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op_helper.c
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/*
* ARM helper routines
*
* Copyright (c) 2005-2007 CodeSourcery, LLC
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, see <http://www.gnu.org/licenses/>.
*/
#include "qemu/osdep.h"
#include "cpu.h"
#include "exec/helper-proto.h"
#include "internals.h"
#include "exec/exec-all.h"
#include "exec/cpu_ldst.h"
#define SIGNBIT (uint32_t)0x80000000
#define SIGNBIT64 ((uint64_t)1 << 63)
static void raise_exception(CPUARMState *env, uint32_t excp,
uint32_t syndrome, uint32_t target_el)
{
CPUState *cs = CPU(arm_env_get_cpu(env));
assert(!excp_is_internal(excp));
cs->exception_index = excp;
env->exception.syndrome = syndrome;
env->exception.target_el = target_el;
cpu_loop_exit(cs);
}
static int exception_target_el(CPUARMState *env)
{
int target_el = MAX(1, arm_current_el(env));
/* No such thing as secure EL1 if EL3 is aarch32, so update the target EL
* to EL3 in this case.
*/
if (arm_is_secure(env) && !arm_el_is_aa64(env, 3) && target_el == 1) {
target_el = 3;
}
return target_el;
}
uint32_t HELPER(neon_tbl)(CPUARMState *env, uint32_t ireg, uint32_t def,
uint32_t rn, uint32_t maxindex)
{
uint32_t val;
uint32_t tmp;
int index;
int shift;
uint64_t *table;
table = (uint64_t *)&env->vfp.regs[rn];
val = 0;
for (shift = 0; shift < 32; shift += 8) {
index = (ireg >> shift) & 0xff;
if (index < maxindex) {
tmp = (table[index >> 3] >> ((index & 7) << 3)) & 0xff;
val |= tmp << shift;
} else {
val |= def & (0xff << shift);
}
}
return val;
}
#if !defined(CONFIG_USER_ONLY)
static inline uint32_t merge_syn_data_abort(uint32_t template_syn,
unsigned int target_el,
bool same_el,
bool s1ptw, int is_write,
int fsc)
{
uint32_t syn;
/* ISV is only set for data aborts routed to EL2 and
* never for stage-1 page table walks faulting on stage 2.
*
* Furthermore, ISV is only set for certain kinds of load/stores.
* If the template syndrome does not have ISV set, we should leave
* it cleared.
*
* See ARMv8 specs, D7-1974:
* ISS encoding for an exception from a Data Abort, the
* ISV field.
*/
if (!(template_syn & ARM_EL_ISV) || target_el != 2 || s1ptw) {
syn = syn_data_abort_no_iss(same_el,
0, 0, s1ptw, is_write == 1, fsc);
} else {
/* Fields: IL, ISV, SAS, SSE, SRT, SF and AR come from the template
* syndrome created at translation time.
* Now we create the runtime syndrome with the remaining fields.
*/
syn = syn_data_abort_with_iss(same_el,
0, 0, 0, 0, 0,
0, 0, s1ptw, is_write == 1, fsc,
false);
/* Merge the runtime syndrome with the template syndrome. */
syn |= template_syn;
}
return syn;
}
/* try to fill the TLB and return an exception if error. If retaddr is
* NULL, it means that the function was called in C code (i.e. not
* from generated code or from helper.c)
*/
void tlb_fill(CPUState *cs, target_ulong addr, int is_write, int mmu_idx,
uintptr_t retaddr)
{
bool ret;
uint32_t fsr = 0;
ARMMMUFaultInfo fi = {};
ret = arm_tlb_fill(cs, addr, is_write, mmu_idx, &fsr, &fi);
if (unlikely(ret)) {
ARMCPU *cpu = ARM_CPU(cs);
CPUARMState *env = &cpu->env;
uint32_t syn, exc;
unsigned int target_el;
bool same_el;
if (retaddr) {
/* now we have a real cpu fault */
cpu_restore_state(cs, retaddr);
}
target_el = exception_target_el(env);
if (fi.stage2) {
target_el = 2;
env->cp15.hpfar_el2 = extract64(fi.s2addr, 12, 47) << 4;
}
same_el = arm_current_el(env) == target_el;
/* AArch64 syndrome does not have an LPAE bit */
syn = fsr & ~(1 << 9);
/* For insn and data aborts we assume there is no instruction syndrome
* information; this is always true for exceptions reported to EL1.
