diff options
| author | Pawan Gupta <pawan.kumar.gupta@linux.intel.com> | 2024-10-25 12:14:58 -0500 |
|---|---|---|
| committer | Borislav Petkov (AMD) <bp@alien8.de> | 2024-10-25 20:44:26 +0200 |
| commit | 45239ba39a5279e9efc671774e2eef29df4d2484 (patch) | |
| tree | 1dca9e92e9d1566d0d76d960a5df4e36137ac1c7 /arch/x86/include/asm/topology.h | |
| parent | b0979e53645825a38f814ca5d3d09aed2745911d (diff) | |
x86/cpu: Add CPU type to struct cpuinfo_topology
Sometimes it is required to take actions based on if a CPU is a performance or
efficiency core. As an example, intel_pstate driver uses the Intel core-type
to determine CPU scaling. Also, some CPU vulnerabilities only affect
a specific CPU type, like RFDS only affects Intel Atom. Hybrid systems that
have variants P+E, P-only(Core) and E-only(Atom), it is not straightforward to
identify which variant is affected by a type specific vulnerability.
Such processors do have CPUID field that can uniquely identify them. Like,
P+E, P-only and E-only enumerates CPUID.1A.CORE_TYPE identification, while P+E
additionally enumerates CPUID.7.HYBRID. Based on this information, it is
possible for boot CPU to identify if a system has mixed CPU types.
Add a new field hw_cpu_type to struct cpuinfo_topology that stores the
hardware specific CPU type. This saves the overhead of IPIs to get the CPU
type of a different CPU. CPU type is populated early in the boot process,
before vulnerabilities are enumerated.
Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Co-developed-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Acked-by: Dave Hansen <dave.hansen@linux.intel.com>
Link: https://lore.kernel.org/r/20241025171459.1093-5-mario.limonciello@amd.com
Diffstat (limited to 'arch/x86/include/asm/topology.h')
| -rw-r--r-- | arch/x86/include/asm/topology.h | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/arch/x86/include/asm/topology.h b/arch/x86/include/asm/topology.h index aef70336d624..9f9376db64e3 100644 --- a/arch/x86/include/asm/topology.h +++ b/arch/x86/include/asm/topology.h @@ -114,6 +114,12 @@ enum x86_topology_domains { TOPO_MAX_DOMAIN, }; +enum x86_topology_cpu_type { + TOPO_CPU_TYPE_PERFORMANCE, + TOPO_CPU_TYPE_EFFICIENCY, + TOPO_CPU_TYPE_UNKNOWN, +}; + struct x86_topology_system { unsigned int dom_shifts[TOPO_MAX_DOMAIN]; unsigned int dom_size[TOPO_MAX_DOMAIN]; @@ -149,6 +155,9 @@ extern unsigned int __max_threads_per_core; extern unsigned int __num_threads_per_package; extern unsigned int __num_cores_per_package; +const char *get_topology_cpu_type_name(struct cpuinfo_x86 *c); +enum x86_topology_cpu_type get_topology_cpu_type(struct cpuinfo_x86 *c); + static inline unsigned int topology_max_packages(void) { return __max_logical_packages; |