For v7M, writes to the CONTROL register are only permitted for
privileged code. However even if the code is privileged, the
write must not affect the SPSEL bit in the CONTROL register
if the CPU is in Thread mode (as documented in the pseudocode
for the MSR instruction). Implement this, instead of permitting
SPSEL to be written in all cases.
This was causing mbed applications not to run, because the
RTX RTOS they use relies on this behaviour.
Backports commit 792dac309c8660306557ba058b8b5a6a75ab3c1f from qemu
Move the code in arm_v7m_cpu_do_interrupt() that calculates the
magic LR value down to when we're actually going to use it.
Having the calculation and use so far apart makes the code
a little harder to understand than it needs to be.
Backports commit bd70b29ba92e4446f9e4eb8b9acc19ef6ff4a4d5 from qemu
Make the arm_cpu_dump_state() debug logging handle the M-profile XPSR
rather than assuming it's an A-profile CPSR. On M profile the PSR
line of a register dump will now look like this:
XPSR=41000000 -Z-- T priv-thread
Backports commit 5b906f3589443a3c69d8feeaac37263843ecfb8d from qemu
We currently store the M profile CPU register state PRIMASK and
FAULTMASK in the daif field of the CPU state in its I and F
bits. This is a legacy from the original implementation, which
tried to share the cpu_exec_interrupt code between A profile
and M profile. We've since separated out the two cases because
they are significantly different, so now there is no common
code between M and A profile which looks at env->daif: all the
uses are either in A-only or M-only code paths. Sharing the state
fields now is just confusing, and will make things awkward
when we implement v8M, where the PRIMASK and FAULTMASK
registers are banked between security states.
Switch M profile over to using v7m.faultmask and v7m.primask
fields for these registers.
Backports commit e6ae5981ea4b0f6feb223009a5108582e7644f8f from qemu
The M profile XPSR is almost the same format as the A profile CPSR,
but not quite. Define some XPSR_* macros and use them where we
definitely dealing with an XPSR rather than reusing the CPSR ones.
Backports commit 987ab45e108953c1c98126c338c2119c243c372b from qemu
When we switched our handling of exception exit to detect
the magic addresses at translate time rather than via
a do_unassigned_access hook, we forgot to update a
comment; correct the omission.
Backports commit 9d17da4b68a05fc78daa47f0f3d914eea5d802ea from qemu
Remove the comment that claims that some MPU_CTRL bits are stored
in sctlr_el[1]. This has never been true since MPU_CTRL was added
in commit 29c483a50607 -- the comment is a leftover from
Michael Davidsaver's original implementation, which I modified
not to use sctlr_el[1]; I forgot to delete the comment then.
Backports commit 59e4972c3fc63d981e8b613ebb3bb01a05848075 from qemu
Tighten up the T32 decoder in the places where new v8M instructions
will be:
* TT/TTT/TTA/TTAT are in what was nominally LDREX/STREX r15, ...
which is UNPREDICTABLE:
make the UNPREDICTABLE behaviour be to UNDEF
* BXNS/BLXNS are distinguished from BX/BLX via the low 3 bits,
which in previous architectural versions are SBZ:
enforce the SBZ via UNDEF rather than ignoring it, and move
the "ARCH(5)" UNDEF case up so we don't leak a TCG temporary
* SG is in the encoding which would be LDRD/STRD with rn = r15;
this is UNPREDICTABLE and we currently UNDEF:
move this check further up the code so that we don't leak
TCG temporaries in the UNDEF case and have a better place
to put the SG decode.
This means that if a v8M binary is accidentally run on v7M
or if a test case hits something that we haven't implemented
yet the behaviour will be obvious (UNDEF) rather than obscure
(plough on treating it as a different instruction).
In the process, add some comments about the instruction patterns
at these points in the decode. Our Thumb and ARM decoders are
very difficult to understand currently, but gradually adding
comments like this should help to clarify what exactly has
been decoded when.
Backports commit ebfe27c593e5b222aa2a1fc545b447be3d995faa from qemu
Currently get_phys_addr() has PMSAv7 handling before the
"is translation disabled?" check, and then PMSAv5 after it.
Tidy this up by making the PMSAv5 code handle the "MPU disabled"
case itself, so that we have all the PMSA code in one place.
This will make adding the PMSAv8 code slightly cleaner, and
also means that pre-v7 PMSA cores benefit from the MPU lookup
logging that the PMSAv7 codepath had.
Backports commit 3279adb95e34dd3d67c66d729458f7784747cf8d from qemu
M profile cores can never trap on WFI or WFE instructions. Check for
M profile in check_wfx_trap() to ensure this.
