On 11.02.2016 22:11, Peter Maydell wrote: > The SRS instruction is: > * UNDEFINED in Hyp mode > * UNPREDICTABLE in User or System mode > * UNPREDICTABLE if the specified mode isn't accessible > * trapped to EL3 if EL3 is AArch64 and we are at Secure EL1 > > Clean up the code to handle all these cases cleanly, including > picking UNDEF as our choice of UNPREDICTABLE behaviour rather > blindly trusting the mode field passed in the instruction. > As part of this, move the check for IS_USER into gen_srs() > itself rather than having it done by the caller. > > The exception is that we don't UNDEF for calls from System > mode, which need a runtime check. This will be dealt with in > the following commits. > > Signed-off-by: Peter Maydell <peter.mayd...@linaro.org>
Reviewed-by: Sergey Fedorov <serge.f...@gmail.com> > --- > target-arm/translate.c | 66 > ++++++++++++++++++++++++++++++++++++++++++++++---- > 1 file changed, 61 insertions(+), 5 deletions(-) > > diff --git a/target-arm/translate.c b/target-arm/translate.c > index cf3dc33..7bceb05 100644 > --- a/target-arm/translate.c > +++ b/target-arm/translate.c > @@ -7578,8 +7578,67 @@ static void gen_srs(DisasContext *s, > uint32_t mode, uint32_t amode, bool writeback) > { > int32_t offset; > - TCGv_i32 addr = tcg_temp_new_i32(); > - TCGv_i32 tmp = tcg_const_i32(mode); > + TCGv_i32 addr, tmp; > + bool undef = false; > + > + /* SRS is: > + * - trapped to EL3 if EL3 is AArch64 and we are at Secure EL1 > + * - UNDEFINED in Hyp mode > + * - UNPREDICTABLE in User or System mode > + * - UNPREDICTABLE if the specified mode is: > + * -- not implemented > + * -- not a valid mode number > + * -- a mode that's at a higher exception level > + * -- Monitor, if we are Non-secure > + * For the UNPREDICTABLE cases we choose to UNDEF, except that for > + * "current mode is System" we will write a garbage SPSR. > + * (This is because we don't have access to our current mode here > + * and would have to do a runtime check to UNDEF for System.) > + */ > + if (s->current_el == 1 && !s->ns) { > + gen_exception_insn(s, 4, EXCP_UDEF, syn_uncategorized(), 3); > + return; > + } > + > + if (s->current_el == 0 || s->current_el == 2) { > + undef = true; > + } > + > + switch (mode) { > + case ARM_CPU_MODE_USR: > + 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: > + break; > + case ARM_CPU_MODE_HYP: > + if (s->current_el == 1 || !arm_dc_feature(s, ARM_FEATURE_EL2)) { > + undef = true; > + } > + break; > + case ARM_CPU_MODE_MON: > + /* No need to check specifically for "are we non-secure" because > + * we've already made EL0 UNDEF and handled the trap for S-EL1; > + * so if this isn't EL3 then we must be non-secure. > + */ > + if (s->current_el != 3) { > + undef = true; > + } > + break; > + default: > + undef = true; > + } > + > + if (undef) { > + gen_exception_insn(s, 4, EXCP_UDEF, syn_uncategorized(), > + default_exception_el(s)); > + return; > + } > + > + addr = tcg_temp_new_i32(); > + tmp = tcg_const_i32(mode); > gen_helper_get_r13_banked(addr, cpu_env, tmp); > tcg_temp_free_i32(tmp); > switch (amode) { > @@ -7739,9 +7798,6 @@ static void disas_arm_insn(DisasContext *s, unsigned > int insn) > } > } else if ((insn & 0x0e5fffe0) == 0x084d0500) { > /* srs */ > - if (IS_USER(s)) { > - goto illegal_op; > - } > ARCH(6); > gen_srs(s, (insn & 0x1f), (insn >> 23) & 3, insn & (1 << 21)); > return;