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From:   "Jiri Slaby (SUSE)" <jirislaby@kernel.org>
To:     linux-kernel@vger.kernel.org
Cc:     Jiri Slaby <jslaby@suse.cz>, Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
        Dave Hansen <dave.hansen@linux.intel.com>,
        "H. Peter Anvin" <hpa@zytor.com>, x86@kernel.org,
        Martin Liska <mliska@suse.cz>
Subject: [PATCH 26/46] x86/apic, lto: Mark apic_driver*() as __noreorder
Date:   Mon, 14 Nov 2022 12:43:24 +0100
Message-Id: <20221114114344.18650-27-jirislaby@kernel.org>
In-Reply-To: <20221114114344.18650-1-jirislaby@kernel.org>
References: <20221114114344.18650-1-jirislaby@kernel.org>
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From: Jiri Slaby <jslaby@suse.cz>

The apic code assumes that the apic drivers are in a particular order in
memory. gcc LTO can violate this. So add __noreorder to apic_driver()
and apic_drivers() to avoid a boot BUG().

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: x86@kernel.org
Cc: Martin Liska <mliska@suse.cz>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
---
 arch/x86/include/asm/apic.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/x86/include/asm/apic.h b/arch/x86/include/asm/apic.h
index 3415321c8240..9c5c69482ab0 100644
--- a/arch/x86/include/asm/apic.h
+++ b/arch/x86/include/asm/apic.h
@@ -363,12 +363,12 @@ extern struct apic *apic;
  * to enforce the order with in them.
  */
 #define apic_driver(sym)					\
-	static const struct apic *__apicdrivers_##sym __used		\
+	static const struct apic *__apicdrivers_##sym __used __noreorder \
 	__aligned(sizeof(struct apic *))			\
 	__section(".apicdrivers") = { &sym }
 
 #define apic_drivers(sym1, sym2)					\
-	static struct apic *__apicdrivers_##sym1##sym2[2] __used	\
+	static struct apic *__apicdrivers_##sym1##sym2[2] __used __noreorder \
 	__aligned(sizeof(struct apic *))				\
 	__section(".apicdrivers") = { &sym1, &sym2 }
 
-- 
2.38.1