Add a build option and a command line parameter to build and enable the support of pseudo-NMIs.
Signed-off-by: Julien Thierry <[email protected]> Suggested-by: Daniel Thompson <[email protected]> Cc: Catalin Marinas <[email protected]> Cc: Will Deacon <[email protected]> --- 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 b799bcf..173e2cc 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -1197,6 +1197,12 @@ 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 a4168d3..8d84bfd 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -1328,6 +1328,20 @@ config ARM64_MODULE_PLTS bool select HAVE_MOD_ARCH_SPECIFIC +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 + config RELOCATABLE bool help diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c index 71c8d4f..9df1217 100644 --- a/arch/arm64/kernel/cpufeature.c +++ b/arch/arm64/kernel/cpufeature.c @@ -1202,10 +1202,19 @@ static void cpu_enable_address_auth(struct arm64_cpu_capabilities const *cap) #endif /* CONFIG_ARM64_PTR_AUTH */ #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
