| Message ID | 20240623115704.315645-2-mark.cave-ayland@ilande.co.uk (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | target/m68k: implement unaligned accesses for m68k CPUs | expand |
On Sun, 23 Jun 2024, Mark Cave-Ayland wrote: > For m68k CPUs that do not support unaligned accesses, any such access should > cause the CPU to raise an Address Error exception. > > Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk> > --- > target/m68k/cpu.c | 1 + > target/m68k/cpu.h | 4 ++++ > target/m68k/op_helper.c | 11 +++++++++++ > 3 files changed, 16 insertions(+) > > diff --git a/target/m68k/cpu.c b/target/m68k/cpu.c > index efd6bbded8..25e95f9f68 100644 > --- a/target/m68k/cpu.c > +++ b/target/m68k/cpu.c > @@ -538,6 +538,7 @@ static const TCGCPUOps m68k_tcg_ops = { > .cpu_exec_interrupt = m68k_cpu_exec_interrupt, > .do_interrupt = m68k_cpu_do_interrupt, > .do_transaction_failed = m68k_cpu_transaction_failed, > + .do_unaligned_access = m68k_cpu_do_unaligned_access, > #endif /* !CONFIG_USER_ONLY */ Why is it sysemu only? Shouldn't user mode cpu only emulation do the same? I also don't get how this is restricted to pre 68020 CPUs or account for differences between data and inst fetch on 20+ but I may be missing somerhing as I don't know this code or 68k behaviour well. So this is just a question, I'm not saying it's wrong but I don't understand why it's right. Regards, BALATON Zoltan > }; > > diff --git a/target/m68k/cpu.h b/target/m68k/cpu.h > index b5bbeedb7a..d4c9531b1c 100644 > --- a/target/m68k/cpu.h > +++ b/target/m68k/cpu.h > @@ -590,6 +590,10 @@ void m68k_cpu_transaction_failed(CPUState *cs, hwaddr physaddr, vaddr addr, > unsigned size, MMUAccessType access_type, > int mmu_idx, MemTxAttrs attrs, > MemTxResult response, uintptr_t retaddr); > +G_NORETURN void m68k_cpu_do_unaligned_access(CPUState *cs, vaddr addr, > + MMUAccessType access_type, > + int mmu_idx, > + uintptr_t retaddr); > #endif > > #include "exec/cpu-all.h" > diff --git a/target/m68k/op_helper.c b/target/m68k/op_helper.c > index 15bad5dd46..417b691d8d 100644 > --- a/target/m68k/op_helper.c > +++ b/target/m68k/op_helper.c > @@ -558,6 +558,17 @@ raise_exception_format2(CPUM68KState *env, int tt, int ilen, uintptr_t raddr) > cpu_loop_exit(cs); > } > > +#if !defined(CONFIG_USER_ONLY) > +G_NORETURN void m68k_cpu_do_unaligned_access(CPUState *cs, vaddr addr, > + MMUAccessType access_type, > + int mmu_idx, uintptr_t retaddr) > +{ > + CPUM68KState *env = cpu_env(cs); > + > + raise_exception(env, EXCP_ADDRESS); > +} > +#endif > + > void HELPER(divuw)(CPUM68KState *env, int destr, uint32_t den, int ilen) > { > uint32_t num = env->dregs[destr]; >
On 6/23/24 04:57, Mark Cave-Ayland wrote: > +G_NORETURN void m68k_cpu_do_unaligned_access(CPUState *cs, vaddr addr, > + MMUAccessType access_type, > + int mmu_idx, uintptr_t retaddr) > +{ > + CPUM68KState *env = cpu_env(cs); > + > + raise_exception(env, EXCP_ADDRESS); > +} Surely the address gets stored in the exception frame somewhere? r~
On 23/06/2024 16:11, BALATON Zoltan wrote: > On Sun, 23 Jun 2024, Mark Cave-Ayland wrote: >> For m68k CPUs that do not support unaligned accesses, any such access should >> cause the CPU to raise an Address Error exception. >> >> Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk> >> --- >> target/m68k/cpu.c | 1 + >> target/m68k/cpu.h | 4 ++++ >> target/m68k/op_helper.c | 11 +++++++++++ >> 3 files changed, 16 insertions(+) >> >> diff --git a/target/m68k/cpu.c b/target/m68k/cpu.c >> index efd6bbded8..25e95f9f68 100644 >> --- a/target/m68k/cpu.c >> +++ b/target/m68k/cpu.c >> @@ -538,6 +538,7 @@ static const TCGCPUOps m68k_tcg_ops = { >> .cpu_exec_interrupt = m68k_cpu_exec_interrupt, >> .do_interrupt = m68k_cpu_do_interrupt, >> .do_transaction_failed = m68k_cpu_transaction_failed, >> + .do_unaligned_access = m68k_cpu_do_unaligned_access, >> #endif /* !CONFIG_USER_ONLY */ > > Why is it sysemu only? Shouldn't user mode cpu only emulation do the same? I also > don't get how this is restricted to pre 68020 CPUs or account for differences between > data and inst fetch on 20+ but I may be missing somerhing as I don't know this code > or 68k behaviour well. So this is just a question, I'm not saying it's wrong but I > don't understand why it's right. I'm not exactly sure, but I'm guessing that this is handled by the host user code since all CPUs that implement do_unaligned_access do so in a block contained within #ifndef CONFIG_USER_ONLY ... #endif. ATB, Mark.
