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target-ppc: implement darn instruction

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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.bangoria@linux.vnet.ibm.com>
Signed-off-by: Nikunj A Dadhania <nikunj@linux.vnet.ibm.com>
[dwg: Added minor clang warning fix for ppc32 target]
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
This commit is contained in:
Ravi Bangoria 2016-09-16 16:21:47 +05:30 committed by David Gibson
parent ddb9ac50ae
commit fec5c62a64
3 changed files with 38 additions and 0 deletions
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2
target-ppc/helper.h
View file

@ -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)

16
target-ppc/int_helper.c
View file

@ -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;
}
#endif
#if defined(TARGET_PPC64)

20
target-ppc/translate.c
View file

@ -528,6 +528,10 @@ EXTRACT_HELPER(FPW, 16, 1);
/* addpcis */
EXTRACT_HELPER_DXFORM(DX, 10, 6, 6, 5, 16, 1, 1, 0, 0)
#if defined(TARGET_PPC64)
/* darn */
EXTRACT_HELPER(L, 16, 2);
#endif
/*** Jump target decoding ***/
/* Immediate address */
@ -1895,6 +1899,21 @@ 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)]);
} else {
tcg_gen_movi_i64(cpu_gpr[rD(ctx->opcode)], -1);
}
}
#endif
/*** Integer rotate ***/
@ -6216,6 +6235,7 @@ 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