* [PATCH] [v2] crypto: serpent - mark __serpent_setkey_sbox noinline
@ 2019-06-18 11:19 Arnd Bergmann
2019-06-18 18:05 ` Eric Biggers
2019-06-28 4:19 ` Herbert Xu
0 siblings, 2 replies; 5+ messages in thread
From: Arnd Bergmann @ 2019-06-18 11:19 UTC (permalink / raw)
To: Herbert Xu, David S. Miller
Cc: Arnd Bergmann, Eric Biggers, linux-crypto, linux-kernel
The same bug that gcc hit in the past is apparently now showing
up with clang, which decides to inline __serpent_setkey_sbox:
crypto/serpent_generic.c:268:5: error: stack frame size of 2112 bytes in function '__serpent_setkey' [-Werror,-Wframe-larger-than=]
Marking it 'noinline' reduces the stack usage from 2112 bytes to
192 and 96 bytes, respectively, and seems to generate more
useful object code.
Fixes: c871c10e4ea7 ("crypto: serpent - improve __serpent_setkey with UBSAN")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
v2: style improvements suggested by Eric Biggers
---
crypto/serpent_generic.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)
diff --git a/crypto/serpent_generic.c b/crypto/serpent_generic.c
index e57757904677..56fa665a4f01 100644
--- a/crypto/serpent_generic.c
+++ b/crypto/serpent_generic.c
@@ -225,7 +225,13 @@
x4 ^= x2; \
})
-static void __serpent_setkey_sbox(u32 r0, u32 r1, u32 r2, u32 r3, u32 r4, u32 *k)
+/*
+ * both gcc and clang have misoptimized this function in the past,
+ * producing horrible object code from spilling temporary variables
+ * on the stack. Forcing this part out of line avoids that.
+ */
+static noinline void __serpent_setkey_sbox(u32 r0, u32 r1, u32 r2,
+ u32 r3, u32 r4, u32 *k)
{
k += 100;
S3(r3, r4, r0, r1, r2); store_and_load_keys(r1, r2, r4, r3, 28, 24);
--
2.20.0
^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: [PATCH] [v2] crypto: serpent - mark __serpent_setkey_sbox noinline
2019-06-18 11:19 [PATCH] [v2] crypto: serpent - mark __serpent_setkey_sbox noinline Arnd Bergmann
@ 2019-06-18 18:05 ` Eric Biggers
2019-06-28 4:19 ` Herbert Xu
1 sibling, 0 replies; 5+ messages in thread
From: Eric Biggers @ 2019-06-18 18:05 UTC (permalink / raw)
To: Arnd Bergmann; +Cc: Herbert Xu, David S. Miller, linux-crypto, linux-kernel
On Tue, Jun 18, 2019 at 01:19:42PM +0200, Arnd Bergmann wrote:
> The same bug that gcc hit in the past is apparently now showing
> up with clang, which decides to inline __serpent_setkey_sbox:
>
> crypto/serpent_generic.c:268:5: error: stack frame size of 2112 bytes in function '__serpent_setkey' [-Werror,-Wframe-larger-than=]
>
> Marking it 'noinline' reduces the stack usage from 2112 bytes to
> 192 and 96 bytes, respectively, and seems to generate more
> useful object code.
>
> Fixes: c871c10e4ea7 ("crypto: serpent - improve __serpent_setkey with UBSAN")
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> ---
> v2: style improvements suggested by Eric Biggers
> ---
> crypto/serpent_generic.c | 8 +++++++-
> 1 file changed, 7 insertions(+), 1 deletion(-)
>
> diff --git a/crypto/serpent_generic.c b/crypto/serpent_generic.c
> index e57757904677..56fa665a4f01 100644
> --- a/crypto/serpent_generic.c
> +++ b/crypto/serpent_generic.c
> @@ -225,7 +225,13 @@
> x4 ^= x2; \
> })
>
> -static void __serpent_setkey_sbox(u32 r0, u32 r1, u32 r2, u32 r3, u32 r4, u32 *k)
> +/*
> + * both gcc and clang have misoptimized this function in the past,
> + * producing horrible object code from spilling temporary variables
> + * on the stack. Forcing this part out of line avoids that.
