Commit graph

132 commits

Author SHA1 Message Date
Peter Maydell 2c4578f46e
target/arm: Implement SG instruction
Implement the SG instruction, which we emulate 'by hand' in the
exception handling code path.

Backports commit 333e10c51ef5876ced26f77b61b69ce0f83161a9 from qemu
2018-03-05 03:28:28 -05:00
Peter Maydell 7988aec017
target/arm: Implement security attribute lookups for memory accesses
Implement the security attribute lookups for memory accesses
in the get_phys_addr() functions, causing these to generate
various kinds of SecureFault for bad accesses.

The major subtlety in this code relates to handling of the
case when the security attributes the SAU assigns to the
address don't match the current security state of the CPU.

In the ARM ARM pseudocode for validating instruction
accesses, the security attributes of the address determine
whether the Secure or NonSecure MPU state is used. At face
value, handling this would require us to encode the relevant
bits of state into mmu_idx for both S and NS at once, which
would result in our needing 16 mmu indexes. Fortunately we
don't actually need to do this because a mismatch between
address attributes and CPU state means either:
* some kind of fault (usually a SecureFault, but in theory
perhaps a UserFault for unaligned access to Device memory)
* execution of the SG instruction in NS state from a
Secure & NonSecure code region

The purpose of SG is simply to flip the CPU into Secure
state, so we can handle it by emulating execution of that
instruction directly in arm_v7m_cpu_do_interrupt(), which
means we can treat all the mismatch cases as "throw an
exception" and we don't need to encode the state of the
other MPU bank into our mmu_idx values.

This commit doesn't include the actual emulation of SG;
it also doesn't include implementation of the IDAU, which
is a per-board way to specify hard-coded memory attributes
for addresses, which override the CPU-internal SAU if they
specify a more secure setting than the SAU is programmed to.

Backports commit 35337cc391245f251bfb9134f181c33e6375d6c1 from qemu
2018-03-05 01:57:07 -05:00
Peter Maydell 3da3a3fb41
target/arm: Add v8M support to exception entry code
Add support for v8M and in particular the security extension
to the exception entry code. This requires changes to:
* calculation of the exception-return magic LR value
* push the callee-saves registers in certain cases
* clear registers when taking non-secure exceptions to avoid
leaking information from the interrupted secure code
* switch to the correct security state on entry
* use the vector table for the security state we're targeting

Backports commit d3392718e1fcf0859fb7c0774a8e946bacb8419c from qemu
2018-03-05 01:51:22 -05:00
Peter Maydell 39466771d6
target/arm: Add support for restoring v8M additional state context
For v8M, exceptions from Secure to Non-Secure state will save
callee-saved registers to the exception frame as well as the
caller-saved registers. Add support for unstacking these
registers in exception exit when necessary.

Backports commit 907bedb3f3ce134c149599bd9cb61856d811b8ca from qemu
2018-03-05 01:47:25 -05:00
Peter Maydell 2feecbac0d
target/arm: Update excret sanity checks for v8M
In v8M, more bits are defined in the exception-return magic
values; update the code that checks these so we accept
the v8M values when the CPU permits them.

Backports commit bfb2eb52788b9605ef2fc9bc72683d4299117fde from qemu
2018-03-05 01:44:33 -05:00
Peter Maydell 7af730ed3e
target/arm: Don't warn about exception return with PC low bit set for v8M
In the v8M architecture, return from an exception to a PC which
has bit 0 set is not UNPREDICTABLE; it is defined that bit 0
is discarded [R_HRJH]. Restrict our complaint about this to v7M.

Backports commit 4e4259d3c574a8e89c3af27bcb84bc19a442efb1 from qemu
2018-03-05 01:41:51 -05:00
Peter Maydell 2aea283c4f
target/arm: Warn about restoring to unaligned stack
Attempting to do an exception return with an exception frame that
is not 8-aligned is UNPREDICTABLE in v8M; warn about this.
(It is not UNPREDICTABLE in v7M, and our implementation can
handle the merely-4-aligned case fine, so we don't need to
do anything except warn.)

