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arm64: cpufeature: Add support for the MPAM v0.1 architecture version

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According to the MPAM spec [1], the supported architecture versions are
v1.0, v1.1 and v0.1. MPAM versions v0.1 and v1.1 are functionally
identical, but v0.1 additionally supports the FORCE_NS feature.

ID_AA64PR | ID_AA64PR | MPAM Extension | Notes
F0_EL1.   | F1_EL1.   | Architecture   |
MPAM      | MPAM_frac | version        |
---------------------------------------------------------------------------
0b0000    | 0b0001    | v0.1           | MPAM v0.1 is implemented.
          |           |                | MPAM v0.1 is the same as MPAM v1.1
          |           |                | with FORCE_NS which is
          |           |                | incompatible with MPAM v1.0.
---------------------------------------------------------------------------
0b0001    | 0b0000    | v1.0           | MPAM v1.0 is implemented.
---------------------------------------------------------------------------
0b0001    | 0b0001    | v1.1           | MPAM v1.1 is implemented.
          |           |                | MPAM v1.1 includes all features of
          |           |                | MPAM v1.0.
          |           |                | It must not include FORCE_NS.

FORCE_NS is a feature that operates in EL3 mode. Consequently, the current
Linux MPAM driver is also compatible with MPAM v0.1. To support v0.1, the
existing driver which only checks ID_AA64PFR0_EL1.MPAM for the major
version needs to examine ID_AA64PFR1_EL1.MPAM_frac for the minor version
as well.

[1] https://developer.arm.com/documentation/ddi0598/db/?lang=en

Signed-off-by: Zeng Heng <zengheng4@huawei.com>
Reviewed-by: James Morse <james.morse@arm.com>
Signed-off-by: James Morse <james.morse@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Will Deacon <will@kernel.org>
This commit is contained in:
Zeng Heng 2026-05-08 17:23:40 +01:00 committed by Will Deacon
parent 254f49634e
commit 5302bc1493
3 changed files with 21 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

7
arch/arm64/include/asm/cpufeature.h
View File

@ -620,6 +620,13 @@ static inline bool id_aa64pfr0_mpam(u64 pfr0)
return val > 0;
}
static inline bool id_aa64pfr1_mpamfrac(u64 pfr1)
{
u32 val = cpuid_feature_extract_unsigned_field(pfr1, ID_AA64PFR1_EL1_MPAM_frac_SHIFT);
return val > 0;
}
static inline bool id_aa64pfr1_mte(u64 pfr1)
{
u32 val = cpuid_feature_extract_unsigned_field(pfr1, ID_AA64PFR1_EL1_MTE_SHIFT);

4
arch/arm64/include/asm/el2_setup.h
View File

@ -510,7 +510,9 @@
#endif
.macro finalise_el2_state
check_override id_aa64pfr0, ID_AA64PFR0_EL1_MPAM_SHIFT, .Linit_mpam_\@, .Lskip_mpam_\@, x1, x2
check_override id_aa64pfr0, ID_AA64PFR0_EL1_MPAM_SHIFT, .Linit_mpam_\@, .Lmpam_minor_\@, x1, x2
.Lmpam_minor_\@:
check_override id_aa64pfr1, ID_AA64PFR1_EL1_MPAM_frac_SHIFT, .Linit_mpam_\@, .Lskip_mpam_\@, x1, x2
.Linit_mpam_\@:
mov x0, #MPAM2_EL2_EnMPAMSM_MASK

15
arch/arm64/kernel/cpufeature.c
View File

@ -1164,6 +1164,14 @@ static __init void detect_system_supports_pseudo_nmi(void)
static inline void detect_system_supports_pseudo_nmi(void) { }
#endif
static bool detect_ftr_has_mpam(void)
{
u64 pfr0 = read_sanitised_ftr_reg(SYS_ID_AA64PFR0_EL1);
u64 pfr1 = read_sanitised_ftr_reg(SYS_ID_AA64PFR1_EL1);
return id_aa64pfr0_mpam(pfr0) || id_aa64pfr1_mpamfrac(pfr1);
}
void __init init_cpu_features(struct cpuinfo_arm64 *info)
{
/* Before we start using the tables, make sure it is sorted */
@ -1211,7 +1219,7 @@ void __init init_cpu_features(struct cpuinfo_arm64 *info)
cpacr_restore(cpacr);
}
if (id_aa64pfr0_mpam(read_sanitised_ftr_reg(SYS_ID_AA64PFR0_EL1))) {
if (detect_ftr_has_mpam()) {
info->reg_mpamidr = read_cpuid(MPAMIDR_EL1);
init_cpu_ftr_reg(SYS_MPAMIDR_EL1, info->reg_mpamidr);
}
@ -1467,7 +1475,7 @@ void update_cpu_features(int cpu,
cpacr_restore(cpacr);
}
if (id_aa64pfr0_mpam(read_sanitised_ftr_reg(SYS_ID_AA64PFR0_EL1))) {
if (detect_ftr_has_mpam()) {
info->reg_mpamidr = read_cpuid(MPAMIDR_EL1);
taint |= check_update_ftr_reg(SYS_MPAMIDR_EL1, cpu,
info->reg_mpamidr, boot->reg_mpamidr);
@ -2486,7 +2494,7 @@ cpucap_panic_on_conflict(const struct arm64_cpu_capabilities *cap)
static bool
test_has_mpam(const struct arm64_cpu_capabilities *entry, int scope)
{
if (!has_cpuid_feature(entry, scope))
if (!detect_ftr_has_mpam())
return false;
/* Check firmware actually enabled MPAM on this cpu. */
@ -3093,7 +3101,6 @@ static const struct arm64_cpu_capabilities arm64_features[] = {
.capability = ARM64_MPAM,
.matches = test_has_mpam,
.cpu_enable = cpu_enable_mpam,
ARM64_CPUID_FIELDS(ID_AA64PFR0_EL1, MPAM, 1)
},
{
.desc = "Memory Partitioning And Monitoring Virtualisation",