Commit 394f3f02 authored by Steven Rostedt's avatar Steven Rostedt Committed by Steven Rostedt (Google)
Browse files

tracing: Use vmap_page_range() to map memmap ring buffer 

The code to map the physical memory retrieved by memmap currently
allocates an array of pages to cover the physical memory and then calls
vmap() to map it to a virtual address. Instead of using this temporary
array of struct page descriptors, simply use vmap_page_range() that can
directly map the contiguous physical memory to a virtual address.

Link: https://lore.kernel.org/all/CAHk-=whUOfVucfJRt7E0AH+GV41ELmS4wJqxHDnui6Giddfkzw@mail.gmail.com/

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Vincent Donnefort <vdonnefort@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Jann Horn <jannh@google.com>
Link: https://lore.kernel.org/20250402144953.754618481@goodmis.org


Suggested-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: default avatarSteven Rostedt (Google) <rostedt@goodmis.org>
parent 34ea8fa0

kernel/trace/trace.c

+16 −17
Original line number Diff line number Diff line
@@ -50,6 +50,7 @@ 
#include <linux/irq_work.h>

#include <linux/workqueue.h>

#include <linux/sort.h>

#include <linux/io.h> /* vmap_page_range() */



#include <asm/setup.h> /* COMMAND_LINE_SIZE */
@@ -9796,29 +9797,27 @@ static int instance_mkdir(const char *name) 
	return ret;

}



static u64 map_pages(u64 start, u64 size)

static u64 map_pages(unsigned long start, unsigned long size)

{

	struct page **pages;

	phys_addr_t page_start;

	unsigned int page_count;

	unsigned int i;

	void *vaddr;



	page_count = DIV_ROUND_UP(size, PAGE_SIZE);

	unsigned long vmap_start, vmap_end;

	struct vm_struct *area;

	int ret;



	page_start = start;

	pages = kmalloc_array(page_count, sizeof(struct page *), GFP_KERNEL);

	if (!pages)

	area = get_vm_area(size, VM_IOREMAP);

	if (!area)

		return 0;



	for (i = 0; i < page_count; i++) {

		phys_addr_t addr = page_start + i * PAGE_SIZE;

		pages[i] = pfn_to_page(addr >> PAGE_SHIFT);

	vmap_start = (unsigned long) area->addr;

	vmap_end = vmap_start + size;



	ret = vmap_page_range(vmap_start, vmap_end,

			      start, pgprot_nx(PAGE_KERNEL));

	if (ret < 0) {

		free_vm_area(area);

		return 0;

	}

	vaddr = vmap(pages, page_count, VM_MAP, PAGE_KERNEL);

	kfree(pages);



	return (u64)(unsigned long)vaddr;

	return (u64)vmap_start;

}



/**