Backports commit cb484f9a6e790205e69d9a444c3e353a3a1cfd84 from qemu
2018-03-05 01:40:40 -05:00
Peter Maydell 5063ca11ab
target/arm: Check for xPSR mismatch usage faults earlier for v8M
ARM v8M specifies that the INVPC usage fault for mismatched
xPSR exception field and handler mode bit should be checked
before updating the PSR and SP, so that the fault is taken
with the existing stack frame rather than by pushing a new one.
Perform this check in the right place for v8M.

Since v7M specifies in its pseudocode that this usage fault
check should happen later, we have to retain the original
code for that check rather than being able to merge the two.
(The distinction is architecturally visible but only in
very obscure corner cases like attempting an invalid exception
return with an exception frame in read only memory.)

Backports commit 224e0c300a0098fb577a03bd29d774d0769f632a from qemu
2018-03-05 01:39:39 -05:00
Peter Maydell 6f08acdcfe
target/arm: Restore SPSEL to correct CONTROL register on exception return
On exception return for v8M, the SPSEL bit in the EXC_RETURN magic
value should be restored to the SPSEL bit in the CONTROL register
banked specified by the EXC_RETURN.ES bit.

Add write_v7m_control_spsel_for_secstate() which behaves like
write_v7m_control_spsel() but allows the caller to specify which
CONTROL bank to use, reimplement write_v7m_control_spsel() in
terms of it, and use it in exception return.

Backports commit 3f0cddeee1f266d43c956581f3050058360a810d from qemu
2018-03-05 01:35:17 -05:00
Peter Maydell 0bb50b9a7e
target/arm: Restore security state on exception return
Now that we can handle the CONTROL.SPSEL bit not necessarily being
in sync with the current stack pointer, we can restore the correct
security state on exception return. This happens before we start
to read registers off the stack frame, but after we have taken
possible usage faults for bad exception return magic values and
updated CONTROL.SPSEL.

Backports commit 3919e60b6efd9a86a0e6ba637aa584222855ac3a from qemu
2018-03-05 01:31:58 -05:00
Peter Maydell c7b5fccfb8
target/arm: Prepare for CONTROL.SPSEL being nonzero in Handler mode
In the v7M architecture, there is an invariant that if the CPU is
in Handler mode then the CONTROL.SPSEL bit cannot be nonzero.
This in turn means that the current stack pointer is always
indicated by CONTROL.SPSEL, even though Handler mode always uses
the Main stack pointer.

In v8M, this invariant is removed, and CONTROL.SPSEL may now
be nonzero in Handler mode (though Handler mode still always
uses the Main stack pointer). In preparation for this change,
change how we handle this bit: rename switch_v7m_sp() to
the now more accurate write_v7m_control_spsel(), and make it
check both the handler mode state and the SPSEL bit.

Note that this implicitly changes the point at which we switch
active SP on exception exit from before we pop the exception
frame to after it.

Backports commit de2db7ec894f11931932ca78cd14a8d2b1389d5b from qemu
2018-03-05 01:29:54 -05:00
Peter Maydell 8036c5b3de
target/arm: Don't switch to target stack early in v7M exception return
Currently our M profile exception return code switches to the
target stack pointer relatively early in the process, before
it tries to pop the exception frame off the stack. This is
awkward for v8M for two reasons:
* in v8M the process vs main stack pointer is not selected
purely by the value of CONTROL.SPSEL, so updating SPSEL
and relying on that to switch to the right stack pointer
won't work
* the stack we should be reading the stack frame from and
the stack we will eventually switch to might not be the
same if the guest is doing strange things

Change our exception return code to use a 'frame pointer'
to read the exception frame rather than assuming that we
can switch the live stack pointer this early.

Backports commit 5b5223997c04b769bb362767cecb5f7ec382c5f0 from qemu
2018-03-05 01:26:05 -05:00
Jan Kiszka ae16a26c20
arm: Fix SMC reporting to EL2 when QEMU provides PSCI
This properly forwards SMC events to EL2 when PSCI is provided by QEMU
itself and, thus, ARM_FEATURE_EL3 is off.

Found and tested with the Jailhouse hypervisor. Solution based on
suggestions by Peter Maydell.

