[PATCH AUTOSEL 5.16 15/30] crypto: x86/chacha20 - Avoid spurious jumps to other functions

From: Sasha Levin
Date: Wed Apr 06 2022 - 21:15:01 EST


From: Peter Zijlstra <peterz@xxxxxxxxxxxxx>

[ Upstream commit 4327d168515fd8b5b92fa1efdf1d219fb6514460 ]

The chacha_Nblock_xor_avx512vl() functions all have their own,
identical, .LdoneN label, however in one particular spot {2,4} jump to
the 8 version instead of their own. Resulting in:

arch/x86/crypto/chacha-x86_64.o: warning: objtool: chacha_2block_xor_avx512vl() falls through to next function chacha_8block_xor_avx512vl()
arch/x86/crypto/chacha-x86_64.o: warning: objtool: chacha_4block_xor_avx512vl() falls through to next function chacha_8block_xor_avx512vl()

Make each function consistently use its own done label.

Reported-by: Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Reviewed-by: Martin Willi <martin@xxxxxxxxxxxxxx>
Signed-off-by: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
arch/x86/crypto/chacha-avx512vl-x86_64.S | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/x86/crypto/chacha-avx512vl-x86_64.S b/arch/x86/crypto/chacha-avx512vl-x86_64.S
index bb193fde123a..8713c16c2501 100644
--- a/arch/x86/crypto/chacha-avx512vl-x86_64.S
+++ b/arch/x86/crypto/chacha-avx512vl-x86_64.S
@@ -172,7 +172,7 @@ SYM_FUNC_START(chacha_2block_xor_avx512vl)
# xor remaining bytes from partial register into output
mov %rcx,%rax
and $0xf,%rcx
- jz .Ldone8
+ jz .Ldone2
mov %rax,%r9
and $~0xf,%r9

@@ -438,7 +438,7 @@ SYM_FUNC_START(chacha_4block_xor_avx512vl)
# xor remaining bytes from partial register into output
mov %rcx,%rax
and $0xf,%rcx
- jz .Ldone8
+ jz .Ldone4
mov %rax,%r9
and $~0xf,%r9

--
2.35.1