linux/arch/arm64/kernel/cacheinfo.c
Sudeep Holla 29906311b3 arm64: cacheinfo: Fix incorrect assignment of signed error value to unsigned fw_level
[ Upstream commit e75d18cecb ]

Though acpi_find_last_cache_level() always returned signed value and the
document states it will return any errors caused by lack of a PPTT table,
it never returned negative values before.

Commit 0c80f9e165 ("ACPI: PPTT: Leave the table mapped for the runtime usage")
however changed it by returning -ENOENT if no PPTT was found. The value
returned from acpi_find_last_cache_level() is then assigned to unsigned
fw_level.

It will result in the number of cache leaves calculated incorrectly as
a huge value which will then cause the following warning from __alloc_pages
as the order would be great than MAX_ORDER because of incorrect and huge
cache leaves value.

  |  WARNING: CPU: 0 PID: 1 at mm/page_alloc.c:5407 __alloc_pages+0x74/0x314
  |  Modules linked in:
  |  CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.19.0-10393-g7c2a8d3ac4c0 #73
  |  pstate: 20000005 (nzCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
  |  pc : __alloc_pages+0x74/0x314
  |  lr : alloc_pages+0xe8/0x318
  |  Call trace:
  |   __alloc_pages+0x74/0x314
  |   alloc_pages+0xe8/0x318
  |   kmalloc_order_trace+0x68/0x1dc
  |   __kmalloc+0x240/0x338
  |   detect_cache_attributes+0xe0/0x56c
  |   update_siblings_masks+0x38/0x284
  |   store_cpu_topology+0x78/0x84
  |   smp_prepare_cpus+0x48/0x134
  |   kernel_init_freeable+0xc4/0x14c
  |   kernel_init+0x2c/0x1b4
  |   ret_from_fork+0x10/0x20

Fix the same by changing fw_level to be signed integer and return the
error from init_cache_level() early in case of error.

Reported-and-Tested-by: Bruno Goncalves <bgoncalv@redhat.com>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Link: https://lore.kernel.org/r/20220808084640.3165368-1-sudeep.holla@arm.com
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-09-15 11:30:01 +02:00

104 lines
2.5 KiB
C

// SPDX-License-Identifier: GPL-2.0-only
/*
* ARM64 cacheinfo support
*
* Copyright (C) 2015 ARM Ltd.
* All Rights Reserved
*/
#include <linux/acpi.h>
#include <linux/cacheinfo.h>
#include <linux/of.h>
#define MAX_CACHE_LEVEL 7 /* Max 7 level supported */
/* Ctypen, bits[3(n - 1) + 2 : 3(n - 1)], for n = 1 to 7 */
#define CLIDR_CTYPE_SHIFT(level) (3 * (level - 1))
#define CLIDR_CTYPE_MASK(level) (7 << CLIDR_CTYPE_SHIFT(level))
#define CLIDR_CTYPE(clidr, level) \
(((clidr) & CLIDR_CTYPE_MASK(level)) >> CLIDR_CTYPE_SHIFT(level))
int cache_line_size(void)
{
if (coherency_max_size != 0)
return coherency_max_size;
return cache_line_size_of_cpu();
}
EXPORT_SYMBOL_GPL(cache_line_size);
static inline enum cache_type get_cache_type(int level)
{
u64 clidr;
if (level > MAX_CACHE_LEVEL)
return CACHE_TYPE_NOCACHE;
clidr = read_sysreg(clidr_el1);
return CLIDR_CTYPE(clidr, level);
}
static void ci_leaf_init(struct cacheinfo *this_leaf,
enum cache_type type, unsigned int level)
{
this_leaf->level = level;
this_leaf->type = type;
}
int init_cache_level(unsigned int cpu)
{
unsigned int ctype, level, leaves;
int fw_level;
struct cpu_cacheinfo *this_cpu_ci = get_cpu_cacheinfo(cpu);
for (level = 1, leaves = 0; level <= MAX_CACHE_LEVEL; level++) {
ctype = get_cache_type(level);
if (ctype == CACHE_TYPE_NOCACHE) {
level--;
break;
}
/* Separate instruction and data caches */
leaves += (ctype == CACHE_TYPE_SEPARATE) ? 2 : 1;
}
if (acpi_disabled)
fw_level = of_find_last_cache_level(cpu);
else
fw_level = acpi_find_last_cache_level(cpu);
if (fw_level < 0)
return fw_level;
if (level < fw_level) {
/*
* some external caches not specified in CLIDR_EL1
* the information may be available in the device tree
* only unified external caches are considered here
*/
leaves += (fw_level - level);
level = fw_level;
}
this_cpu_ci->num_levels = level;
this_cpu_ci->num_leaves = leaves;
return 0;
}
int populate_cache_leaves(unsigned int cpu)
{
unsigned int level, idx;
enum cache_type type;
struct cpu_cacheinfo *this_cpu_ci = get_cpu_cacheinfo(cpu);
struct cacheinfo *this_leaf = this_cpu_ci->info_list;
for (idx = 0, level = 1; level <= this_cpu_ci->num_levels &&
idx < this_cpu_ci->num_leaves; idx++, level++) {
type = get_cache_type(level);
if (type == CACHE_TYPE_SEPARATE) {
ci_leaf_init(this_leaf++, CACHE_TYPE_DATA, level);
ci_leaf_init(this_leaf++, CACHE_TYPE_INST, level);
} else {
ci_leaf_init(this_leaf++, type, level);
}
}
return 0;
}