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authorLinus Torvalds <torvalds@linux-foundation.org>2022-09-27 00:53:38 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2022-09-27 00:53:38 +0300
commita1375562c0a87f0fa2eaf3e8ce15824696d4170a (patch)
treec56e40167a7531d26d19433566533b7510a6f9ba /drivers/acpi
parent3800a713b6070d4f03fb43613a7b7d536a99b2b7 (diff)
parente400ad8b7e6a1b9102123c6240289a811501f7d9 (diff)
downloadlinux-a1375562c0a87f0fa2eaf3e8ce15824696d4170a.tar.xz
Merge tag 'x86_urgent_for_v6.0-rc8' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 fixes from Dave Hansen: - A performance fix for recent large AMD systems that avoids an ancient cpu idle hardware workaround - A new Intel model number. Folks like these upstream as soon as possible so that each developer doing feature development doesn't need to carry their own #define - SGX fixes for a userspace crash and a rare kernel warning * tag 'x86_urgent_for_v6.0-rc8' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: ACPI: processor idle: Practically limit "Dummy wait" workaround to old Intel systems x86/sgx: Handle VA page allocation failure for EAUG on PF. x86/sgx: Do not fail on incomplete sanitization on premature stop of ksgxd x86/cpu: Add CPU model numbers for Meteor Lake
Diffstat (limited to 'drivers/acpi')
-rw-r--r--drivers/acpi/processor_idle.c23
1 files changed, 20 insertions, 3 deletions
diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c
index 16a1663d02d4..9f40917c49ef 100644
--- a/drivers/acpi/processor_idle.c
+++ b/drivers/acpi/processor_idle.c
@@ -531,10 +531,27 @@ static void wait_for_freeze(void)
/* No delay is needed if we are in guest */
if (boot_cpu_has(X86_FEATURE_HYPERVISOR))
return;
+ /*
+ * Modern (>=Nehalem) Intel systems use ACPI via intel_idle,
+ * not this code. Assume that any Intel systems using this
+ * are ancient and may need the dummy wait. This also assumes
+ * that the motivating chipset issue was Intel-only.
+ */
+ if (boot_cpu_data.x86_vendor != X86_VENDOR_INTEL)
+ return;
#endif
- /* Dummy wait op - must do something useless after P_LVL2 read
- because chipsets cannot guarantee that STPCLK# signal
- gets asserted in time to freeze execution properly. */
+ /*
+ * Dummy wait op - must do something useless after P_LVL2 read
+ * because chipsets cannot guarantee that STPCLK# signal gets
+ * asserted in time to freeze execution properly
+ *
+ * This workaround has been in place since the original ACPI
+ * implementation was merged, circa 2002.
+ *
+ * If a profile is pointing to this instruction, please first
+ * consider moving your system to a more modern idle
+ * mechanism.
+ */
inl(acpi_gbl_FADT.xpm_timer_block.address);
}