summaryrefslogtreecommitdiff
path: root/arch/s390/kernel/vdso64/vgetrandom-chacha.S
AgeCommit message (Collapse)Author
2024-09-23s390/vdso: Use one large alternative instead of an alternative branchHeiko Carstens
Replace the alternative branch with a larger alternative that contains both paths. That way the two paths are closer together and it is easier to change both paths if the need should arise. Signed-off-by: Heiko Carstens <hca@linux.ibm.com> Reviewed-by: Jens Remus <jremus@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2024-09-23s390/vdso: Use SYM_DATA_START_LOCAL()/SYM_DATA_END() for data objectsHeiko Carstens
Use SYM_DATA_START_LOCAL()/SYM_DATA_END() in vgetrandom-chacha.S so that the constants end up in an object with correct size: readelf -Ws vgetrandom-chacha.o Num: Value Size Type Bind Vis Ndx Name ... 5: 0000000000000000 32 OBJECT LOCAL DEFAULT 5 chacha20_constants Signed-off-by: Heiko Carstens <hca@linux.ibm.com> Reviewed-by: Jens Remus <jremus@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2024-09-23s390/vdso: Add CFI annotations to __arch_chacha20_blocks_nostack()Jens Remus
This allows proper unwinding, for instance when using a debugger such as GDB. Signed-off-by: Jens Remus <jremus@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com> Acked-by: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2024-09-23s390/vdso: Fix comment within __arch_chacha20_blocks_nostack()Heiko Carstens
Fix comment within __arch_chacha20_blocks_nostack() so the comment reflects what the code is doing. Signed-off-by: Heiko Carstens <hca@linux.ibm.com> Reviewed-by: Jens Remus <jremus@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2024-09-23s390/vdso: Get rid of permutation constantsHeiko Carstens
The three byte masks for VECTOR PERMUTE are not needed, since the instruction VECTOR SHIFT LEFT DOUBLE BY BYTE can be used to implement the required "rotate left" easily. Signed-off-by: Heiko Carstens <hca@linux.ibm.com> Reviewed-by: Jens Remus <jremus@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2024-09-13s390/vdso: Wire up getrandom() vdso implementationHeiko Carstens
Provide the s390 specific vdso getrandom() architecture backend. _vdso_rng_data required data is placed within the _vdso_data vvar page, by using a hardcoded offset larger than vdso_data. As required the chacha20 implementation does not write to the stack. The implementation follows more or less the arm64 implementations and makes use of vector instructions. It has a fallback to the getrandom() system call for machines where the vector facility is not installed. The check if the vector facility is installed, as well as an optimization for machines with the vector-enhancements facility 2, is implemented with alternatives, avoiding runtime checks. Note that __kernel_getrandom() is implemented without the vdso user wrapper which would setup a stack frame for odd cases (aka very old glibc variants) where the caller has not done that. All callers of __kernel_getrandom() are required to setup a stack frame, like the C ABI requires it. The vdso testcases vdso_test_getrandom and vdso_test_chacha pass. Benchmark on a z16: $ ./vdso_test_getrandom bench-single vdso: 25000000 times in 0.493703559 seconds syscall: 25000000 times in 6.584025337 seconds Signed-off-by: Heiko Carstens <hca@linux.ibm.com> Reviewed-by: Harald Freudenberger <freude@linux.ibm.com> Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>