Backports commit 77077a83006c3c9bdca496727f1735a3c5c5355d from qemu
2018-03-05 01:19:22 -05:00
Peter Maydell 4b8bdda695
target/arm: Implement MSR/MRS access to NS banked registers
In v8M the MSR and MRS instructions have extra register value
encodings to allow secure code to access the non-secure banked
version of various special registers.

(We don't implement the MSPLIM_NS or PSPLIM_NS aliases, because
we don't currently implement the stack limit registers at all.)

Backports commit 50f11062d4c896408731d6a286bcd116d1e08465 from qemu
2018-03-05 00:53:13 -05:00
Peter Maydell 6a951f17ed
target/arm: Rename 'type' to 'excret' in do_v7m_exception_exit()
In the v7M and v8M ARM ARM, the magic exception return values are
referred to as EXC_RETURN values, and in QEMU we use V7M_EXCRET_*
constants to define bits within them. Rename the 'type' variable
which holds the exception return value in do_v7m_exception_exit()
to excret, making it clearer that it does hold an EXC_RETURN value.

Backports commit 351e527a613147aa2a2e6910f92923deef27ee48 from qemu
2018-03-04 23:14:22 -05:00
Peter Maydell 1301cb1771
target/arm: Add and use defines for EXCRET constants
The exception-return magic values get some new bits in v8M, which
makes some bit definitions for them worthwhile.

We don't use the bit definitions for the switch on the low bits
which checks the return type for v7M, because this is defined
in the v7M ARM ARM as a set of valid values rather than via
per-bit checks.

Backports commit 4d1e7a4745c050f7ccac49a1c01437526b5130b5 from qemu
2018-03-04 23:12:37 -05:00
Peter Maydell aa71933721
target/arm: Remove unnecessary '| 0xf0000000' from do_v7m_exception_exit()
In do_v7m_exception_exit(), there's no need to force the high 4
bits of 'type' to 1 when calling v7m_exception_taken(), because
we know that they're always 1 or we could not have got to this
"handle return to magic exception return address" code. Remove
the unnecessary ORs.

Backports commit 7115cdf5782922611bcc44c89eec5990db7f6466 from qemu
2018-03-04 23:11:13 -05:00
Peter Maydell 2718aa8233
target/arm: Get PRECISERR and IBUSERR the right way round
For a bus fault, the M profile BFSR bit PRECISERR means a bus
fault on a data access, and IBUSERR means a bus fault on an
instruction access. We had these the wrong way around; fix this.

Backports commit c6158878650c01b2c753b2ea7d0967c8fe5ca59e from qemu
2018-03-04 23:10:33 -05:00
Peter Maydell ceccd92940
target/arm: Clear exclusive monitor on v7M reset, exception entry/exit
For M profile we must clear the exclusive monitor on reset, exception
entry and exception exit. We weren't doing any of these things; fix
this bug.

Backports commit dc3c4c14f0f12854dbd967be3486f4db4e66d25b from qemu
2018-03-04 23:09:41 -05:00
Peter Maydell 4b816fe0aa
target/arm: Implement BXNS, and banked stack pointers
Implement the BXNS v8M instruction, which is like BX but will do a
jump-and-switch-to-NonSecure if the branch target address has bit 0
clear.

This is the first piece of code which implements "switch to the
other security state", so the commit also includes the code to
switch the stack pointers around, which is the only complicated
part of switching security state.

BLXNS is more complicated than just "BXNS but set the link register",
so we leave it for a separate commit.

Backports commit fb602cb726b3ebdd01ef3b1732d74baf9fee7ec9 from qemu
2018-03-04 21:21:23 -05:00
Peter Maydell 221232fb35
target/arm: Move regime_is_secure() to target/arm/internals.h
Move the regime_is_secure() utility function to internals.h;
we are going to want to call it from translate.c.

Backports commit 61fcd69b0db268e7612b07fadc436b93def91768 from qemu
2018-03-04 21:14:05 -05:00
Peter Maydell 07b9144ef2
target/arm: Make CFSR register banked for v8M
Make the CFSR register banked if v8M security extensions are enabled.

Not all the bits in this register are banked: the BFSR
bits [15:8] are shared between S and NS, and we store them
in the NS copy of the register.

Backports commit 334e8dad7a109d15cb20b090131374ae98682a50 from qemu
2018-03-04 21:12:55 -05:00
Peter Maydell 74c66cc2a9
target/arm: Make MMFAR banked for v8M
Make the MMFAR register banked if v8M security extensions are
enabled.

