linux-kernel - [PATCH 4/5] x86/ftrace: Remove SYSTEM

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Message-ID: <20221025201057.945960823@infradead.org>
Date:   Tue, 25 Oct 2022 22:07:00 +0200
From:   Peter Zijlstra <peterz@...radead.org>
To:     torvalds@...ux-foundation.org, rostedt@...dmis.org,
        dave.hansen@...el.com
Cc:     linux-kernel@...r.kernel.org, peterz@...radead.org, x86@...nel.org,
        keescook@...omium.org, seanjc@...gle.com
Subject: [PATCH 4/5] x86/ftrace: Remove SYSTEM_BOOTING exceptions

Now that text_poke is available before ftrace, remove the
SYSTEM_BOOTING exceptions.

Specifically, this cures a W+X case during boot.

Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
---
 arch/x86/kernel/alternative.c |   10 ----------
 arch/x86/kernel/ftrace.c      |    3 +--
 2 files changed, 1 insertion(+), 12 deletions(-)

--- a/arch/x86/kernel/alternative.c
+++ b/arch/x86/kernel/alternative.c
@@ -1681,11 +1681,6 @@ void __ref text_poke_queue(void *addr, c
 {
 	struct text_poke_loc *tp;
 
-	if (unlikely(system_state == SYSTEM_BOOTING)) {
-		text_poke_early(addr, opcode, len);
-		return;
-	}
-
 	text_poke_flush(addr);
 
 	tp = &tp_vec[tp_vec_nr++];
@@ -1707,11 +1702,6 @@ void __ref text_poke_bp(void *addr, cons
 {
 	struct text_poke_loc tp;
 
-	if (unlikely(system_state == SYSTEM_BOOTING)) {
-		text_poke_early(addr, opcode, len);
-		return;
-	}
-
 	text_poke_loc_init(&tp, addr, opcode, len, emulate);
 	text_poke_bp_batch(&tp, 1);
 }
--- a/arch/x86/kernel/ftrace.c
+++ b/arch/x86/kernel/ftrace.c
@@ -415,8 +415,7 @@ create_trampoline(struct ftrace_ops *ops
 
 	set_vm_flush_reset_perms(trampoline);
 
-	if (likely(system_state != SYSTEM_BOOTING))
-		set_memory_ro((unsigned long)trampoline, npages);
+	set_memory_ro((unsigned long)trampoline, npages);
 	set_memory_x((unsigned long)trampoline, npages);
 	return (unsigned long)trampoline;
 fail: