linux-kernel - [PATCH v1] ARM: vfp: Use long jump to fix THUMB2 kernel compilation error

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Message-Id: <20201021225737.739-1-digetx@gmail.com>
Date:   Thu, 22 Oct 2020 01:57:37 +0300
From:   Dmitry Osipenko <digetx@...il.com>
To:     Russell King <linux@...linux.org.uk>,
        Kees Cook <keescook@...omium.org>,
        Nick Desaulniers <ndesaulniers@...gle.com>,
        Ingo Molnar <mingo@...nel.org>
Cc:     linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: [PATCH v1] ARM: vfp: Use long jump to fix THUMB2 kernel compilation error

The vfp_kmode_exception() function now is unreachable using relative
branching in THUMB2 kernel configuration, resulting in a "relocation
truncated to fit: R_ARM_THM_JUMP19 against symbol `vfp_kmode_exception'"
linker error. Let's use long jump in order to fix the issue.

Fixes: eff8728fe698 ("vmlinux.lds.h: Add PGO and AutoFDO input sections")
Signed-off-by: Dmitry Osipenko <digetx@...il.com>
---
 arch/arm/vfp/vfphw.S | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/arm/vfp/vfphw.S b/arch/arm/vfp/vfphw.S
index 4fcff9f59947..6e2b29f0c48d 100644
--- a/arch/arm/vfp/vfphw.S
+++ b/arch/arm/vfp/vfphw.S
@@ -82,7 +82,8 @@ ENTRY(vfp_support_entry)
 	ldr	r3, [sp, #S_PSR]	@ Neither lazy restore nor FP exceptions
 	and	r3, r3, #MODE_MASK	@ are supported in kernel mode
 	teq	r3, #USR_MODE
-	bne	vfp_kmode_exception	@ Returns through lr
+	ldr	r1, =vfp_kmode_exception
+	bxne	r1			@ Returns through lr
 
 	VFPFMRX	r1, FPEXC		@ Is the VFP enabled?
 	DBGSTR1	"fpexc %08x", r1
-- 
2.27.0