[PATCH v6 24/24] arm64: Enable the support of pseudo-NMIs
From: Julien Thierry <hidden>
Date: 2018-11-12 11:58:23
Also in:
lkml
Subsystem:
arm64 port (aarch64 architecture), documentation, the rest · Maintainers:
Catalin Marinas, Will Deacon, Jonathan Corbet, Linus Torvalds
Add a build option and a command line parameter to build and enable the support of pseudo-NMIs. Signed-off-by: Julien Thierry <redacted> Suggested-by: Daniel Thompson <redacted> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <redacted> --- Documentation/admin-guide/kernel-parameters.txt | 6 ++++++ arch/arm64/Kconfig | 14 ++++++++++++++ arch/arm64/kernel/cpufeature.c | 11 ++++++++++- 3 files changed, 30 insertions(+), 1 deletion(-)
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 81d1d5a..63dbd56 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt@@ -1183,6 +1183,12 @@ to discrete, to make X server driver able to add WB entry later. This parameter enables that. + enable_pseudo_nmi [ARM64] + Enables support for pseudo-NMIs in the kernel. This + requires both the kernel to be built with + CONFIG_ARM64_PSEUDO_NMI and to be running on a + platform with GICv3. + enable_timer_pin_1 [X86] Enable PIN 1 of APIC timer Can be useful to work around chipset bugs
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 787d785..4729cf0 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig@@ -958,6 +958,20 @@ config ARM64_SSBD If unsure, say Y. +config ARM64_PSEUDO_NMI + bool "Support for NMI-like interrupts" + select CONFIG_ARM_GIC_V3 + help + Adds support for mimicking Non-Maskable Interrupts through the use of + GIC interrupt priority. This support requires version 3 or later of + Arm GIC. + + This high priority configuration for interrupts need to be + explicitly enabled through the new kernel parameter + "enable_pseudo_nmi". + + If unsure, say N + menuconfig ARMV8_DEPRECATED bool "Emulate deprecated/obsolete ARMv8 instructions" depends on COMPAT
diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index 58a4978..acf1d06 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c@@ -1149,10 +1149,19 @@ static void cpu_clear_disr(const struct arm64_cpu_capabilities *__unused) #endif /* CONFIG_ARM64_RAS_EXTN */ #ifdef CONFIG_ARM64_PSEUDO_NMI +static bool enable_pseudo_nmi; + +static int __init early_enable_pseudo_nmi(char *p) +{ + enable_pseudo_nmi = true; + return 0; +} +early_param("enable_pseudo_nmi", early_enable_pseudo_nmi); + static bool can_use_gic_priorities(const struct arm64_cpu_capabilities *entry, int scope) { - return false; + return enable_pseudo_nmi && has_useable_gicv3_cpuif(entry, scope); } #endif
--
1.9.1