*/
if (is_write == 2) {
syn = syn_insn_abort(same_el, 0, fi.s1ptw, syn);
exc = EXCP_PREFETCH_ABORT;
} else {
syn = merge_syn_data_abort(env->exception.syndrome, target_el,
same_el, fi.s1ptw, is_write, syn);
if (is_write == 1 && arm_feature(env, ARM_FEATURE_V6)) {
fsr |= (1 << 11);
}
exc = EXCP_DATA_ABORT;
}
env->exception.vaddress = addr;
env->exception.fsr = fsr;
raise_exception(env, exc, syn, target_el);
}
}
/* Raise a data fault alignment exception for the specified virtual address */
void arm_cpu_do_unaligned_access(CPUState *cs, vaddr vaddr, int is_write,
int is_user, uintptr_t retaddr)
{
ARMCPU *cpu = ARM_CPU(cs);
CPUARMState *env = &cpu->env;
int target_el;
bool same_el;
uint32_t syn;
if (retaddr) {
/* now we have a real cpu fault */
cpu_restore_state(cs, retaddr);
}
target_el = exception_target_el(env);
same_el = (arm_current_el(env) == target_el);
env->exception.vaddress = vaddr;
/* the DFSR for an alignment fault depends on whether we're using
* the LPAE long descriptor format, or the short descriptor format
*/
if (arm_s1_regime_using_lpae_format(env, cpu_mmu_index(env, false))) {
env->exception.fsr = 0x21;
} else {
env->exception.fsr = 0x1;
}
if (is_write == 1 && arm_feature(env, ARM_FEATURE_V6)) {
env->exception.fsr |= (1 << 11);
}
syn = merge_syn_data_abort(env->exception.syndrome, target_el,
same_el, 0, is_write, 0x21);
raise_exception(env, EXCP_DATA_ABORT, syn, target_el);
}
#endif /* !defined(CONFIG_USER_ONLY) */
uint32_t HELPER(add_setq)(CPUARMState *env, uint32_t a, uint32_t b)
{
uint32_t res = a + b;
if (((res ^ a) & SIGNBIT) && !((a ^ b) & SIGNBIT))
env->QF = 1;
return res;
}
uint32_t HELPER(add_saturate)(CPUARMState *env, uint32_t a, uint32_t b)
{
uint32_t res = a + b;
if (((res ^ a) & SIGNBIT) && !((a ^ b) & SIGNBIT)) {
env->QF = 1;
res = ~(((int32_t)a >> 31) ^ SIGNBIT);
}
return res;
}
uint32_t HELPER(sub_saturate)(CPUARMState *env, uint32_t a, uint32_t b)
{
uint32_t res = a - b;
if (((res ^ a) & SIGNBIT) && ((a ^ b) & SIGNBIT)) {
env->QF = 1;
res = ~(((int32_t)a >> 31) ^ SIGNBIT);
}
return res;
}
uint32_t HELPER(double_saturate)(CPUARMState *env, int32_t val)
{
uint32_t res;
if (val >= 0x40000000) {
res = ~SIGNBIT;
env->QF = 1;
} else if (val <= (int32_t)0xc0000000) {
res = SIGNBIT;
env->QF = 1;
} else {
res = val << 1;
}
return res;
}
uint32_t HELPER(add_usaturate)(CPUARMState *env, uint32_t a, uint32_t b)
{
uint32_t res = a + b;
if (res < a) {
env->QF = 1;
res = ~0;
}
return res;
}
uint32_t HELPER(sub_usaturate)(CPUARMState *env, uint32_t a, uint32_t b)
{
uint32_t res = a - b;
if (res > a) {
env->QF = 1;
res = 0;
}
return res;
}
/* Signed saturation. */
static inline uint32_t do_ssat(CPUARMState *env, int32_t val, int shift)
{
int32_t top;
uint32_t mask;