The existing code will do the right thing for v7M cores because
the hcr_el2 and scr_el3 registers will be all-zeroes and so we
won't attempt to trap, but when we start setting ARM_FEATURE_V8
for v8M cores the v8A handling of SCTLR.nTWE and .nTWI will not
give the right results.
Backports commit 0e2845689ebdb4ea7174f96f6797e2d8942bd114 from qemu
In the ARM get_phys_addr() code, switch to using the MMUAccessType
enum and its MMU_* values rather than int and literal 0/1/2.
Backports commit 03ae85f858fc46495258a5dd4551fff2c34bd495 from qemu
According to the ARM ARM exclusive loads require the same alignment as
exclusive stores. Let's update the memops used for the load to match
that of the store. This adds the alignment requirement to the memops.
Backports commit 4a2fdb78e794c1ad93aa9e160235d6a61a2125de from qemu
We are not providing the required single-copy atomic semantics for
the 64-bit operation that is the 32-bit paired load.
At the same time, leave the entire 64-bit value in cpu_exclusive_val
and stop writing to cpu_exclusive_high. This means that we do not
have to re-assemble the 64-bit quantity when it comes time to store.
At the same time, drop a redundant temporary and perform all loads
directly into the cpu_exclusive_* globals.
Backports commit 19514cde3b92938df750acaecf2caaa85e1d36a6 from qemu
When we perform the atomic_cmpxchg operation we want to perform the
operation on a pair of 32-bit registers. Previously we were just passing
the register size in which was set to MO_32. This would result in the
high register to be ignored. To fix this issue we hardcode the size to
be 64-bits long when operating on 32-bit pairs.
Backports commit 955fd0ad5d610f62ba2f4ce46a872bf50434dcf8 from qemu
When the PMSAv7 implementation was originally added it was for R profile
CPUs only, and reset was handled using the cpreg .resetfn hooks.
Unfortunately for M profile cores this doesn't work, because they do
not register any cpregs. Move the reset handling into arm_cpu_reset(),
where it will work for both R profile and M profile cores.
Backports commit 69ceea64bf565559a2b865ffb2a097d2caab805b from qemu
Almost all of the PMSAv7 state is in the pmsav7 substruct of
the ARM CPU state structure. The exception is the region
number register, which is in cp15.c6_rgnr. This exception
is a bit odd for M profile, which otherwise generally does
not store state in the cp15 substruct.
Rename cp15.c6_rgnr to pmsav7.rnr accordingly.
Backports commit 8531eb4f614a60e6582d4832b15eee09f7d27874 from qemu
For an M profile v7PMSA, the system space (0xe0000000 - 0xffffffff) can
never be executable, even if the guest tries to set the MPU registers
up that way. Enforce this restriction.
Backports commit bf446a11dfb17ae7d8ed2b61a2444804eb458075 from qemu
The M profile PMSAv7 specification says that if the address being looked
up is in the PPB region (0xe0000000 - 0xe00fffff) then we do not use
the MPU regions but always use the default memory map. Implement this
(we were previously behaving like an R profile PMSAv7, which does not
special case this).
Backports commit 38aaa60ca464b48e6feef346709e97335d01b289 from qemu
Correct off-by-one bug in the PSMAv7 MPU tracing where it would print
a write access as "reading", an insn fetch as "writing", and a read
access as "execute".
Since we have an MMUAccessType enum now, we can make the code clearer
in the process by using that rather than the raw 0/1/2 values.
Backports commit 709e4407add7acacc593cb6cdac026558c9a8fb6 from qemu
Previously DISAS_JUMP did ensure this but with the optimisation of
8a6b28c7 (optimize indirect branches) we might not leave the loop.
This means if any pending interrupts are cleared by changing IRQ flags
we might never get around to servicing them. You usually notice this
by seeing the lookup_tb_ptr() helper gainfully chaining TBs together
while cpu->interrupt_request remains high and the exit_request has not
been set.
This breaks amongst other things the OPTEE test suite which executes
an eret from the secure world after a non-secure world IRQ has gone
pending which then never gets serviced.
Instead of using the previously implied semantics of DISAS_JUMP we use
DISAS_EXIT which will always exit the run-loop.
Backports commit b29fd33db578decacd14f34933b29aece3e7c25e from qemu
While an ISB will ensure any raised IRQs happen on the next
instruction it doesn't cause any to get raised by itself. We can
therefore use a simple tb exit for ISB instructions and rely on the
exit_request check at the top of each TB to deal with exiting if
needed.
Backports commit 0b609cc128ba5ef16cc841bcade898d1898f1dc3 from qemu
As the gen_goto_tb function can do both static and dynamic jumps it
should also set the is_jmp field. This matches the behaviour of the
a64 code.
