2d9206b227
This adds two atomic opcodes BPF_XCHG and BPF_CMPXCHG on ppc32, 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/20220610155552.25892-6-hbathini@linux.ibm.com
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.