top = val >> shift;
mask = (1u << shift) - 1;
if (top > 0) {
env->QF = 1;
return mask;
} else if (top < -1) {
env->QF = 1;
return ~mask;
}
return val;
}
/* Unsigned saturation. */
static inline uint32_t do_usat(CPUARMState *env, int32_t val, int shift)
{
uint32_t max;
max = (1u << shift) - 1;
if (val < 0) {
env->QF = 1;
return 0;
} else if (val > max) {
env->QF = 1;
return max;
}
return val;
}
/* Signed saturate. */
uint32_t HELPER(ssat)(CPUARMState *env, uint32_t x, uint32_t shift)
{
return do_ssat(env, x, shift);
}
/* Dual halfword signed saturate. */
uint32_t HELPER(ssat16)(CPUARMState *env, uint32_t x, uint32_t shift)
{
uint32_t res;
res = (uint16_t)do_ssat(env, (int16_t)x, shift);
res |= do_ssat(env, ((int32_t)x) >> 16, shift) << 16;
return res;
}
/* Unsigned saturate. */
uint32_t HELPER(usat)(CPUARMState *env, uint32_t x, uint32_t shift)
{
return do_usat(env, x, shift);
}
/* Dual halfword unsigned saturate. */
uint32_t HELPER(usat16)(CPUARMState *env, uint32_t x, uint32_t shift)
{
uint32_t res;
res = (uint16_t)do_usat(env, (int16_t)x, shift);
res |= do_usat(env, ((int32_t)x) >> 16, shift) << 16;
return res;
}
void HELPER(setend)(CPUARMState *env)
{
env->uncached_cpsr ^= CPSR_E;
}
/* Function checks whether WFx (WFI/WFE) instructions are set up to be trapped.
* The function returns the target EL (1-3) if the instruction is to be trapped;
* otherwise it returns 0 indicating it is not trapped.
*/
static inline int check_wfx_trap(CPUARMState *env, bool is_wfe)
{
int cur_el = arm_current_el(env);
uint64_t mask;
/* If we are currently in EL0 then we need to check if SCTLR is set up for
* WFx instructions being trapped to EL1. These trap bits don't exist in v7.
*/
if (cur_el < 1 && arm_feature(env, ARM_FEATURE_V8)) {
int target_el;
mask = is_wfe ? SCTLR_nTWE : SCTLR_nTWI;
if (arm_is_secure_below_el3(env) && !arm_el_is_aa64(env, 3)) {
/* Secure EL0 and Secure PL1 is at EL3 */
target_el = 3;
} else {
target_el = 1;
}
if (!(env->cp15.sctlr_el[target_el] & mask)) {
return target_el;
}
}
/* We are not trapping to EL1; trap to EL2 if HCR_EL2 requires it
* No need for ARM_FEATURE check as if HCR_EL2 doesn't exist the
* bits will be zero indicating no trap.
*/
if (cur_el < 2 && !arm_is_secure(env)) {
mask = (is_wfe) ? HCR_TWE : HCR_TWI;
if (env->cp15.hcr_el2 & mask) {
return 2;
}
}
/* We are not trapping to EL1 or EL2; trap to EL3 if SCR_EL3 requires it */
if (cur_el < 3) {
mask = (is_wfe) ? SCR_TWE : SCR_TWI;
if (env->cp15.scr_el3 & mask) {
return 3;
}
}
return 0;
}
void HELPER(wfi)(CPUARMState *env)
{
CPUState *cs = CPU(arm_env_get_cpu(env));
int target_el = check_wfx_trap(env, false);
if (cpu_has_work(cs)) {
/* Don't bother to go into our "low power state" if
* we would just wake up immediately.