Backports commit 4cae8f56fbab2798586576a56cc669f0127d04fb from qemu
We already have an exit condition, DISAS_UPDATE which will exit the
run-loop. Expand on the difference with DISAS_EXIT in the comments
Backports commit abd1fb0ee2c58b99f4b2d15718f1825fe4984e12 from qemu
DISAS_UPDATE should be used when the wider CPU state other than just
the PC has been updated and we should therefore exit the TCG runtime
and return to the main execution loop rather assuming DISAS_JUMP would
do that.
Backports commit e8d5230221851e8933811f1579fd13371f576955 from qemu
The Cortex-M3 and M4 CPUs always have 8 PMSA MPU regions (this isn't
a configurable option for the hardware). Make the default value of
the pmsav7-dregion property be set per-cpu, so we don't need to have
every user of these CPUs set it manually. (The existing default of
16 is correct for the other PMSAv7 core, the Cortex-R5.)
This fixes a bug where we were creating the M3 and M4 with
too many regions; most guest software would not notice or
care, though, since it would just not use the registers
associated with the unexpected extra regions.
Backports commit 8d92e26b452f8961ec90df3f93cf5f3b7a9d158f from qemu
Instead of unconditionally exiting to the exec loop, use the
lookup_and_goto_ptr helper to jump to the target if it is valid.
Perf impact: see next commit's log.
Backports commit 7ad55b4ffd982c80f26f7f3658138d94cdc678e8 from qemu
The cp15, CRn=15, opc1=0, CRm=5, opc2=0 instruction invalidates all the
data cache on the cortex-r5. Implementing it as a NOP.
Backports commit 95e9a242e2a393c7d4e5cc04340e39c3a9420f03 from qemu
M profile doesn't implement ARM, and the architecturally required
behaviour for attempts to execute with the Thumb bit clear is to
generate a UsageFault with the CFSR INVSTATE bit set. We were
incorrectly implementing this as generating an UNDEFINSTR UsageFault;
fix this.
Backports commit e13886e3a790b52f0b2e93cb5e84fdc2ada5471a from qemu
Implement the exception return consistency checks
described in the v7M pseudocode ExceptionReturn().
Inspired by a patch from Michael Davidsaver's series, but
this is a reimplementation from scratch based on the
ARM ARM pseudocode.
Backports commit aa488fe3bb5460c6675800ccd80f6dccbbd70159 from qemu
Extract the code from the tail end of arm_v7m_do_interrupt() which
enters the exception handler into a pair of utility functions
v7m_exception_taken() and v7m_push_stack(), which correspond roughly
to the pseudocode PushStack() and ExceptionTaken().
This also requires us to move the arm_v7m_load_vector() utility
routine up so we can call it.
Handling illegal exception returns has some cases where we want to
take a UsageFault either on an existing stack frame or with a new
stack frame but with a specific LR value, so we want to be able to
call these without having to go via arm_v7m_cpu_do_interrupt().
Backports commit 39ae2474e337247e5930e8be783b689adc9f6215 from qemu
All the places in armv7m_cpu_do_interrupt() which pend an
exception in the NVIC are doing so for synchronous
exceptions. We know that we will always take some
exception in this case, so we can just acknowledge it
immediately, rather than returning and then immediately
being called again because the NVIC has raised its outbound
IRQ line.
Backports commit a25dc805e2e63a55029e787a52335e12dabf07dc from qemu
The M profile condition for when we can take a pending exception or
interrupt is not the same as that for A/R profile. The code
originally copied from the A/R profile version of the
cpu_exec_interrupt function only worked by chance for the
very simple case of exceptions being masked by PRIMASK.
Replace it with a call to a function in the NVIC code that
correctly compares the priority of the pending exception
against the current execution priority of the CPU.
Backports commit 7ecdaa4a9635f1ded0dfa9218c25273b6d4dcd44 from qemu
Having armv7m_nvic_acknowledge_irq() return the new value of
env->v7m.exception and its one caller assign the return value
back to env->v7m.exception is pointless. Just make the return
type void instead.
Backports commit a5d8235545e98c1ce02560d5f4f57552d937efe9 from qemu
Implement HFNMIENA support for the M profile MPU. This bit controls
whether the MPU is treated as enabled when executing at execution
priorities of less than zero (in NMI, HardFault or with the FAULTMASK
bit set).
Doing this requires us to use a different MMU index for "running
at execution priority < 0", because we will have different
access permissions for that case versus the normal case.
