From f220125b999b2c9694149c6bda2798d8096f47ed Mon Sep 17 00:00:00 2001 From: "Borislav Petkov (AMD)" Date: Mon, 15 May 2023 16:07:26 +0200 Subject: x86/retbleed: Add __x86_return_thunk alignment checks Add a linker assertion and compute the 0xcc padding dynamically so that __x86_return_thunk is always cacheline-aligned. Leave the SYM_START() macro in as the untraining doesn't need ENDBR annotations anyway. Suggested-by: Andrew Cooper Signed-off-by: Borislav Petkov (AMD) Reviewed-by: Andrew Cooper Link: https://lore.kernel.org/r/20230515140726.28689-1-bp@alien8.de --- arch/x86/kernel/vmlinux.lds.S | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'arch/x86/kernel/vmlinux.lds.S') diff --git a/arch/x86/kernel/vmlinux.lds.S b/arch/x86/kernel/vmlinux.lds.S index 25f155205770..03c885d3640f 100644 --- a/arch/x86/kernel/vmlinux.lds.S +++ b/arch/x86/kernel/vmlinux.lds.S @@ -508,4 +508,8 @@ INIT_PER_CPU(irq_stack_backing_store); "fixed_percpu_data is not at start of per-cpu area"); #endif +#ifdef CONFIG_RETHUNK +. = ASSERT((__x86_return_thunk & 0x3f) == 0, "__x86_return_thunk not cacheline-aligned"); +#endif + #endif /* CONFIG_X86_64 */ -- cgit v1.2.3