Backports commit c51a5cfc9fae82099028eb12cb1d064ee07f348e from qemu
2018-03-04 21:10:47 -05:00
Peter Maydell 4b24f6d87b
target/arm: Make CCR register banked for v8M
Make the CCR register banked if v8M security extensions are enabled.

This is slightly more complicated than the other "add banking"
patches because there is one bit in the register which is not
banked. We keep the live data in the NS copy of the register,
and adjust it on register reads and writes. (Since we don't
currently implement the behaviour that the bit controls, there
is nowhere else that needs to care.)

This patch includes the enforcement of the bits which are newly
RES1 in ARMv8M.

Backports commit 9d40cd8a68cfc7606f4548cc9e812bab15c6dc28 from qemu
2018-03-04 21:09:34 -05:00
Peter Maydell f88f4b5e31
target/arm: Make MPU_CTRL register banked for v8M
Make the MPU_CTRL register banked if v8M security extensions are
enabled.

Backports commit ecf5e8eae8b0b5fa41f00b53d67747b42fd1b8b9 from qemu
2018-03-04 21:08:16 -05:00
Peter Maydell 683830d5ac
target/arm: Make MPU_RNR register banked for v8M
Make the MPU_RNR register banked if v8M security extensions are
enabled.

Backports commit 1bc04a8880374407c4b12d82ceb8752e12ff5336 from qemu
2018-03-04 21:06:01 -05:00
Peter Maydell 5e14b33c65
target/arm: Make MPU_RBAR, MPU_RLAR banked for v8M
Make the MPU registers MPU_MAIR0 and MPU_MAIR1 banked if v8M security
extensions are enabled.

We can freely add more items to vmstate_m_security without
breaking migration compatibility, because no CPU currently
has the ARM_FEATURE_M_SECURITY bit enabled and so this
subsection is not yet used by anything.

Backports commit 62c58ee0b24eafb44c06402fe059fbd7972eb409 from qemu
2018-03-04 21:04:41 -05:00
Peter Maydell 3e35eee327
target/arm: Make VTOR register banked for v8M
Make the VTOR register banked if v8M security extensions are enabled.

Backports commit 45db7ba681ede57113a67499840e69ee586bcdf2 from qemu
2018-03-04 21:01:51 -05:00
Peter Maydell 59c6845ada
target/arm: Make CONTROL register banked for v8M
Make the CONTROL register banked if v8M security extensions are enabled.

Backports commit 8bfc26ea302ec03585d7258a7cf8938f76512730 from qemu
2018-03-04 21:00:58 -05:00
Peter Maydell 14cb6925f3
target/arm: Make FAULTMASK register banked for v8M
Make the FAULTMASK register banked if v8M security extensions are enabled.

Note that we do not yet implement the functionality of the new
AIRCR.PRIS bit (which allows the effect of the NS copy of FAULTMASK to
be restricted).

This patch includes the code to determine for v8M which copy
of FAULTMASK should be updated on exception exit; further
changes will be required to the exception exit code in general
to support v8M, so this is just a small piece of that.

The v8M ARM ARM introduces a notation where individual paragraphs
are labelled with R (for rule) or I (for information) followed
by a random group of subscript letters. In comments where we want
to refer to a particular part of the manual we use this convention,
which should be more stable across document revisions than using
section or page numbers.

Backports commit 42a6686b2f6199d086a58edd7731faeb2dbe7c14 from qemu
2018-03-04 20:58:38 -05:00
Peter Maydell ff3f7811ce
target/arm: Make PRIMASK register banked for v8M
Make the PRIMASK register banked if v8M security extensions are enabled.

Note that we do not yet implement the functionality of the new
AIRCR.PRIS bit (which allows the effect of the NS copy of PRIMASK to
be restricted).

Backports commit 6d8048341995b31a77dc2e0dcaaf4e3df0e3121a from qemu
2018-03-04 20:55:49 -05:00
Peter Maydell c9a7aad4dc
target/arm: Make BASEPRI register banked for v8M
Make the BASEPRI register banked if v8M security extensions are enabled.

