target/mips: Implement emulation of nanoMIPS LLWP/SCWP pair

Implement support for nanoMIPS LLWP/SCWP instructions. Beside
adding core functionality of these instructions, this patch adds
support for availability control via configuration bit XNP.

Backports commit 0b16dcd180bdbe3add9edea42c2374d427882661 from qemu
This commit is contained in:
Aleksandar Rikalo 2018-08-27 05:25:02 -04:00 committed by Lioncash
parent 128bfa00d2
commit 371bb5a134
No known key found for this signature in database
GPG key ID: 4E3C3CC1031BA9C7
2 changed files with 90 additions and 0 deletions

View file

@ -507,6 +507,8 @@ struct CPUMIPSState {
uint64_t lladdr;
target_ulong llval;
target_ulong llnewval;
uint64_t llval_wp;
uint32_t llnewval_wp;
target_ulong llreg;
uint64_t CP0_LLAddr_rw_bitmask;
int CP0_LLAddr_shift;

View file

@ -1922,6 +1922,18 @@ static inline void check_mvh(DisasContext *ctx)
}
#endif
/*
* This code generates a "reserved instruction" exception if the
* Config5 XNP bit is set.
*/
static inline void check_xnp(DisasContext *ctx)
{
if (unlikely(ctx->CP0_Config5 & (1 << CP0C5_XNP))) {
generate_exception_end(ctx, EXCP_RI);
}
}
/* Define small wrappers for gen_load_fpr* so that we have a uniform
calling interface for 32 and 64-bit FPRs. No sense in changing
all callers for gen_load_fpr32 when we need the CTX parameter for
@ -2377,6 +2389,32 @@ static void gen_ld(DisasContext *ctx, uint32_t opc,
tcg_temp_free(tcg_ctx, t0);
}
static void gen_llwp(DisasContext *ctx, uint32_t base, int16_t offset,
uint32_t reg1, uint32_t reg2)
{
TCGContext *tcg_ctx = ctx->uc->tcg_ctx;
TCGv taddr = tcg_temp_new(tcg_ctx);
TCGv_i64 tval = tcg_temp_new_i64(tcg_ctx);
TCGv tmp1 = tcg_temp_new(tcg_ctx);
TCGv tmp2 = tcg_temp_new(tcg_ctx);
gen_base_offset_addr(ctx, taddr, base, offset);
tcg_gen_qemu_ld64(ctx->uc, tval, taddr, ctx->mem_idx);
#ifdef TARGET_WORDS_BIGENDIAN
tcg_gen_extr_i64_tl(tcg_ctx, tmp2, tmp1, tval);
#else
tcg_gen_extr_i64_tl(tcg_ctx, tmp1, tmp2, tval);
#endif
gen_store_gpr(tcg_ctx, tmp1, reg1);
tcg_temp_free(tcg_ctx, tmp1);
gen_store_gpr(tcg_ctx, tmp2, reg2);
tcg_temp_free(tcg_ctx, tmp2);
tcg_gen_st_i64(tcg_ctx, tval, tcg_ctx->cpu_env, offsetof(CPUMIPSState, llval_wp));
tcg_temp_free_i64(tcg_ctx, tval);
tcg_gen_st_tl(tcg_ctx, taddr, tcg_ctx->cpu_env, offsetof(CPUMIPSState, lladdr));
tcg_temp_free(tcg_ctx, taddr);
}
/* Store */
static void gen_st (DisasContext *ctx, uint32_t opc, int rt,
int base, int offset)
@ -2475,6 +2513,52 @@ static void gen_st_cond (DisasContext *ctx, uint32_t opc, int rt,
tcg_temp_free(tcg_ctx, t0);
}
static void gen_scwp(DisasContext *ctx, uint32_t base, int16_t offset,
uint32_t reg1, uint32_t reg2)
{
TCGContext *tcg_ctx = ctx->uc->tcg_ctx;
TCGv taddr = tcg_temp_local_new(tcg_ctx);
TCGv lladdr = tcg_temp_local_new(tcg_ctx);
TCGv_i64 tval = tcg_temp_new_i64(tcg_ctx);
TCGv_i64 llval = tcg_temp_new_i64(tcg_ctx);
TCGv_i64 val = tcg_temp_new_i64(tcg_ctx);
TCGv tmp1 = tcg_temp_new(tcg_ctx);
TCGv tmp2 = tcg_temp_new(tcg_ctx);
TCGLabel *lab_fail = gen_new_label(tcg_ctx);
TCGLabel *lab_done = gen_new_label(tcg_ctx);
gen_base_offset_addr(ctx, taddr, base, offset);
tcg_gen_ld_tl(tcg_ctx, lladdr, tcg_ctx->cpu_env, offsetof(CPUMIPSState, lladdr));
tcg_gen_brcond_tl(tcg_ctx, TCG_COND_NE, taddr, lladdr, lab_fail);
gen_load_gpr(ctx, tmp1, reg1);
gen_load_gpr(ctx, tmp2, reg2);
#ifdef TARGET_WORDS_BIGENDIAN
tcg_gen_concat_tl_i64(tcg_ctx, tval, tmp2, tmp1);
#else
tcg_gen_concat_tl_i64(tcg_ctx, tval, tmp1, tmp2);
#endif
tcg_gen_ld_i64(tcg_ctx, llval, tcg_ctx->cpu_env, offsetof(CPUMIPSState, llval_wp));
tcg_gen_atomic_cmpxchg_i64(tcg_ctx, val, taddr, llval, tval,
ctx->mem_idx, MO_64);
if (reg1 != 0) {
tcg_gen_movi_tl(tcg_ctx, tcg_ctx->cpu_gpr[reg1], 1);
}
tcg_gen_brcond_i64(tcg_ctx, TCG_COND_EQ, val, llval, lab_done);
gen_set_label(tcg_ctx, lab_fail);
if (reg1 != 0) {
tcg_gen_movi_tl(tcg_ctx, tcg_ctx->cpu_gpr[reg1], 0);
}
gen_set_label(tcg_ctx, lab_done);
tcg_gen_movi_tl(tcg_ctx, lladdr, -1);
tcg_gen_st_tl(tcg_ctx, lladdr, tcg_ctx->cpu_env, offsetof(CPUMIPSState, lladdr));
}
/* Load and store */
static void gen_flt_ldst (DisasContext *ctx, uint32_t opc, int ft,
TCGv t0)
@ -18240,6 +18324,8 @@ static int decode_nanomips_32_48_opc(CPUMIPSState *env, DisasContext *ctx)
gen_ld(ctx, OPC_LL, rt, rs, s);
break;
case NM_LLWP:
check_xnp(ctx);
gen_llwp(ctx, rs, 0, rt, extract32(ctx->opcode, 3, 5));
break;
}
break;
@ -18249,6 +18335,8 @@ static int decode_nanomips_32_48_opc(CPUMIPSState *env, DisasContext *ctx)
gen_st_cond(ctx, OPC_SC, rt, rs, s);
break;
case NM_SCWP:
check_xnp(ctx);
gen_scwp(ctx, rs, 0, rt, extract32(ctx->opcode, 3, 5));
break;
}
break;