Orange Pi5 kernel

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *
 * Copyright (C) IBM Corporation, 2005
 *               Jeff Muizelaar, 2006, 2007
 *               Pekka Paalanen, 2008 <pq@iki.fi>
 *
 * Derived from the read-mod example from relay-examples by Tom Zanussi.
 */
 
#define pr_fmt(fmt) "mmiotrace: " fmt
 
#define DEBUG 1
 
#include <linux/moduleparam.h>
#include <linux/debugfs.h>
#include <linux/slab.h>
#include <linux/uaccess.h>
#include <linux/io.h>
#include <linux/mmiotrace.h>
#include <linux/pgtable.h>
#include <asm/e820/api.h> /* for ISA_START_ADDRESS */
#include <linux/atomic.h>
#include <linux/percpu.h>
#include <linux/cpu.h>
 
#include "pf_in.h"
 
struct trap_reason {
<------>unsigned long addr;
<------>unsigned long ip;
<------>enum reason_type type;
<------>int active_traces;
};
 
struct remap_trace {
<------>struct list_head list;
<------>struct kmmio_probe probe;
<------>resource_size_t phys;
<------>unsigned long id;
};
 
/* Accessed per-cpu. */
static DEFINE_PER_CPU(struct trap_reason, pf_reason);
static DEFINE_PER_CPU(struct mmiotrace_rw, cpu_trace);
 
static DEFINE_MUTEX(mmiotrace_mutex);
static DEFINE_SPINLOCK(trace_lock);
static atomic_t mmiotrace_enabled;
static LIST_HEAD(trace_list);		/* struct remap_trace */
 
/*
 * Locking in this file:
 * - mmiotrace_mutex enforces enable/disable_mmiotrace() critical sections.
 * - mmiotrace_enabled may be modified only when holding mmiotrace_mutex
 *   and trace_lock.
 * - Routines depending on is_enabled() must take trace_lock.
 * - trace_list users must hold trace_lock.
 * - is_enabled() guarantees that mmio_trace_{rw,mapping} are allowed.
 * - pre/post callbacks assume the effect of is_enabled() being true.
 */
 
/* module parameters */
static unsigned long	filter_offset;
static bool		nommiotrace;
static bool		trace_pc;
 
module_param(filter_offset, ulong, 0);
module_param(nommiotrace, bool, 0);
module_param(trace_pc, bool, 0);
 
MODULE_PARM_DESC(filter_offset, "Start address of traced mappings.");
MODULE_PARM_DESC(nommiotrace, "Disable actual MMIO tracing.");
MODULE_PARM_DESC(trace_pc, "Record address of faulting instructions.");
 
static bool is_enabled(void)
{
<------>return atomic_read(&mmiotrace_enabled);
}
 
static void print_pte(unsigned long address)
{
<------>unsigned int level;
<------>pte_t *pte = lookup_address(address, &level);
 
<------>if (!pte) {
<------><------>pr_err("Error in %s: no pte for page 0x%08lx\n",
<------><------>       __func__, address);
<------><------>return;
<------>}
 
<------>if (level == PG_LEVEL_2M) {
<------><------>pr_emerg("4MB pages are not currently supported: 0x%08lx\n",
<------><------><------> address);
<------><------>BUG();
<------>}
<------>pr_info("pte for 0x%lx: 0x%llx 0x%llx\n",
<------><------>address,
<------><------>(unsigned long long)pte_val(*pte),
<------><------>(unsigned long long)pte_val(*pte) & _PAGE_PRESENT);
}
 
/*
 * For some reason the pre/post pairs have been called in an
 * unmatched order. Report and die.
 */
static void die_kmmio_nesting_error(struct pt_regs *regs, unsigned long addr)
{
<------>const struct trap_reason *my_reason = &get_cpu_var(pf_reason);
<------>pr_emerg("unexpected fault for address: 0x%08lx, last fault for address: 0x%08lx\n",
<------><------> addr, my_reason->addr);
<------>print_pte(addr);
<------>pr_emerg("faulting IP is at %pS\n", (void *)regs->ip);
<------>pr_emerg("last faulting IP was at %pS\n", (void *)my_reason->ip);
#ifdef __i386__
<------>pr_emerg("eax: %08lx   ebx: %08lx   ecx: %08lx   edx: %08lx\n",
<------><------> regs->ax, regs->bx, regs->cx, regs->dx);
<------>pr_emerg("esi: %08lx   edi: %08lx   ebp: %08lx   esp: %08lx\n",
<------><------> regs->si, regs->di, regs->bp, regs->sp);
#else
<------>pr_emerg("rax: %016lx   rcx: %016lx   rdx: %016lx\n",
<------><------> regs->ax, regs->cx, regs->dx);
<------>pr_emerg("rsi: %016lx   rdi: %016lx   rbp: %016lx   rsp: %016lx\n",
<------><------> regs->si, regs->di, regs->bp, regs->sp);
#endif
<------>put_cpu_var(pf_reason);
<------>BUG();
}
 
