From 6aaf49b495b446ff6eec0ac983f781ca0dc56a73 Mon Sep 17 00:00:00 2001
From: Leonard Crestez <leonard.crestez@nxp.com>
Date: Tue, 13 Mar 2018 22:17:23 +0200
Subject: [PATCH] crypto: arm,arm64 - Fix random regeneration of S_shipped
Git-commit: 6aaf49b495b446ff6eec0ac983f781ca0dc56a73
Patch-mainline: v4.17-rc1
References: bsc#1051510

The decision to rebuild .S_shipped is made based on the relative
timestamps of .S_shipped and .pl files but git makes this essentially
random. This means that the perl script might run anyway (usually at
most once per checkout), defeating the whole purpose of _shipped.

Fix by skipping the rule unless explicit make variables are provided:
REGENERATE_ARM_CRYPTO or REGENERATE_ARM64_CRYPTO.

This can produce nasty occasional build failures downstream, for example
for toolchains with broken perl. The solution is minimally intrusive to
make it easier to push into stable.

Another report on a similar issue here: https://lkml.org/lkml/2018/3/8/1379

Signed-off-by: Leonard Crestez <leonard.crestez@nxp.com>
Cc: <stable@vger.kernel.org>
Reviewed-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 arch/arm/crypto/Makefile   |    2 ++
 arch/arm64/crypto/Makefile |    2 ++
 2 files changed, 4 insertions(+)

--- a/arch/arm/crypto/Makefile
+++ b/arch/arm/crypto/Makefile
@@ -53,6 +53,7 @@ crct10dif-arm-ce-y	:= crct10dif-ce-core.
 crc32-arm-ce-y:= crc32-ce-core.o crc32-ce-glue.o
 chacha20-neon-y := chacha20-neon-core.o chacha20-neon-glue.o
 
+ifdef REGENERATE_ARM_CRYPTO
 quiet_cmd_perl = PERL    $@
       cmd_perl = $(PERL) $(<) > $(@)
 
@@ -61,5 +62,6 @@ $(src)/sha256-core.S_shipped: $(src)/sha
 
 $(src)/sha512-core.S_shipped: $(src)/sha512-armv4.pl
 	$(call cmd,perl)
+endif
 
 .PRECIOUS: $(obj)/sha256-core.S $(obj)/sha512-core.S
--- a/arch/arm64/crypto/Makefile
+++ b/arch/arm64/crypto/Makefile
@@ -58,6 +58,7 @@ CFLAGS_aes-glue-ce.o	:= -DUSE_V8_CRYPTO_
 $(obj)/aes-glue-%.o: $(src)/aes-glue.c FORCE
 	$(call if_changed_rule,cc_o_c)
 
+ifdef REGENERATE_ARM64_CRYPTO
 quiet_cmd_perlasm = PERLASM $@
       cmd_perlasm = $(PERL) $(<) void $(@)
 
@@ -66,5 +67,6 @@ $(src)/sha256-core.S_shipped: $(src)/sha
 
 $(src)/sha512-core.S_shipped: $(src)/sha512-armv8.pl
 	$(call cmd,perlasm)
+endif
 
 .PRECIOUS: $(obj)/sha256-core.S $(obj)/sha512-core.S