| Message ID | 20201006034854.2277538-1-jeremy.linton@arm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [BUG] crypto: arm64: Avoid indirect branch to bti_c | expand |
On Mon, Oct 05, 2020 at 10:48:54PM -0500, Jeremy Linton wrote: > The AES code uses a 'br x7' as part of a function called by > a macro. That branch needs a bti_j as a target. This results > in a panic as seen below. Instead of trying to replace the branch > target with a bti_jc, lets replace the indirect branch with a > bl/ret, bl sequence that can target the existing bti_c. > > Bad mode in Synchronous Abort handler detected on CPU1, code 0x34000003 -- BTI > CPU: 1 PID: 265 Comm: cryptomgr_test Not tainted 5.8.11-300.fc33.aarch64 #1 > pstate: 20400c05 (nzCv daif +PAN -UAO BTYPE=j-) > pc : aesbs_encrypt8+0x0/0x5f0 [aes_neon_bs] > lr : aesbs_xts_encrypt+0x48/0xe0 [aes_neon_bs] > sp : ffff80001052b730 > > aesbs_encrypt8+0x0/0x5f0 [aes_neon_bs] > __xts_crypt+0xb0/0x2dc [aes_neon_bs] > xts_encrypt+0x28/0x3c [aes_neon_bs] > crypto_skcipher_encrypt+0x50/0x84 > simd_skcipher_encrypt+0xc8/0xe0 > crypto_skcipher_encrypt+0x50/0x84 > test_skcipher_vec_cfg+0x224/0x5f0 > test_skcipher+0xbc/0x120 > alg_test_skcipher+0xa0/0x1b0 > alg_test+0x3dc/0x47c > cryptomgr_test+0x38/0x60 > > Fixes: commit 0e89640b640d ("crypto: arm64 - Use modern annotations for assembly functions") nit: the "commit" string shouldn't be here, and I think the linux-next scripts will yell at us if we don't remove it. > Signed-off-by: Jeremy Linton <jeremy.linton@arm.com> > --- > arch/arm64/crypto/aes-neonbs-core.S | 6 +++--- > 1 file changed, 3 insertions(+), 3 deletions(-) > > diff --git a/arch/arm64/crypto/aes-neonbs-core.S b/arch/arm64/crypto/aes-neonbs-core.S > index b357164379f6..32f53ebe5e2c 100644 > --- a/arch/arm64/crypto/aes-neonbs-core.S > +++ b/arch/arm64/crypto/aes-neonbs-core.S > @@ -788,7 +788,7 @@ SYM_FUNC_START_LOCAL(__xts_crypt8) > > 0: mov bskey, x21 > mov rounds, x22 > - br x7 > + ret > SYM_FUNC_END(__xts_crypt8) > > .macro __xts_crypt, do8, o0, o1, o2, o3, o4, o5, o6, o7 > @@ -806,8 +806,8 @@ SYM_FUNC_END(__xts_crypt8) > uzp1 v30.4s, v30.4s, v25.4s > ld1 {v25.16b}, [x24] > > -99: adr x7, \do8 > - bl __xts_crypt8 > +99: bl __xts_crypt8 > + bl \do8 > > ldp q16, q17, [sp, #.Lframe_local_offset] > ldp q18, q19, [sp, #.Lframe_local_offset + 32] Acked-by: Will Deacon <will@kernel.org> Catalin -- can you pick this for 5.9 please? Will
On Tue, Oct 06, 2020 at 09:27:48AM +0100, Will Deacon wrote: > On Mon, Oct 05, 2020 at 10:48:54PM -0500, Jeremy Linton wrote: > > The AES code uses a 'br x7' as part of a function called by > > a macro. That branch needs a bti_j as a target. This results > > in a panic as seen below. Instead of trying to replace the branch > > target with a bti_jc, lets replace the indirect branch with a > > bl/ret, bl sequence that can target the existing bti_c. > > > > Bad mode in Synchronous Abort handler detected on CPU1, code 0x34000003 -- BTI > > CPU: 1 PID: 265 Comm: cryptomgr_test Not tainted 5.8.11-300.fc33.aarch64 #1 > > pstate: 20400c05 (nzCv daif +PAN -UAO BTYPE=j-) > > pc : aesbs_encrypt8+0x0/0x5f0 [aes_neon_bs] > > lr : aesbs_xts_encrypt+0x48/0xe0 [aes_neon_bs] > > sp : ffff80001052b730 > > > > aesbs_encrypt8+0x0/0x5f0 [aes_neon_bs] > > __xts_crypt+0xb0/0x2dc [aes_neon_bs] > > xts_encrypt+0x28/0x3c [aes_neon_bs] > > crypto_skcipher_encrypt+0x50/0x84 > > simd_skcipher_encrypt+0xc8/0xe0 > > crypto_skcipher_encrypt+0x50/0x84 > > test_skcipher_vec_cfg+0x224/0x5f0 > > test_skcipher+0xbc/0x120 > > alg_test_skcipher+0xa0/0x1b0 > > alg_test+0x3dc/0x47c > > cryptomgr_test+0x38/0x60 > > > > Fixes: commit 0e89640b640d ("crypto: arm64 - Use modern annotations for assembly functions") > > nit: the "commit" string shouldn't be here, and I think the linux-next > scripts will yell at us if we don't remove it. > > > Signed-off-by: Jeremy Linton <jeremy.linton@arm.com> > > --- > > arch/arm64/crypto/aes-neonbs-core.S | 6 +++--- > > 1 file changed, 3 insertions(+), 3 deletions(-) > > > > diff --git a/arch/arm64/crypto/aes-neonbs-core.S b/arch/arm64/crypto/aes-neonbs-core.S > > index b357164379f6..32f53ebe5e2c 100644 > > --- a/arch/arm64/crypto/aes-neonbs-core.S > > +++ b/arch/arm64/crypto/aes-neonbs-core.S > > @@ -788,7 +788,7 @@ SYM_FUNC_START_LOCAL(__xts_crypt8) > > > > 0: mov bskey, x21 > > mov rounds, x22 > > - br x7 > > + ret Dang, replied on an old version. Since this is logically a tail call, could we simply be using br x16 or br x17 for this? The architecture makes special provision for that so that the compiler can generate tail-calls. This assumes that those regs aren't clobbered by any veneered function call in the meantime, but all the calls here are local, so I don't think that is a concern. [...] Cheers ---Dave
On Tue, Oct 06, 2020 at 11:01:21AM +0100, Dave Martin wrote: > On Tue, Oct 06, 2020 at 09:27:48AM +0100, Will Deacon wrote: > > On Mon, Oct 05, 2020 at 10:48:54PM -0500, Jeremy Linton wrote: > > > The AES code uses a 'br x7' as part of a function called by > > > a macro. That branch needs a bti_j as a target. This results > > > in a panic as seen below. Instead of trying to replace the branch > > > target with a bti_jc, lets replace the indirect branch with a > > > bl/ret, bl sequence that can target the existing bti_c. > > > > > > Bad mode in Synchronous Abort handler detected on CPU1, code 0x34000003 -- BTI > > > CPU: 1 PID: 265 Comm: cryptomgr_test Not tainted 5.8.11-300.fc33.aarch64 #1 > > > pstate: 20400c05 (nzCv daif +PAN -UAO BTYPE=j-) > > > pc : aesbs_encrypt8+0x0/0x5f0 [aes_neon_bs] > > > lr : aesbs_xts_encrypt+0x48/0xe0 [aes_neon_bs] > > > sp : ffff80001052b730 > > > > > > aesbs_encrypt8+0x0/0x5f0 [aes_neon_bs] > > > __xts_crypt+0xb0/0x2dc [aes_neon_bs] > > > xts_encrypt+0x28/0x3c [aes_neon_bs] > > > crypto_skcipher_encrypt+0x50/0x84 > > > simd_skcipher_encrypt+0xc8/0xe0 > > > crypto_skcipher_encrypt+0x50/0x84 > > > test_skcipher_vec_cfg+0x224/0x5f0 > > > test_skcipher+0xbc/0x120 > > > alg_test_skcipher+0xa0/0x1b0 > > > alg_test+0x3dc/0x47c > > > cryptomgr_test+0x38/0x60 > > > > > > Fixes: commit 0e89640b640d ("crypto: arm64 - Use modern annotations for assembly functions") > > > > nit: the "commit" string shouldn't be here, and I think the linux-next > > scripts will yell at us if we don't remove it. > > > > > Signed-off-by: Jeremy Linton <jeremy.linton@arm.com> > > > --- > > > arch/arm64/crypto/aes-neonbs-core.S | 6 +++--- > > > 1 file changed, 