*/
return;
}
if (target_el) {
env->pc -= 4;
raise_exception(env, EXCP_UDEF, syn_wfx(1, 0xe, 0), target_el);
}
cs->exception_index = EXCP_HLT;
cs->halted = 1;
cpu_loop_exit(cs);
}
void HELPER(wfe)(CPUARMState *env)
{
/* This is a hint instruction that is semantically different
* from YIELD even though we currently implement it identically.
* Don't actually halt the CPU, just yield back to top
* level loop. This is not going into a "low power state"
* (ie halting until some event occurs), so we never take
* a configurable trap to a different exception level.
*/
HELPER(yield)(env);
}
void HELPER(yield)(CPUARMState *env)
{
ARMCPU *cpu = arm_env_get_cpu(env);
CPUState *cs = CPU(cpu);
/* This is a non-trappable hint instruction that generally indicates
* that the guest is currently busy-looping. Yield control back to the
* top level loop so that a more deserving VCPU has a chance to run.
*/
cs->exception_index = EXCP_YIELD;
cpu_loop_exit(cs);
}
/* Raise an internal-to-QEMU exception. This is limited to only
* those EXCP values which are special cases for QEMU to interrupt
* execution and not to be used for exceptions which are passed to
* the guest (those must all have syndrome information and thus should
* use exception_with_syndrome).
*/
void HELPER(exception_internal)(CPUARMState *env, uint32_t excp)
{
CPUState *cs = CPU(arm_env_get_cpu(env));
assert(excp_is_internal(excp));
cs->exception_index = excp;
cpu_loop_exit(cs);
}
/* Raise an exception with the specified syndrome register value */
void HELPER(exception_with_syndrome)(CPUARMState *env, uint32_t excp,
uint32_t syndrome, uint32_t target_el)
{
raise_exception(env, excp, syndrome, target_el);
}
uint32_t HELPER(cpsr_read)(CPUARMState *env)
{
return cpsr_read(env) & ~(CPSR_EXEC | CPSR_RESERVED);
}
void HELPER(cpsr_write)(CPUARMState *env, uint32_t val, uint32_t mask)
{
cpsr_write(env, val, mask, CPSRWriteByInstr);
}
/* Write the CPSR for a 32-bit exception return */
void HELPER(cpsr_write_eret)(CPUARMState *env, uint32_t val)
{
cpsr_write(env, val, CPSR_ERET_MASK, CPSRWriteExceptionReturn);
}
/* Access to user mode registers from privileged modes. */
uint32_t HELPER(get_user_reg)(CPUARMState *env, uint32_t regno)
{
uint32_t val;
if (regno == 13) {
val = env->banked_r13[BANK_USRSYS];
} else if (regno == 14) {
val = env->banked_r14[BANK_USRSYS];
} else if (regno >= 8
&& (env->uncached_cpsr & 0x1f) == ARM_CPU_MODE_FIQ) {
val = env->usr_regs[regno - 8];
} else {
val = env->regs[regno];
}
return val;
}
void HELPER(set_user_reg)(CPUARMState *env, uint32_t regno, uint32_t val)
{
if (regno == 13) {
env->banked_r13[BANK_USRSYS] = val;
} else if (regno == 14) {
env->banked_r14[BANK_USRSYS] = val;
} else if (regno >= 8
&& (env->uncached_cpsr & 0x1f) == ARM_CPU_MODE_FIQ) {
env->usr_regs[regno - 8] = val;
} else {
env->regs[regno] = val;
}
}
void HELPER(set_r13_banked)(CPUARMState *env, uint32_t mode, uint32_t val)
{
if ((env->uncached_cpsr & CPSR_M) == mode) {
env->regs[13] = val;
} else {
env->banked_r13[bank_number(mode)] = val;
}
}
uint32_t HELPER(get_r13_banked)(CPUARMState *env, uint32_t mode)
{
if ((env->uncached_cpsr & CPSR_M) == ARM_CPU_MODE_SYS) {
/* SRS instruction is UNPREDICTABLE from System mode; we UNDEF.
