On Mon, Sep 12, 2016 at 12:11:40PM +0530, Nikunj A Dadhania wrote:
> From: Ravi Bangoria <ravi.bango...@linux.vnet.ibm.com>
>
> darn: Deliver A Random Number
>
> Currently return invalid random number for all the case. This needs
> proper algorithm to provide cryptographically suitable random data.
> Reading from /dev/random can block and that is not an expected behaviour
> while the cpu instruction is getting executed. Moreover, /dev/random
> would only work for linux-user
>
> Signed-off-by: Ravi Bangoria <ravi.bango...@linux.vnet.ibm.com>
> Signed-off-by: Nikunj A Dadhania <nik...@linux.vnet.ibm.com>
> ---
> target-ppc/helper.h | 2 ++
> target-ppc/int_helper.c | 16 ++++++++++++++++
> target-ppc/translate.c | 18 ++++++++++++++++++
> 3 files changed, 36 insertions(+)
>
> diff --git a/target-ppc/helper.h b/target-ppc/helper.h
> index e75d070..966f2ce 100644
> --- a/target-ppc/helper.h
> +++ b/target-ppc/helper.h
> @@ -50,6 +50,8 @@ DEF_HELPER_FLAGS_1(cnttzd, TCG_CALL_NO_RWG_SE, tl, tl)
> DEF_HELPER_FLAGS_1(popcntd, TCG_CALL_NO_RWG_SE, tl, tl)
> DEF_HELPER_FLAGS_2(bpermd, TCG_CALL_NO_RWG_SE, i64, i64, i64)
> DEF_HELPER_3(srad, tl, env, tl, tl)
> +DEF_HELPER_0(darn32, tl)
> +DEF_HELPER_0(darn64, tl)
> #endif
>
> DEF_HELPER_FLAGS_1(cntlsw32, TCG_CALL_NO_RWG_SE, i32, i32)
> diff --git a/target-ppc/int_helper.c b/target-ppc/int_helper.c
> index 291fba0..51a9ac5 100644
> --- a/target-ppc/int_helper.c
> +++ b/target-ppc/int_helper.c
> @@ -182,6 +182,22 @@ target_ulong helper_cnttzd(target_ulong t)
> {
> return ctz64(t);
> }
> +
> +/* Return invalid random number.
> + *
> + * FIXME: Add rng backend or other mechanism to get cryptographically
> suitable
> + * random number
> + */
> +target_ulong helper_darn32(void)
> +{
> + return -1;
> +}
> +
> +target_ulong helper_darn64(void)
> +{
> + return -1;
> +}
> +
TBH, I think you're going to want a single helper for both 32-bit and
64-bit cases.
> #endif
>
> #if defined(TARGET_PPC64)
> diff --git a/target-ppc/translate.c b/target-ppc/translate.c
> index 133c531..e9dad3f 100644
> --- a/target-ppc/translate.c
> +++ b/target-ppc/translate.c
> @@ -528,6 +528,8 @@ EXTRACT_HELPER(FPW, 16, 1);
>
> /* addpcis */
> EXTRACT_HELPER_DXFORM(DX, 10, 6, 6, 5, 16, 1, 1, 0, 0)
> +/* darn */
> +EXTRACT_HELPER(L, 16, 2);
>
> /*** Jump target decoding
> ***/
> /* Immediate address */
> @@ -1895,6 +1897,21 @@ static void gen_cnttzd(DisasContext *ctx)
> gen_set_Rc0(ctx, cpu_gpr[rA(ctx->opcode)]);
> }
> }
> +
> +/* darn */
> +static void gen_darn(DisasContext *ctx)
> +{
> + int l = L(ctx->opcode);
> +
> + if (l == 0) {
> + gen_helper_darn32(cpu_gpr[rD(ctx->opcode)]);
> + } else if (l <= 2) {
> + /* Return 64-bit random for both CRN and RRN */
> + gen_helper_darn64(cpu_gpr[rD(ctx->opcode)]);
So it might be simpler to just leave out the helper stubs for now, and
always return the invalid value from the generated code.
> + } else {
> + tcg_gen_movi_i64(cpu_gpr[rD(ctx->opcode)], -1);
> + }
> +}
> #endif
>
> /*** Integer rotate
> ***/
> @@ -6212,6 +6229,7 @@ GEN_HANDLER_E(prtyw, 0x1F, 0x1A, 0x04, 0x0000F801,
> PPC_NONE, PPC2_ISA205),
> GEN_HANDLER(popcntd, 0x1F, 0x1A, 0x0F, 0x0000F801, PPC_POPCNTWD),
> GEN_HANDLER(cntlzd, 0x1F, 0x1A, 0x01, 0x00000000, PPC_64B),
> GEN_HANDLER_E(cnttzd, 0x1F, 0x1A, 0x11, 0x00000000, PPC_NONE, PPC2_ISA300),
> +GEN_HANDLER_E(darn, 0x1F, 0x13, 0x17, 0x001CF801, PPC_NONE, PPC2_ISA300),
> GEN_HANDLER_E(prtyd, 0x1F, 0x1A, 0x05, 0x0000F801, PPC_NONE, PPC2_ISA205),
> GEN_HANDLER_E(bpermd, 0x1F, 0x1C, 0x07, 0x00000001, PPC_NONE,
> PPC2_PERM_ISA206),
> #endif
--
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
http://www.ozlabs.org/~dgibson
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