[coreboot-gerrit] Change in coreboot[master]: soc/intel/common/block/acpi: Fix get_cores_per_package

[Tim Wawrzynczak (Code Review)]

Tim Wawrzynczak has submitted this change. ( https://review.coreboot.org/c/coreboot/+/48691 )

Change subject: soc/intel/common/block/acpi: Fix get_cores_per_package
......................................................................

soc/intel/common/block/acpi: Fix get_cores_per_package

Current implementation uses CPUID 0Bh function that returns the number
of logical cores of requested level. The problem with this approach is
that this value doesn't change when HyperThreading is disabled (it's in
the Intel docs), so it breaks generate_cpu_entries() because `numcpus`
ends up being zero due to integer division truncation.

- Use MSR 0x35 instead, which returns the correct number of logical
  processors with and without HT.

- Use cpu_read_topology() to gather the required information

Tested on Prodrive Hermes, the ACPI code is now generated even with
HyperThreading disabled.

Change-Id: Id9b985a07cd3f99a823622f766c80ff240ac1188
Signed-off-by: Patrick Rudolph 
Reviewed-on: https://review.coreboot.org/c/coreboot/+/48691
Tested-by: build bot (Jenkins) 
Reviewed-by: Angel Pons 
---
M src/soc/intel/common/block/acpi/acpi.c
1 file changed, 13 insertions(+), 26 deletions(-)

Approvals:
  build bot (Jenkins): Verified
  Angel Pons: Looks good to me, approved

diff --git a/src/soc/intel/common/block/acpi/acpi.c b/src/soc/intel/common/block/acpi/acpi.c
index 934a92f7..e3e72fd 100644
--- a/src/soc/intel/common/block/acpi/acpi.c
+++ b/src/soc/intel/common/block/acpi/acpi.c
@@ -14,7 +14,6 @@
 #include <cpu/x86/smm.h>
 #include <intelblocks/acpi.h>
 #include <intelblocks/lpc_lib.h>
-#include <intelblocks/msr.h>
 #include <intelblocks/pmclib.h>
 #include <intelblocks/uart.h>
 #include <soc/gpio.h>
@@ -284,22 +283,6 @@
    return power;
 }

-static int get_cores_per_package(void)
-{
-	struct cpuinfo_x86 c;
-	struct cpuid_result result;
-	int cores = 1;
-
-	get_fms(&c, cpuid_eax(1));
-	if (c.x86 != 6)
-		return 1;
-
-	result = cpuid_ext(0xb, 1);
-	cores = result.ebx & 0xff;
-
-	return cores;
-}
-
 static void generate_c_state_entries(void)
 {
    acpi_cstate_t *c_state_map;
@@ -450,21 +433,25 @@
    int core_id, cpu_id, pcontrol_blk = ACPI_BASE_ADDRESS;
    int plen = 6;
    int totalcores = dev_count_cpu();
-	int cores_per_package = get_cores_per_package();
-	int numcpus = totalcores / cores_per_package;
+	unsigned int num_virt;
+	unsigned int num_phys;

-	printk(BIOS_DEBUG, "Found %d CPU(s) with %d core(s) each.\n",
-	       numcpus, cores_per_package);
+	cpu_read_topology(&num_phys, &num_virt);
+
+	int numcpus = totalcores / num_virt;
+
+	printk(BIOS_DEBUG, "Found %d CPU(s) with %d/%d physical/logical core(s) each.\n",
+	       numcpus, num_phys, num_virt);

for (cpu_id = 0; cpu_id < numcpus; cpu_id++) {
-		for (core_id = 0; core_id < cores_per_package; core_id++) {
+		for (core_id = 0; core_id < num_virt; core_id++) {
    		if (core_id > 0) {
    			pcontrol_blk = 0;
    			plen = 0;
    		}

/* Generate processor _SB.CPUx */
-			acpigen_write_processor((cpu_id) * cores_per_package +
+			acpigen_write_processor((cpu_id) * num_virt +
    					core_id, pcontrol_blk, plen);

/* Generate C-state tables */
@@ -473,17 +460,17 @@
    		generate_cppc_entries(core_id);

/* Soc specific power states generation */
-			soc_power_states_generation(core_id, cores_per_package);
+			soc_power_states_generation(core_id, num_virt);

acpigen_pop_len();
    	}
    }
    /* PPKG is usually used for thermal management
       of the first and only package. */
-	acpigen_write_processor_package("PPKG", 0, cores_per_package);
+	acpigen_write_processor_package("PPKG", 0, num_virt);

/* Add a method to notify processor nodes */
-	acpigen_write_processor_cnot(cores_per_package);
+	acpigen_write_processor_cnot(num_virt);
 }

#if CONFIG(SOC_INTEL_COMMON_ACPI_WAKE_SOURCE)