From 1fac13956e9877483ece9d090a62239cdfe9deb7 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Wed, 9 Apr 2025 21:16:01 +0200 Subject: [PATCH] x86/ibt: Fix hibernate Todd reported, and Len confirmed, that commit 582077c94052 ("x86/cfi: Clean up linkage") broke S4 hiberate on a fair number of machines. Turns out these machines trip #CP when trying to restore the image. As it happens, the commit in question removes two ENDBR instructions in the hibernate code, and clearly got it wrong. Notably restore_image() does an indirect jump to relocated_restore_code(), which is a relocated copy of core_restore_code(). In turn, core_restore_code(), will at the end do an indirect jump to restore_jump_address (r8), which is pointing at a relocated restore_registers(). So both sites do indeed need to be ENDBR. Fixes: 582077c94052 ("x86/cfi: Clean up linkage") Reported-by: Todd Brandt Signed-off-by: Peter Zijlstra (Intel) Tested-by: Todd Brandt Tested-by: Len Brown Link: https://bugzilla.kernel.org/show_bug.cgi?id=219998 Closes: https://bugzilla.kernel.org/show_bug.cgi?id=219998 --- arch/x86/power/hibernate_asm_64.S | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/x86/power/hibernate_asm_64.S b/arch/x86/power/hibernate_asm_64.S index 8c534c36adfa2..66f066b8fedad 100644 --- a/arch/x86/power/hibernate_asm_64.S +++ b/arch/x86/power/hibernate_asm_64.S @@ -26,7 +26,7 @@ /* code below belongs to the image kernel */ .align PAGE_SIZE SYM_FUNC_START(restore_registers) - ANNOTATE_NOENDBR + ENDBR /* go back to the original page tables */ movq %r9, %cr3 @@ -120,7 +120,7 @@ SYM_FUNC_END(restore_image) /* code below has been relocated to a safe page */ SYM_FUNC_START(core_restore_code) - ANNOTATE_NOENDBR + ENDBR /* switch to temporary page tables */ movq %rax, %cr3 /* flush TLB */ -- 2.50.1