* Other UNPREDICTABLE and UNDEF cases were caught at translate time.
*/
raise_exception(env, EXCP_UDEF, syn_uncategorized(),
exception_target_el(env));
}
if ((env->uncached_cpsr & CPSR_M) == mode) {
return env->regs[13];
} else {
return env->banked_r13[bank_number(mode)];
}
}
static void msr_mrs_banked_exc_checks(CPUARMState *env, uint32_t tgtmode,
uint32_t regno)
{
/* Raise an exception if the requested access is one of the UNPREDICTABLE
* cases; otherwise return. This broadly corresponds to the pseudocode
* BankedRegisterAccessValid() and SPSRAccessValid(),
* except that we have already handled some cases at translate time.
*/
int curmode = env->uncached_cpsr & CPSR_M;
if (curmode == tgtmode) {
goto undef;
}
if (tgtmode == ARM_CPU_MODE_USR) {
switch (regno) {
case 8 ... 12:
if (curmode != ARM_CPU_MODE_FIQ) {
goto undef;
}
break;
case 13:
if (curmode == ARM_CPU_MODE_SYS) {
goto undef;
}
break;
case 14:
if (curmode == ARM_CPU_MODE_HYP || curmode == ARM_CPU_MODE_SYS) {
goto undef;
}
break;
default:
break;
}
}
if (tgtmode == ARM_CPU_MODE_HYP) {
switch (regno) {
case 17: /* ELR_Hyp */
if (curmode != ARM_CPU_MODE_HYP && curmode != ARM_CPU_MODE_MON) {
goto undef;
}
break;
default:
if (curmode != ARM_CPU_MODE_MON) {
goto undef;
}
break;
}
}
return;
undef:
raise_exception(env, EXCP_UDEF, syn_uncategorized(),
exception_target_el(env));
}
void HELPER(msr_banked)(CPUARMState *env, uint32_t value, uint32_t tgtmode,
uint32_t regno)
{
msr_mrs_banked_exc_checks(env, tgtmode, regno);
switch (regno) {
case 16: /* SPSRs */
env->banked_spsr[bank_number(tgtmode)] = value;
break;
case 17: /* ELR_Hyp */
env->elr_el[2] = value;
break;
case 13:
env->banked_r13[bank_number(tgtmode)] = value;
break;
case 14:
env->banked_r14[bank_number(tgtmode)] = value;
break;
case 8 ... 12:
switch (tgtmode) {
case ARM_CPU_MODE_USR:
env->usr_regs[regno - 8] = value;
break;
case ARM_CPU_MODE_FIQ:
env->fiq_regs[regno - 8] = value;
break;
default:
g_assert_not_reached();
}
break;
default:
g_assert_not_reached();
}
}
uint32_t HELPER(mrs_banked)(CPUARMState *env, uint32_t tgtmode, uint32_t regno)
{
msr_mrs_banked_exc_checks(env, tgtmode, regno);
switch (regno) {
case 16: /* SPSRs */
return env->banked_spsr[bank_number(tgtmode)];
case 17: /* ELR_Hyp */
return env->elr_el[2];
case 13:
return env->banked_r13[bank_number(tgtmode)];
case 14:
return env->banked_r14[bank_number(tgtmode)];
case 8 ... 12:
switch (tgtmode) {
case ARM_CPU_MODE_USR:
return env->usr_regs[regno - 8];
case ARM_CPU_MODE_FIQ:
return env->fiq_regs[regno - 8];
default:
g_assert_not_reached();
}
default:
g_assert_not_reached();
}
}
void HELPER(access_check_cp_reg)(CPUARMState *env, void *rip, uint32_t syndrome,
uint32_t isread)
{
const ARMCPRegInfo *ri = rip;
int target_el;
if (arm_feature(env, ARM_FEATURE_XSCALE) && ri->cp < 14
&& extract32(env->cp15.c15_cpar, ri->cp, 1) == 0) {
raise_exception(env, EXCP_UDEF, syndrome, exception_target_el(env));
}
if (!ri->accessfn) {
return;
}
switch (ri->accessfn(env, ri, isread)) {
case CP_ACCESS_OK:
return;
case CP_ACCESS_TRAP:
target_el = exception_target_el(env);
break;
case CP_ACCESS_TRAP_EL2:
/* Requesting a trap to EL2 when we're in EL3 or S-EL0/1 is
* a bug in the access function.
