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The generic storage implementation provides the same features as the
custom one. However it can be shared between architectures, making
maintenance easier.
Co-developed-by: Nam Cao <namcao@linutronix.de>
Signed-off-by: Nam Cao <namcao@linutronix.de>
Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Link: https://lore.kernel.org/all/20250204-vdso-store-rng-v3-14-13a4669dfc8c@linutronix.de
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Since the generic VDSO clock mode storage is used, this header file is
unused and can be removed.
This avoids including a non-VDSO header while building the VDSO,
which can lead to compilation errors.
Also drop the comment which is out of date and in the wrong place.
Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/20241010-vdso-generic-arch_update_vsyscall-v1-4-7fe5a3ea4382@linutronix.de
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To be consistent with other VDSO functions, the function is called
__kernel_getrandom()
__arch_chacha20_blocks_nostack() fonction is implemented basically
with 32 bits operations. It performs 4 QUARTERROUND operations in
parallele. There are enough registers to avoid using the stack:
On input:
r3: output bytes
r4: 32-byte key input
r5: 8-byte counter input/output
r6: number of 64-byte blocks to write to output
During operation:
stack: pointer to counter (r5) and non-volatile registers (r14-131)
r0: counter of blocks (initialised with r6)
r4: Value '4' after key has been read, used for indexing
r5-r12: key
r14-r15: block counter
r16-r31: chacha state
At the end:
r0, r6-r12: Zeroised
r5, r14-r31: Restored
Performance on powerpc 885 (using kernel selftest):
~# ./vdso_test_getrandom bench-single
vdso: 25000000 times in 62.938002291 seconds
libc: 25000000 times in 535.581916866 seconds
syscall: 25000000 times in 531.525042806 seconds
Performance on powerpc 8321 (using kernel selftest):
~# ./vdso_test_getrandom bench-single
vdso: 25000000 times in 16.899318858 seconds
libc: 25000000 times in 131.050596522 seconds
syscall: 25000000 times in 129.794790389 seconds
This first patch adds support for VDSO32. As selftests cannot easily
be generated only for VDSO32, and because the following patch brings
support for VDSO64 anyway, this patch opts out all code in
__arch_chacha20_blocks_nostack() so that vdso_test_chacha will not
fail to compile and will not crash on PPC64/PPC64LE, allthough the
selftest itself will fail.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Acked-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
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With the C VDSO, the performance is slightly lower, but it is worth
it as it will ease maintenance and evolution, and also brings clocks
that are not supported with the ASM VDSO.
On an 8xx at 132 MHz, vdsotest with the ASM VDSO:
gettimeofday: vdso: 828 nsec/call
clock-getres-realtime-coarse: vdso: 391 nsec/call
clock-gettime-realtime-coarse: vdso: 614 nsec/call
clock-getres-realtime: vdso: 460 nsec/call
clock-gettime-realtime: vdso: 876 nsec/call
clock-getres-monotonic-coarse: vdso: 399 nsec/call
clock-gettime-monotonic-coarse: vdso: 691 nsec/call
clock-getres-monotonic: vdso: 460 nsec/call
clock-gettime-monotonic: vdso: 1026 nsec/call
On an 8xx at 132 MHz, vdsotest with the C VDSO:
gettimeofday: vdso: 955 nsec/call
clock-getres-realtime-coarse: vdso: 545 nsec/call
clock-gettime-realtime-coarse: vdso: 592 nsec/call
clock-getres-realtime: vdso: 545 nsec/call
clock-gettime-realtime: vdso: 941 nsec/call
clock-getres-monotonic-coarse: vdso: 545 nsec/call
clock-gettime-monotonic-coarse: vdso: 591 nsec/call
clock-getres-monotonic: vdso: 545 nsec/call
clock-gettime-monotonic: vdso: 940 nsec/call
It is even better for gettime with monotonic clocks.
Unsupported clocks with ASM VDSO:
clock-gettime-boottime: vdso: 3851 nsec/call
clock-gettime-tai: vdso: 3852 nsec/call
clock-gettime-monotonic-raw: vdso: 3396 nsec/call
Same clocks with C VDSO:
clock-gettime-tai: vdso: 941 nsec/call
clock-gettime-monotonic-raw: vdso: 1001 nsec/call
clock-gettime-monotonic-coarse: vdso: 591 nsec/call
On an 8321E at 333 MHz, vdsotest with the ASM VDSO:
gettimeofday: vdso: 220 nsec/call
clock-getres-realtime-coarse: vdso: 102 nsec/call
clock-gettime-realtime-coarse: vdso: 178 nsec/call
clock-getres-realtime: vdso: 129 nsec/call
clock-gettime-realtime: vdso: 235 nsec/call
clock-getres-monotonic-coarse: vdso: 105 nsec/call
clock-gettime-monotonic-coarse: vdso: 208 nsec/call
clock-getres-monotonic: vdso: 129 nsec/call
clock-gettime-monotonic: vdso: 274 nsec/call
On an 8321E at 333 MHz, vdsotest with the C VDSO:
gettimeofday: vdso: 272 nsec/call
clock-getres-realtime-coarse: vdso: 160 nsec/call
clock-gettime-realtime-coarse: vdso: 184 nsec/call
clock-getres-realtime: vdso: 166 nsec/call
clock-gettime-realtime: vdso: 281 nsec/call
clock-getres-monotonic-coarse: vdso: 160 nsec/call
clock-gettime-monotonic-coarse: vdso: 184 nsec/call
clock-getres-monotonic: vdso: 169 nsec/call
clock-gettime-monotonic: vdso: 275 nsec/call
On a Power9 Nimbus DD2.2 at 3.8GHz, with the ASM VDSO:
clock-gettime-monotonic: vdso: 35 nsec/call
clock-getres-monotonic: vdso: 16 nsec/call
clock-gettime-monotonic-coarse: vdso: 18 nsec/call
clock-getres-monotonic-coarse: vdso: 522 nsec/call
clock-gettime-monotonic-raw: vdso: 598 nsec/call
clock-getres-monotonic-raw: vdso: 520 nsec/call
clock-gettime-realtime: vdso: 34 nsec/call
clock-getres-realtime: vdso: 16 nsec/call
clock-gettime-realtime-coarse: vdso: 18 nsec/call
clock-getres-realtime-coarse: vdso: 517 nsec/call
getcpu: vdso: 8 nsec/call
gettimeofday: vdso: 25 nsec/call
And with the C VDSO:
clock-gettime-monotonic: vdso: 37 nsec/call
clock-getres-monotonic: vdso: 20 nsec/call
clock-gettime-monotonic-coarse: vdso: 21 nsec/call
clock-getres-monotonic-coarse: vdso: 19 nsec/call
clock-gettime-monotonic-raw: vdso: 38 nsec/call
clock-getres-monotonic-raw: vdso: 20 nsec/call
clock-gettime-realtime: vdso: 37 nsec/call
clock-getres-realtime: vdso: 20 nsec/call
clock-gettime-realtime-coarse: vdso: 20 nsec/call
clock-getres-realtime-coarse: vdso: 19 nsec/call
getcpu: vdso: 8 nsec/call
gettimeofday: vdso: 28 nsec/call
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20201126131006.2431205-8-mpe@ellerman.id.au
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