Allow ARMv8M to handle small MPU and SAU region sizes, by making
get_phys_add_pmsav8() set the page size to the 1 if the MPU or
SAU region covers less than a TARGET_PAGE_SIZE.
We choose to use a size of 1 because it makes no difference to
the core code, and avoids having to track both the base and
limit for SAU and MPU and then convert into an artificially
restricted "page size" that the core code will then ignore.
Since the core TCG code can't handle execution from small
MPU regions, we strip the exec permission from them so that
any execution attempts will cause an MPU exception, rather
than allowing it to end up with a cpu_abort() in
get_page_addr_code().
(The previous code's intention was to make any small page be
treated as having no permissions, but unfortunately errors
in the implementation meant that it didn't behave that way.
It's possible that some binaries using small regions were
accidentally working with our old behaviour and won't now.)
We also retain an existing bug, where we ignored the possibility
that the SAU region might not cover the entire page, in the
case of executable regions. This is necessary because some
currently-working guest code images rely on being able to
execute from addresses which are covered by a page-sized
MPU region but a smaller SAU region. We can remove this
workaround if we ever support execution from small regions.
Backports commit 720424359917887c926a33d248131fbff84c9c28 from qemu
We want to handle small MPU region sizes for ARMv7M. To do this,
make get_phys_addr_pmsav7() set the page size to the region
size if it is less that TARGET_PAGE_SIZE, rather than working
only in TARGET_PAGE_SIZE chunks.
Since the core TCG code con't handle execution from small
MPU regions, we strip the exec permission from them so that
any execution attempts will cause an MPU exception, rather
than allowing it to end up with a cpu_abort() in
get_page_addr_code().
(The previous code's intention was to make any small page be
treated as having no permissions, but unfortunately errors
in the implementation meant that it didn't behave that way.
It's possible that some binaries using small regions were
accidentally working with our old behaviour and won't now.)
Backports commit e5e40999b5e03567ef654546e3d448431643f8f3 from qemu
Depending on the host abi, float16, aka uint16_t, values are
passed and returned either zero-extended in the host register
or with garbage at the top of the host register.
The tcg code generator has so far been assuming garbage, as that
matches the x86 abi, but this is incorrect for other host abis.
Further, target/arm has so far been assuming zero-extended results,
so that it may store the 16-bit value into a 32-bit slot with the
high 16-bits already clear.
Rectify both problems by mapping "f16" in the helper definition
to uint32_t instead of (a typedef for) uint16_t. This forces
the host compiler to assume garbage in the upper 16 bits on input
and to zero-extend the result on output.
Backports commit 6c2be133a7478e443c99757b833d0f265c48e0a6 from qemu
This is a preparation for the coming feature of creating dynamically an XML
description for the ARM sysregs.
Add "_S" suffix to the secure version of sysregs that have both S and NS views
Replace (S) and (NS) by _S and _NS for the register that are manually defined,
so all the registers follow the same convention.
Backports commit 9c513e786d85cc58b8ba56a482566f759e0835b6 from qemu
This is a preparation for the coming feature of creating dynamically an XML
description for the ARM sysregs.
A register has ARM_CP_NO_GDB enabled will not be shown in the dynamic XML.
This bit is enabled automatically when creating CP_ANY wildcard aliases.
This bit could be enabled manually for any register we want to remove from the
dynamic XML description.
Backports commit 1f16378718fa87d63f70d0797f4546a88d8e3dd7 from qemu
The ARM ARM specifies FZ16 is suppressed for conversions. Rather than
pushing this logic into the softfloat code we can simply save the FZ
state and temporarily disable it for the softfloat call.
Backports commit 0acb9e7cb341cd767e39ec0875c8706eb2f1c359 from qemu
Instead of passing env and leaving it up to the helper to get the
right fpstatus we pass it explicitly. There was already a get_fpstatus
helper for neon for the 32 bit code. We also add an get_ahp_flag() for
passing the state of the alternative FP16 format flag. This leaves
scope for later tracking the AHP state in translation flags.
Backports commit 486624fcd3eaca6165ab8401d73bbae6c0fb81c1 from qemu
The instruction "ucvtf v0.4h, v04h, #2", with input 0x8000u,
overflows the intermediate float16 to infinity before we have a
chance to scale the output. Use float64 as the intermediate type
so that no input argument (uint32_t in this case) can overflow
or round before scaling. Given the declared argument, the signed
int32_t function has the same problem.
When converting from float16 to integer, using u/int32_t instead
of u/int16_t means that the bounding is incorrect.
