diff options
| author | Christian Loehle <christian.loehle@arm.com> | 2026-08-03 22:05:26 +0100 |
|---|---|---|
| committer | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2026-08-05 15:09:45 +0200 |
| commit | 9c5ab33a6d2cfa34a6d64c819503f7bfd837bb78 (patch) | |
| tree | 856947b85c22359987314ab3851436a91b689637 /include | |
| parent | 9d9157ee90e3eed393e92b4032b83ddb8691de64 (diff) | |
ACPI: CPPC: Avoid locking standalone full-width registers
cpc_write() serializes every SystemMemory write with the per-CPU
rmw_lock. The lock is required for read-modify-write fields and for
registers whose access units overlap, but not for a full-width register
in a standalone access unit.
The _CPC layout is immutable after it has been parsed. Classify each
SystemMemory register at probe time and retain locking for partial
fields, invalid access widths, and overlapping access units. Allow
standalone full-width registers to bypass the descriptor lookup and
spinlock.
Store the classification in existing structure padding so that struct
cpc_register_resource does not grow.
Signed-off-by: Christian Loehle <christian.loehle@arm.com>
Link: https://patch.msgid.link/20260803210527.1285229-3-christian.loehle@arm.com
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'include')
| -rw-r--r-- | include/acpi/cppc_acpi.h | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/include/acpi/cppc_acpi.h b/include/acpi/cppc_acpi.h index 8c191b9ac18f..19830146c644 100644 --- a/include/acpi/cppc_acpi.h +++ b/include/acpi/cppc_acpi.h @@ -69,7 +69,10 @@ struct cpc_register_resource { acpi_object_type type; u64 __iomem *sys_mem_vaddr; union { - struct cpc_reg reg; + struct { + struct cpc_reg reg; + bool use_rmw_lock; + }; u64 int_value; } cpc_entry; }; |