Messages in this thread | | | From | Puranjay Mohan <> | Subject | Re: [PATCH bpf-next 6/8] arm32, bpf: add support for 64 bit division instruction | Date | Wed, 06 Sep 2023 09:29:19 +0000 |
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On Tue, Sep 05 2023, Russell King (Oracle) wrote:
> On Tue, Sep 05, 2023 at 09:06:19PM +0000, Puranjay Mohan wrote: >> +cont: >> + >> + /* Call appropriate function */ >> + if (sign) >> + emit_mov_i(ARM_IP, op == BPF_DIV ? (u32)jit_sdiv64 : (u32)jit_smod64, ctx); >> + else >> + emit_mov_i(ARM_IP, op == BPF_DIV ? (u32)jit_udiv64 : (u32)jit_mod64, ctx); > > Same comment as the previous patch here.
Will fix both in next version.
> >> + >> + emit_blx_r(ARM_IP, ctx); >> + >> + /* Save return value */ >> + if (rd[1] != ARM_R0) { >> + emit(ARM_MOV_R(rd[0], ARM_R1), ctx); >> + emit(ARM_MOV_R(rd[1], ARM_R0), ctx); >> + } >> + >> + /* Recover {R1, R0} from stack if it is not Rd */ >> + if (rd[1] != ARM_R0) >> + emit(ARM_POP(BIT(ARM_R0) | BIT(ARM_R1)), ctx); >> + else >> + emit(ARM_ADD_I(ARM_SP, ARM_SP, 8), ctx); >> + >> + /* Recover {R3, R2} from stack if it is not Rd */ >> + if (rd[1] != ARM_R2) >> + emit(ARM_POP(BIT(ARM_R2) | BIT(ARM_R3)), ctx); >> + else >> + emit(ARM_ADD_I(ARM_SP, ARM_SP, 8), ctx); > > if (rd[1] != ARM_R0) { > emit(ARM_POP(BIT(ARM_R0) | BIT(ARM_R1)), ctx); > emit(ARM_ADD_I(ARM_SP, ARM_SP, 8), ctx); > } else if (rd[1] != ARM_R2) { > emit(ARM_ADD_I(ARM_SP, ARM_SP, 8), ctx); > emit(ARM_POP(BIT(ARM_R2) | BIT(ARM_R3)), ctx); > } else { > emit(ARM_ADD_I(ARM_SP, ARM_SP, 16), ctx); > } > > Hmm?
Actually, there can also be a situation where rd[1] != ARM_R0 && rd[1] != ARM_R2, so should I do it like:
if (rd[1] != ARM_R0 && rd[1] != ARM_R2) { emit(ARM_POP(BIT(ARM_R0) | BIT(ARM_R1)), ctx); emit(ARM_POP(BIT(ARM_R2) | BIT(ARM_R3)), ctx); } else if (rd[1] != ARM_R0) { emit(ARM_POP(BIT(ARM_R0) | BIT(ARM_R1)), ctx); emit(ARM_ADD_I(ARM_SP, ARM_SP, 8), ctx); } else if (rd[1] != ARM_R2) { emit(ARM_ADD_I(ARM_SP, ARM_SP, 8), ctx); emit(ARM_POP(BIT(ARM_R2) | BIT(ARM_R3)), ctx); } else { emit(ARM_ADD_I(ARM_SP, ARM_SP, 16), ctx); }
Thanks, Puranjay
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