Note that we do not yet implement the functionality of the new
AIRCR.PRIS bit (which allows the effect of the NS copy of BASEPRI to
be restricted).

Backports commit acf949411ffb675edbfb707e235800b02e6a36f8 from qemu
2018-03-04 20:54:44 -05:00
Peter Maydell f4d155ad3a
target/arm: Add MMU indexes for secure v8M
Now that MPU lookups can return different results for v8M
when the CPU is in secure vs non-secure state, we need to
have separate MMU indexes; add the secure counterparts
to the existing three M profile MMU indexes.

Backports commit 66787c7868d05d29974e09201611b718c976f955 from qemu
2018-03-04 20:53:04 -05:00
Peter Maydell 829a34ec55
target/arm: Implement new PMSAv8 behaviour
Implement the behavioural side of the new PMSAv8 specification.

Backports commit 504e3cc36b68b34c176f3f4116b1d5677471ec20 from qemu
2018-03-04 20:47:54 -05:00
Peter Maydell 06619904c6
target/arm: Create and use new function arm_v7m_is_handler_mode()
Add a utility function for testing whether the CPU is in Handler
mode; this is just a check whether v7m.exception is non-zero, but
we do it in several places and it makes the code a bit easier
to read to not have to mentally figure out what the test is testing.

Backports commit 15b3f556bab4f961bf92141eb8521c8da3df5eb2 from qemu
2018-03-04 13:06:45 -05:00
Peter Maydell a897ee919b
target-arm: v7M: ignore writes to CONTROL.SPSEL from Thread mode
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
2018-03-04 13:04:20 -05:00
Peter Maydell 4ae080e27f
target/arm: Don't calculate lr in arm_v7m_cpu_do_interrupt() until needed
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
2018-03-04 12:59:38 -05:00
Peter Maydell 9056a93c9a
target/arm: Don't store M profile PRIMASK and FAULTMASK in daif
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
2018-03-04 12:56:29 -05:00
Peter Maydell 5d6b031550
target/arm: Define and use XPSR bit masks
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
2018-03-04 12:54:41 -05:00
Peter Maydell 64c6727e4a
target/arm: Fix outdated comment about exception exit
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
2018-03-04 12:52:34 -05:00
Peter Maydell 6f4afe1a13
target/arm: Consolidate PMSA handling in get_phys_addr()
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
2018-03-04 12:48:22 -05:00
Peter Maydell 2c9a196efe
target/arm: Use MMUAccessType enum rather than int
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
2018-03-04 12:45:56 -05:00
Peter Maydell d72175d671
target/arm: Move PMSAv7 reset into arm_cpu_reset() so M profile MPUs get reset
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
2018-03-04 01:20:57 -05:00
Peter Maydell 6add2f0f65
target/arm: Rename cp15.c6_rgnr to pmsav7.rnr
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
2018-03-04 01:18:53 -05:00
Peter Maydell 266885f50f
target/arm: Don't allow guest to make System space executable for M profile
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
2018-03-04 01:17:01 -05:00
Peter Maydell 34b9740081
target/arm: Don't do MPU lookups for addresses in M profile PPB region
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
2018-03-04 01:14:22 -05:00
Peter Maydell 4dc69f4b26
target/arm: Correct MPU trace handling of write vs execute
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
2018-03-04 01:13:19 -05:00
Peter Maydell 565626ca63
armv7m: Raise correct kind of UsageFault for attempts to execute ARM code
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
2018-03-02 20:00:58 -05:00
Peter Maydell fbfeca93b3
armv7m: Check exception return consistency
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
2018-03-02 19:59:18 -05:00
Peter Maydell 0736054d6d
armv7m: Extract "exception taken" code into functions
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
2018-03-02 19:54:46 -05:00
Michael Davidsaver 5b9f53bd27
armv7m: Simpler and faster exception start
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
2018-03-02 19:52:01 -05:00
Peter Maydell 50c956db7e
arm: Implement HFNMIENA support for M profile MPU
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
2018-03-02 19:33:24 -05:00
Michael Davidsaver 611a711f7b
arm: add MPU support to M profile CPUs
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
2018-03-02 19:30:20 -05:00
Michael Davidsaver 09d69209a0
armv7m: Classify faults as MemManage or BusFault
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
2018-03-02 19:28:21 -05:00
Michael Davidsaver 4d8ae4a2b2
armv7m: Implement M profile default memory map
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
2018-03-02 19:25:02 -05:00
Michael Davidsaver 7c845dabe8
armv7m: Improve "-d mmu" tracing for PMSAv7 MPU
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
2018-03-02 19:17:05 -05:00
Peter Maydell bfe99e9a0b
arm: Remove unnecessary check on cpu->pmsav7_dregion
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
2018-03-02 19:14:50 -05:00
Peter Maydell 349227bb05
arm: Don't let no-MPU PMSA cores write to SCTLR.M
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
2018-03-02 19:13:37 -05:00
Peter Maydell 6614ba9615
arm: Clean up handling of no-MPU PMSA CPUs
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
2018-03-02 19:05:31 -05:00
Peter Maydell b50d2da03c
arm: Use different ARMMMUIdx values for M profile
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
2018-03-02 19:01:42 -05:00
Michael Davidsaver f532e80749
armv7m: Escalate exceptions to HardFault if necessary
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
2018-03-02 18:59:13 -05:00
Peter Maydell b7bf752d3c
arm: Add support for M profile CPUs having different MMU index semantics
The M profile CPU's MPU has an awkward corner case which we
would like to implement with a different MMU index.

