target-arm: A64: expand decoding skeleton for system instructions
Decode the various kinds of system instructions: hints (HINT), which include NOP, YIELD, WFE, WFI, SEV, SEL sync instructions, which include CLREX, DSB, DMB, ISB msr_i, which move immediate to processor state field sys, which include all SYS and SYSL instructions msr, which move from a gp register to a system register mrs, which move from a system register to a gp register Provide implementations where they are trivial nops. Signed-off-by: Claudio Fontana <claudio.fontana@linaro.org> Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Richard Henderson <rth@twiddle.net>
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@ -190,12 +190,139 @@ static void disas_cond_b_imm(DisasContext *s, uint32_t insn)
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unsupported_encoding(s, insn);
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unsupported_encoding(s, insn);
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}
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}
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/* System */
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/* C5.6.68 HINT */
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static void disas_system(DisasContext *s, uint32_t insn)
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static void handle_hint(DisasContext *s, uint32_t insn,
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unsigned int op1, unsigned int op2, unsigned int crm)
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{
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unsigned int selector = crm << 3 | op2;
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if (op1 != 3) {
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unallocated_encoding(s);
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return;
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}
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switch (selector) {
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case 0: /* NOP */
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return;
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case 1: /* YIELD */
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case 2: /* WFE */
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case 3: /* WFI */
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case 4: /* SEV */
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case 5: /* SEVL */
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/* we treat all as NOP at least for now */
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return;
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default:
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/* default specified as NOP equivalent */
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return;
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}
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}
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/* CLREX, DSB, DMB, ISB */
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static void handle_sync(DisasContext *s, uint32_t insn,
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unsigned int op1, unsigned int op2, unsigned int crm)
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{
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if (op1 != 3) {
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unallocated_encoding(s);
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return;
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}
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switch (op2) {
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case 2: /* CLREX */
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unsupported_encoding(s, insn);
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return;
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case 4: /* DSB */
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case 5: /* DMB */
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case 6: /* ISB */
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/* We don't emulate caches so barriers are no-ops */
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return;
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default:
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unallocated_encoding(s);
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return;
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}
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}
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/* C5.6.130 MSR (immediate) - move immediate to processor state field */
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static void handle_msr_i(DisasContext *s, uint32_t insn,
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unsigned int op1, unsigned int op2, unsigned int crm)
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{
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{
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unsupported_encoding(s, insn);
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unsupported_encoding(s, insn);
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}
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}
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/* C5.6.204 SYS */
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static void handle_sys(DisasContext *s, uint32_t insn, unsigned int l,
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unsigned int op1, unsigned int op2,
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unsigned int crn, unsigned int crm, unsigned int rt)
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{
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unsupported_encoding(s, insn);
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}
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/* C5.6.129 MRS - move from system register */
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static void handle_mrs(DisasContext *s, uint32_t insn, unsigned int op0,
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unsigned int op1, unsigned int op2,
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unsigned int crn, unsigned int crm, unsigned int rt)
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{
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unsupported_encoding(s, insn);
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}
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/* C5.6.131 MSR (register) - move to system register */
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static void handle_msr(DisasContext *s, uint32_t insn, unsigned int op0,
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unsigned int op1, unsigned int op2,
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unsigned int crn, unsigned int crm, unsigned int rt)
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{
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unsupported_encoding(s, insn);
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}
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/* C3.2.4 System
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* 31 22 21 20 19 18 16 15 12 11 8 7 5 4 0
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* +---------------------+---+-----+-----+-------+-------+-----+------+
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* | 1 1 0 1 0 1 0 1 0 0 | L | op0 | op1 | CRn | CRm | op2 | Rt |
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* +---------------------+---+-----+-----+-------+-------+-----+------+
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*/
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static void disas_system(DisasContext *s, uint32_t insn)
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{
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unsigned int l, op0, op1, crn, crm, op2, rt;
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l = extract32(insn, 21, 1);
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op0 = extract32(insn, 19, 2);
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op1 = extract32(insn, 16, 3);
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crn = extract32(insn, 12, 4);
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crm = extract32(insn, 8, 4);
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op2 = extract32(insn, 5, 3);
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rt = extract32(insn, 0, 5);
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if (op0 == 0) {
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if (l || rt != 31) {
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unallocated_encoding(s);
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return;
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}
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switch (crn) {
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case 2: /* C5.6.68 HINT */
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handle_hint(s, insn, op1, op2, crm);
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break;
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case 3: /* CLREX, DSB, DMB, ISB */
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handle_sync(s, insn, op1, op2, crm);
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break;
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case 4: /* C5.6.130 MSR (immediate) */
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handle_msr_i(s, insn, op1, op2, crm);
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break;
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default:
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unallocated_encoding(s);
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break;
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}
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return;
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}
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if (op0 == 1) {
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/* C5.6.204 SYS */
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handle_sys(s, insn, l, op1, op2, crn, crm, rt);
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} else if (l) { /* op0 > 1 */
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/* C5.6.129 MRS - move from system register */
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handle_mrs(s, insn, op0, op1, op2, crn, crm, rt);
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} else {
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/* C5.6.131 MSR (register) - move to system register */
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handle_msr(s, insn, op0, op1, op2, crn, crm, rt);
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}
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}
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/* Exception generation */
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/* Exception generation */
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static void disas_exc(DisasContext *s, uint32_t insn)
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static void disas_exc(DisasContext *s, uint32_t insn)
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{
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{
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