*/
assert(!arm_is_secure(env) && arm_current_el(env) != 3);
target_el = 2;
break;
case CP_ACCESS_TRAP_EL3:
target_el = 3;
break;
case CP_ACCESS_TRAP_UNCATEGORIZED:
target_el = exception_target_el(env);
syndrome = syn_uncategorized();
break;
case CP_ACCESS_TRAP_UNCATEGORIZED_EL2:
target_el = 2;
syndrome = syn_uncategorized();
break;
case CP_ACCESS_TRAP_UNCATEGORIZED_EL3:
target_el = 3;
syndrome = syn_uncategorized();
break;
case CP_ACCESS_TRAP_FP_EL2:
target_el = 2;
/* Since we are an implementation that takes exceptions on a trapped
* conditional insn only if the insn has passed its condition code
* check, we take the IMPDEF choice to always report CV=1 COND=0xe
* (which is also the required value for AArch64 traps).
*/
syndrome = syn_fp_access_trap(1, 0xe, false);
break;
case CP_ACCESS_TRAP_FP_EL3:
target_el = 3;
syndrome = syn_fp_access_trap(1, 0xe, false);
break;
default:
g_assert_not_reached();
}
raise_exception(env, EXCP_UDEF, syndrome, target_el);
}
void HELPER(set_cp_reg)(CPUARMState *env, void *rip, uint32_t value)
{
const ARMCPRegInfo *ri = rip;
ri->writefn(env, ri, value);
}
uint32_t HELPER(get_cp_reg)(CPUARMState *env, void *rip)
{
const ARMCPRegInfo *ri = rip;
return ri->readfn(env, ri);
}
void HELPER(set_cp_reg64)(CPUARMState *env, void *rip, uint64_t value)
{
const ARMCPRegInfo *ri = rip;
ri->writefn(env, ri, value);
}
uint64_t HELPER(get_cp_reg64)(CPUARMState *env, void *rip)
{
const ARMCPRegInfo *ri = rip;
return ri->readfn(env, ri);
}
void HELPER(msr_i_pstate)(CPUARMState *env, uint32_t op, uint32_t imm)
{
/* MSR_i to update PSTATE. This is OK from EL0 only if UMA is set.
* Note that SPSel is never OK from EL0; we rely on handle_msr_i()
* to catch that case at translate time.
*/
if (arm_current_el(env) == 0 && !(env->cp15.sctlr_el[1] & SCTLR_UMA)) {
uint32_t syndrome = syn_aa64_sysregtrap(0, extract32(op, 0, 3),
extract32(op, 3, 3), 4,
imm, 0x1f, 0);
raise_exception(env, EXCP_UDEF, syndrome, exception_target_el(env));
}
switch (op) {
case 0x05: /* SPSel */
update_spsel(env, imm);
break;
case 0x1e: /* DAIFSet */
env->daif |= (imm << 6) & PSTATE_DAIF;
break;
case 0x1f: /* DAIFClear */
env->daif &= ~((imm << 6) & PSTATE_DAIF);
break;
default:
g_assert_not_reached();
}
}
void HELPER(clear_pstate_ss)(CPUARMState *env)
{
env->pstate &= ~PSTATE_SS;
}
void HELPER(pre_hvc)(CPUARMState *env)
{
ARMCPU *cpu = arm_env_get_cpu(env);
int cur_el = arm_current_el(env);
/* FIXME: Use actual secure state. */
bool secure = false;
bool undef;
if (arm_is_psci_call(cpu, EXCP_HVC)) {
/* If PSCI is enabled and this looks like a valid PSCI call then
* that overrides the architecturally mandated HVC behaviour.
