From a97756cbec448032f84b5bbfe4e101478d1e01e0 Mon Sep 17 00:00:00 2001 From: "Xin Li (Intel)" Date: Tue, 9 Jul 2024 08:40:48 -0700 Subject: x86/fred: Enable FRED right after init_mem_mapping() On 64-bit init_mem_mapping() relies on the minimal page fault handler provided by the early IDT mechanism. The real page fault handler is installed right afterwards into the IDT. This is problematic on CPUs which have X86_FEATURE_FRED set because the real page fault handler retrieves the faulting address from the FRED exception stack frame and not from CR2, but that does obviously not work when FRED is not yet enabled in the CPU. To prevent this enable FRED right after init_mem_mapping() without interrupt stacks. Those are enabled later in trap_init() after the CPU entry area is set up. [ tglx: Encapsulate the FRED details ] Fixes: 14619d912b65 ("x86/fred: FRED entry/exit and dispatch code") Reported-by: Hou Wenlong Suggested-by: Thomas Gleixner Signed-off-by: Xin Li (Intel) Signed-off-by: Thomas Gleixner Link: https://lore.kernel.org/all/20240709154048.3543361-4-xin@zytor.com --- arch/x86/kernel/setup.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) (limited to 'arch/x86/kernel/setup.c') diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c index 6129dc2ba784..f1fea506e20f 100644 --- a/arch/x86/kernel/setup.c +++ b/arch/x86/kernel/setup.c @@ -1039,7 +1039,12 @@ void __init setup_arch(char **cmdline_p) init_mem_mapping(); - idt_setup_early_pf(); + /* + * init_mem_mapping() relies on the early IDT page fault handling. + * Now either enable FRED or install the real page fault handler + * for 64-bit in the IDT. + */ + cpu_init_replace_early_idt(); /* * Update mmu_cr4_features (and, indirectly, trampoline_cr4_features) -- cgit v1.2.3