMLINUX_LOAD_ADDRESS; + + if (random_offset) { + kernel_length = (long)(_end) - (long)(_text); + + /* Copy the kernel to it's new location */ + memcpy(location_new, _text, kernel_length); + + /* Sync the caches ready for execution of new kernel */ + __asm__ __volatile__ ( + "ibar 0 \t\n" + "dbar 0 \t\n" + ::: "memory"); + + reloc_offset += random_offset; + + /* The current thread is now within the relocated kernel */ + __current_thread_info = RELOCATED_KASLR(__current_thread_info); + + update_reloc_offset(&reloc_offset, random_offset); + } + + if (reloc_offset) + relocate_relative(); + + relocate_absolute(random_offset); + + return random_offset; +} + +/* + * 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); -- cgit v1.2.3