3 insertions(+), 3 deletions(-) > > > > > > diff --git a/arch/arm64/crypto/aes-neonbs-core.S b/arch/arm64/crypto/aes-neonbs-core.S > > > index b357164379f6..32f53ebe5e2c 100644 > > > --- a/arch/arm64/crypto/aes-neonbs-core.S > > > +++ b/arch/arm64/crypto/aes-neonbs-core.S > > > @@ -788,7 +788,7 @@ SYM_FUNC_START_LOCAL(__xts_crypt8) > > > > > > 0: mov bskey, x21 > > > mov rounds, x22 > > > - br x7 > > > + ret > > Dang, replied on an old version. They're not versioned, so who knows which one is older! > Since this is logically a tail call, could we simply be using br x16 or > br x17 for this? Yup, that would work too. This was just "obviously correct" and it would be nice to get a fix in for 5.9. Will
On Tue, Oct 06, 2020 at 11:01:21AM +0100, Dave P Martin wrote: > On Tue, Oct 06, 2020 at 09:27:48AM +0100, Will Deacon wrote: > > On Mon, Oct 05, 2020 at 10:48:54PM -0500, Jeremy Linton wrote: > > > The AES code uses a 'br x7' as part of a function called by > > > a macro. That branch needs a bti_j as a target. This results > > > in a panic as seen below. Instead of trying to replace the branch > > > target with a bti_jc, lets replace the indirect branch with a > > > bl/ret, bl sequence that can target the existing bti_c. > > > > > > Bad mode in Synchronous Abort handler detected on CPU1, code 0x34000003 -- BTI > > > CPU: 1 PID: 265 Comm: cryptomgr_test Not tainted 5.8.11-300.fc33.aarch64 #1 > > > pstate: 20400c05 (nzCv daif +PAN -UAO BTYPE=j-) > > > pc : aesbs_encrypt8+0x0/0x5f0 [aes_neon_bs] > > > lr : aesbs_xts_encrypt+0x48/0xe0 [aes_neon_bs] > > > sp : ffff80001052b730 > > > > > > aesbs_encrypt8+0x0/0x5f0 [aes_neon_bs] > > > __xts_crypt+0xb0/0x2dc [aes_neon_bs] > > > xts_encrypt+0x28/0x3c [aes_neon_bs] > > > crypto_skcipher_encrypt+0x50/0x84 > > > simd_skcipher_encrypt+0xc8/0xe0 > > > crypto_skcipher_encrypt+0x50/0x84 > > > test_skcipher_vec_cfg+0x224/0x5f0 > > > test_skcipher+0xbc/0x120 > > > alg_test_skcipher+0xa0/0x1b0 > > > alg_test+0x3dc/0x47c > > > cryptomgr_test+0x38/0x60 > > > > > > Fixes: commit 0e89640b640d ("crypto: arm64 - Use modern annotations for assembly functions") > > > > nit: the "commit" string shouldn't be here, and I think the linux-next > > scripts will yell at us if we don't remove it. > > > > > Signed-off-by: Jeremy Linton <jeremy.linton@arm.com> > > > --- > > > arch/arm64/crypto/aes-neonbs-core.S | 6 +++--- > > > 1 file changed, 3 insertions(+), 3 deletions(-) > > > > > > diff --git a/arch/arm64/crypto/aes-neonbs-core.S b/arch/arm64/crypto/aes-neonbs-core.S > > > index b357164379f6..32f53ebe5e2c 100644 > > > --- a/arch/arm64/crypto/aes-neonbs-core.S > > > +++ b/arch/arm64/crypto/aes-neonbs-core.S > > > @@ -788,7 +788,7 @@ SYM_FUNC_START_LOCAL(__xts_crypt8) > > > > > > 0: mov bskey, x21 > > > mov rounds, x22 > > > - br x7 > > > + ret > > Dang, replied on an old version. Which I ignored (by default, when the kbuild test robot complains ;)). > Since this is logically a tail call, could we simply be using br x16 or > br x17 for this? > > The architecture makes special provision for that so that the compiler > can generate tail-calls. So a "br x16" is compatible with a bti_c landing pad. I think it makes more sense to keep it as a tail call.
On Mon, Oct 05, 2020 at 10:48:54PM -0500, Jeremy Linton wrote: > The AES code uses a 'br x7' as part of a function called by > a macro. That branch needs a bti_j as a target. This results > in a panic as seen below. Instead of trying to replace the branch > target with a bti_jc, lets replace the indirect branch with a > bl/ret, bl sequence that can target the existing bti_c. Reviewed-by: Mark Brown <broonie@kernel.org>
On Tue, Oct 06, 2020 at 11:25:11AM +0100, Catalin Marinas wrote: > On Tue, Oct 06, 2020 at 11:01:21AM +0100, Dave P Martin wrote: > > On Tue, Oct 06, 2020 at 09:27:48AM +0100, Will Deacon wrote: > > > On Mon, Oct 05, 2020 at 10:48:54PM -0500, Jeremy Linton wrote: > > > > The AES code uses a 'br x7' as part of a function called by > > > > a macro. That branch needs a bti_j as a target. This results > > > > in a panic as seen below. Instead of trying to replace the branch > > > > target with a bti_jc, lets replace the indirect branch with a > > > > bl/ret, bl sequence that can target the existing bti_c. > > > > > > > > Bad mode in Synchronous Abort handler detected on CPU1, code 0x34000003 -- BTI > > > > CPU: 1 PID: 265 Comm: cryptomgr_test Not tainted 5.8.11-300.fc33.aarch64 #1 > > > > pstate: 20400c05 (nzCv daif +PAN -UAO BTYPE=j-) > > > > pc : aesbs_encrypt8+0x0/0x5f0 [aes_neon_bs] > > > > lr : aesbs_xts_encrypt+0x48/0xe0 [aes_neon_bs] > > > > sp : ffff80001052b730 > > > > > > > > aesbs_encrypt8+0x0/0x5f0 [aes_neon_bs] > > > > __xts_crypt+0xb0/0x2dc [aes_neon_bs] > > > > xts_encrypt+0x28/0x3c [aes_neon_bs] > > > > crypto_skcipher_encrypt+0x50/0x84 > > > > simd_skcipher_encrypt+0xc8/0xe0 > > > > crypto_skcipher_encrypt+0x50/0x84 > > > > test_skcipher_vec_cfg+0x224/0x5f0 > > > > test_skcipher+0xbc/0x120 > > > > alg_test_skcipher+0xa0/0x1b0 > > > > alg_test+0x3dc/0x47c > > > > cryptomgr_test+0x38/0x60 > > > > > > > > Fixes: commit 0e89640b640d ("crypto: arm64 - Use modern annotations for assembly functions") > > > > > > nit: the "commit" string shouldn't be here, and I think the linux-next > > > scripts will yell at us if we don't remove it. > > > > > > > Signed-off-by: Jeremy Linton <jeremy.linton@arm.com> > > > > --- > > > > arch/arm64/crypto/aes-neonbs-core.S | 6 +++--- > > > > 1 file changed, 3 insertions(+), 3 deletions(-) > > > > > > > > diff --git a/arch/arm64/crypto/aes-neonbs-core.S b/arch/arm64/crypto/aes-neonbs-core.S > > > > index b357164379f6..32f53ebe5e2c 100644 > > > > --- a/arch/arm64/crypto/aes-neonbs-core.S > > > > +++ b/arch/arm64/crypto/aes-neonbs-core.S > > > > @@ -788,7 +788,7 @@ SYM_FUNC_START_LOCAL(__xts_crypt8) > > > > > > > > 0: mov bskey, x21 > > > > mov rounds, x22 > > > > - br x7 > > > > + ret > > > > Dang, replied on an old version. > > Which I ignored (by default, when the kbuild test robot complains ;)). > > > Since this is logically a tail call, could we simply be using br x16 or > > br x17 for this? > > > > The architecture makes special provision for that so that the compiler > > can generate tail-calls. > > So a "br x16" is compatible with a bti_c landing pad. I think it makes > more sense to keep it as a tail call. Just to be clear, I'm happy either way, but I thought it would make sense to point this out. Normally, "bti j" would be used just for weird stuff like jump tables, but .S files all count as "weird stuff" to some extent -- so there are no hard and fast rules. Cheers ---Dave