*/
return;
}
if (!arm_feature(env, ARM_FEATURE_EL2)) {
/* If EL2 doesn't exist, HVC always UNDEFs */
undef = true;
} else if (arm_feature(env, ARM_FEATURE_EL3)) {
/* EL3.HCE has priority over EL2.HCD. */
undef = !(env->cp15.scr_el3 & SCR_HCE);
} else {
undef = env->cp15.hcr_el2 & HCR_HCD;
}
/* In ARMv7 and ARMv8/AArch32, HVC is undef in secure state.
* For ARMv8/AArch64, HVC is allowed in EL3.
* Note that we've already trapped HVC from EL0 at translation
* time.
*/
if (secure && (!is_a64(env) || cur_el == 1)) {
undef = true;
}
if (undef) {
raise_exception(env, EXCP_UDEF, syn_uncategorized(),
exception_target_el(env));
}
}
void HELPER(pre_smc)(CPUARMState *env, uint32_t syndrome)
{
ARMCPU *cpu = arm_env_get_cpu(env);
int cur_el = arm_current_el(env);
bool secure = arm_is_secure(env);
bool smd = env->cp15.scr_el3 & SCR_SMD;
/* On ARMv8 with EL3 AArch64, SMD applies to both S and NS state.
* On ARMv8 with EL3 AArch32, or ARMv7 with the Virtualization
* extensions, SMD only applies to NS state.
* On ARMv7 without the Virtualization extensions, the SMD bit
* doesn't exist, but we forbid the guest to set it to 1 in scr_write(),
* so we need not special case this here.
*/
bool undef = arm_feature(env, ARM_FEATURE_AARCH64) ? smd : smd && !secure;
if (arm_is_psci_call(cpu, EXCP_SMC)) {
/* If PSCI is enabled and this looks like a valid PSCI call then
* that overrides the architecturally mandated SMC behaviour.
*/
return;
}
if (!arm_feature(env, ARM_FEATURE_EL3)) {
/* If we have no EL3 then SMC always UNDEFs */
undef = true;
} else if (!secure && cur_el == 1 && (env->cp15.hcr_el2 & HCR_TSC)) {
/* In NS EL1, HCR controlled routing to EL2 has priority over SMD. */
raise_exception(env, EXCP_HYP_TRAP, syndrome, 2);
}
if (undef) {
raise_exception(env, EXCP_UDEF, syn_uncategorized(),
exception_target_el(env));
}
}
static int el_from_spsr(uint32_t spsr)
{
/* Return the exception level that this SPSR is requesting a return to,
* or -1 if it is invalid (an illegal return)
*/
if (spsr & PSTATE_nRW) {
switch (spsr & CPSR_M) {
case ARM_CPU_MODE_USR:
return 0;
case ARM_CPU_MODE_HYP:
return 2;
case ARM_CPU_MODE_FIQ:
case ARM_CPU_MODE_IRQ:
case ARM_CPU_MODE_SVC:
case ARM_CPU_MODE_ABT:
case ARM_CPU_MODE_UND:
case ARM_CPU_MODE_SYS:
return 1;
case ARM_CPU_MODE_MON:
/* Returning to Mon from AArch64 is never possible,
* so this is an illegal return.
