From: Borislav Petkov <bp@suse.de>
Date: Wed, 13 Oct 2021 07:07:19 +0000 (+0200)
Subject: x86/mce: Allow instrumentation during task work queueing
X-Git-Tag: v6.1-rc5~2317^2~12
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=4fbce464db81a42f9a57ee242d6150ec7f996415;p=platform%2Fkernel%2Flinux-starfive.git

x86/mce: Allow instrumentation during task work queueing

Fixes

  vmlinux.o: warning: objtool: do_machine_check()+0xdb1: call to queue_task_work() leaves .noinstr.text section

Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20211208111343.8130-6-bp@alien8.de
---

diff --git a/arch/x86/kernel/cpu/mce/core.c b/arch/x86/kernel/cpu/mce/core.c
index c11fc8d..d788ccc 100644
--- a/arch/x86/kernel/cpu/mce/core.c
+++ b/arch/x86/kernel/cpu/mce/core.c
@@ -1459,6 +1459,14 @@ noinstr void do_machine_check(struct pt_regs *regs)
 	if (worst != MCE_AR_SEVERITY && !kill_current_task)
 		goto out;
 
+	/*
+	 * Enable instrumentation around the external facilities like
+	 * task_work_add() (via queue_task_work()), fixup_exception() etc.
+	 * For now, that is. Fixing this properly would need a lot more involved
+	 * reorganization.
+	 */
+	instrumentation_begin();
+
 	/* Fault was in user mode and we need to take some action */
 	if ((m.cs & 3) == 3) {
 		/* If this triggers there is no way to recover. Die hard. */
@@ -1487,6 +1495,9 @@ noinstr void do_machine_check(struct pt_regs *regs)
 		if (m.kflags & MCE_IN_KERNEL_COPYIN)
 			queue_task_work(&m, msg, kill_me_never);
 	}
+
+	instrumentation_end();
+
 out:
 	mce_wrmsrl(MSR_IA32_MCG_STATUS, 0);
 }