static void pre(struct kmmio_probe *p, struct pt_regs *regs,
<------><------><------><------><------><------>unsigned long addr)
{
<------>struct trap_reason *my_reason = &get_cpu_var(pf_reason);
<------>struct mmiotrace_rw *my_trace = &get_cpu_var(cpu_trace);
<------>const unsigned long instptr = instruction_pointer(regs);
<------>const enum reason_type type = get_ins_type(instptr);
<------>struct remap_trace *trace = p->private;
 
<------>/* it doesn't make sense to have more than one active trace per cpu */
<------>if (my_reason->active_traces)
<------><------>die_kmmio_nesting_error(regs, addr);
<------>else
<------><------>my_reason->active_traces++;
 
<------>my_reason->type = type;
<------>my_reason->addr = addr;
<------>my_reason->ip = instptr;
 
<------>my_trace->phys = addr - trace->probe.addr + trace->phys;
<------>my_trace->map_id = trace->id;
 
<------>/*
<------> * Only record the program counter when requested.
<------> * It may taint clean-room reverse engineering.
<------> */
<------>if (trace_pc)
<------><------>my_trace->pc = instptr;
<------>else
<------><------>my_trace->pc = 0;
 
<------>/*
<------> * XXX: the timestamp recorded will be *after* the tracing has been
<------> * done, not at the time we hit the instruction. SMP implications
<------> * on event ordering?
<------> */
 
<------>switch (type) {
<------>case REG_READ:
<------><------>my_trace->opcode = MMIO_READ;
<------><------>my_trace->width = get_ins_mem_width(instptr);
<------><------>break;
<------>case REG_WRITE:
<------><------>my_trace->opcode = MMIO_WRITE;
<------><------>my_trace->width = get_ins_mem_width(instptr);
<------><------>my_trace->value = get_ins_reg_val(instptr, regs);
<------><------>break;
<------>case IMM_WRITE:
<------><------>my_trace->opcode = MMIO_WRITE;
<------><------>my_trace->width = get_ins_mem_width(instptr);
<------><------>my_trace->value = get_ins_imm_val(instptr);
<------><------>break;
<------>default:
<------><------>{
<------><------><------>unsigned char *ip = (unsigned char *)instptr;
<------><------><------>my_trace->opcode = MMIO_UNKNOWN_OP;
<------><------><------>my_trace->width = 0;
<------><------><------>my_trace->value = (*ip) << 16 | *(ip + 1) << 8 |
<------><------><------><------><------><------><------><------>*(ip + 2);
<------><------>}
<------>}
<------>put_cpu_var(cpu_trace);
<------>put_cpu_var(pf_reason);
}
 
static void post(struct kmmio_probe *p, unsigned long condition,
<------><------><------><------><------><------><------>struct pt_regs *regs)
{
<------>struct trap_reason *my_reason = &get_cpu_var(pf_reason);
<------>struct mmiotrace_rw *my_trace = &get_cpu_var(cpu_trace);
 
<------>/* this should always return the active_trace count to 0 */
<------>my_reason->active_traces--;
<------>if (my_reason->active_traces) {
<------><------>pr_emerg("unexpected post handler");
<------><------>BUG();
<------>}
 
<------>switch (my_reason->type) {
<------>case REG_READ:
<------><------>my_trace->value = get_ins_reg_val(my_reason->ip, regs);
<------><------>break;
<------>default:
<------><------>break;
<------>}
 