Backports commit 88808a022c06f98d81cd3f2d105a5734c5614839 from qemu
The duplication of id_tlbtr_reginfo was unintentionally added within
3281af8114c6b8ead02f08b58e3c36895c1ea047 which should have been
id_mpuir_reginfo.
The effect was that for OMAP and StrongARM CPUs we would
incorrectly UNDEF writes to MPUIR rather than NOPing them.
Backports commit 100061121c1f69a672ce7bb3e9e3781f8018f9f6 from qemu
This is a bug fix to ensure 64-bit reads of these registers don't read
adjacent data.
Backports commit e4e91a217c17fff4045dd4b423cdcb471b3d6a0e from qemu
Because the design of the PMU requires that the counter values be
converted between their delta and guest-visible forms for mode
filtering, an additional hook which occurs before the EL is changed is
necessary.
Backports commit b5c53d1b3886387874f8c8582b205aeb3e4c3df6 from qemu
In commit 95695effe8caa552b8f2 we changed the v7M/v8M stack
pop code to use a new v7m_stack_read() function that checks
whether the read should fail due to an MPU or bus abort.
We missed one call though, the one which reads the signature
word for the callee-saved register part of the frame.
Correct the omission.
Backports commit 4818bad98c8212fbbb0525d10761b6b65279ab92 from qemu
Remove a stale TODO comment -- we have now made the arm_ldl_ptw()
and arm_ldq_ptw() functions propagate physical memory read errors
out to their callers.
Backports commit 145772707fe80395b87c244ccf5699a756f1946b from qemu
Currently our PMSAv7 and ARMv7M MPU implementation cannot handle
MPU region sizes smaller than our TARGET_PAGE_SIZE. However we
report that in a slightly confusing way:
DRSR[3]: No support for MPU (sub)region alignment of 9 bits. Minimum is 10
The problem is not the alignment of the region, but its size;
tweak the error message to say so:
DRSR[3]: No support for MPU (sub)region size of 512 bytes. Minimum is 1024.
Backports commit 8aec759b45fa6986c0b159cb27353d6abb0d5d73 from qemu
Now that we have a helper function specifically for the BRK and
BKPT instructions, we can set the exception.fsr there rather
than in arm_cpu_do_interrupt_aarch32(). This allows us to
use our new arm_debug_exception_fsr() helper.
In particular this fixes a bug where we were hardcoding the
short-form IFSR value, which is wrong if the target exception
level has LPAE enabled.
Fixes: https://bugs.launchpad.net/qemu/+bug/1756927
Backports commit 62b94f31d0df75187bb00684fc29e8639eacc0c5 from qemu
Backports commits 2994fd96d986578a342f2342501b4ad30f6d0a85,
701e3c78ce45fa630ffc6826c4b9a4218954bc7f, and
d1853231c60d16af78cf4d1608d043614bfbac0b from qemuu
Much like recpe the ARM ARM has simplified the pseudo code for the
calculation which is done on a fixed point 9 bit integer maths. So
while adding f16 we can also clean this up to be a little less heavy
on the floating point and just return the fractional part and leave
the calle's to do the final packing of the result.
Backports commit d719cbc7641991d16b891ffbbfc3a16a04e37b9a from qemu
Also removes a load of symbols that seem unnecessary from the header_gen script
It looks like the ARM ARM has simplified the pseudo code for the
calculation which is done on a fixed point 9 bit integer maths. So
while adding f16 we can also clean this up to be a little less heavy
on the floating point and just return the fractional part and leave
the calle's to do the final packing of the result.
Backports commit 5eb70735af1c0b607bf2671a53aff3710cc1672f from qemu
As the rounding mode is now split between FP16 and the rest of
floating point we need to be explicit when tweaking it. Instead of
passing the CPU env we now pass the appropriate fpst pointer directly.
Backports commit 9b04991686785e18b18a36d193b68f08f7c91648 from qemu
Half-precision flush to zero behaviour is controlled by a separate
FZ16 bit in the FPCR. To handle this we pass a pointer to
fp_status_fp16 when working on half-precision operations. The value of
the presented FPCR is calculated from an amalgam of the two when read.
Backports commit d81ce0ef2c4f1052fcdef891a12499eca3084db7 from qemu
The register definitions for VMIDR and VMPIDR have separate
reginfo structs for the AArch32 and AArch64 registers. However
the 32-bit versions are wrong:
* they use offsetof instead of offsetoflow32 to mark where
the 32-bit value lives in the uint64_t CPU state field
* they don't mark themselves as ARM_CP_ALIAS
In particular this means that if you try to use an Arm guest CPU
which enables EL2 on a big-endian host it will assert at reset:
target/arm/cpu.c:114: cp_reg_check_reset: Assertion `oldvalue == newvalue' failed.
because the reset of the 32-bit register writes to the top
half of the uint64_t.
