Re: git: 3a60869237b8 - main - Add assembly optimized code for OpenSSL on powerpc, powerpc64 and powerpc64le

On Wed, Nov 24, 2021 at 6:52 PM Piotr Kubaj <pkubaj@anongoth.pl> wrote:

> On 21-11-24 10:34:36, John Baldwin wrote:
> > On 11/24/21 10:24 AM, Piotr Kubaj wrote:
> > > OK, it looks like ossl uses fpu_kern functions and those are available
> only an aarch64, amd64 and i386:
> > > cc  -O2 -pipe -fno-common  -fno-strict-aliasing -Werror -D_KERNEL
> -DKLD_MODULE -nostdinc   -include
> /usr/obj/usr/src/powerpc.powerpc64/sys/modules/ossl/opt_global.h -I.
> -I/usr/src/sys -I/usr/src/sys/contrib/ck/include -fno-common  -fPIC
> -mlongcall -fno-omit-frame-pointer
> -fdebug-prefix-map=./machine=/usr/src/sys/powerpc/include     -MD
> -MF.depend.ossl.o -MTossl.o -mno-altivec -msoft-float -mabi=elfv2
> -ffreestanding -fwrapv -fstack-protector -Wall -Wredundant-decls
> -Wnested-externs -Wstrict-prototypes -Wmissing-prototypes -Wpointer-arith
> -Wcast-qual -Wundef -Wno-pointer-sign -D__printf__=__freebsd_kprintf__
> -Wmissing-include-dirs -fdiagnostics-show-option -Wno-unknown-pragmas
> -Wno-error-tautological-compare -Wno-error-empty-body
> -Wno-error-parentheses-equality -Wno-error-unused-function
> -Wno-error-pointer-sign -Wno-error-shift-negative-value
> -Wno-address-of-packed-member -Wno-format-zero-length     -std=iso9899:1999
> -c /usr/src/sys/crypto/openssl/ossl.c -o ossl.o
> > > /usr/src/sys/crypto/openssl/ossl.c:190:4: error: implicit declaration
> of function 'fpu_kern_enter' is invalid in C99
> [-Werror,-Wimplicit-function-declaration]
> > >                          fpu_kern_enter(curthread, NULL,
> FPU_KERN_NOCTX);
> > >                          ^
> > > /usr/src/sys/crypto/openssl/ossl.c:190:36: error: use of undeclared
> identifier 'FPU_KERN_NOCTX'
> > >                          fpu_kern_enter(curthread, NULL,
> FPU_KERN_NOCTX);
> > >                                                          ^
> > > /usr/src/sys/crypto/openssl/ossl.c:193:4: error: implicit declaration
> of function 'fpu_kern_leave' is invalid in C99
> [-Werror,-Wimplicit-function-declaration]
> > >                          fpu_kern_leave(curthread, NULL);
> > >                          ^
> > > /usr/src/sys/crypto/openssl/ossl.c:193:4: note: did you mean
> 'fpu_kern_enter'?
> > > /usr/src/sys/crypto/openssl/ossl.c:190:4: note: 'fpu_kern_enter'
> declared here
> > >                          fpu_kern_enter(curthread, NULL,
> FPU_KERN_NOCTX);
> > >                          ^
> > > /usr/src/sys/crypto/openssl/ossl.c:214:6: error: implicit declaration
> of function 'is_fpu_kern_thread' is invalid in C99
> [-Werror,-Wimplicit-function-declaration]
> > >          if (is_fpu_kern_thread(0)) {
> > >              ^
> > > /usr/src/sys/crypto/openssl/ossl.c:217:3: error: implicit declaration
> of function 'fpu_kern_enter' is invalid in C99
> [-Werror,-Wimplicit-function-declaration]
> > >                  fpu_kern_enter(curthread, NULL, FPU_KERN_NOCTX);
> > >                  ^
> > > /usr/src/sys/crypto/openssl/ossl.c:217:35: error: use of undeclared
> identifier 'FPU_KERN_NOCTX'
> > >                  fpu_kern_enter(curthread, NULL, FPU_KERN_NOCTX);
> > >                                                  ^
> > > /usr/src/sys/crypto/openssl/ossl.c:263:3: error: implicit declaration
> of function 'fpu_kern_leave' is invalid in C99
> [-Werror,-Wimplicit-function-declaration]
> > >                  fpu_kern_leave(curthread, NULL);
> > >                  ^
> > > 7 errors generated.
> > >
> > > AFAIK porting those is not easy and it's certainly above my pay grade.
> >
> > Do the powerpc instructions use additional registers that are not part
> of the normal
> > GPRs saved/restored on a context switch?  If so, then, yes, you will
> need to implement
> > something here (though the FPU_KERN_NOCTX variant is a bit simpler as it
> disables
> > context switches and it's sufficient just to init the registers and
> permit accesses
> > without raising a trap until fpu_kern_leave).  If not, then you can make
> the use of
> > those functions conditional on architecture.
>
> I guess bdragon, jhibbits, luporl or adalava would be better source of
> information.
>
> That said, after looking at
> https://community.nxp.com/t5/MPC5xxx/Example-code-for-context-switch-for-MPC56XX-PowerPC/m-p/732248/highlight/true,
> it seems like indeed registers other than GPRs are saved and restored.
>
>
> I tried looking at
> https://cgit.freebsd.org/src/diff/?id=6ed982a221e024d64dd0ab776e6197643fa1530e.
> fpu_kern_enter() and fpu_kern_leave() are quite scary :)
>
>
AFAIK, non-integer registers are also saved/restored on a context switch on
PowerPC, but only if there is an underlying user process that has used any
FPU/Altivec/VSX instruction.
I guess it will need some adjustments if the kernel itself starts using
those registers.


> >
> > > On 21-11-24 08:15:26, John Baldwin wrote:
> > >> On 11/23/21 2:27 PM, Piotr Kubaj wrote:
> > >>> The branch main has been updated by pkubaj (ports committer):
> > >>>
> > >>> URL:
> https://cgit.FreeBSD.org/src/commit/?id=3a60869237b8b315fe66497cf5299ec08b688533
> > >>>
> > >>> commit 3a60869237b8b315fe66497cf5299ec08b688533
> > >>> Author:     Piotr Kubaj <pkubaj@FreeBSD.org>
> > >>> AuthorDate: 2021-11-22 02:28:46 +0000
> > >>> Commit:     Piotr Kubaj <pkubaj@FreeBSD.org>
> > >>> CommitDate: 2021-11-23 22:26:53 +0000
> > >>>
> > >>>       Add assembly optimized code for OpenSSL on powerpc, powerpc64
> and powerpc64le
> > >>>
> > >>>       Summary:
> > >>>       1.
> https://github.com/openssl/openssl/commit/34ab13b7d8e3e723adb60be8142e38b7c9cd382a
> > >>>       needs to be merged for ELFv2 support on big-endian.
> > >>>       2. crypto/openssl/crypto/ppccap.c needs to be patched.
> > >>>       Same reason as in
> https://github.com/openssl/openssl/pull/17082.
> > >>
> > >> Have you looked at adding powerpc support to ossl(4)?  It should be
> fairly simple
> > >> (just adding the right asm files in Makefiles and the powerpc
> equivalent of
> > >> OSSL_cpuid).
> > >>
> > >> --
> > >> John Baldwin
> >
> >
> > --
> > John Baldwin
>
> --
>