<------>mmio_trace_rw(my_trace);
<------>put_cpu_var(cpu_trace);
<------>put_cpu_var(pf_reason);
}
 
static void ioremap_trace_core(resource_size_t offset, unsigned long size,
<------><------><------><------><------><------><------>void __iomem *addr)
{
<------>static atomic_t next_id;
<------>struct remap_trace *trace = kmalloc(sizeof(*trace), GFP_KERNEL);
<------>/* These are page-unaligned. */
<------>struct mmiotrace_map map = {
<------><------>.phys = offset,
<------><------>.virt = (unsigned long)addr,
<------><------>.len = size,
<------><------>.opcode = MMIO_PROBE
<------>};
 
<------>if (!trace) {
<------><------>pr_err("kmalloc failed in ioremap\n");
<------><------>return;
<------>}
 
<------>*trace = (struct remap_trace) {
<------><------>.probe = {
<------><------><------>.addr = (unsigned long)addr,
<------><------><------>.len = size,
<------><------><------>.pre_handler = pre,
<------><------><------>.post_handler = post,
<------><------><------>.private = trace
<------><------>},
<------><------>.phys = offset,
<------><------>.id = atomic_inc_return(&next_id)
<------>};
<------>map.map_id = trace->id;
 
<------>spin_lock_irq(&trace_lock);
<------>if (!is_enabled()) {
<------><------>kfree(trace);
<------><------>goto not_enabled;
<------>}
 
<------>mmio_trace_mapping(&map);
<------>list_add_tail(&trace->list, &trace_list);
<------>if (!nommiotrace)
<------><------>register_kmmio_probe(&trace->probe);
 
not_enabled:
<------>spin_unlock_irq(&trace_lock);
}
 
void mmiotrace_ioremap(resource_size_t offset, unsigned long size,
<------><------><------><------><------><------>void __iomem *addr)
{
<------>if (!is_enabled()) /* recheck and proper locking in *_core() */
<------><------>return;
 
<------>pr_debug("ioremap_*(0x%llx, 0x%lx) = %p\n",
<------><------> (unsigned long long)offset, size, addr);
<------>if ((filter_offset) && (offset != filter_offset))
<------><------>return;
<------>ioremap_trace_core(offset, size, addr);
}
 
static void iounmap_trace_core(volatile void __iomem *addr)
{
<------>struct mmiotrace_map map = {
<------><------>.phys = 0,
<------><------>.virt = (unsigned long)addr,
<------><------>.len = 0,
<------><------>.opcode = MMIO_UNPROBE
<------>};
<------>struct remap_trace *trace;
<------>struct remap_trace *tmp;
<------>struct remap_trace *found_trace = NULL;
 
<------>pr_debug("Unmapping %p.\n", addr);
 
<------>spin_lock_irq(&trace_lock);
<------>if (!is_enabled())
<------><------>goto not_enabled;
 
<------>list_for_each_entry_safe(trace, tmp, &trace_list, list) {
<------><------>if ((unsigned long)addr == trace->probe.addr) {
<------><------><------>if (!nommiotrace)
<------><------><------><------>unregister_kmmio_probe(&trace->probe);
<------><------><------>list_del(&trace->list);
<------><------><------>found_trace = trace;
<------><------><------>break;
<------><------>}
<------>}
<------>map.map_id = (found_trace) ? found_trace->id : -1;
<------>mmio_trace_mapping(&map);
 
not_enabled:
<------>spin_unlock_irq(&trace_lock);
<------>if (found_trace) {
<------><------>synchronize_rcu(); /* unregister_kmmio_probe() requirement */
<------><------>kfree(found_trace);
<------>}
}
 
void mmiotrace_iounmap(volatile void __iomem *addr)
{
<------>might_sleep();
<------>if (is_enabled()) /* recheck and proper locking in *_core() */
<------><------>iounmap_trace_core(addr);
}
 
int mmiotrace_printk(const char *fmt, ...)
{
<------>int ret = 0;
<------>va_list args;
<------>unsigned long flags;
<------>va_start(args, fmt);
 
<------>spin_lock_irqsave(&trace_lock, flags);
<------>if (is_enabled())
<------><------>ret = mmio_trace_printk(fmt, args);
<------>spin_unlock_irqrestore(&trace_lock, flags);
 
<------>va_end(args);
<------>return ret;
}
EXPORT_SYMBOL(mmiotrace_printk);
 
static void clear_trace_list(void)
{
<------>struct remap_trace *trace;
<------>struct remap_trace *tmp;
 
