| Message ID | 20190617115927.3813471-1-arnd@arndb.de (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | Herbert Xu |
| Headers | show |
| Series | crypto: serpent - mark __serpent_setkey_sbox noinline | expand |
Hi Arnd, On Mon, Jun 17, 2019 at 01:59:08PM +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> > --- > crypto/serpent_generic.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/crypto/serpent_generic.c b/crypto/serpent_generic.c > index e57757904677..183661faf420 100644 > --- a/crypto/serpent_generic.c > +++ b/crypto/serpent_generic.c > @@ -225,7 +225,7 @@ > x4 ^= x2; \ > }) > > -static void __serpent_setkey_sbox(u32 r0, u32 r1, u32 r2, u32 r3, u32 r4, u32 *k) > +static void noinline __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 > A few nits: 'static noinline void' seems to be the much more common order, presumably to match 'static inline void'. Line breaking at 80 characters would also be nice. Finally, a brief comment explaining the purpose of 'noinline' might be helpful for people working with this code later. - Eric
diff --git a/crypto/serpent_generic.c b/crypto/serpent_generic.c index e57757904677..183661faf420 100644 --- a/crypto/serpent_generic.c +++ b/crypto/serpent_generic.c @@ -225,7 +225,7 @@ x4 ^= x2; \ }) -static void __serpent_setkey_sbox(u32 r0, u32 r1, u32 r2, u32 r3, u32 r4, u32 *k) +static void noinline __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> --- crypto/serpent_generic.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)