From 2c3c1048746a4622d8c89a29670120dc8fab93c4 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sun, 7 Apr 2024 20:49:45 +0200 Subject: Adding upstream version 6.1.76. Signed-off-by: Daniel Baumann --- arch/arm64/kernel/patching.c | 150 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 150 insertions(+) create mode 100644 arch/arm64/kernel/patching.c (limited to 'arch/arm64/kernel/patching.c') diff --git a/arch/arm64/kernel/patching.c b/arch/arm64/kernel/patching.c new file mode 100644 index 000000000..33e0fabc0 --- /dev/null +++ b/arch/arm64/kernel/patching.c @@ -0,0 +1,150 @@ +// SPDX-License-Identifier: GPL-2.0-only +#include +#include +#include +#include +#include +#include + +#include +#include +#include +#include +#include +#include + +static DEFINE_RAW_SPINLOCK(patch_lock); + +static bool is_exit_text(unsigned long addr) +{ + /* discarded with init text/data */ + return system_state < SYSTEM_RUNNING && + addr >= (unsigned long)__exittext_begin && + addr < (unsigned long)__exittext_end; +} + +static bool is_image_text(unsigned long addr) +{ + return core_kernel_text(addr) || is_exit_text(addr); +} + +static void __kprobes *patch_map(void *addr, int fixmap) +{ + unsigned long uintaddr = (uintptr_t) addr; + bool image = is_image_text(uintaddr); + struct page *page; + + if (image) + page = phys_to_page(__pa_symbol(addr)); + else if (IS_ENABLED(CONFIG_STRICT_MODULE_RWX)) + page = vmalloc_to_page(addr); + else + return addr; + + BUG_ON(!page); + return (void *)set_fixmap_offset(fixmap, page_to_phys(page) + + (uintaddr & ~PAGE_MASK)); +} + +static void __kprobes patch_unmap(int fixmap) +{ + clear_fixmap(fixmap); +} +/* + * In ARMv8-A, A64 instructions have a fixed length of 32 bits and are always + * little-endian. + */ +int __kprobes aarch64_insn_read(void *addr, u32 *insnp) +{ + int ret; + __le32 val; + + ret = copy_from_kernel_nofault(&val, addr, AARCH64_INSN_SIZE); + if (!ret) + *insnp = le32_to_cpu(val); + + return ret; +} + +static int __kprobes __aarch64_insn_write(void *addr, __le32 insn) +{ + void *waddr = addr; + unsigned long flags = 0; + int ret; + + raw_spin_lock_irqsave(&patch_lock, flags); + waddr = patch_map(addr, FIX_TEXT_POKE0); + + ret = copy_to_kernel_nofault(waddr, &insn, AARCH64_INSN_SIZE); + + patch_unmap(FIX_TEXT_POKE0); + raw_spin_unlock_irqrestore(&patch_lock, flags); + + return ret; +} + +int __kprobes aarch64_insn_write(void *addr, u32 insn) +{ + return __aarch64_insn_write(addr, cpu_to_le32(insn)); +} + +int __kprobes aarch64_insn_patch_text_nosync(void *addr, u32 insn) +{ + u32 *tp = addr; + int ret; + + /* A64 instructions must be word aligned */ + if ((uintptr_t)tp & 0x3) + return -EINVAL; + + ret = aarch64_insn_write(tp, insn); + if (ret == 0) + caches_clean_inval_pou((uintptr_t)tp, + (uintptr_t)tp + AARCH64_INSN_SIZE); + + return ret; +} + +struct aarch64_insn_patch { + void **text_addrs; + u32 *new_insns; + int insn_cnt; + atomic_t cpu_count; +}; + +static int __kprobes aarch64_insn_patch_text_cb(void *arg) +{ + int i, ret = 0; + struct aarch64_insn_patch *pp = arg; + + /* The last CPU becomes master */ + if (atomic_inc_return(&pp->cpu_count) == num_online_cpus()) { + for (i = 0; ret == 0 && i < pp->insn_cnt; i++) + ret = aarch64_insn_patch_text_nosync(pp->text_addrs[i], + pp->new_insns[i]); + /* Notify other processors with an additional increment. */ + atomic_inc(&pp->cpu_count); + } else { + while (atomic_read(&pp->cpu_count) <= num_online_cpus()) + cpu_relax(); + isb(); + } + + return ret; +} + +int __kprobes aarch64_insn_patch_text(void *addrs[], u32 insns[], int cnt) +{ + struct aarch64_insn_patch patch = { + .text_addrs = addrs, + .new_insns = insns, + .insn_cnt = cnt, + .cpu_count = ATOMIC_INIT(0), + }; + + if (cnt <= 0) + return -EINVAL; + + return stop_machine_cpuslocked(aarch64_insn_patch_text_cb, &patch, + cpu_online_mask); +} -- cgit v1.2.3