[PATCH 8/9] x86/hreset: Configure history reset

Ricardo Neri
2024-02-03T04:04:09Z

Configure the MSR that controls the behavior of HRESET on each logical
processor.

Cc: Len Brown <len.brown@intel.com>
Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Cc: Stanislaw Gruszka <stanislaw.gruszka@linux.intel.com>
Cc: Zhao Liu <zhao1.liu@linux.intel.com>
Cc: Zhuocheng Ding <zhuocheng.ding@intel.com>
Cc: x86@kernel.org
Cc: linux-pm@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com>
---
Patch cherry-picked from the IPC classes patchset
---
---
arch/x86/kernel/cpu/common.c | 23 ++++++++++++++++++++++-
1 file changed, 22 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index 0b97bcde70c6..bce8719b47c9 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -381,6 +381,26 @@ static __always_inline void setup_umip(struct cpuinfo_x86 *c)
cr4_clear_bits(X86_CR4_UMIP);
}

+static u32 hardware_history_features __ro_after_init;
+
+static __always_inline void setup_hreset(struct cpuinfo_x86 *c)
+{
+ if (!cpu_feature_enabled(X86_FEATURE_HRESET))
+ return;
+
+ /*
+ * Use on all CPUs the hardware history features that the boot
+ * CPU supports.
+ */
+ if (c == &boot_cpu_data)
+ hardware_history_features = cpuid_ebx(0x20);
+
+ if (!hardware_history_features)
+ return;
+
+ wrmsrl(MSR_IA32_HW_HRESET_ENABLE, hardware_history_features);
+}
+
/* These bits should not change their value after CPU init is finished. */
static const unsigned long cr4_pinned_mask =
X86_CR4_SMEP | X86_CR4_SMAP | X86_CR4_UMIP |
@@ -1872,10 +1892,11 @@ static void identify_cpu(struct cpuinfo_x86 *c)
/* Disable the PN if appropriate */
squash_the_stupid_serial_number(c);

- /* Set up SMEP/SMAP/UMIP */
+ /* Set up SMEP/SMAP/UMIP/HRESET */
setup_smep(c);
setup_smap(c);
setup_umip(c);
+ setup_hreset(c);

/* Enable FSGSBASE instructions if available. */
if (cpu_has(c, X86_FEATURE_FSGSBASE)) {
--
2.25.1