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 <ravi.bangoria@xxxxxxx>
Reviewed-by: Tom Lendacky <thomas.lendacky@xxxxxxx>
---
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 db2aad850a8f..d422247b2882 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -2429,7 +2429,7 @@ 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);
}
--
2.34.1
