drivers/soc/qcom/minidump_log.c

// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (c) 2017-2018, The Linux Foundation. All rights reserved.
 */

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/kallsyms.h>
#include <linux/slab.h>
#include <linux/thread_info.h>
#include <soc/qcom/minidump.h>
#include <asm/sections.h>
#include <linux/mm.h>
#include <linux/sched/task.h>

static void __init register_log_buf(void)
{
	char **log_bufp;
	uint32_t *log_buf_lenp;
	struct md_region md_entry;

	log_bufp = (char **)kallsyms_lookup_name("log_buf");
	log_buf_lenp = (uint32_t *)kallsyms_lookup_name("log_buf_len");
	if (!log_bufp || !log_buf_lenp) {
		pr_err("Unable to find log_buf by kallsyms!\n");
		return;
	}
	/*Register logbuf to minidump, first idx would be from bss section */
	strlcpy(md_entry.name, "KLOGBUF", sizeof(md_entry.name));
	md_entry.virt_addr = (uintptr_t) (*log_bufp);
	md_entry.phys_addr = virt_to_phys(*log_bufp);
	md_entry.size = *log_buf_lenp;
	if (msm_minidump_add_region(&md_entry))
		pr_err("Failed to add logbuf in Minidump\n");
}

static void register_stack_entry(struct md_region *ksp_entry, u64 sp, u64 size,
				 u32 cpu)
{
	struct page *sp_page;
	struct vm_struct *stack_vm_area = task_stack_vm_area(current);

	ksp_entry->virt_addr = sp;
	ksp_entry->size = size;
	if (stack_vm_area) {
		sp_page = vmalloc_to_page((const void *) sp);
		ksp_entry->phys_addr = page_to_phys(sp_page);
	} else {
		ksp_entry->phys_addr = virt_to_phys((uintptr_t *)sp);
	}

	if (msm_minidump_add_region(ksp_entry))
		pr_err("Failed to add stack of cpu %d in Minidump\n", cpu);
}

static void __init register_kernel_sections(void)
{
	struct md_region ksec_entry;
	char *data_name = "KDATABSS";
	const size_t static_size = __per_cpu_end - __per_cpu_start;
	void __percpu *base = (void __percpu *)__per_cpu_start;
	unsigned int cpu;

	strlcpy(ksec_entry.name, data_name, sizeof(ksec_entry.name));
	ksec_entry.virt_addr = (uintptr_t)_sdata;
	ksec_entry.phys_addr = virt_to_phys(_sdata);
	ksec_entry.size = roundup((__bss_stop - _sdata), 4);
	if (msm_minidump_add_region(&ksec_entry))
		pr_err("Failed to add data section in Minidump\n");

	/* Add percpu static sections */
	for_each_possible_cpu(cpu) {
		void *start = per_cpu_ptr(base, cpu);

		memset(&ksec_entry, 0, sizeof(ksec_entry));
		scnprintf(ksec_entry.name, sizeof(ksec_entry.name),
			"KSPERCPU%d", cpu);
		ksec_entry.virt_addr = (uintptr_t)start;
		ksec_entry.phys_addr = per_cpu_ptr_to_phys(start);
		ksec_entry.size = static_size;
		if (msm_minidump_add_region(&ksec_entry))
			pr_err("Failed to add percpu sections in Minidump\n");
	}
}

static inline bool in_stack_range(u64 sp, u64 base_addr, unsigned int
				  stack_size)
{
	u64 min_addr = base_addr;
	u64 max_addr = base_addr + stack_size;

	return (min_addr <= sp && sp < max_addr);
}

static unsigned int calculate_copy_pages(u64 sp, struct vm_struct *stack_area)
{
	u64 tsk_stack_base = (u64) stack_area->addr;
	u64 offset;
	unsigned int stack_pages, copy_pages;

	if (in_stack_range(sp, tsk_stack_base, get_vm_area_size(stack_area))) {
		offset = sp - tsk_stack_base;
		stack_pages = get_vm_area_size(stack_area) / PAGE_SIZE;
		copy_pages = stack_pages - (offset / PAGE_SIZE);
	} else {
		copy_pages = 0;
	}
	return copy_pages;
}

void dump_stack_minidump(u64 sp)
{
	struct md_region ksp_entry, ktsk_entry;
	u32 cpu = smp_processor_id();
	struct vm_struct *stack_vm_area;
	unsigned int i, copy_pages;

	if (is_idle_task(current))
		return;

	if (sp < KIMAGE_VADDR || sp > -256UL)
		sp = current_stack_pointer;

	/*
	 * Since stacks are now allocated with vmalloc, the translation to
	 * physical address is not a simple linear transformation like it is
	 * for kernel logical addresses, since vmalloc creates a virtual
	 * mapping. Thus, virt_to_phys() should not be used in this context;
	 * instead the page table must be walked to acquire the physical
	 * address of one page of the stack.
	 */
	stack_vm_area = task_stack_vm_area(current);
	if (stack_vm_area) {
		sp &= ~(PAGE_SIZE - 1);
		copy_pages = calculate_copy_pages(sp, stack_vm_area);
		for (i = 0; i < copy_pages; i++) {
			scnprintf(ksp_entry.name, sizeof(ksp_entry.name),
				  "KSTACK%d_%d", cpu, i);
			register_stack_entry(&ksp_entry, sp, PAGE_SIZE, cpu);
			sp += PAGE_SIZE;
		}
	} else {
		sp &= ~(THREAD_SIZE - 1);
		scnprintf(ksp_entry.name, sizeof(ksp_entry.name), "KSTACK%d",
			  cpu);
		register_stack_entry(&ksp_entry, sp, THREAD_SIZE, cpu);
	}

	scnprintf(ktsk_entry.name, sizeof(ktsk_entry.name), "KTASK%d", cpu);
	ktsk_entry.virt_addr = (u64)current;
	ktsk_entry.phys_addr = virt_to_phys((uintptr_t *)current);
	ktsk_entry.size = sizeof(struct task_struct);
	if (msm_minidump_add_region(&ktsk_entry))
		pr_err("Failed to add current task %d in Minidump\n", cpu);
}

static int __init msm_minidump_log_init(void)
{
	register_kernel_sections();
	register_log_buf();
	return 0;
}
late_initcall(msm_minidump_log_init);