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xemu/target-arm/op_helper.c
Peter Maydell 7ea47fe7be target-arm: Implement ARMv8 single-step handling for A64 code 
Implement ARMv8 software single-step handling for A64 code:
correctly update the single-step state machine and generate
debug exceptions when stepping A64 code.

This patch has no behavioural change since MDSCR_EL1.SS can't
be set by the guest yet.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com>
2014-08-19 19:02:03 +01:00

524 lines
13 KiB
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 "cpu.h"
#include "exec/helper-proto.h"
#include "internals.h"
#include "exec/cpu_ldst.h"
#define SIGNBIT (uint32_t)0x80000000
#define SIGNBIT64 ((uint64_t)1 << 63)
static void raise_exception(CPUARMState *env, int tt)
{
ARMCPU *cpu = arm_env_get_cpu(env);
CPUState *cs = CPU(cpu);
cs->exception_index = tt;
cpu_loop_exit(cs);
}
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)
/* 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)
{
int ret;
ret = arm_cpu_handle_mmu_fault(cs, addr, is_write, mmu_idx);
if (unlikely(ret)) {
ARMCPU *cpu = ARM_CPU(cs);
CPUARMState *env = &cpu->env;
if (retaddr) {
/* now we have a real cpu fault */
cpu_restore_state(cs, retaddr);
}
raise_exception(env, cs->exception_index);
}
}
#endif
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(wfi)(CPUARMState *env)
{
CPUState *cs = CPU(arm_env_get_cpu(env));
cs->exception_index = EXCP_HLT;
cs->halted = 1;
cpu_loop_exit(cs);
}
void HELPER(wfe)(CPUARMState *env)
{
CPUState *cs = CPU(arm_env_get_cpu(env));
/* Don't actually halt the CPU, just yield back to top
* level loop
*/
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)
{
CPUState *cs = CPU(arm_env_get_cpu(env));
assert(!excp_is_internal(excp));
cs->exception_index = excp;
env->exception.syndrome = syndrome;
cpu_loop_exit(cs);
}
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);
}
/* 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[0];
} else if (regno == 14) {
val = env->banked_r14[0];
} 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[0] = val;
} else if (regno == 14) {
env->banked_r14[0] = 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(access_check_cp_reg)(CPUARMState *env, void *rip, uint32_t syndrome)
{
const ARMCPRegInfo *ri = rip;
switch (ri->accessfn(env, ri)) {
case CP_ACCESS_OK:
return;
case CP_ACCESS_TRAP:
env->exception.syndrome = syndrome;
break;
case CP_ACCESS_TRAP_UNCATEGORIZED:
env->exception.syndrome = syn_uncategorized();
break;
default:
g_assert_not_reached();
}
raise_exception(env, EXCP_UDEF);
}
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_pl(env) == 0 && !(env->cp15.c1_sys & SCTLR_UMA)) {
raise_exception(env, EXCP_UDEF);
}
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(exception_return)(CPUARMState *env)
{
int cur_el = arm_current_pl(env);
unsigned int spsr_idx = aarch64_banked_spsr_index(cur_el);
uint32_t spsr = env->banked_spsr[spsr_idx];
int new_el, i;
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;
}
if (spsr & PSTATE_nRW) {
/* TODO: We currently assume EL1/2/3 are running in AArch64. */
env->aarch64 = 0;
new_el = 0;
env->uncached_cpsr = 0x10;
cpsr_write(env, spsr, ~0);
if (!arm_singlestep_active(env)) {
env->uncached_cpsr &= ~PSTATE_SS;
}
for (i = 0; i < 15; i++) {
env->regs[i] = env->xregs[i];
}
env->regs[15] = env->elr_el[1] & ~0x1;
} else {
new_el = extract32(spsr, 2, 2);
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 (extract32(spsr, 1, 1)) {
/* Return with reserved M[1] bit set */
goto illegal_return;
}
if (new_el == 0 && (spsr & PSTATE_SP)) {
/* Return to EL0 with M[0] bit set */
goto illegal_return;
}
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;
}
}
/* ??? Flag setting arithmetic is awkward because we need to do comparisons.
The only way to do that in TCG is a conditional branch, which clobbers
all our temporaries. For now implement these as helper functions. */
/* Similarly for variable shift instructions. */
uint32_t HELPER(shl_cc)(CPUARMState *env, uint32_t x, uint32_t i)
{
int shift = i & 0xff;
if (shift >= 32) {
if (shift == 32)
env->CF = x & 1;
else
env->CF = 0;
return 0;
} else if (shift != 0) {
env->CF = (x >> (32 - shift)) & 1;
return x << shift;
}
return x;
}
uint32_t HELPER(shr_cc)(CPUARMState *env, uint32_t x, uint32_t i)
{
int shift = i & 0xff;
if (shift >= 32) {
if (shift == 32)
env->CF = (x >> 31) & 1;
else
env->CF = 0;
return 0;
} else if (shift != 0) {
env->CF = (x >> (shift - 1)) & 1;
return x >> shift;
}
return x;
}
uint32_t HELPER(sar_cc)(CPUARMState *env, uint32_t x, uint32_t i)
{
int shift = i & 0xff;
if (shift >= 32) {
env->CF = (x >> 31) & 1;
return (int32_t)x >> 31;
} else if (shift != 0) {
env->CF = (x >> (shift - 1)) & 1;
return (int32_t)x >> shift;
}
return x;
}
uint32_t HELPER(ror_cc)(CPUARMState *env, uint32_t x, uint32_t i)
{
int shift1, shift;
shift1 = i & 0xff;
shift = shift1 & 0x1f;
if (shift == 0) {
if (shift1 != 0)
env->CF = (x >> 31) & 1;
return x;
} else {
env->CF = (x >> (shift - 1)) & 1;
return ((uint32_t)x >> shift) | (x << (32 - shift));
}
}
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