We can avoid having to bump the number of MMU modes ARM
uses, because some of our existing MMU indexes are only
used by non-M-profile CPUs, so we can borrow one.
To avoid that getting too confusing, clean up the code
to try to keep the two meanings of the index separate.

Instead of ARMMMUIdx enum values being identical to core QEMU
MMU index values, they are now the core index values with some
high bits set. Any particular CPU always uses the same high
bits (so eventually A profile cores and M profile cores will
use different bits). New functions arm_to_core_mmu_idx()
and core_to_arm_mmu_idx() convert between the two.

In general core index values are stored in 'int' types, and
ARM values are stored in ARMMMUIdx types.

Backports commit 8bd5c82030b2cb09d3eef6b444f1620911cc9fc5 from qemu
2018-03-02 18:59:13 -05:00
Peter Maydell 1cf80d7536
arm: Move excnames[] array into arm_log_exceptions()
The excnames[] array is defined in internals.h because we used
to use it from two different source files for handling logging
of AArch32 and AArch64 exception entry. Refactoring means that
it's now used only in arm_log_exception() in helper.c, so move
the array into that function.

Backports commit 2c4a7cc5afb1bfc1728a39abd951ddd7714c476e from qemu
2018-03-02 14:39:37 -05:00
Peter Maydell 78303d4c1b
arm: Fix APSR writes via M profile MSR
Our implementation of writes to the APSR for M-profile via the MSR
instruction was badly broken.

First and worst, we had the sense wrong on the test of bit 2 of the
SYSm field -- this is supposed to request an APSR write if bit 2 is 0
but we were doing it if bit 2 was 1. This bug was introduced in
commit 58117c9bb429cd, so hasn't been in a QEMU release.

Secondly, the choice of exactly which parts of APSR should be written
is defined by bits in the 'mask' field. We were not passing these
through from instruction decode, making it impossible to check them
in the helper.

Pass the mask bits through from the instruction decode to the helper
function and process them appropriately; fix the wrong sense of the
SYSm bit 2 check.

Invalid mask values and invalid combinations of mask and register
number are UNPREDICTABLE; we choose to treat them as if the mask
values were valid.

Backports commit b28b3377d7e9ba35611d454d5a63ef50cab1f8c5 from qemu
2018-03-02 14:08:13 -05:00
Peter Maydell fce8138187
armv7m: Report no-coprocessor faults correctly
For v7M attempts to access a nonexistent coprocessor are reported
differently from plain undefined instructions (as UsageFaults of type
NOCP rather than type UNDEFINSTR). Split them out into a new
EXCP_NOCP so we can report the FSR value correctly.

Backports commit 7517748e3f71a3099e57915fba95c4c308e6d842 from qemu
2018-03-02 13:47:14 -05:00
Michael Davidsaver eaa080e232
armv7m: set CFSR.UNDEFINSTR on undefined instructions
When we take an exception for an undefined instruction, set the
appropriate CFSR bit.