On 23/06/2024 20:47, Richard Henderson wrote: > On 6/23/24 04:57, Mark Cave-Ayland wrote: >> +G_NORETURN void m68k_cpu_do_unaligned_access(CPUState *cs, vaddr addr, >> + MMUAccessType access_type, >> + int mmu_idx, uintptr_t retaddr) >> +{ >> + CPUM68KState *env = cpu_env(cs); >> + >> + raise_exception(env, EXCP_ADDRESS); >> +} > > Surely the address gets stored in the exception frame somewhere? > > r~ Well. There is already some logic there for EXCP_ADDRESS in m68k_interrupt_all() so I thought this would just work as-is, but upon closer reading of older CPU datasheets it appears there are at least 2 different stack frame formats for CPUs before the 68040. It looks like I'll have to do a bit more research before posting a v2. ATB, Mark.
diff --git a/target/m68k/cpu.c b/target/m68k/cpu.c index efd6bbded8..25e95f9f68 100644 --- a/target/m68k/cpu.c +++ b/target/m68k/cpu.c @@ -538,6 +538,7 @@ static const TCGCPUOps m68k_tcg_ops = { .cpu_exec_interrupt = m68k_cpu_exec_interrupt, .do_interrupt = m68k_cpu_do_interrupt, .do_transaction_failed = m68k_cpu_transaction_failed, + .do_unaligned_access = m68k_cpu_do_unaligned_access, #endif /* !CONFIG_USER_ONLY */ }; diff --git a/target/m68k/cpu.h b/target/m68k/cpu.h index b5bbeedb7a..d4c9531b1c 100644 --- a/target/m68k/cpu.h +++ b/target/m68k/cpu.h @@ -590,6 +590,10 @@ void m68k_cpu_transaction_failed(CPUState *cs, hwaddr physaddr, vaddr addr, unsigned size, MMUAccessType access_type, int mmu_idx, MemTxAttrs attrs, MemTxResult response, uintptr_t retaddr); +G_NORETURN void m68k_cpu_do_unaligned_access(CPUState *cs, vaddr addr, + MMUAccessType access_type, + int mmu_idx, + uintptr_t retaddr); #endif #include "exec/cpu-all.h" diff --git a/target/m68k/op_helper.c b/target/m68k/op_helper.c index 15bad5dd46..417b691d8d 100644 --- a/target/m68k/op_helper.c +++ b/target/m68k/op_helper.c @@ -558,6 +558,17 @@ raise_exception_format2(CPUM68KState *env, int tt, int ilen, uintptr_t raddr) cpu_loop_exit(cs); } +#if !defined(CONFIG_USER_ONLY) +G_NORETURN void m68k_cpu_do_unaligned_access(CPUState *cs, vaddr addr, + MMUAccessType access_type, + int mmu_idx, uintptr_t retaddr) +{ + CPUM68KState *env = cpu_env(cs); + + raise_exception(env, EXCP_ADDRESS); +} +#endif + void HELPER(divuw)(CPUM68KState *env, int destr, uint32_t den, int ilen) { uint32_t num = env->dregs[destr];
For m68k CPUs that do not support unaligned accesses, any such access should cause the CPU to raise an Address Error exception. Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk> --- target/m68k/cpu.c | 1 + target/m68k/cpu.h | 4 ++++ target/m68k/op_helper.c | 11 +++++++++++ 3 files changed, 16 insertions(+)