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| author | Hari Bathini <hbathini@linux.ibm.com> | 2022-06-10 18:55:50 +0300 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2022-06-29 12:37:08 +0300 |
| commit | 1e82dfaa7819f03f0b0022be7ca15bbc83090da1 (patch) | |
| tree | 37f5857b32825463b5deb8ca7875339d9dfe9412 /Documentation | |
| parent | dbe6e2456fb0263a5a961a92836d2cebdbca979c (diff) | |
| download | linux-1e82dfaa7819f03f0b0022be7ca15bbc83090da1.tar.xz | |
powerpc/bpf/64: Add instructions for atomic_[cmp]xchg
This adds two atomic opcodes BPF_XCHG and BPF_CMPXCHG on ppc64, both
of which include the BPF_FETCH flag. The kernel's atomic_cmpxchg
operation fundamentally has 3 operands, but we only have two register
fields. Therefore the operand we compare against (the kernel's API
calls it 'old') is hard-coded to be BPF_REG_R0. Also, kernel's
atomic_cmpxchg returns the previous value at dst_reg + off. JIT the
same for BPF too with return value put in BPF_REG_0.
BPF_REG_R0 = atomic_cmpxchg(dst_reg + off, BPF_REG_R0, src_reg);
Signed-off-by: Hari Bathini <hbathini@linux.ibm.com>
Tested-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> (ppc64le)
Reviewed-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220610155552.25892-4-hbathini@linux.ibm.com
Diffstat (limited to 'Documentation')
0 files changed, 0 insertions, 0 deletions