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Commit ef6bea6d authored by Borislav Petkov's avatar Borislav Petkov Committed by Matt Fleming
Browse files

x86, ptdump: Add the functionality to dump an arbitrary pagetable 



With reusing the ->trampoline_pgd page table for mapping EFI regions in
order to use them after having switched to EFI virtual mode, it is very
useful to be able to dump aforementioned page table in dmesg. This adds
that functionality through the walk_pgd_level() interface which can be
called from somewhere else.

The original functionality of dumping to debugfs remains untouched.

Cc: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: default avatarBorislav Petkov <bp@suse.de>
Tested-by: default avatarToshi Kani <toshi.kani@hp.com>
Signed-off-by: default avatarMatt Fleming <matt.fleming@intel.com>
parent 9b7d2049

arch/x86/include/asm/pgtable.h

+2 −1
Original line number Diff line number Diff line
@@ -15,9 +15,10 @@ 
	 : (prot))



#ifndef __ASSEMBLY__



#include <asm/x86_init.h>



void ptdump_walk_pgd_level(struct seq_file *m, pgd_t *pgd);



/*

 * ZERO_PAGE is a global shared page that is always zero: used

 * for zero-mapped memory areas etc..

arch/x86/mm/dump_pagetables.c

+54 −30
Original line number Diff line number Diff line
@@ -30,6 +30,7 @@ struct pg_state { 
	unsigned long start_address;

	unsigned long current_address;

	const struct addr_marker *marker;

	bool to_dmesg;

};



struct addr_marker {
@@ -88,10 +89,28 @@ static struct addr_marker address_markers[] = { 
#define PUD_LEVEL_MULT (PTRS_PER_PMD * PMD_LEVEL_MULT)

#define PGD_LEVEL_MULT (PTRS_PER_PUD * PUD_LEVEL_MULT)



#define pt_dump_seq_printf(m, to_dmesg, fmt, args...)		\

({								\

	if (to_dmesg)					\

		printk(KERN_INFO fmt, ##args);			\

	else							\

		if (m)						\

			seq_printf(m, fmt, ##args);		\

})



#define pt_dump_cont_printf(m, to_dmesg, fmt, args...)		\

({								\

	if (to_dmesg)					\

		printk(KERN_CONT fmt, ##args);			\

	else							\

		if (m)						\

			seq_printf(m, fmt, ##args);		\

})



/*

 * Print a readable form of a pgprot_t to the seq_file

 */

static void printk_prot(struct seq_file *m, pgprot_t prot, int level)

static void printk_prot(struct seq_file *m, pgprot_t prot, int level, bool dmsg)

{

	pgprotval_t pr = pgprot_val(prot);

	static const char * const level_name[] =
@@ -99,47 +118,47 @@ static void printk_prot(struct seq_file *m, pgprot_t prot, int level) 


	if (!pgprot_val(prot)) {

		/* Not present */

		seq_printf(m, "                          ");

		pt_dump_cont_printf(m, dmsg, "                          ");

	} else {

		if (pr & _PAGE_USER)

			seq_printf(m, "USR ");

			pt_dump_cont_printf(m, dmsg, "USR ");

		else

			seq_printf(m, "    ");

			pt_dump_cont_printf(m, dmsg, "    ");

		if (pr & _PAGE_RW)

			seq_printf(m, "RW ");

			pt_dump_cont_printf(m, dmsg, "RW ");

		else

			seq_printf(m, "ro ");

			pt_dump_cont_printf(m, dmsg, "ro ");

		if (pr & _PAGE_PWT)

			seq_printf(m, "PWT ");

			pt_dump_cont_printf(m, dmsg, "PWT ");

		else

			seq_printf(m, "    ");

			pt_dump_cont_printf(m, dmsg, "    ");

		if (pr & _PAGE_PCD)

			seq_printf(m, "PCD ");

			pt_dump_cont_printf(m, dmsg, "PCD ");

		else

			seq_printf(m, "    ");

			pt_dump_cont_printf(m, dmsg, "    ");