Backports commit 81dd9648c69bb89afdd6f4bb3ed6f3efdac96524 from qemu
2018-03-02 13:45:56 -05:00
Michael Davidsaver 2297b8134b
armv7m: honour CCR.STACKALIGN on exception entry
The CCR.STACKALIGN bit controls whether the CPU is supposed to force
8-alignment of the stack pointer on entry to the exception handler.

Backports commit dc858c6633a9af8b80c1509cf6f825e4390d3ad1 from qemu
2018-03-02 13:45:06 -05:00
Michael Davidsaver 7f044bf8cc
armv7m: Clear FAULTMASK on return from non-NMI exceptions
FAULTMASK must be cleared on return from all
exceptions other than NMI.

Backports commit a20ee6005564590d33eabec11ed4dc7c432db36b from qemu
2018-03-02 13:41:16 -05:00
Michael Davidsaver cc9458cf59
armv7m: Explicit error for bad vector table
Give an explicit error and abort when a load
from the vector table fails. Architecturally this
should HardFault (which will then immediately
fail to load the HardFault vector and go into Lockup).
Since we don't model Lockup, just report this guest
error via cpu_abort(). This is more helpful than the
previous behaviour of reading a zero, which is the
address of the reset stack pointer and not a sensible
location to jump to.

Backports commit 1b9ea408fca1ce8caae67b792355b023c69c5ac5 from qemu
2018-03-02 13:38:08 -05:00
Michael Davidsaver 8828b4e595
armv7m: MRS/MSR: handle unprivileged access
The MRS and MSR instruction handling has a number of flaws:
* unprivileged accesses should only be able to read
CONTROL and the xPSR subfields, and only write APSR
(others RAZ/WI)
* privileged access should not be able to write xPSR
subfields other than APSR
* accesses to unimplemented registers should log as
guest errors, not abort QEMU

Backports commit 58117c9bb429cd9552d998687aa99088eb1d8528 from qemu
2018-03-02 13:29:59 -05:00
Michael Davidsaver 2769c6ada0
armv7m: Fix reads of CONTROL register bit 1
The v7m CONTROL register bit 1 is SPSEL, which indicates
the stack being used. We were storing this information
not in v7m.control but in the separate v7m.other_sp
structure field. Unfortunately, the code handling reads
of the CONTROL register didn't take account of this, and
so if SPSEL was updated by an exception entry or exit then
a subsequent guest read of CONTROL would get the wrong value.

Using a separate structure field doesn't really gain us
anything in efficiency, so drop this unnecessary complexity
in favour of simply storing all the bits in v7m.control.

This is a migration compatibility break for M profile
CPUs only.

Backports commit abc24d86cc0364f402e438fae3acb14289b40734 from qemu
2018-03-02 13:26:38 -05:00
Andrew Baumann 76cd64dd7e
target/arm: implement armv8 PMUSERENR (user-mode enable bits)
In armv8, this register implements more than a single bit, with
fine-grained enables for read access to event counters, cycles
counters, and write access to the software increment. This change
implements those checks using custom access functions for the relevant
registers.

Backports commit 6ecd0b6ba0591ef280ed984103924d4bdca5ac32 from qemu
2018-03-02 12:55:46 -05:00
Alex Bennée b8caaac110
target/arm/helper: make it clear the EC field is also in hex
..just like the rest of the displayed ESR register. Otherwise people
might scratch their heads if a not obviously hex number is displayed
for the EC field.

Backports commit 6568da459b611845ef55526cd23afc9fa9f4647f from qemu
2018-03-02 12:50:33 -05:00
Alex Bennée 454932263c
cputlb and arm/sparc targets: convert mmuidx flushes from varg to bitmap
While the vargs approach was flexible the original MTTCG ended up
having munge the bits to a bitmap so the data could be used in
deferred work helpers. Instead of hiding that in cputlb we push the
change to the API to make it take a bitmap of MMU indexes instead.

