diff options
Diffstat (limited to 'arch/x86/kernel/process.c')
| -rw-r--r-- | arch/x86/kernel/process.c | 26 |
1 files changed, 12 insertions, 14 deletions
diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c index 1b7960cf6eb0..4c718f8adc59 100644 --- a/arch/x86/kernel/process.c +++ b/arch/x86/kernel/process.c @@ -89,6 +89,16 @@ DEFINE_PER_CPU(bool, __tss_limit_invalid); EXPORT_PER_CPU_SYMBOL_GPL(__tss_limit_invalid); /* + * The cache may be in an incoherent state and needs flushing during kexec. + * E.g., on SME/TDX platforms, dirty cacheline aliases with and without + * encryption bit(s) can coexist and the cache needs to be flushed before + * booting to the new kernel to avoid the silent memory corruption due to + * dirty cachelines with different encryption property being written back + * to the memory. + */ +DEFINE_PER_CPU(bool, cache_state_incoherent); + +/* * this gets called so that we can store lazy state into memory and copy the * current task into the new thread. */ @@ -159,7 +169,7 @@ __visible void ret_from_fork(struct task_struct *prev, struct pt_regs *regs, int copy_thread(struct task_struct *p, const struct kernel_clone_args *args) { - unsigned long clone_flags = args->flags; + u64 clone_flags = args->flags; unsigned long sp = args->stack; unsigned long tls = args->tls; struct inactive_task_frame *frame; @@ -827,19 +837,7 @@ void __noreturn stop_this_cpu(void *dummy) disable_local_APIC(); mcheck_cpu_clear(c); - /* - * Use wbinvd on processors that support SME. This provides support - * for performing a successful kexec when going from SME inactive - * to SME active (or vice-versa). The cache must be cleared so that - * if there are entries with the same physical address, both with and - * without the encryption bit, they don't race each other when flushed - * and potentially end up with the wrong entry being committed to - * memory. - * - * Test the CPUID bit directly because the machine might've cleared - * X86_FEATURE_SME due to cmdline options. - */ - if (c->extended_cpuid_level >= 0x8000001f && (cpuid_eax(0x8000001f) & BIT(0))) + if (this_cpu_read(cache_state_incoherent)) wbinvd(); /* |