| Message ID | 20190618111953.3183723-1-arnd@arndb.de (mailing list archive) |
|---|---|
| State | Accepted |
| Delegated to: | Herbert Xu |
| Headers | show |
| Series | [v2] crypto: serpent - mark __serpent_setkey_sbox noinline | expand |
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
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.
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
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,
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);
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(-)