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x86/cacheinfo: Delete global num_cache_leaves

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Linux remembers cpu_cachinfo::num_leaves per CPU, but x86 initializes all
CPUs from the same global "num_cache_leaves".

This is erroneous on systems such as Meteor Lake, where each CPU has a
distinct num_leaves value. Delete the global "num_cache_leaves" and
initialize num_leaves on each CPU.

init_cache_level() no longer needs to set num_leaves. Also, it never had to
set num_levels as it is unnecessary in x86. Keep checking for zero cache
leaves. Such condition indicates a bug.

  [ bp: Cleanup. ]

Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Cc: stable@vger.kernel.org # 6.3+
Link: https://lore.kernel.org/r/20241128002247.26726-3-ricardo.neri-calderon@linux.intel.com
This commit is contained in:
Ricardo Neri 2024-11-27 16:22:47 -08:00 committed by Borislav Petkov (AMD)
parent b3fce429a1
commit 9677be09e5
1 changed files with 21 additions and 22 deletions
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43
arch/x86/kernel/cpu/cacheinfo.c
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@ -178,8 +178,6 @@ struct _cpuid4_info_regs {
struct amd_northbridge *nb; struct amd_northbridge *nb;
}; };
static unsigned short num_cache_leaves;
/* AMD doesn't have CPUID4. Emulate it here to report the same /* AMD doesn't have CPUID4. Emulate it here to report the same
information to the user. This makes some assumptions about the machine: information to the user. This makes some assumptions about the machine:
L2 not shared, no SMT etc. that is currently true on AMD CPUs. L2 not shared, no SMT etc. that is currently true on AMD CPUs.
@ -717,20 +715,23 @@ void cacheinfo_hygon_init_llc_id(struct cpuinfo_x86 *c)
void init_amd_cacheinfo(struct cpuinfo_x86 *c) void init_amd_cacheinfo(struct cpuinfo_x86 *c)
{ {
struct cpu_cacheinfo *ci = get_cpu_cacheinfo(c->cpu_index);
if (boot_cpu_has(X86_FEATURE_TOPOEXT)) { if (boot_cpu_has(X86_FEATURE_TOPOEXT)) {
num_cache_leaves = find_num_cache_leaves(c); ci->num_leaves = find_num_cache_leaves(c);
} else if (c->extended_cpuid_level >= 0x80000006) { } else if (c->extended_cpuid_level >= 0x80000006) {
if (cpuid_edx(0x80000006) & 0xf000) if (cpuid_edx(0x80000006) & 0xf000)
num_cache_leaves = 4; ci->num_leaves = 4;
else else
num_cache_leaves = 3; ci->num_leaves = 3;
} }
} }
void init_hygon_cacheinfo(struct cpuinfo_x86 *c) void init_hygon_cacheinfo(struct cpuinfo_x86 *c)
{ {
num_cache_leaves = find_num_cache_leaves(c); struct cpu_cacheinfo *ci = get_cpu_cacheinfo(c->cpu_index);
ci->num_leaves = find_num_cache_leaves(c);
} }
void init_intel_cacheinfo(struct cpuinfo_x86 *c) void init_intel_cacheinfo(struct cpuinfo_x86 *c)
@ -740,21 +741,21 @@ void init_intel_cacheinfo(struct cpuinfo_x86 *c)
unsigned int new_l1d = 0, new_l1i = 0; /* Cache sizes from cpuid(4) */ unsigned int new_l1d = 0, new_l1i = 0; /* Cache sizes from cpuid(4) */
unsigned int new_l2 = 0, new_l3 = 0, i; /* Cache sizes from cpuid(4) */ unsigned int new_l2 = 0, new_l3 = 0, i; /* Cache sizes from cpuid(4) */
unsigned int l2_id = 0, l3_id = 0, num_threads_sharing, index_msb; unsigned int l2_id = 0, l3_id = 0, num_threads_sharing, index_msb;
struct cpu_cacheinfo *ci = get_cpu_cacheinfo(c->cpu_index);
if (c->cpuid_level > 3) { if (c->cpuid_level > 3) {
static int is_initialized; /*
* There should be at least one leaf. A non-zero value means
if (is_initialized == 0) { * that the number of leaves has been initialized.
/* Init num_cache_leaves from boot CPU */ */
num_cache_leaves = find_num_cache_leaves(c); if (!ci->num_leaves)
is_initialized++; ci->num_leaves = find_num_cache_leaves(c);
}
/* /*
* Whenever possible use cpuid(4), deterministic cache * Whenever possible use cpuid(4), deterministic cache
* parameters cpuid leaf to find the cache details * parameters cpuid leaf to find the cache details
*/ */
for (i = 0; i < num_cache_leaves; i++) { for (i = 0; i < ci->num_leaves; i++) {
struct _cpuid4_info_regs this_leaf = {}; struct _cpuid4_info_regs this_leaf = {};
int retval; int retval;
@ -790,14 +791,14 @@ void init_intel_cacheinfo(struct cpuinfo_x86 *c)
* Don't use cpuid2 if cpuid4 is supported. For P4, we use cpuid2 for * Don't use cpuid2 if cpuid4 is supported. For P4, we use cpuid2 for
* trace cache * trace cache
*/ */
if ((num_cache_leaves == 0 || c->x86 == 15) && c->cpuid_level > 1) { if ((!ci->num_leaves || c->x86 == 15) && c->cpuid_level > 1) {
/* supports eax=2 call */ /* supports eax=2 call */
int j, n; int j, n;
unsigned int regs[4]; unsigned int regs[4];
unsigned char *dp = (unsigned char *)regs; unsigned char *dp = (unsigned char *)regs;
int only_trace = 0; int only_trace = 0;
if (num_cache_leaves != 0 && c->x86 == 15) if (ci->num_leaves && c->x86 == 15)
only_trace = 1; only_trace = 1;
/* Number of times to iterate */ /* Number of times to iterate */
@ -991,14 +992,12 @@ static void ci_leaf_init(struct cacheinfo *this_leaf,
int init_cache_level(unsigned int cpu) int init_cache_level(unsigned int cpu)
{ {
struct cpu_cacheinfo *this_cpu_ci = get_cpu_cacheinfo(cpu); struct cpu_cacheinfo *ci = get_cpu_cacheinfo(cpu);
if (!num_cache_leaves) /* There should be at least one leaf. */
if (!ci->num_leaves)
return -ENOENT; return -ENOENT;
if (!this_cpu_ci)
return -EINVAL;
this_cpu_ci->num_levels = 3;
this_cpu_ci->num_leaves = num_cache_leaves;
return 0; return 0;
} }