cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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resctrl.h (2788B)

      1/* SPDX-License-Identifier: GPL-2.0 */
      2#ifndef _ASM_X86_RESCTRL_H
      3#define _ASM_X86_RESCTRL_H
      4
      5#ifdef CONFIG_X86_CPU_RESCTRL
      6
      7#include <linux/sched.h>
      8#include <linux/jump_label.h>
      9
     10#define IA32_PQR_ASSOC	0x0c8f
     11
     12/**
     13 * struct resctrl_pqr_state - State cache for the PQR MSR
     14 * @cur_rmid:		The cached Resource Monitoring ID
     15 * @cur_closid:	The cached Class Of Service ID
     16 * @default_rmid:	The user assigned Resource Monitoring ID
     17 * @default_closid:	The user assigned cached Class Of Service ID
     18 *
     19 * The upper 32 bits of IA32_PQR_ASSOC contain closid and the
     20 * lower 10 bits rmid. The update to IA32_PQR_ASSOC always
     21 * contains both parts, so we need to cache them. This also
     22 * stores the user configured per cpu CLOSID and RMID.
     23 *
     24 * The cache also helps to avoid pointless updates if the value does
     25 * not change.
     26 */
     27struct resctrl_pqr_state {
     28	u32			cur_rmid;
     29	u32			cur_closid;
     30	u32			default_rmid;
     31	u32			default_closid;
     32};
     33
     34DECLARE_PER_CPU(struct resctrl_pqr_state, pqr_state);
     35
     36DECLARE_STATIC_KEY_FALSE(rdt_enable_key);
     37DECLARE_STATIC_KEY_FALSE(rdt_alloc_enable_key);
     38DECLARE_STATIC_KEY_FALSE(rdt_mon_enable_key);
     39
     40/*
     41 * __resctrl_sched_in() - Writes the task's CLOSid/RMID to IA32_PQR_MSR
     42 *
     43 * Following considerations are made so that this has minimal impact
     44 * on scheduler hot path:
     45 * - This will stay as no-op unless we are running on an Intel SKU
     46 *   which supports resource control or monitoring and we enable by
     47 *   mounting the resctrl file system.
     48 * - Caches the per cpu CLOSid/RMID values and does the MSR write only
     49 *   when a task with a different CLOSid/RMID is scheduled in.
     50 * - We allocate RMIDs/CLOSids globally in order to keep this as
     51 *   simple as possible.
     52 * Must be called with preemption disabled.
     53 */
     54static void __resctrl_sched_in(void)
     55{
     56	struct resctrl_pqr_state *state = this_cpu_ptr(&pqr_state);
     57	u32 closid = state->default_closid;
     58	u32 rmid = state->default_rmid;
     59	u32 tmp;
     60
     61	/*
     62	 * If this task has a closid/rmid assigned, use it.
     63	 * Else use the closid/rmid assigned to this cpu.
     64	 */
     65	if (static_branch_likely(&rdt_alloc_enable_key)) {
     66		tmp = READ_ONCE(current->closid);
     67		if (tmp)
     68			closid = tmp;
     69	}
     70
     71	if (static_branch_likely(&rdt_mon_enable_key)) {
     72		tmp = READ_ONCE(current->rmid);
     73		if (tmp)
     74			rmid = tmp;
     75	}
     76
     77	if (closid != state->cur_closid || rmid != state->cur_rmid) {
     78		state->cur_closid = closid;
     79		state->cur_rmid = rmid;
     80		wrmsr(IA32_PQR_ASSOC, rmid, closid);
     81	}
     82}
     83
     84static inline void resctrl_sched_in(void)
     85{
     86	if (static_branch_likely(&rdt_enable_key))
     87		__resctrl_sched_in();
     88}
     89
     90void resctrl_cpu_detect(struct cpuinfo_x86 *c);
     91
     92#else
     93
     94static inline void resctrl_sched_in(void) {}
     95static inline void resctrl_cpu_detect(struct cpuinfo_x86 *c) {}
     96
     97#endif /* CONFIG_X86_CPU_RESCTRL */
     98
     99#endif /* _ASM_X86_RESCTRL_H */