On Tue, Oct 06, 2020 at 11:43:14AM +0100, Dave P Martin wrote: > On Tue, Oct 06, 2020 at 11:25:11AM +0100, Catalin Marinas wrote: > > On Tue, Oct 06, 2020 at 11:01:21AM +0100, Dave P Martin wrote: > > > On Tue, Oct 06, 2020 at 09:27:48AM +0100, Will Deacon wrote: > > > > On Mon, Oct 05, 2020 at 10:48:54PM -0500, Jeremy Linton wrote: > > > > > The AES code uses a 'br x7' as part of a function called by > > > > > a macro. That branch needs a bti_j as a target. This results > > > > > in a panic as seen below. Instead of trying to replace the branch > > > > > target with a bti_jc, lets replace the indirect branch with a > > > > > bl/ret, bl sequence that can target the existing bti_c. > > > > > > > > > > Bad mode in Synchronous Abort handler detected on CPU1, code 0x34000003 -- BTI > > > > > CPU: 1 PID: 265 Comm: cryptomgr_test Not tainted 5.8.11-300.fc33.aarch64 #1 > > > > > pstate: 20400c05 (nzCv daif +PAN -UAO BTYPE=j-) > > > > > pc : aesbs_encrypt8+0x0/0x5f0 [aes_neon_bs] > > > > > lr : aesbs_xts_encrypt+0x48/0xe0 [aes_neon_bs] > > > > > sp : ffff80001052b730 > > > > > > > > > > aesbs_encrypt8+0x0/0x5f0 [aes_neon_bs] > > > > > __xts_crypt+0xb0/0x2dc [aes_neon_bs] > > > > > xts_encrypt+0x28/0x3c [aes_neon_bs] > > > > > crypto_skcipher_encrypt+0x50/0x84 > > > > > simd_skcipher_encrypt+0xc8/0xe0 > > > > > crypto_skcipher_encrypt+0x50/0x84 > > > > > test_skcipher_vec_cfg+0x224/0x5f0 > > > > > test_skcipher+0xbc/0x120 > > > > > alg_test_skcipher+0xa0/0x1b0 > > > > > alg_test+0x3dc/0x47c > > > > > cryptomgr_test+0x38/0x60 > > > > > > > > > > Fixes: commit 0e89640b640d ("crypto: arm64 - Use modern annotations for assembly functions") > > > > > > > > nit: the "commit" string shouldn't be here, and I think the linux-next > > > > scripts will yell at us if we don't remove it. > > > > > > > > > Signed-off-by: Jeremy Linton <jeremy.linton@arm.com> > > > > > --- > > > > > arch/arm64/crypto/aes-neonbs-core.S | 6 +++--- > > > > > 1 file changed, 3 insertions(+), 3 deletions(-) > > > > > > > > > > diff --git a/arch/arm64/crypto/aes-neonbs-core.S b/arch/arm64/crypto/aes-neonbs-core.S > > > > > index b357164379f6..32f53ebe5e2c 100644 > > > > > --- a/arch/arm64/crypto/aes-neonbs-core.S > > > > > +++ b/arch/arm64/crypto/aes-neonbs-core.S > > > > > @@ -788,7 +788,7 @@ SYM_FUNC_START_LOCAL(__xts_crypt8) > > > > > > > > > > 0: mov bskey, x21 > > > > > mov rounds, x22 > > > > > - br x7 > > > > > + ret > > > > > > Dang, replied on an old version. > > > > Which I ignored (by default, when the kbuild test robot complains ;)). > > > > > Since this is logically a tail call, could we simply be using br x16 or > > > br x17 for this? > > > > > > The architecture makes special provision for that so that the compiler > > > can generate tail-calls. > > > > So a "br x16" is compatible with a bti_c landing pad. I think it makes > > more sense to keep it as a tail call. > > Just to be clear, I'm happy either way, but I thought it would make > sense to point this out. I'd prefer the replacement with a br x16/17, it keeps the code pretty much unchanged. Jeremy, could you please respin this patch and give it a try? Thanks.
