From 408eb7417a92c5354c7be34f7425b305dfe30ad9 Mon Sep 17 00:00:00 2001 From: Ravi Bangoria Date: Thu, 8 Aug 2024 06:29:35 +0000 Subject: [PATCH] x86/bus_lock: Add support for AMD Add Bus Lock Detect (called Bus Lock Trap in AMD docs) support for AMD platforms. Bus Lock Detect is enumerated with CPUID Fn0000_0007_ECX_x0 bit [24 / BUSLOCKTRAP]. It can be enabled through MSR_IA32_DEBUGCTLMSR. When enabled, hardware clears DR6[11] and raises a #DB exception on occurrence of Bus Lock if CPL > 0. More detail about the feature can be found in AMD APM[1]. [1]: AMD64 Architecture Programmer's Manual Pub. 40332, Rev. 4.07 - June 2023, Vol 2, 13.1.3.6 Bus Lock Trap https://bugzilla.kernel.org/attachment.cgi?id=304653 Signed-off-by: Ravi Bangoria Signed-off-by: Thomas Gleixner Reviewed-by: Tom Lendacky Link: https://lore.kernel.org/all/20240808062937.1149-3-ravi.bangoria@amd.com --- Documentation/arch/x86/buslock.rst | 3 ++- arch/x86/Kconfig | 2 +- arch/x86/kernel/cpu/common.c | 2 ++ arch/x86/kernel/cpu/intel.c | 1 - 4 files changed, 5 insertions(+), 3 deletions(-) diff --git a/Documentation/arch/x86/buslock.rst b/Documentation/arch/x86/buslock.rst index 4c5a4822eeb7..31f1bfdff16f 100644 --- a/Documentation/arch/x86/buslock.rst +++ b/Documentation/arch/x86/buslock.rst @@ -26,7 +26,8 @@ Detection ========= Intel processors may support either or both of the following hardware -mechanisms to detect split locks and bus locks. +mechanisms to detect split locks and bus locks. Some AMD processors also +support bus lock detect. #AC exception for split lock detection -------------------------------------- diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 9c4e69a1ae7a..e3d53fc7419a 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -2428,7 +2428,7 @@ source "kernel/livepatch/Kconfig" config X86_BUS_LOCK_DETECT bool "Split Lock Detect and Bus Lock Detect support" - depends on CPU_SUP_INTEL + depends on CPU_SUP_INTEL || CPU_SUP_AMD default y help Enable Split Lock Detect and Bus Lock Detect functionalities. diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c index d4e539d4e158..a37670e1ab4d 100644 --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -1832,6 +1832,8 @@ static void identify_cpu(struct cpuinfo_x86 *c) if (this_cpu->c_init) this_cpu->c_init(c); + bus_lock_init(); + /* Disable the PN if appropriate */ squash_the_stupid_serial_number(c); diff --git a/arch/x86/kernel/cpu/intel.c b/arch/x86/kernel/cpu/intel.c index 8a483f4ad026..799f18545c6e 100644 --- a/arch/x86/kernel/cpu/intel.c +++ b/arch/x86/kernel/cpu/intel.c @@ -610,7 +610,6 @@ static void init_intel(struct cpuinfo_x86 *c) init_intel_misc_features(c); split_lock_init(); - bus_lock_init(); intel_init_thermal(c); }