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| author | Christophe Leroy <christophe.leroy@csgroup.eu> | 2021-08-24 07:56:35 +0000 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2021-08-25 13:35:47 +1000 |
| commit | 33e1402435cb9f3021439a15935ea2dc69ec1844 (patch) | |
| tree | aa036b96b414c8702dc8ea8d835d5bdbbfec561f /arch/powerpc/kernel/misc.S | |
| parent | f5007dbf4da729baa850b33a64dc3cc53757bdf8 (diff) | |
| download | lwn-33e1402435cb9f3021439a15935ea2dc69ec1844.tar.gz lwn-33e1402435cb9f3021439a15935ea2dc69ec1844.zip | |
powerpc: Avoid link stack corruption in misc asm functions
bl;mflr is used at several places to get code position.
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 <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/c6eabb4fb6c156f75d56dcbcc6f243e5ac0fba42.1629791763.git.christophe.leroy@csgroup.eu
Diffstat (limited to 'arch/powerpc/kernel/misc.S')
| -rw-r--r-- | arch/powerpc/kernel/misc.S | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/powerpc/kernel/misc.S b/arch/powerpc/kernel/misc.S index 5be96feccb55..fb7de3543c03 100644 --- a/arch/powerpc/kernel/misc.S +++ b/arch/powerpc/kernel/misc.S @@ -29,7 +29,7 @@ _GLOBAL(reloc_offset) li r3, 0 _GLOBAL(add_reloc_offset) mflr r0 - bl 1f + bcl 20,31,$+4 1: mflr r5 PPC_LL r4,(2f-1b)(r5) subf r5,r4,r5 |