On Tue, 6 Oct 2020 at 14:33, Catalin Marinas <catalin.marinas@arm.com> wrote: > > On Tue, Oct 06, 2020 at 11:43:14AM +0100, Dave P Martin wrote: > > On Tue, Oct 06, 2020 at 11:25:11AM +0100, Catalin Marinas wrote: > > > On Tue, Oct 06, 2020 at 11:01:21AM +0100, Dave P Martin wrote: > > > > On Tue, Oct 06, 2020 at 09:27:48AM +0100, Will Deacon wrote: > > > > > On Mon, Oct 05, 2020 at 10:48:54PM -0500, Jeremy Linton wrote: > > > > > > The AES code uses a 'br x7' as part of a function called by > > > > > > a macro. That branch needs a bti_j as a target. This results > > > > > > in a panic as seen below. Instead of trying to replace the branch > > > > > > target with a bti_jc, lets replace the indirect branch with a > > > > > > bl/ret, bl sequence that can target the existing bti_c. > > > > > > > > > > > > Bad mode in Synchronous Abort handler detected on CPU1, code 0x34000003 -- BTI > > > > > > CPU: 1 PID: 265 Comm: cryptomgr_test Not tainted 5.8.11-300.fc33.aarch64 #1 > > > > > > pstate: 20400c05 (nzCv daif +PAN -UAO BTYPE=j-) > > > > > > pc : aesbs_encrypt8+0x0/0x5f0 [aes_neon_bs] > > > > > > lr : aesbs_xts_encrypt+0x48/0xe0 [aes_neon_bs] > > > > > > sp : ffff80001052b730 > > > > > > > > > > > > aesbs_encrypt8+0x0/0x5f0 [aes_neon_bs] > > > > > > __xts_crypt+0xb0/0x2dc [aes_neon_bs] > > > > > > xts_encrypt+0x28/0x3c [aes_neon_bs] > > > > > > crypto_skcipher_encrypt+0x50/0x84 > > > > > > simd_skcipher_encrypt+0xc8/0xe0 > > > > > > crypto_skcipher_encrypt+0x50/0x84 > > > > > > test_skcipher_vec_cfg+0x224/0x5f0 > > > > > > test_skcipher+0xbc/0x120 > > > > > > alg_test_skcipher+0xa0/0x1b0 > > > > > > alg_test+0x3dc/0x47c > > > > > > cryptomgr_test+0x38/0x60 > > > > > > > > > > > > Fixes: commit 0e89640b640d ("crypto: arm64 - Use modern annotations for assembly functions") > > > > > > > > > > nit: the "commit" string shouldn't be here, and I think the linux-next > > > > > scripts will yell at us if we don't remove it. > > > > > > > > > > > Signed-off-by: Jeremy Linton <jeremy.linton@arm.com> > > > > > > --- > > > > > > arch/arm64/crypto/aes-neonbs-core.S | 6 +++--- > > > > > > 1 file changed, 3 insertions(+), 3 deletions(-) > > > > > > > > > > > > diff --git a/arch/arm64/crypto/aes-neonbs-core.S b/arch/arm64/crypto/aes-neonbs-core.S > > > > > > index b357164379f6..32f53ebe5e2c 100644 > > > > > > --- a/arch/arm64/crypto/aes-neonbs-core.S > > > > > > +++ b/arch/arm64/crypto/aes-neonbs-core.S > > > > > > @@ -788,7 +788,7 @@ SYM_FUNC_START_LOCAL(__xts_crypt8) > > > > > > > > > > > > 0: mov bskey, x21 > > > > > > mov rounds, x22 > > > > > > - br x7 > > > > > > + ret > > > > > > > > Dang, replied on an old version. > > > > > > Which I ignored (by default, when the kbuild test robot complains ;)). > > > > > > > Since this is logically a tail call, could we simply