diff options
| author | Jason A. Donenfeld <Jason@zx2c4.com> | 2024-09-22 03:45:29 +0200 |
|---|---|---|
| committer | Gopher Robot <gobot@golang.org> | 2024-09-28 01:07:09 +0000 |
| commit | eb6f2c24cd17c0ca1df7e343f8d9187eef7d6e13 (patch) | |
| tree | d76c58100622eb5d33e3ffc451dd726a3dd898bd /src/runtime/sys_linux_amd64.s | |
| parent | 677b6cc17544e5e667d4bb67d063f5d775c69e32 (diff) | |
| download | go-eb6f2c24cd17c0ca1df7e343f8d9187eef7d6e13.tar.xz | |
runtime: use vDSO for getrandom() on linux
Linux 6.11 supports calling getrandom() from the vDSO. It operates on a
thread-local opaque state allocated with mmap using flags specified by
the vDSO.
Opaque states are allocated in chunks, ideally ncpu at a time as a hint,
rounding up to as many fit in a complete page. On first use, a state is
assigned to an m, which owns that state, until the m exits, at which
point it is given back to the pool.
Performance appears to be quite good:
│ sec/op │ sec/op vs base │
Read/4-16 222.45n ± 3% 27.13n ± 6% -87.80% (p=0.000 n=10)
│ B/s │ B/s vs base │
Read/4-16 17.15Mi ± 3% 140.61Mi ± 6% +719.82% (p=0.000 n=10)
Fixes #69577.
Change-Id: Ib6f44e8f2f3940c94d970eaada0eb566ec297dc7
Reviewed-on: https://go-review.googlesource.com/c/go/+/614835
Reviewed-by: Filippo Valsorda <filippo@golang.org>
Reviewed-by: Cuong Manh Le <cuong.manhle.vn@gmail.com>
Auto-Submit: Jason Donenfeld <Jason@zx2c4.com>
Reviewed-by: Paul Murphy <murp@ibm.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: David Chase <drchase@google.com>
Reviewed-by: Michael Pratt <mpratt@google.com>
Diffstat (limited to 'src/runtime/sys_linux_amd64.s')
| -rw-r--r-- | src/runtime/sys_linux_amd64.s | 33 |
1 files changed, 33 insertions, 0 deletions
diff --git a/src/runtime/sys_linux_amd64.s b/src/runtime/sys_linux_amd64.s index b6c64dc095..941f70b0e8 100644 --- a/src/runtime/sys_linux_amd64.s +++ b/src/runtime/sys_linux_amd64.s @@ -704,3 +704,36 @@ TEXT runtime·sbrk0(SB),NOSPLIT,$0-8 SYSCALL MOVQ AX, ret+0(FP) RET + +// func vgetrandom1(buf *byte, length uintptr, flags uint32, state uintptr, stateSize uintptr) int +TEXT runtime·vgetrandom1<ABIInternal>(SB),NOSPLIT,$16-48 + MOVQ SI, R8 // stateSize + MOVL CX, DX // flags + MOVQ DI, CX // state + MOVQ BX, SI // length + MOVQ AX, DI // buf + + MOVQ SP, R12 + + MOVQ runtime·vdsoGetrandomSym(SB), AX + MOVQ g_m(R14), BX + + MOVQ m_vdsoPC(BX), R9 + MOVQ R9, 0(SP) + MOVQ m_vdsoSP(BX), R9 + MOVQ R9, 8(SP) + LEAQ buf+0(FP), R9 + MOVQ R9, m_vdsoSP(BX) + MOVQ -8(R9), R9 + MOVQ R9, m_vdsoPC(BX) + + ANDQ $~15, SP + + CALL AX + + MOVQ R12, SP + MOVQ 8(SP), R9 + MOVQ R9, m_vdsoSP(BX) + MOVQ 0(SP), R9 + MOVQ R9, m_vdsoPC(BX) + RET |