For ARM some the resulting flushes end up being quite long so to aid
readability I've tended to move the index shifting to a new line so
all the bits being or-ed together line up nicely, for example:

tlb_flush_page_by_mmuidx(other_cs, pageaddr,
(1 << ARMMMUIdx_S1SE1) |
(1 << ARMMMUIdx_S1SE0));

Backports commit 0336cbf8532935d8e23c2aabf3e2ce2c0697b6ac from qemu
2018-03-02 10:12:40 -05:00
Wei Huang c9bdf5e6c7
target-arm: Enable vPMU support under TCG mode
This patch contains several fixes to enable vPMU under TCG mode. It
first removes the checking of kvm_enabled() while unsetting
ARM_FEATURE_PMU. With it, the .pmu option can be used to turn on/off vPMU
under TCG mode. Secondly the PMU node of DT table is now created under TCG.
The last fix is to disable the masking of PMUver field of ID_AA64DFR0_EL1.

Backports commit d6f02ce3b8a43ddd8f83553fe754a34b26fb273f from qemu
2018-03-02 07:58:48 -05:00
Wei Huang 5e3349a818
target-arm: Add support for PMU register PMINTENSET_EL1
This patch adds access support for PMINTENSET_EL1.

Backports commit e6ec54571e424bb1d6e50e32fe317c616cde3e05 from qemu
2018-03-02 07:57:40 -05:00
Wei Huang 3b34b7f0f9
target-arm: Add support for AArch64 PMU register PMXEVTYPER_EL0
In order to support Linux perf, which uses PMXEVTYPER register,
this patch adds read/write access support for PMXEVTYPER. The access
is CONSTRAINED UNPREDICTABLE when PMSELR is not 0x1f. Additionally
this patch adds support for PMXEVTYPER_EL0.

Backports commit fdb8665672ded05f650d18f8b62d5c8524b4385b from qemu
2018-03-02 07:53:05 -05:00
Wei Huang 1165020022
target-arm: Add support for PMU register PMSELR_EL0
This patch adds support for AArch64 register PMSELR_EL0. The existing
PMSELR definition is revised accordingly.

Backports commit 6b0407805d46bbeba70f4be426285d0a0e669750 from qemu
2018-03-02 07:39:43 -05:00
Peter Maydell 48825c1be2
target/arm: Drop IS_M() macro
We only use the IS_M() macro in two places, and it's a bit of a
namespace grab to put in cpu.h. Drop it in favour of just explicitly
calling arm_feature() in the places where it was used.

Backports commit 531c60a97ab51618b4b9ccef1c5fe00607079706 from qemu
2018-03-01 23:59:09 -05:00
Peter Maydell 468e2849cd
target/arm: Implement DBGVCR32_EL2 system register
The DBGVCR_EL2 system register is needed to run a 32-bit
EL1 guest under a Linux EL2 64-bit hypervisor. Its only
purpose is to provide AArch64 with access to the state of
the DBGVCR AArch32 register. Since we only have a dummy
DBGVCR, implement a corresponding dummy DBGVCR32_EL2.

Backports commit 4d2ec4da1c2d60c9fd8bad137506870c2f980410 from qemu
2018-03-01 23:02:28 -05:00
Peter Maydell 0db334c0e4
target/arm: Handle VIRQ and VFIQ in arm_cpu_do_interrupt_aarch32()
To run a VM in 32-bit EL1 our AArch32 interrupt handling code
needs to be able to cope with VIRQ and VFIQ exceptions.
These behave like IRQ and FIQ except that we don't need to try
to route them to Monitor mode.

Backports commit 87a4b270348c69a446ebcddc039bfae31b1675cb from qemu
2018-03-01 22:59:08 -05:00
Thomas Huth b2f1326437
Move target-* CPU file into a target/ folder
We've currently got 18 architectures in QEMU, and thus 18 target-xxx
folders in the root folder of the QEMU source tree. More architectures
(e.g. RISC-V, AVR) are likely to be included soon, too, so the main
folder of the QEMU sources slowly gets quite overcrowded with the
target-xxx folders.
To disburden the main folder a little bit, let's move the target-xxx
folders into a dedicated target/ folder, so that target-xxx/ simply
becomes target/xxx/ instead.

Backports commit fcf5ef2ab52c621a4617ebbef36bf43b4003f4c0 from qemu
2018-03-01 22:50:58 -05:00
Renamed from qemu/target-arm/helper.c (Browse further)