be using br x16 or > > > > br x17 for this? > > > > > > > > The architecture makes special provision for that so that the compiler > > > > can generate tail-calls. > > > > > > So a "br x16" is compatible with a bti_c landing pad. I think it makes > > > more sense to keep it as a tail call. > > > > Just to be clear, I'm happy either way, but I thought it would make > > sense to point this out. > > I'd prefer the replacement with a br x16/17, it keeps the code pretty > much unchanged. > +1 > Jeremy, could you please respin this patch and give it a try? > > Thanks. > > -- > Catalin
Hi, On 10/6/20 7:33 AM, Catalin Marinas wrote: > On Tue, Oct 06, 2020 at 11:43:14AM +0100, Dave P Martin wrote: >> On Tue, Oct 06, 2020 at 11:25:11AM +0100, Catalin Marinas wrote: >>> On Tue, Oct 06, 2020 at 11:01:21AM +0100, Dave P Martin wrote: >>>> On Tue, Oct 06, 2020 at 09:27:48AM +0100, Will Deacon wrote: >>>>> On Mon, Oct 05, 2020 at 10:48:54PM -0500, Jeremy Linton wrote: >>>>>> The AES code uses a 'br x7' as part of a function called by >>>>>> a macro. That branch needs a bti_j as a target. This results >>>>>> in a panic as seen below. Instead of trying to replace the branch >>>>>> target with a bti_jc, lets replace the indirect branch with a >>>>>> bl/ret, bl sequence that can target the existing bti_c. >>>>>> >>>>>> Bad mode in Synchronous Abort handler detected on CPU1, code 0x34000003 -- BTI >>>>>> CPU: 1 PID: 265 Comm: cryptomgr_test Not tainted 5.8.11-300.fc33.aarch64 #1 >>>>>> pstate: 20400c05 (nzCv daif +PAN -UAO BTYPE=j-) >>>>>> pc : aesbs_encrypt8+0x0/0x5f0 [aes_neon_bs] >>>>>> lr : aesbs_xts_encrypt+0x48/0xe0 [aes_neon_bs] >>>>>> sp : ffff80001052b730 >>>>>> >>>>>> aesbs_encrypt8+0x0/0x5f0 [aes_neon_bs] >>>>>> __xts_crypt+0xb0/0x2dc [aes_neon_bs] >>>>>> xts_encrypt+0x28/0x3c [aes_neon_bs] >>>>>> crypto_skcipher_encrypt+0x50/0x84 >>>>>> simd_skcipher_encrypt+0xc8/0xe0 >>>>>> crypto_skcipher_encrypt+0x50/0x84 >>>>>> test_skcipher_vec_cfg+0x224/0x5f0 >>>>>> test_skcipher+0xbc/0x120 >>>>>> alg_test_skcipher+0xa0/0x1b0 >>>>>> alg_test+0x3dc/0x47c >>>>>> cryptomgr_test+0x38/0x60 >>>>>> >>>>>> Fixes: commit 0e89640b640d ("crypto: arm64 - Use modern annotations for assembly functions") >>>>> >>>>> nit: the "commit" string shouldn't be here, and I think the linux-next >>>>> scripts will yell at us if we don't remove it. >>>>> >>>>>> Signed-off-by: Jeremy Linton <jeremy.linton@arm.com> >>>>>> --- >>>>>> arch/arm64/crypto/aes-neonbs-core.S | 6 +++--- >>>>>> 1 file changed, 3 insertions(+), 3 deletions(-) >>>>>> >>>>>> diff --git a/arch/arm64/crypto/aes-neonbs-core.S b/arch/arm64/crypto/aes-neonbs-core.S >>>>>> index b357164379f6..32f53ebe5e2c 100644 >>>>>> --- a/arch/arm64/crypto/aes-neonbs-core.S >>>>>> +++ b/arch/arm64/crypto/aes-neonbs-core.S >>>>>> @@ -788,7 +788,7 @@ SYM_FUNC_START_LOCAL(__xts_crypt8) >>>>>> >>>>>> 0: mov bskey, x21 >>>>>> mov rounds, x22 >>>>>> - br x7 >>>>>> + ret >>>> >>>> Dang, replied on an old version. >>> >>> Which I ignored (by default, when the kbuild test robot complains ;)). >>> >>>> Since this is logically a tail call, could we simply be using br x16 or >>>> br x17 for this? >>>> >>>> The architecture makes special provision for that so that the compiler >>>> can generate tail-calls. >>> >>> So a "br x16" is compatible with a bti_c landing pad. I think it makes >>> more sense to keep it as a tail call. >> >> Just to be clear, I'm happy either way, but I thought it would make >> sense to point this out. > > I'd prefer the replacement with a br x16/17, it keeps the code pretty > much unchanged. > > Jeremy, could you please respin this patch and give it a try? Sounds like a plan. I'm probably going to change the subject again, guess I will put a v3 on it too. :)
diff --git a/arch/arm64/crypto/aes-neonbs-core.S b/arch/arm64/crypto/aes-neonbs-core.S index b357164379f6..32f53ebe5e2c 100644 --- a/arch/arm64/crypto/aes-neonbs-core.S +++ b/arch/arm64/crypto/aes-neonbs-core.S @@ -788,7 +788,7 @@ SYM_FUNC_START_LOCAL(__xts_crypt8) 0: mov bskey, x21 mov rounds, x22 - br x7 + ret SYM_FUNC_END(__xts_crypt8) .macro __xts_crypt, do8, o0, o1, o2, o3, o4, o5, o6, o7 @@ -806,8 +806,8 @@ SYM_FUNC_END(__xts_crypt8) uzp1 v30.4s, v30.4s, v25.4s ld1 {v25.16b}, [x24] -99: adr x7, \do8 - bl __xts_crypt8 +99: bl __xts_crypt8 + bl \do8 ldp q16, q17, [sp, #.Lframe_local_offset] ldp q18, q19, [sp, #.Lframe_local_offset + 32]
The AES code uses a 'br x7' as part of a function called by a macro. That branch needs a bti_j as a target. This results in a panic as seen below. Instead of trying to replace the branch target with a bti_jc, lets replace the indirect branch with a bl/ret, bl sequence that can target the existing bti_c. Bad mode in Synchronous Abort handler detected on CPU1, code 0x34000003 -- BTI CPU: 1 PID: 265 Comm: cryptomgr_test Not tainted 5.8.11-300.fc33.aarch64 #1 pstate: 20400c05 (nzCv daif +PAN -UAO BTYPE=j-) pc : aesbs_encrypt8+0x0/0x5f0 [aes_neon_bs] lr : aesbs_xts_encrypt+0x48/0xe0 [aes_neon_bs] sp : ffff80001052b730 aesbs_encrypt8+0x0/0x5f0 [aes_neon_bs] __xts_crypt+0xb0/0x2dc [aes_neon_bs] xts_encrypt+0x28/0x3c [aes_neon_bs] crypto_skcipher_encrypt+0x50/0x84 simd_skcipher_encrypt+0xc8/0xe0 crypto_skcipher_encrypt+0x50/0x84 test_skcipher_vec_cfg+0x224/0x5f0 test_skcipher+0xbc/0x120 alg_test_skcipher+0xa0/0x1b0 alg_test+0x3dc/0x47c cryptomgr_test+0x38/0x60 Fixes: commit 0e89640b640d ("crypto: arm64 - Use modern annotations for assembly functions") Signed-off-by: Jeremy Linton <jeremy.linton@arm.com> --- arch/arm64/crypto/aes-neonbs-core.S | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)