Commit 4d20f38a authored by James Morse's avatar James Morse Committed by Borislav Petkov (AMD)
Browse files

x86/resctrl: Make prefetch_disable_bits belong to the arch code 



prefetch_disable_bits is set by rdtgroup_locksetup_enter() from a value
provided by the architecture, but is largely read by other architecture
helpers.

Make resctrl_arch_get_prefetch_disable_bits() set prefetch_disable_bits so
that it can be isolated to arch-code from where the other arch-code helpers
can use its cached value.

Signed-off-by: default avatarJames Morse <james.morse@arm.com>
Signed-off-by: default avatarBorislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: default avatarShaopeng Tan <tan.shaopeng@jp.fujitsu.com>
Reviewed-by: default avatarTony Luck <tony.luck@intel.com>
Reviewed-by: default avatarReinette Chatre <reinette.chatre@intel.com>
Reviewed-by: default avatarFenghua Yu <fenghuay@nvidia.com>
Reviewed-by: default avatarBabu Moger <babu.moger@amd.com>
Tested-by: Carl Worth <carl@os.amperecomputing.com> # arm64
Tested-by: default avatarShaopeng Tan <tan.shaopeng@jp.fujitsu.com>
Tested-by: default avatarPeter Newman <peternewman@google.com>
Tested-by: Amit Singh Tomar <amitsinght@marvell.com> # arm64
Tested-by: Shanker Donthineni <sdonthineni@nvidia.com> # arm64
Tested-by: default avatarBabu Moger <babu.moger@amd.com>
Link: https://lore.kernel.org/r/20250311183715.16445-26-james.morse@arm.com
parent 70288405

arch/x86/kernel/cpu/resctrl/pseudo_lock.c

+8 −5
Original line number Diff line number Diff line
@@ -84,6 +84,8 @@ static const struct class pseudo_lock_class = { 
 */

u64 resctrl_arch_get_prefetch_disable_bits(void)

{

	prefetch_disable_bits = 0;



	if (boot_cpu_data.x86_vendor != X86_VENDOR_INTEL ||

	    boot_cpu_data.x86 != 6)

		return 0;
@@ -99,7 +101,8 @@ u64 resctrl_arch_get_prefetch_disable_bits(void) 
		 * 3    DCU IP Prefetcher Disable (R/W)

		 * 63:4 Reserved

		 */

		return 0xF;

		prefetch_disable_bits = 0xF;

		break;

	case INTEL_ATOM_GOLDMONT:

	case INTEL_ATOM_GOLDMONT_PLUS:

		/*
@@ -110,10 +113,11 @@ u64 resctrl_arch_get_prefetch_disable_bits(void) 
		 * 2     DCU Hardware Prefetcher Disable (R/W)

		 * 63:3  Reserved

		 */

		return 0x5;

		prefetch_disable_bits = 0x5;

		break;

	}



	return 0;

	return prefetch_disable_bits;

}



/**
@@ -713,8 +717,7 @@ int rdtgroup_locksetup_enter(struct rdtgroup *rdtgrp) 
	 * Not knowing the bits to disable prefetching implies that this

	 * platform does not support Cache Pseudo-Locking.

	 */

	prefetch_disable_bits = resctrl_arch_get_prefetch_disable_bits();

	if (prefetch_disable_bits == 0) {

	if (resctrl_arch_get_prefetch_disable_bits() == 0) {

		rdt_last_cmd_puts("Pseudo-locking not supported\n");

		return -EINVAL;

	}