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| author |  Xin Li <xin3.li@intel.com>
| 2023-12-05 02:50:14 -0800 |
|---|---|---|
| committer |  Borislav Petkov (AMD) <bp@alien8.de>
| 2024-01-31 22:02:25 +0100 |
| commit | ffa4901f0e004e1a0a4e18a2452a1fcc27277cc0 (patch) | |
| tree | 60e6d412a80c6bdc2b656fb6c9954573addc75a2 /arch | |
| parent | x86/fred: Add a NMI entry stub for FRED (diff) | |
| download | linux-ffa4901f0e004e1a0a4e18a2452a1fcc27277cc0.tar.gz linux-ffa4901f0e004e1a0a4e18a2452a1fcc27277cc0.tar.bz2 linux-ffa4901f0e004e1a0a4e18a2452a1fcc27277cc0.zip | |
x86/fred: Add a machine check entry stub for FRED
Like #DB, when occurred on different ring level, i.e., from user or kernel
context, #MCE needs to be handled on different stack: User #MCE on current
task stack, while kernel #MCE on a dedicated stack.
This is exactly how FRED event delivery invokes an exception handler: ring
3 event on level 0 stack, i.e., current task stack; ring 0 event on the
the FRED machine check entry stub doesn't do stack switch.
Signed-off-by: Xin Li <xin3.li@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Tested-by: Shan Kang <shan.kang@intel.com>
Link: https://lore.kernel.org/r/20231205105030.8698-26-xin3.li@intel.com
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/kernel/cpu/mce/core.c | 26 |
1 files changed, 26 insertions, 0 deletions
diff --git a/arch/x86/kernel/cpu/mce/core.c b/arch/x86/kernel/cpu/mce/core.c index bc39252bc54f..04acdc3534c8 100644 --- a/arch/x86/kernel/cpu/mce/core.c +++ b/arch/x86/kernel/cpu/mce/core.c @@ -46,6 +46,7 @@ #include <linux/hardirq.h> #include <linux/kexec.h> +#include <asm/fred.h> #include <asm/intel-family.h> #include <asm/processor.h> #include <asm/traps.h> @@ -2166,6 +2167,31 @@ DEFINE_IDTENTRY_MCE_USER(exc_machine_check) exc_machine_check_user(regs); local_db_restore(dr7); } + +#ifdef CONFIG_X86_FRED +/* + * When occurred on different ring level, i.e., from user or kernel + * context, #MCE needs to be handled on different stack: User #MCE + * on current task stack, while kernel #MCE on a dedicated stack. + * + * This is exactly how FRED event delivery invokes an exception + * handler: ring 3 event on level 0 stack, i.e., current task stack; + * ring 0 event on the #MCE dedicated stack specified in the + * IA32_FRED_STKLVLS MSR. So unlike IDT, the FRED machine check entry + * stub doesn't do stack switch. + */ +DEFINE_FREDENTRY_MCE(exc_machine_check) +{ + unsigned long dr7; + + dr7 = local_db_save(); + if (user_mode(regs)) + exc_machine_check_user(regs); + else + exc_machine_check_kernel(regs); + local_db_restore(dr7); +} +#endif #else /* 32bit unified entry point */ DEFINE_IDTENTRY_RAW(exc_machine_check) |