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From: Christophe Leroy <>
To: Benjamin Herrenschmidt <>,
	Paul Mackerras <>,
	Michael Ellerman <>
Subject: [PATCH] powerpc: Avoid link stack corruption in {add_}reloc_offset
Date: Fri, 20 Aug 2021 05:16:11 +0000 (UTC)	[thread overview]
Message-ID: <> (raw)

reloc_offset() / add_reloc_offset() used bl;mflr to get code

Use bcl 20,31,+4 instead of bl in order to preserve link stack.

See commit c974809a26a1 ("powerpc/vdso: Avoid link stack corruption
in __get_datapage()") for details.

Signed-off-by: Christophe Leroy <>
 arch/powerpc/kernel/misc.S | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/powerpc/kernel/misc.S b/arch/powerpc/kernel/misc.S
index 5be96feccb55..acd557637a3c 100644
--- a/arch/powerpc/kernel/misc.S
+++ b/arch/powerpc/kernel/misc.S
@@ -29,7 +29,7 @@ _GLOBAL(reloc_offset)
 	li	r3, 0
 	mflr	r0
-	bl	1f
+	bcl	20,31,1f
 1:	mflr	r5
 	PPC_LL	r4,(2f-1b)(r5)
 	subf	r5,r4,r5

                 reply	other threads:[~2021-08-20  5:16 UTC|newest]

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