*/
default:
return -1;
}
} else {
if (extract32(spsr, 1, 1)) {
/* Return with reserved M[1] bit set */
return -1;
}
if (extract32(spsr, 0, 4) == 1) {
/* return to EL0 with M[0] bit set */
return -1;
}
return extract32(spsr, 2, 2);
}
}
void HELPER(exception_return)(CPUARMState *env)
{
int cur_el = arm_current_el(env);
unsigned int spsr_idx = aarch64_banked_spsr_index(cur_el);
uint32_t spsr = env->banked_spsr[spsr_idx];
int new_el;
bool return_to_aa64 = (spsr & PSTATE_nRW) == 0;
aarch64_save_sp(env, cur_el);
env->exclusive_addr = -1;
/* We must squash the PSTATE.SS bit to zero unless both of the
* following hold:
* 1. debug exceptions are currently disabled
* 2. singlestep will be active in the EL we return to
* We check 1 here and 2 after we've done the pstate/cpsr write() to
* transition to the EL we're going to.
*/
if (arm_generate_debug_exceptions(env)) {
spsr &= ~PSTATE_SS;
}
new_el = el_from_spsr(spsr);
if (new_el == -1) {
goto illegal_return;
}
if (new_el > cur_el
|| (new_el == 2 && !arm_feature(env, ARM_FEATURE_EL2))) {
/* Disallow return to an EL which is unimplemented or higher
* than the current one.
*/
goto illegal_return;
}
if (new_el != 0 && arm_el_is_aa64(env, new_el) != return_to_aa64) {
/* Return to an EL which is configured for a different register width */
goto illegal_return;
}
if (new_el == 2 && arm_is_secure_below_el3(env)) {
/* Return to the non-existent secure-EL2 */
goto illegal_return;
}
if (new_el == 1 && (env->cp15.hcr_el2 & HCR_TGE)
&& !arm_is_secure_below_el3(env)) {
goto illegal_return;
}
if (!return_to_aa64) {
env->aarch64 = 0;
/* We do a raw CPSR write because aarch64_sync_64_to_32()
* will sort the register banks out for us, and we've already
* caught all the bad-mode cases in el_from_spsr().
*/
cpsr_write(env, spsr, ~0, CPSRWriteRaw);
if (!arm_singlestep_active(env)) {
env->uncached_cpsr &= ~PSTATE_SS;
}
aarch64_sync_64_to_32(env);
if (spsr & CPSR_T) {
env->regs[15] = env->elr_el[cur_el] & ~0x1;
} else {
env->regs[15] = env->elr_el[cur_el] & ~0x3;
}
} else {
env->aarch64 = 1;
pstate_write(env, spsr);
if (!arm_singlestep_active(env)) {
env->pstate &= ~PSTATE_SS;
}
aarch64_restore_sp(env, new_el);
env->pc = env->elr_el[cur_el];
}
return;
illegal_return:
/* Illegal return events of various kinds have architecturally
* mandated behaviour:
* restore NZCV and DAIF from SPSR_ELx
* set PSTATE.IL
* restore PC from ELR_ELx
* no change to exception level, execution state or stack pointer
*/
env->pstate |= PSTATE_IL;
env->pc = env->elr_el[cur_el];
spsr &= PSTATE_NZCV | PSTATE_DAIF;
spsr |= pstate_read(env) & ~(PSTATE_NZCV | PSTATE_DAIF);
pstate_write(env, spsr);
if (!arm_singlestep_active(env)) {
env->pstate &= ~PSTATE_SS;
}
}
/* Return true if the linked breakpoint entry lbn passes its checks */
static bool linked_bp_matches(ARMCPU *cpu, int lbn)
{
CPUARMState *env = &cpu->env;
uint64_t bcr = env->cp15.dbgbcr[lbn];
int brps = extract32(cpu->dbgdidr, 24, 4);
int ctx_cmps = extract32(cpu->dbgdidr, 20, 4);
int bt;
uint32_t contextidr;