Commit 841ecc97 authored by Thomas Bogendoerfer's avatar Thomas Bogendoerfer
Browse files

MIPS: mm: kmalloc tlb_vpn array to avoid stack overflow 



Owing to Config4.MMUSizeExt and VTLB/FTLB MMU features later MIPSr2+
cores can have more than 64 TLB entries.  Therefore allocate an array
for uniquification instead of placing too an small array on the stack.

Fixes: 35ad7e18 ("MIPS: mm: tlb-r4k: Uniquify TLB entries on init")
Co-developed-by: default avatarMaciej W. Rozycki <macro@orcam.me.uk>
Signed-off-by: default avatarMaciej W. Rozycki <macro@orcam.me.uk>
Cc: stable@vger.kernel.org # v6.17+: 9f048fa4: MIPS: mm: Prevent a TLB shutdown on initial uniquification
Cc: stable@vger.kernel.org # v6.17+
Tested-by: default avatarGregory CLEMENT <gregory.clement@bootlin.com>
Tested-by: default avatarKlara Modin <klarasmodin@gmail.com>
Signed-off-by: default avatarThomas Bogendoerfer <tsbogend@alpha.franken.de>
parent ac3fd01e

arch/mips/mm/tlb-r4k.c

+16 −2
Original line number Diff line number Diff line
@@ -12,6 +12,7 @@ 
#include <linux/init.h>

#include <linux/sched.h>

#include <linux/smp.h>

#include <linux/memblock.h>

#include <linux/mm.h>

#include <linux/hugetlb.h>

#include <linux/export.h>
@@ -522,17 +523,26 @@ static int r4k_vpn_cmp(const void *a, const void *b) 
 * Initialise all TLB entries with unique values that do not clash with

 * what we have been handed over and what we'll be using ourselves.

 */

static void r4k_tlb_uniquify(void)

static void __ref r4k_tlb_uniquify(void)

{

	unsigned long tlb_vpns[1 << MIPS_CONF1_TLBS_SIZE];

	int tlbsize = current_cpu_data.tlbsize;

	bool use_slab = slab_is_available();

	int start = num_wired_entries();

	phys_addr_t tlb_vpn_size;

	unsigned long *tlb_vpns;

	unsigned long vpn_mask;

	int cnt, ent, idx, i;



	vpn_mask = GENMASK(cpu_vmbits - 1, 13);

	vpn_mask |= IS_ENABLED(CONFIG_64BIT) ? 3ULL << 62 : 1 << 31;



	tlb_vpn_size = tlbsize * sizeof(*tlb_vpns);

	tlb_vpns = (use_slab ?

		    kmalloc(tlb_vpn_size, GFP_KERNEL) :

		    memblock_alloc_raw(tlb_vpn_size, sizeof(*tlb_vpns)));

	if (WARN_ON(!tlb_vpns))

		return; /* Pray local_flush_tlb_all() is good enough. */



	htw_stop();



	for (i = start, cnt = 0; i < tlbsize; i++, cnt++) {
@@ -585,6 +595,10 @@ static void r4k_tlb_uniquify(void) 
	tlbw_use_hazard();

	htw_start();

	flush_micro_tlb();

	if (use_slab)

		kfree(tlb_vpns);

	else

		memblock_free(tlb_vpns, tlb_vpn_size);

}



/*