Backports commit 3bef7012560a7f0ea27b265105de5090ba117514 from qemu
The M series MPU is almost the same as the already implemented R
profile MPU (v7 PMSA). So all we need to implement here is the MPU
register interface in the system register space.
This implementation has the same restriction as the R profile MPU
that it doesn't permit regions to be sized down smaller than 1K.
We also do not yet implement support for MPU_CTRL.HFNMIENA; this
bit should if zero disable use of the MPU when running HardFault,
NMI or with FAULTMASK set to 1 (ie at an execution priority of
less than zero) -- if the MPU is enabled we don't treat these
cases any differently.
Backports commit 29c483a506070e8f554c77d22686f405e30b9114 from qemu
General logic is that operations stopped by the MPU are MemManage,
and those which go through the MPU and are caught by the unassigned
handle are BusFault. Distinguish these by looking at the
exception.fsr values, and set the CFSR bits and (if appropriate)
fill in the BFAR or MMFAR with the exception address.
Backports commit 5dd0641d234e355597be62e5279d8a519c831625 from qemu
All M profile CPUs are PMSA, so set the feature bit.
(We haven't actually implemented the M profile MPU register
interface yet, but setting this feature bit gives us closer
to correct behaviour for the MPU-disabled case.)
Backports commit 790a11503cfb5e1dcd031ea2212bbebae4ca3cec from qemu
Add support for the M profile default memory map which is used
if the MPU is not present or disabled.
The main differences in behaviour from implementing this
correctly are that we set the PAGE_EXEC attribute on
the right regions of memory, such that device regions
are not executable.
Backports commit 3a00d560bcfca7ad04327062c1986a016c104b1f from qemu
Improve the "-d mmu" tracing for the PMSAv7 MPU translation
process as an aid in debugging guest MPU configurations:
* fix a missing newline for a guest-error log
* report the region number with guest-error or unimp
logs of bad region register values
* add a log message for the overall result of the lookup
* print "0x" prefix for hex values
Backports commit c9f9f1246d630960bce45881e9c0d27b55be71e2 from qemu
Now that we enforce both:
* pmsav7_dregion == 0 implies has_mpu == false
* PMSA with has_mpu == false means SCTLR.M cannot be set
we can remove a check on pmsav7_dregion from get_phys_addr_pmsav7(),
because we can only reach this code path if the MPU is enabled
(and so region_translation_disabled() returned false).
Backports commit e9235c6983b261e04e897e8ff900b2b7a391e644 from qemu
If the CPU is a PMSA config with no MPU implemented, then the
SCTLR.M bit should be RAZ/WI, so that the guest can never
turn on the non-existent MPU.
Backports commit 06312febfb2d35367006ef23608ddd6a131214d4 from qemu
Fix the handling of QOM properties for PMSA CPUs with no MPU:
Allow no-MPU to be specified by either:
* has-mpu = false
* pmsav7_dregion = 0
and make setting one imply the other. Don't clear the PMSA
feature bit in this situation.
Backports commit f50cd31413d8bc9d1eef8edd1f878324543bf65d from qemu
ARM CPUs come in two flavours:
* proper MMU ("VMSA")
* only an MPU ("PMSA")
For PMSA, the MPU may be implemented, or not (in which case there
is default "always acts the same" behaviour, but it isn't guest
programmable).
QEMU is a bit confused about how we indicate this: we have an
ARM_FEATURE_MPU, but it's not clear whether this indicates
"PMSA, not VMSA" or "PMSA and MPU present" , and sometimes we
use it for one purpose and sometimes the other.
Currently trying to implement a PMSA-without-MPU core won't
work correctly because we turn off the ARM_FEATURE_MPU bit
and then a lot of things which should still exist get
turned off too.
As the first step in cleaning this up, rename the feature
bit to ARM_FEATURE_PMSA, which indicates a PMSA CPU (with
or without MPU).
Backports commit 452a095526a0537f16c271516a2200877a272ea8 from qemu
Make M profile use completely separate ARMMMUIdx values from
those that A profile CPUs use. This is a prelude to adding
support for the MPU and for v8M, which together will require
6 MMU indexes which don't map cleanly onto the A profile
uses:
non secure User
non secure Privileged
non secure Privileged, execution priority < 0
secure User
secure Privileged
secure Privileged, execution priority < 0
Backports commit e7b921c2d9efc249f99b9feb0e7dca82c96aa5c4 from qemu
The v7M exception architecture requires that if a synchronous
exception cannot be taken immediately (because it is disabled
or at too low a priority) then it should be escalated to
HardFault (and the HardFault exception is then taken).
Implement this escalation logic.
Backports commit a73c98e159d18155445d29b6044be6ad49fd802f from qemu
