[PATCH v3][BPF] cpu: fix offset16 type, update c-calls in bpf.cpu

[Jose E. Marchesi]

Hi David.

    Correct the type of the offset16 field to HI, and simplify memory
    accesses which use it. Also update c-calls in semantics for a
    few instructions.

Applied in master.
Thanks.
    
    cpu/
    2020-06-25 David Faust  <david.faust@oracle.com>
    
    	* bpf.cpu (f-offset16): Change type from INT to HI.
    	(dxli): Simplify memory access.
    	(dxsi): Likewise.
    	(define-endian-insn): Update c-call in semantics.
    	(dlabs) Likewise.
    	(dlind) Likewise.
    ---
    
    --- a/cpu/bpf.cpu
    +++ b/cpu/bpf.cpu
    @@ -273,7 +273,7 @@
     ;; difficulty: we put them in their own instruction word so the
     ;; byte-endianness will be properly applied.
     
    -(dwf f-offset16 "eBPF offset field" (all-isas) 16 16 15 16 INT)
    +(dwf f-offset16 "eBPF offset field" (all-isas) 16 16 15 16 HI)
     (dwf f-imm32 "eBPF 32-bit immediate field" (all-isas) 32 32 31 32 INT)
     
     ;; For the disjoint 64-bit signed immediate, however, we need to use a
    @@ -488,7 +488,7 @@
            (+  (f-offset16 0) ((.sym f-src x-endian) 0) (.sym dst x-endian) endsize
                OP_CLASS_ALU x-op-src OP_CODE_END)
            (set (.sym dst x-endian)
    -            (c-call DI "bpfbf_end" (.sym dst x-endian) endsize))
    +            (c-call DI (.str "bpfbf_end" x-suffix) (.sym dst x-endian) endsize))
            ()))
     
     (define-endian-insn "le" OP_SRC_K le)
    @@ -538,11 +538,7 @@
                           (mem DI
                                (add DI
                                     (reg DI h-gpr 6) ;; Pointer to struct sk_buff
    -                                (const DI 0)))   ;; XXX offsetof
    -                      ;; (struct sk_buff, data) XXX but the offset
    -                      ;; depends on CONFIG_* options, so this should
    -                      ;; be configured in the simulator and driven by
    -                      ;; command-line options.  Handle with a c-call.
    +                                (c-call "bpfbf_skb_data_offset")))
                           imm32)))
            ;; XXX this clobbers R1-R5
            ()))
    @@ -572,11 +568,7 @@
                           (mem DI
                                (add DI
                                     (reg DI h-gpr 6) ;; Pointer to struct sk_buff
    -                                (const DI 0)))   ;; XXX offsetof
    -                      ;; (struct sk_buff, data) XXX but the offset
    -                      ;; depends on CONFIG_* options, so this should
    -                      ;; be configured in the simulator and driven by
    -                      ;; command-line options.  Handle with a c-call.
    +                                (c-call "bpfbf_skb_data_offset")))
                           (add DI
                                (.sym src x-endian)
                                imm32))))
    @@ -612,7 +604,7 @@
               OP_CLASS_LDX (.sym OP_SIZE_ x-size) OP_MODE_MEM)
            (set x-mode
                 (.sym dst x-endian)
    -            (mem x-mode (add DI (.sym src x-endian) (ext DI (trunc HI offset16)))))
    +            (mem x-mode (add DI (.sym src x-endian) offset16)))
            ()))
     
     (define-pmacro (dxsi x-basename x-suffix x-size x-endian x-mode)
    @@ -623,7 +615,7 @@
            (+ (f-imm32 0) offset16 (.sym src x-endian) (.sym dst x-endian)
               OP_CLASS_STX (.sym OP_SIZE_ x-size) OP_MODE_MEM)
            (set x-mode
    -            (mem x-mode (add DI (.sym dst x-endian) (ext DI (trunc HI offset16))))
    +            (mem x-mode (add DI (.sym dst x-endian) offset16))
                 (.sym src x-endian)) ;; XXX address is section-relative
            ()))