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Commit fec0962e authored by venkatesh.pallipadi@intel.com's avatar venkatesh.pallipadi@intel.com Committed by H. Peter Anvin
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x86: Add a debugfs interface to dump PAT memtype 



Add a debugfs interface to list out all the PAT memtype reservations.
Appears at debugfs x86/pat_memtype_list and output format is
type @ <start addr>-<end addr>

We do not hold the lock while printing the entire list. So, the list may not be
a consistent copy in case where regions are getting added or deleted
at the same time.

Signed-off-by: default avatarVenkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: default avatarH. Peter Anvin <hpa@zytor.com>
parent ae79cdaa

arch/x86/mm/pat.c

+88 −0
Original line number Diff line number Diff line
@@ -12,6 +12,8 @@ 
#include <linux/gfp.h>

#include <linux/fs.h>

#include <linux/bootmem.h>

#include <linux/debugfs.h>

#include <linux/seq_file.h>



#include <asm/msr.h>

#include <asm/tlbflush.h>
@@ -489,3 +491,89 @@ void unmap_devmem(unsigned long pfn, unsigned long size, pgprot_t vma_prot) 


	free_memtype(addr, addr + size);

}



#if defined(CONFIG_DEBUG_FS)



/* get Nth element of the linked list */

static struct memtype *memtype_get_idx(loff_t pos)

{

	struct memtype *list_node, *print_entry;

	int i = 1;



	print_entry  = kmalloc(sizeof(struct memtype), GFP_KERNEL);

	if (!print_entry)

		return NULL;



	spin_lock(&memtype_lock);

	list_for_each_entry(list_node, &memtype_list, nd) {

		if (pos == i) {

			*print_entry = *list_node;

			spin_unlock(&memtype_lock);

			return print_entry;

		}

		++i;

	}

	spin_unlock(&memtype_lock);

	kfree(print_entry);

	return NULL;

}



static void *memtype_seq_start(struct seq_file *seq, loff_t *pos)

{

	if (*pos == 0) {

		++*pos;

		seq_printf(seq, "PAT memtype list:\n");

	}



	return memtype_get_idx(*pos);

}



static void *memtype_seq_next(struct seq_file *seq, void *v, loff_t *pos)

{

	++*pos;

	return memtype_get_idx(*pos);

}



static void memtype_seq_stop(struct seq_file *seq, void *v)

{

}



static int memtype_seq_show(struct seq_file *seq, void *v)

{

	struct memtype *print_entry = (struct memtype *)v;



	seq_printf(seq, "%s @ 0x%Lx-0x%Lx\n", cattr_name(print_entry->type),

			print_entry->start, print_entry->end);

	kfree(print_entry);

	return 0;

}



static struct seq_operations memtype_seq_ops = {

	.start = memtype_seq_start,

	.next  = memtype_seq_next,

	.stop  = memtype_seq_stop,

	.show  = memtype_seq_show,

};



static int memtype_seq_open(struct inode *inode, struct file *file)

{

	return seq_open(file, &memtype_seq_ops);

}



static const struct file_operations memtype_fops = {

	.open    = memtype_seq_open,

	.read    = seq_read,

	.llseek  = seq_lseek,

	.release = seq_release,

};



static int __init pat_memtype_list_init(void)

{

	debugfs_create_file("pat_memtype_list", S_IRUSR, arch_debugfs_dir,

				NULL, &memtype_fops);

	return 0;

}



late_initcall(pat_memtype_list_init);



#endif /* CONFIG_DEBUG_FS */