[PATCH 6.12 417/567] LoongArch: Correct the calculation logic of thread_count

Greg Kroah-Hartman
2026-01-06T17:37:23Z

From: Qiang Ma <maqianga@uniontech.com>

commit 1de0ae21f136efa6c5d8a4d3e07b7d1ca39c750f upstream.

For thread_count, the current calculation method has a maximum of 255,
which may not be sufficient in the future. Therefore, we are correcting
it now.

Reference: SMBIOS Specification, 7.5 Processor Information (Type 4)[1]

[1]: https://www.dmtf.org/sites/default/files/standards/documents/DSP0134_3.9.0.pdf

Cc: stable@vger.kernel.org
Signed-off-by: Qiang Ma <maqianga@uniontech.com>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
arch/loongarch/kernel/setup.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)

--- a/arch/loongarch/kernel/setup.c
+++ b/arch/loongarch/kernel/setup.c
@@ -56,6 +56,7 @@
#define SMBIOS_FREQLOW_MASK 0xFF
#define SMBIOS_CORE_PACKAGE_OFFSET 0x23
#define SMBIOS_THREAD_PACKAGE_OFFSET 0x25
+#define SMBIOS_THREAD_PACKAGE_2_OFFSET 0x2E
#define LOONGSON_EFI_ENABLE (1 << 3)

unsigned long fw_arg0, fw_arg1, fw_arg2;
@@ -126,7 +127,12 @@ static void __init parse_cpu_table(const
cpu_clock_freq = freq_temp * 1000000;

loongson_sysconf.cpuname = (void *)dmi_string_parse(dm, dmi_data[16]);
- loongson_sysconf.cores_per_package = *(dmi_data + SMBIOS_THREAD_PACKAGE_OFFSET);
+ loongson_sysconf.cores_per_package = *(u8 *)(dmi_data + SMBIOS_THREAD_PACKAGE_OFFSET);
+ if (dm->length >= 0x30 && loongson_sysconf.cores_per_package == 0xff) {
+ /* SMBIOS 3.0+ has ThreadCount2 for more than 255 threads */
+ loongson_sysconf.cores_per_package =
+ *(u16 *)(dmi_data + SMBIOS_THREAD_PACKAGE_2_OFFSET);
+ }

pr_info("CpuClock = %llu\n", cpu_clock_freq);
}