Commit a4316603 authored by Juergen Gross's avatar Juergen Gross Committed by Borislav Petkov (AMD)
Browse files

x86/mtrr: Add mtrr=debug command line option 



Add a new command line option "mtrr=debug" for getting debug output
after building the new cache mode map. The output will include MTRR
register values and the resulting map.

Signed-off-by: default avatarJuergen Gross <jgross@suse.com>
Signed-off-by: default avatarBorislav Petkov (AMD) <bp@alien8.de>
Tested-by: default avatarMichael Kelley <mikelley@microsoft.com>
Link: https://lore.kernel.org/r/20230502120931.20719-13-jgross@suse.com


Signed-off-by: default avatarBorislav Petkov (AMD) <bp@alien8.de>
parent 061b984a

Documentation/admin-guide/kernel-parameters.txt

+4 −0
Original line number Diff line number Diff line
@@ -3423,6 +3423,10 @@ 
			[HW] Make the MicroTouch USB driver use raw coordinates

			('y', default) or cooked coordinates ('n')



	mtrr=debug	[X86]

			Enable printing debug information related to MTRR

			registers at boot time.



	mtrr_chunk_size=nn[KMG] [X86]

			used for mtrr cleanup. It is largest continuous chunk

			that could hold holes aka. UC entries.

arch/x86/kernel/cpu/mtrr/generic.c

+45 −19
Original line number Diff line number Diff line
@@ -41,6 +41,23 @@ struct cache_map { 
	u64 fixed:1;

};



static bool mtrr_debug;



static int __init mtrr_param_setup(char *str)

{

	int rc = 0;



	if (!str)

		return -EINVAL;

	if (!strcmp(str, "debug"))

		mtrr_debug = true;

	else

		rc = -EINVAL;



	return rc;

}

early_param("mtrr", mtrr_param_setup);



/*

 * CACHE_MAP_MAX is the maximum number of memory ranges in cache_map, where

 * no 2 adjacent ranges have the same cache mode (those would be merged).
@@ -515,6 +532,14 @@ void __init mtrr_build_map(void) 
	pr_info("MTRR map: %u entries (%u fixed + %u variable; max %u), built from %u variable MTRRs\n",

		cache_map_n, cache_map_fixed, cache_map_n - cache_map_fixed,

		get_cache_map_size(), num_var_ranges + (mtrr_tom2 != 0));



	if (mtrr_debug) {

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

			pr_info("%3u: %016llx-%016llx %s\n", i,

				cache_map[i].start, cache_map[i].end - 1,

				mtrr_attrib_to_str(cache_map[i].type));

		}

	}

}



/* Copy the cache_map from __initdata memory to dynamically allocated one. */
@@ -721,7 +746,7 @@ static void __init print_fixed_last(void) 
	if (!last_fixed_end)

		return;



	pr_debug("  %05X-%05X %s\n", last_fixed_start,

	pr_info("  %05X-%05X %s\n", last_fixed_start,

		last_fixed_end - 1, mtrr_attrib_to_str(last_fixed_type));



	last_fixed_end = 0;
@@ -760,10 +785,10 @@ static void __init print_mtrr_state(void) 
	unsigned int i;

	int high_width;



	pr_debug("MTRR default type: %s\n",

	pr_info("MTRR default type: %s\n",

		mtrr_attrib_to_str(mtrr_state.def_type));

	if (mtrr_state.have_fixed) {

		pr_debug("MTRR fixed ranges %sabled:\n",

		pr_info("MTRR fixed ranges %sabled:\n",

			((mtrr_state.enabled & MTRR_STATE_MTRR_ENABLED) &&

			 (mtrr_state.enabled & MTRR_STATE_MTRR_FIXED_ENABLED)) ?

			 "en" : "dis");
@@ -778,13 +803,13 @@ static void __init print_mtrr_state(void) 
		/* tail */

		print_fixed_last();

	}

	pr_debug("MTRR variable ranges %sabled:\n",

	pr_info("MTRR variable ranges %sabled:\n",

		mtrr_state.enabled & MTRR_STATE_MTRR_ENABLED ? "en" : "dis");

	high_width = (boot_cpu_data.x86_phys_bits - (32 - PAGE_SHIFT) + 3) / 4;



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

		if (mtrr_state.var_ranges[i].mask_lo & MTRR_PHYSMASK_V)

			pr_debug("  %u base %0*X%05X000 mask %0*X%05X000 %s\n",

			pr_info("  %u base %0*X%05X000 mask %0*X%05X000 %s\n",

				i,

				high_width,

				mtrr_state.var_ranges[i].base_hi,
@@ -795,10 +820,10 @@ static void __init print_mtrr_state(void) 
				mtrr_attrib_to_str(mtrr_state.var_ranges[i].base_lo &

						    MTRR_PHYSBASE_TYPE));

		else

			pr_debug("  %u disabled\n", i);

			pr_info("  %u disabled\n", i);

	}

	if (mtrr_tom2)

		pr_debug("TOM2: %016llx aka %lldM\n", mtrr_tom2, mtrr_tom2>>20);

		pr_info("TOM2: %016llx aka %lldM\n", mtrr_tom2, mtrr_tom2>>20);

}



/* Grab all of the MTRR state for this CPU into *state */
@@ -833,6 +858,7 @@ bool __init get_mtrr_state(void) 
		mtrr_tom2 &= 0xffffff800000ULL;

	}



	if (mtrr_debug)

		print_mtrr_state();



	mtrr_state_set = 1;