From f944a854ce4007000accf7c191b5b52916947198 Mon Sep 17 00:00:00 2001 From: Rebecca Cran Date: Sun, 7 Feb 2021 23:56:58 -0700 Subject: [PATCH] target/arm: Support AA32 DIT by moving PSTATE_SS from cpsr into env->pstate cpsr has been treated as being the same as spsr, but it isn't. Since PSTATE_SS isn't in cpsr, remove it and move it into env->pstate. This allows us to add support for CPSR_DIT, adding helper functions to merge SPSR_ELx to and from CPSR. Signed-off-by: Rebecca Cran Reviewed-by: Richard Henderson Message-id: 20210208065700.19454-3-rebecca@nuviainc.com Signed-off-by: Peter Maydell --- target/arm/helper-a64.c | 27 +++++++++++++++++++++++---- target/arm/helper.c | 24 ++++++++++++++++++------ target/arm/op_helper.c | 9 +-------- 3 files changed, 42 insertions(+), 18 deletions(-) diff --git a/target/arm/helper-a64.c b/target/arm/helper-a64.c index c426c23d2c..ae611d73c2 100644 --- a/target/arm/helper-a64.c +++ b/target/arm/helper-a64.c @@ -945,11 +945,31 @@ static int el_from_spsr(uint32_t spsr) } } +static void cpsr_write_from_spsr_elx(CPUARMState *env, + uint32_t val) +{ + uint32_t mask; + + /* Save SPSR_ELx.SS into PSTATE. */ + env->pstate = (env->pstate & ~PSTATE_SS) | (val & PSTATE_SS); + val &= ~PSTATE_SS; + + /* Move DIT to the correct location for CPSR */ + if (val & PSTATE_DIT) { + val &= ~PSTATE_DIT; + val |= CPSR_DIT; + } + + mask = aarch32_cpsr_valid_mask(env->features, \ + &env_archcpu(env)->isar); + cpsr_write(env, val, mask, CPSRWriteRaw); +} + void HELPER(exception_return)(CPUARMState *env, uint64_t new_pc) { int cur_el = arm_current_el(env); unsigned int spsr_idx = aarch64_banked_spsr_index(cur_el); - uint32_t mask, spsr = env->banked_spsr[spsr_idx]; + uint32_t spsr = env->banked_spsr[spsr_idx]; int new_el; bool return_to_aa64 = (spsr & PSTATE_nRW) == 0; @@ -998,10 +1018,9 @@ void HELPER(exception_return)(CPUARMState *env, uint64_t new_pc) * will sort the register banks out for us, and we've already * caught all the bad-mode cases in el_from_spsr(). */ - mask = aarch32_cpsr_valid_mask(env->features, &env_archcpu(env)->isar); - cpsr_write(env, spsr, mask, CPSRWriteRaw); + cpsr_write_from_spsr_elx(env, spsr); if (!arm_singlestep_active(env)) { - env->uncached_cpsr &= ~PSTATE_SS; + env->pstate &= ~PSTATE_SS; } aarch64_sync_64_to_32(env); diff --git a/target/arm/helper.c b/target/arm/helper.c index cf8e80419d..2c27077fb2 100644 --- a/target/arm/helper.c +++ b/target/arm/helper.c @@ -9445,7 +9445,7 @@ static void take_aarch32_exception(CPUARMState *env, int new_mode, * For exceptions taken to AArch32 we must clear the SS bit in both * PSTATE and in the old-state value we save to SPSR_, so zero it now. */ - env->uncached_cpsr &= ~PSTATE_SS; + env->pstate &= ~PSTATE_SS; env->spsr = cpsr_read(env); /* Clear IT bits. */ env->condexec_bits = 0; @@ -9801,6 +9801,21 @@ static int aarch64_regnum(CPUARMState *env, int aarch32_reg) } } +static uint32_t cpsr_read_for_spsr_elx(CPUARMState *env) +{ + uint32_t ret = cpsr_read(env); + + /* Move DIT to the correct location for SPSR_ELx */ + if (ret & CPSR_DIT) { + ret &= ~CPSR_DIT; + ret |= PSTATE_DIT; + } + /* Merge PSTATE.SS into SPSR_ELx */ + ret |= env->pstate & PSTATE_SS; + + return ret; +} + /* Handle exception entry to a target EL which is using AArch64 */ static void arm_cpu_do_interrupt_aarch64(CPUState *cs) { @@ -9923,7 +9938,7 @@ static void arm_cpu_do_interrupt_aarch64(CPUState *cs) aarch64_save_sp(env, arm_current_el(env)); env->elr_el[new_el] = env->pc; } else { - old_mode = cpsr_read(env); + old_mode = cpsr_read_for_spsr_elx(env); env->elr_el[new_el] = env->regs[15]; aarch64_sync_32_to_64(env); @@ -13217,7 +13232,6 @@ void cpu_get_tb_cpu_state(CPUARMState *env, target_ulong *pc, target_ulong *cs_base, uint32_t *pflags) { uint32_t flags = env->hflags; - uint32_t pstate_for_ss; *cs_base = 0; assert_hflags_rebuild_correctly(env); @@ -13227,7 +13241,6 @@ void cpu_get_tb_cpu_state(CPUARMState *env, target_ulong *pc, if (cpu_isar_feature(aa64_bti, env_archcpu(env))) { flags = FIELD_DP32(flags, TBFLAG_A64, BTYPE, env->btype); } - pstate_for_ss = env->pstate; } else { *pc = env->regs[15]; @@ -13275,7 +13288,6 @@ void cpu_get_tb_cpu_state(CPUARMState *env, target_ulong *pc, flags = FIELD_DP32(flags, TBFLAG_AM32, THUMB, env->thumb); flags = FIELD_DP32(flags, TBFLAG_AM32, CONDEXEC, env->condexec_bits); - pstate_for_ss = env->uncached_cpsr; } /* @@ -13288,7 +13300,7 @@ void cpu_get_tb_cpu_state(CPUARMState *env, target_ulong *pc, * SS_ACTIVE is set in hflags; PSTATE_SS is computed every TB. */ if (FIELD_EX32(flags, TBFLAG_ANY, SS_ACTIVE) && - (pstate_for_ss & PSTATE_SS)) { + (env->pstate & PSTATE_SS)) { flags = FIELD_DP32(flags, TBFLAG_ANY, PSTATE_SS, 1); } diff --git a/target/arm/op_helper.c b/target/arm/op_helper.c index 5e0f123043..65cb37d088 100644 --- a/target/arm/op_helper.c +++ b/target/arm/op_helper.c @@ -389,14 +389,7 @@ void HELPER(exception_bkpt_insn)(CPUARMState *env, uint32_t syndrome) uint32_t HELPER(cpsr_read)(CPUARMState *env) { - /* - * We store the ARMv8 PSTATE.SS bit in env->uncached_cpsr. - * This is convenient for populating SPSR_ELx, but must be - * hidden from aarch32 mode, where it is not visible. - * - * TODO: ARMv8.4-DIT -- need to move SS somewhere else. - */ - return cpsr_read(env) & ~(CPSR_EXEC | PSTATE_SS); + return cpsr_read(env) & ~CPSR_EXEC; } void HELPER(cpsr_write)(CPUARMState *env, uint32_t val, uint32_t mask) -- 2.11.0