> + */
> +static noinline void __serpent_setkey_sbox(u32 r0, u32 r1, u32 r2,
> + u32 r3, u32 r4, u32 *k)
> {
> k += 100;
> S3(r3, r4, r0, r1, r2); store_and_load_keys(r1, r2, r4, r3, 28, 24);
> --
> 2.20.0
>
Reviewed-by: Eric Biggers <ebiggers@kernel.org>
- Eric
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] [v2] crypto: serpent - mark __serpent_setkey_sbox noinline
2019-06-18 11:19 [PATCH] [v2] crypto: serpent - mark __serpent_setkey_sbox noinline Arnd Bergmann
2019-06-18 18:05 ` Eric Biggers
@ 2019-06-28 4:19 ` Herbert Xu
2019-06-28 17:04 ` Eric Biggers
1 sibling, 1 reply; 5+ messages in thread
From: Herbert Xu @ 2019-06-28 4:19 UTC (permalink / raw)
To: Arnd Bergmann; +Cc: David S. Miller, Eric Biggers, linux-crypto, linux-kernel
On Tue, Jun 18, 2019 at 01:19:42PM +0200, Arnd Bergmann wrote:
> The same bug that gcc hit in the past is apparently now showing
> up with clang, which decides to inline __serpent_setkey_sbox:
>
> crypto/serpent_generic.c:268:5: error: stack frame size of 2112 bytes in function '__serpent_setkey' [-Werror,-Wframe-larger-than=]
>
> Marking it 'noinline' reduces the stack usage from 2112 bytes to
> 192 and 96 bytes, respectively, and seems to generate more
> useful object code.
>
> Fixes: c871c10e4ea7 ("crypto: serpent - improve __serpent_setkey with UBSAN")
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> ---
> v2: style improvements suggested by Eric Biggers
> ---
> crypto/serpent_generic.c | 8 +++++++-
> 1 file changed, 7 insertions(+), 1 deletion(-)
Patch applied. Thanks.
--
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] [v2] crypto: serpent - mark __serpent_setkey_sbox noinline
2019-06-28 4:19 ` Herbert Xu
@ 2019-06-28 17:04 ` Eric Biggers
2019-06-29 1:15 ` Herbert Xu
0 siblings, 1 reply; 5+ messages in thread
From: Eric Biggers @ 2019-06-28 17:04 UTC (permalink / raw)
To: Herbert Xu; +Cc: Arnd Bergmann, David S. Miller, linux-crypto, linux-kernel
On Fri, Jun 28, 2019 at 12:19:12PM +0800, Herbert Xu wrote:
> On Tue, Jun 18, 2019 at 01:19:42PM +0200, Arnd Bergmann wrote:
> > The same bug that gcc hit in the past is apparently now showing
> > up with clang, which decides to inline __serpent_setkey_sbox:
> >
> > crypto/serpent_generic.c:268:5: error: stack frame size of 2112 bytes in function '__serpent_setkey' [-Werror,-Wframe-larger-than=]
> >
> > Marking it 'noinline' reduces the stack usage from 2112 bytes to
> > 192 and 96 bytes, respectively, and seems to generate more
> > useful object code.
> >
> > Fixes: c871c10e4ea7 ("crypto: serpent - improve __serpent_setkey with UBSAN")
> > Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> > ---
> > v2: style improvements suggested by Eric Biggers
> > ---
> > crypto/serpent_generic.c | 8 +++++++-
> > 1 file changed, 7 insertions(+), 1 deletion(-)
>
> Patch applied. Thanks.
> --
Hi Herbert, seems you forgot to push? I don't see this in cryptodev.
- Eric
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] [v2] crypto: serpent - mark __serpent_setkey_sbox noinline
2019-06-28 17:04 ` Eric Biggers
@ 2019-06-29 1:15 ` Herbert Xu
0 siblings, 0 replies; 5+ messages in thread
From: Herbert Xu @ 2019-06-29 1:15 UTC (permalink / raw)
To: Eric Biggers; +Cc: Arnd Bergmann, David S. Miller, linux-crypto, linux-kernel
On Fri, Jun 28, 2019 at 10:04:38AM -0700, Eric Biggers wrote:
>
> Hi Herbert, seems you forgot to push? I don't see this in cryptodev.
Yes you're right. It should be there now.
Thanks,
--
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
^ permalink raw reply [flat|nested] 5+ messages in thread
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2019-06-18 11:19 [PATCH] [v2] crypto: serpent - mark __serpent_setkey_sbox noinline Arnd Bergmann
2019-06-18 18:05 ` Eric Biggers
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2019-06-28 17:04 ` Eric Biggers
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