<------>/*
<------> * No locking required, because the caller ensures we are in a
<------> * critical section via mutex, and is_enabled() is false,
<------> * i.e. nothing can traverse or modify this list.
<------> * Caller also ensures is_enabled() cannot change.
<------> */
<------>list_for_each_entry(trace, &trace_list, list) {
<------><------>pr_notice("purging non-iounmapped trace @0x%08lx, size 0x%lx.\n",
<------><------><------>  trace->probe.addr, trace->probe.len);
<------><------>if (!nommiotrace)
<------><------><------>unregister_kmmio_probe(&trace->probe);
<------>}
<------>synchronize_rcu(); /* unregister_kmmio_probe() requirement */
 
<------>list_for_each_entry_safe(trace, tmp, &trace_list, list) {
<------><------>list_del(&trace->list);
<------><------>kfree(trace);
<------>}
}
 
#ifdef CONFIG_HOTPLUG_CPU
static cpumask_var_t downed_cpus;
 
static void enter_uniprocessor(void)
{
<------>int cpu;
<------>int err;
 
<------>if (!cpumask_available(downed_cpus) &&
<------>    !alloc_cpumask_var(&downed_cpus, GFP_KERNEL)) {
<------><------>pr_notice("Failed to allocate mask\n");
<------><------>goto out;
<------>}
 
<------>get_online_cpus();
<------>cpumask_copy(downed_cpus, cpu_online_mask);
<------>cpumask_clear_cpu(cpumask_first(cpu_online_mask), downed_cpus);
<------>if (num_online_cpus() > 1)
<------><------>pr_notice("Disabling non-boot CPUs...\n");
<------>put_online_cpus();
 
<------>for_each_cpu(cpu, downed_cpus) {
<------><------>err = remove_cpu(cpu);
<------><------>if (!err)
<------><------><------>pr_info("CPU%d is down.\n", cpu);
<------><------>else
<------><------><------>pr_err("Error taking CPU%d down: %d\n", cpu, err);
<------>}
out:
<------>if (num_online_cpus() > 1)
<------><------>pr_warn("multiple CPUs still online, may miss events.\n");
}
 
static void leave_uniprocessor(void)
{
<------>int cpu;
<------>int err;
 
<------>if (!cpumask_available(downed_cpus) || cpumask_weight(downed_cpus) == 0)
<------><------>return;
<------>pr_notice("Re-enabling CPUs...\n");
<------>for_each_cpu(cpu, downed_cpus) {
<------><------>err = add_cpu(cpu);
<------><------>if (!err)
<------><------><------>pr_info("enabled CPU%d.\n", cpu);
<------><------>else
<------><------><------>pr_err("cannot re-enable CPU%d: %d\n", cpu, err);
<------>}
}
 
#else /* !CONFIG_HOTPLUG_CPU */
static void enter_uniprocessor(void)
{
<------>if (num_online_cpus() > 1)
<------><------>pr_warn("multiple CPUs are online, may miss events. "
<------><------><------>"Suggest booting with maxcpus=1 kernel argument.\n");
}
 
static void leave_uniprocessor(void)
{
}
#endif
 
void enable_mmiotrace(void)
{
<------>mutex_lock(&mmiotrace_mutex);
<------>if (is_enabled())
<------><------>goto out;
 
<------>if (nommiotrace)
<------><------>pr_info("MMIO tracing disabled.\n");
<------>kmmio_init();
<------>enter_uniprocessor();
<------>spin_lock_irq(&trace_lock);
<------>atomic_inc(&mmiotrace_enabled);
<------>spin_unlock_irq(&trace_lock);
<------>pr_info("enabled.\n");
out:
<------>mutex_unlock(&mmiotrace_mutex);
}
 
void disable_mmiotrace(void)
{
<------>mutex_lock(&mmiotrace_mutex);
<------>if (!is_enabled())
<------><------>goto out;
 
<------>spin_lock_irq(&trace_lock);
<------>atomic_dec(&mmiotrace_enabled);
<------>BUG_ON(is_enabled());
<------>spin_unlock_irq(&trace_lock);
 
<------>clear_trace_list(); /* guarantees: no more kmmio callbacks */
<------>leave_uniprocessor();
<------>kmmio_cleanup();
<------>pr_info("disabled.\n");
out:
<------>mutex_unlock(&mmiotrace_mutex);
}