The patch below does not apply to the 5.15-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.15.y git checkout FETCH_HEAD git cherry-pick -x d8df126349dad855cdfedd6bbf315bad2e901c2f # <resolve conflicts, build, test, etc.> git commit -s git send-email --to 'stable@vger.kernel.org' --in-reply-to '2025082517-crazily-renewed-62e6@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^..

Possible dependencies:

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From d8df126349dad855cdfedd6bbf315bad2e901c2f Mon Sep 17 00:00:00 2001 From: Tianxiang Peng txpeng@tencent.com Date: Mon, 23 Jun 2025 17:31:53 +0800 Subject: [PATCH] x86/cpu/hygon: Add missing resctrl_cpu_detect() in bsp_init helper

Since

923f3a2b48bd ("x86/resctrl: Query LLC monitoring properties once during boot")

resctrl_cpu_detect() has been moved from common CPU initialization code to the vendor-specific BSP init helper, while Hygon didn't put that call in their code.

This triggers a division by zero fault during early booting stage on our machines with X86_FEATURE_CQM* supported, where get_rdt_mon_resources() tries to calculate mon_l3_config with uninitialized boot_cpu_data.x86_cache_occ_scale.

Add the missing resctrl_cpu_detect() in the Hygon BSP init helper.

[ bp: Massage commit message. ]

Fixes: 923f3a2b48bd ("x86/resctrl: Query LLC monitoring properties once during boot") Signed-off-by: Tianxiang Peng txpeng@tencent.com Signed-off-by: Borislav Petkov (AMD) bp@alien8.de Reviewed-by: Hui Li caelli@tencent.com Cc: stable@kernel.org Link: https://lore.kernel.org/20250623093153.3016937-1-txpeng@tencent.com

diff --git a/arch/x86/kernel/cpu/hygon.c b/arch/x86/kernel/cpu/hygon.c index 2154f12766fb..1fda6c3a2b65 100644 --- a/arch/x86/kernel/cpu/hygon.c +++ b/arch/x86/kernel/cpu/hygon.c @@ -16,6 +16,7 @@ #include <asm/spec-ctrl.h> #include <asm/delay.h> #include <asm/msr.h> +#include <asm/resctrl.h>

#include "cpu.h"

@@ -117,6 +118,8 @@ static void bsp_init_hygon(struct cpuinfo_x86 *c) x86_amd_ls_cfg_ssbd_mask = 1ULL << 10; } } + + resctrl_cpu_detect(c); }

static void early_init_hygon(struct cpuinfo_x86 *c)