Correct the errors in the structures.
Backports commit 36476562d57a3b64bbe86db26e63677dd21907c5 from qemu
As cpu.h is another typically widely included file which doesn't need
full access to the softfloat API we can remove the includes from here
as well. Where they do need types it's typically for float_status and
the rounding modes so we move that to softfloat-types.h as well.
As a result of not having softfloat in every cpu.h call we now need to
add it to various helpers that do need the full softfloat.h
definitions.
Backports commit 24f91e81b65fcdd0552d1f0fcb0ea7cfe3829c19 from qemu
The v8M architecture includes hardware support for enforcing
stack pointer limits. We don't implement this behaviour yet,
but provide the MSPLIM and PSPLIM stack pointer limit registers
as reads-as-written, so that when we do implement the checks
in future this won't break guest migration.
Backports commit 57bb31568114023f67680d6fe478ceb13c51aa7d from qemu
In commit 50f11062d4c896 we added support for MSR/MRS access
to the NS banked special registers, but we forgot to implement
the support for writing to CONTROL_NS. Correct the omission.
Backports commit 6eb3a64e2a96f5ced1f7896042b01f002bf0a91f from qemu
Handle possible MPU faults, SAU faults or bus errors when
popping register state off the stack during exception return.
Backports commit 95695effe8caa552b8f243bceb3a08de4003c882 from qemu
Make the load of the exception vector from the vector table honour
the SAU and any bus error on the load (possibly provoking a derived
exception), rather than simply aborting if the load fails.
Backports commit 600c33f24752a00e81e9372261e35c2befea612b from qemu
Make v7m_push_callee_stack() honour the MPU by using the
new v7m_stack_write() function. We return a flag to indicate
whether the pushes failed, which we can then use in
v7m_exception_taken() to cause us to handle the derived
exception correctly.
Backports commit 65b4234ff73a4d4865438ce30bdfaaa499464efa from qemu
The memory writes done to push registers on the stack
on exception entry in M profile CPUs are supposed to
go via MPU permissions checks, which may cause us to
take a derived exception instead of the original one of
the MPU lookup fails. We were implementing these as
always-succeeds direct writes to physical memory.
Rewrite v7m_push_stack() to do the necessary checks.
Backports commit fd592d890ec40e3686760de84044230a8ebb1eb3 from qemu
In the v8M architecture, if the process of taking an exception
results in a further exception this is called a derived exception
(for example, an MPU exception when writing the exception frame to
memory). If the derived exception happens while pushing the initial
stack frame, we must ignore any subsequent possible exception
pushing the callee-saves registers.
In preparation for making the stack writes check for exceptions,
add a return value from v7m_push_stack() and a new parameter to
v7m_exception_taken(), so that the former can tell the latter that
it needs to ignore failures to write to the stack. We also plumb
the argument through to v7m_push_callee_stack(), which is where
the code to ignore the failures will be.
(Note that the v8M ARM pseudocode structures this slightly differently:
derived exceptions cause the attempt to process the original
exception to be abandoned; then at the top level it calls
DerivedLateArrival to prioritize the derived exception and call
TakeException from there. We choose to let the NVIC do the prioritization
and continue forward with a call to TakeException which will then
take either the original or the derived exception. The effect is
the same, but this structure works better for QEMU because we don't
have a convenient top level place to do the abandon-and-retry logic.)
Backports commit 0094ca70e165cfb69882fa2e100d935d45f1c983 from qemu
Currently armv7m_nvic_acknowledge_irq() does three things:
* make the current highest priority pending interrupt active
* return a bool indicating whether that interrupt is targeting
Secure or NonSecure state
* implicitly tell the caller which is the highest priority
pending interrupt by setting env->v7m.exception
We need to split these jobs, because v7m_exception_taken()
needs to know whether the pending interrupt targets Secure so
it can choose to stack callee-saves registers or not, but it
must not make the interrupt active until after it has done
that stacking, in case the stacking causes a derived exception.
Similarly, it needs to know the number of the pending interrupt
so it can read the correct vector table entry before the
interrupt is made active, because vector table reads might
also cause a derived exception.
Create a new armv7m_nvic_get_pending_irq_info() function which simply
returns information about the highest priority pending interrupt, and
use it to rearrange the v7m_exception_taken() code so we don't
acknowledge the exception until we've done all the things which could
possibly cause a derived exception.
Backports part of commit 6c9485188170e11ad31ce477c8ce200b8e8ce59d from qemu
