From 1d3551ced64e1a4f4869446a92713c235f20b0ca Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Wed, 10 Aug 2022 17:59:11 -0700 Subject: [PATCH] crypto: blake2b: effectively disable frame size warning MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit It turns out that gcc-12.1 has some nasty problems with register allocation on a 32-bit x86 build for the 64-bit values used in the generic blake2b implementation, where the pattern of 64-bit rotates and xor operations ends up making gcc generate horrible code. As a result it ends up with a ridiculously large stack frame for all the spills it generates, resulting in the following build problem: crypto/blake2b_generic.c: In function ‘blake2b_compress_one_generic’: crypto/blake2b_generic.c:109:1: error: the frame size of 2640 bytes is larger than 2048 bytes [-Werror=frame-larger-than=] on the same test-case, clang ends up generating a stack frame that is just 296 bytes (and older gcc versions generate a slightly bigger one at 428 bytes - still nowhere near that almost 3kB monster stack frame of gcc-12.1). The issue is fixed both in mainline and the GCC 12 release branch [1], but current release compilers end up failing the i386 allmodconfig build due to this issue. Disable the warning for now by simply raising the frame size for this one file, just to keep this issue from having people turn off WERROR. Link: https://lore.kernel.org/all/CAHk-=wjxqgeG2op+=W9sqgsWqCYnavC+SRfVyopu9-31S6xw+Q@mail.gmail.com/ Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105930 [1] Signed-off-by: Linus Torvalds --- crypto/Makefile | 1 + 1 file changed, 1 insertion(+) diff --git a/crypto/Makefile b/crypto/Makefile index 167c004dbf4f..a6f94e04e1da 100644 --- a/crypto/Makefile +++ b/crypto/Makefile @@ -84,6 +84,7 @@ obj-$(CONFIG_CRYPTO_STREEBOG) += streebog_generic.o obj-$(CONFIG_CRYPTO_WP512) += wp512.o CFLAGS_wp512.o := $(call cc-option,-fno-schedule-insns) # https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79149 obj-$(CONFIG_CRYPTO_BLAKE2B) += blake2b_generic.o +CFLAGS_blake2b_generic.o := -Wframe-larger-than=4096 # https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105930 obj-$(CONFIG_CRYPTO_GF128MUL) += gf128mul.o obj-$(CONFIG_CRYPTO_ECB) += ecb.o obj-$(CONFIG_CRYPTO_CBC) += cbc.o