		/* Bit 9 has a different meaning on level 3 vs 4 */

		if (level <= 3) {

			if (pr & _PAGE_PSE)

				seq_printf(m, "PSE ");

				pt_dump_cont_printf(m, dmsg, "PSE ");

			else

				seq_printf(m, "    ");

				pt_dump_cont_printf(m, dmsg, "    ");

		} else {

			if (pr & _PAGE_PAT)

				seq_printf(m, "pat ");

				pt_dump_cont_printf(m, dmsg, "pat ");

			else

				seq_printf(m, "    ");

				pt_dump_cont_printf(m, dmsg, "    ");

		}

		if (pr & _PAGE_GLOBAL)

			seq_printf(m, "GLB ");

			pt_dump_cont_printf(m, dmsg, "GLB ");

		else

			seq_printf(m, "    ");

			pt_dump_cont_printf(m, dmsg, "    ");

		if (pr & _PAGE_NX)

			seq_printf(m, "NX ");

			pt_dump_cont_printf(m, dmsg, "NX ");

		else

			seq_printf(m, "x  ");

			pt_dump_cont_printf(m, dmsg, "x  ");

	}

	seq_printf(m, "%s\n", level_name[level]);

	pt_dump_cont_printf(m, dmsg, "%s\n", level_name[level]);

}



/*
@@ -178,7 +197,8 @@ static void note_page(struct seq_file *m, struct pg_state *st, 
		st->current_prot = new_prot;

		st->level = level;

		st->marker = address_markers;

		seq_printf(m, "---[ %s ]---\n", st->marker->name);

		pt_dump_seq_printf(m, st->to_dmesg, "---[ %s ]---\n",

				   st->marker->name);

	} else if (prot != cur || level != st->level ||

		   st->current_address >= st->marker[1].start_address) {

		const char *unit = units;
@@ -188,7 +208,7 @@ static void note_page(struct seq_file *m, struct pg_state *st, 
		/*

		 * Now print the actual finished series

		 */

		seq_printf(m, "0x%0*lx-0x%0*lx   ",

		pt_dump_seq_printf(m, st->to_dmesg,  "0x%0*lx-0x%0*lx   ",

				   width, st->start_address,

				   width, st->current_address);
@@ -197,8 +217,8 @@ static void note_page(struct seq_file *m, struct pg_state *st, 
			delta >>= 10;

			unit++;

		}

		seq_printf(m, "%9lu%c ", delta, *unit);

		printk_prot(m, st->current_prot, st->level);

		pt_dump_cont_printf(m, st->to_dmesg, "%9lu%c ", delta, *unit);

		printk_prot(m, st->current_prot, st->level, st->to_dmesg);



		/*

		 * We print markers for special areas of address space,
@@ -207,7 +227,8 @@ static void note_page(struct seq_file *m, struct pg_state *st, 
		 */

		if (st->current_address >= st->marker[1].start_address) {

			st->marker++;

			seq_printf(m, "---[ %s ]---\n", st->marker->name);

			pt_dump_seq_printf(m, st->to_dmesg, "---[ %s ]---\n",

					   st->marker->name);

		}



		st->start_address = st->current_address;
@@ -296,7 +317,7 @@ static void walk_pud_level(struct seq_file *m, struct pg_state *st, pgd_t addr, 
#define pgd_none(a)  pud_none(__pud(pgd_val(a)))

#endif



static void walk_pgd_level(struct seq_file *m)

void ptdump_walk_pgd_level(struct seq_file *m, pgd_t *pgd)

{

#ifdef CONFIG_X86_64

	pgd_t *start = (pgd_t *) &init_level4_pgt;
@@ -304,9 +325,12 @@ static void walk_pgd_level(struct seq_file *m) 
	pgd_t *start = swapper_pg_dir;

#endif

	int i;

	struct pg_state st;

	struct pg_state st = {};



	memset(&st, 0, sizeof(st));

	if (pgd) {

		start = pgd;

		st.to_dmesg = true;

	}



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

		st.current_address = normalize_addr(i * PGD_LEVEL_MULT);
@@ -331,7 +355,7 @@ static void walk_pgd_level(struct seq_file *m) 


static int ptdump_show(struct seq_file *m, void *v)

{

	walk_pgd_level(m);

	ptdump_walk_pgd_level(m, NULL);

	return 0;

}