linux-kernel - [PATCH v3] LoongArch: Correct the calculation logic of thread

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Message-Id: <20251127101946.3531069-1-maqianga@uniontech.com>
Date: Thu, 27 Nov 2025 18:19:46 +0800
From: Qiang Ma <maqianga@...ontech.com>
To: chenhuacai@...nel.org,
	kernel@...0n.name,
	hengqi.chen@...il.com
Cc: loongarch@...ts.linux.dev,
	linux-kernel@...r.kernel.org,
	Qiang Ma <maqianga@...ontech.com>
Subject: [PATCH v3] LoongArch: Correct the calculation logic of thread_count

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

Signed-off-by: Qiang Ma <maqianga@...ontech.com>
---
 arch/loongarch/kernel/setup.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/arch/loongarch/kernel/setup.c b/arch/loongarch/kernel/setup.c
index 25a87378e48e..eb6e3ac27436 100644
--- 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 struct dmi_header *dm)
 	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);
 }
-- 
2.20.1