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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: 35ad7e1815 ("MIPS: mm: tlb-r4k: Uniquify TLB entries on init")
Co-developed-by: Maciej W. Rozycki <macro@orcam.me.uk>
Signed-off-by: Maciej W. Rozycki <macro@orcam.me.uk>
Cc: stable@vger.kernel.org # v6.17+: 9f048fa48740: MIPS: mm: Prevent a TLB shutdown on initial uniquification
Cc: stable@vger.kernel.org # v6.17+
Tested-by: Gregory CLEMENT <gregory.clement@bootlin.com>
Tested-by: Klara Modin <klarasmodin@gmail.com>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
This commit is contained in:
Thomas Bogendoerfer 2025-11-28 16:53:46 +00:00
parent ac3fd01e4c
commit 841ecc979b
1 changed files with 16 additions and 2 deletions
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18
arch/mips/mm/tlb-r4k.c
View File

@ -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);
}
/*