From 0d6526f82c3cdefcca47f73f5fc08dc6f335eac6 Mon Sep 17 00:00:00 2001 From: Tim Chen Date: Mon, 21 Sep 2026 17:37:22 -0700 Subject: sched/cache: Keep nr_pref_llc_running in the runnable domain, to fix LLC mis-scheduling bug alb_break_llc() decides whether to break LLC preference during active load balance. It does so by testing that every runnable fair task on the source rq prefers its LLC: env->src_rq->nr_pref_llc_running == env->src_rq->cfs.h_nr_runnable But the two counters cover different sets. nr_pref_llc_running is updated in account_llc_enqueue()/account_llc_dequeue(), next to cfs_rq->nr_queued, so it follows queued tasks. h_nr_runnable is updated in set_delayed()/ clear_delayed() and drops delay-dequeued tasks. So under DELAY_DEQUEUE, a preferring task that goes to sleep stays counted in nr_pref_llc_running while h_nr_runnable falls. The equality then breaks, alb_break_llc() returns false, and active balance is free to pull a task off its preferred LLC. Active balance only moves runnable tasks, and this is the only LLC check it consults: once the stopper runs, LBF_ACTIVE_LB skips the per-task test in can_migrate_task(). The runnable set is the one we want. Fix it on the counter side. A task should be counted in nr_pref_llc_running exactly while it is both queued on its preferred LLC (pref_llc_queued) and runnable (!sched_delayed). Define that membership once in task_pref_llc_runnable(), and adjust the counter only through pref_llc_running_inc()/pref_llc_running_dec() from the four sites that change either input: account_llc_enqueue(), account_llc_dequeue(), set_delayed() and clear_delayed(). Gating every update on the same predicate keeps the delay, wake and dequeue paths from double-counting or underflowing; see the comments at those sites for the ordering. nr_llc_running and sd->llc_counts are not touched and stay on queued semantics. Fixes: 714059f79ff0 ("sched/cache: Handle moving single tasks to/from their preferred LLC") Closes: https://lore.kernel.org/lkml/20260827135000.735138-1-zhanxusheng@xiaomi.com/ Reported-by: Zhan Xusheng Suggested-by: Chen Yu Signed-off-by: Tim Chen Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Ingo Molnar Reviewed-by: Kayra Cizmeci Cc: # v7.2.x Link: https://patch.msgid.link/06af61afedac32e6477f57feb4d658f6c411c3af.1790035273.git.tim.c.chen@linux.intel.com --- drivers/firmware/qcom/Kconfig | 97 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 97 insertions(+) create mode 100644 drivers/firmware/qcom/Kconfig (limited to 'drivers/firmware/qcom/Kconfig') diff --git a/drivers/firmware/qcom/Kconfig b/drivers/firmware/qcom/Kconfig new file mode 100644 index 000000000..c7f8413ab --- /dev/null +++ b/drivers/firmware/qcom/Kconfig @@ -0,0 +1,97 @@ +# SPDX-License-Identifier: GPL-2.0-only +# +# For a description of the syntax of this configuration file, +# see Documentation/kbuild/kconfig-language.rst. +# + +menu "Qualcomm firmware drivers" + +config QCOM_PAS + tristate "Qualcomm generic PAS interface driver" + help + Enable the generic Peripheral Authentication Service (PAS) provided + by the firmware. It acts as the common layer with different TZ + backends plugged in whether it's an SCM implementation or a proper + TEE bus based PAS service implementation. + +config QCOM_PAS_TEE + tristate "Qualcomm PAS TEE interface driver" + select QCOM_PAS + depends on TEE + depends on !CPU_BIG_ENDIAN + default m if ARCH_QCOM + help + Enable the generic Peripheral Authentication Service (PAS) provided + by the firmware TEE implementation as the backend. + +config QCOM_SCM + tristate "Qualcomm PAS SCM interface driver" + select QCOM_PAS + select QCOM_TZMEM + default y if ARCH_QCOM + +config QCOM_TZMEM + tristate + select GENERIC_ALLOCATOR + +choice + prompt "TrustZone interface memory allocator mode" + depends on QCOM_TZMEM + default QCOM_TZMEM_MODE_GENERIC + help + Selects the mode of the memory allocator providing memory buffers of + suitable format for sharing with the TrustZone. If in doubt, select + 'Generic'. + +config QCOM_TZMEM_MODE_GENERIC + bool "Generic" + help + Use the generic allocator mode. The memory is page-aligned, non-cachable + and physically contiguous. + +config QCOM_TZMEM_MODE_SHMBRIDGE + bool "SHM Bridge" + help + Use Qualcomm Shared Memory Bridge. The memory has the same alignment as + in the 'Generic' allocator but is also explicitly marked as an SHM Bridge + buffer. + + With this selected, all buffers passed to the TrustZone must be allocated + using the TZMem allocator or else the TrustZone will refuse to use them. + +endchoice + +config QCOM_QSEECOM + bool "Qualcomm QSEECOM interface driver" + depends on QCOM_SCM=y + select AUXILIARY_BUS + help + Various Qualcomm SoCs have a Secure Execution Environment (SEE) running + in the Trust Zone. This module provides an interface to that via the + QSEECOM mechanism, using SCM calls. + + The QSEECOM interface allows, among other things, access to applications + running in the SEE. An example of such an application is 'uefisecapp', + which is required to access UEFI variables on certain systems. If + selected, the interface will also attempt to detect and register client + devices for supported applications. + + Select Y here to enable the QSEECOM interface driver. + +config QCOM_QSEECOM_UEFISECAPP + bool "Qualcomm SEE UEFI Secure App client driver" + depends on QCOM_QSEECOM + depends on EFI + help + Various Qualcomm SoCs do not allow direct access to EFI variables. + Instead, these need to be accessed via the UEFI Secure Application + (uefisecapp), residing in the Secure Execution Environment (SEE). + + This module provides a client driver for uefisecapp, installing efivar + operations to allow the kernel accessing EFI variables, and via that also + provide user-space with access to EFI variables via efivarfs. + + Select Y here to provide access to EFI variables on the aforementioned + platforms. + +endmenu -- cgit v1.3.1