In op_bfx, note that tcg_gen_{,s}extract_i32 already checks
for width == 32, so we don't need to special case that here.
Backports commit 86d21e4b509a2835ed79f234f476a4c5191d435b from qemu
Pass the T5 encoding of SUBS PC, LR, #IMM through the normal SUBS path
to make it clear exactly what's happening -- we hit ALUExceptionReturn
along that path.
Backports commit ef11bc3c461e2c650e8bef552146a4b08f81884e from qemu
Document our choice about the T32 CONSTRAINED UNPREDICTABLE behaviour.
This matches the undocumented choice made by the legacy decoder.
Backports commit 4c97f5b2f0fa9b37f9ff497f15411d809e6fd098 from qemu
The m-profile and a-profile decodings overlap. Only return false
for the case of wrong profile; handle UNDEFINED for permission failure
directly. This ensures that we don't accidentally pass an insn that
applies to the wrong profile.
Backports commit d0b26644502103ca97093ef67749812dc1df7eea from qemu
By shifting the 16-bit input left by 16, we can align the desired
portion of the 48-bit product and use tcg_gen_muls2_i32.
Backports commit 485b607d4f393e0de92c922806a68aef22340c98 from qemu
Since all of the inputs and outputs are i32, dispense with
the intermediate promotion to i64 and use tcg_gen_add2_i32.
Backports commit ea96b374641bc429269096d88d4e91ee544273e9 from qemu
Since all of the inputs and outputs are i32, dispense with
the intermediate promotion to i64 and use tcg_gen_mulu2_i32
and tcg_gen_add2_i32.
Backports commit 2409d56454f0d028619fb1002eda86bf240906dd from qemu
Convert the modified immediate form of the data processing insns.
For A32, we can finally remove any code that was intertwined with
the register and register-shifted-register forms.
Backports commit 581c6ebd17c8f56ad52772216e6c6d8cc8997e8b from qemu
Convert the register shifted by register form of the data
processing insns. For A32, we cannot yet remove any code
because the legacy decoder intertwines the immediate form.
Backports commit 5be2c12337f4cbdbda4efe6ab485350f730faaad from qemu
Convert the register shifted by immediate form of the data
processing insns. For A32, we cannot yet remove any code
because the legacy decoder intertwines the reg-shifted-reg
and immediate forms.
Backports commit 25ae32c558182c07fc6ad01b936e9151cbf00c44 from qemu
Add the infrastructure that will become the new decoder.
No instructions adjusted so far.
Backports commit 51409b9e8cfe997b1ac3365df7400e0c6e844437 from qemu
This function already includes the test for an interworking write
to PC from a load. Change the T32 LDM implementation to match the
A32 LDM implementation.
For LDM, the reordering of the tests does not change valid
behaviour because the only case that differs is has rn == 15,
which is UNPREDICTABLE.
Backports commit 69be3e13764111737e1a7a13bb0c231e4d5be756 from qemu
The previous simplification got the order of operands to the
subtraction wrong. Since the 64-bit product is the subtrahend,
we must use a 64-bit subtract to properly compute the borrow
from the low-part of the product.
Fixes: 5f8cd06ebcf5 ("target/arm: Simplify SMMLA, SMMLAR, SMMLS, SMMLSR")
Backports commit e0a0c8322b8ebcdad674f443a3e86db8708d6738 from qemu
Currently the only part of an ARMCPRegInfo which is allowed to cause
a CPU exception is the access function, which returns a value indicating
that some flavour of UNDEF should be generated.
For the ATS system instructions, we would like to conditionally
generate exceptions as part of the writefn, because some faults
during the page table walk (like external aborts) should cause
an exception to be raised rather than returning a value.
There are several ways we could do this:
* plumb the GETPC() value from the top level set_cp_reg/get_cp_reg
helper functions through into the readfn and writefn hooks
* add extra readfn_with_ra/writefn_with_ra hooks that take the GETPC()
value
* require the ATS instructions to provide a dummy accessfn,
which serves no purpose except to cause the code generation
to emit TCG ops to sync the CPU state
* add an ARM_CP_ flag to mark the ARMCPRegInfo as possibly
throwing an exception in its read/write hooks, and make the
codegen sync the CPU state before calling the hooks if the
flag is set
This patch opts for the last of these, as it is fairly simple
to implement and doesn't require invasive changes like updating
the readfn/writefn hook function prototype signature.
Backports commit 37ff584c15bc3e1dd2c26b1998f00ff87189538c from qemu
Make this a static function private to translate.c.
Thus we can use the same idiom between aarch64 and aarch32
without actually sharing function implementations.
Backports commit 1ce21ba1eaf08b22da5925f3e37fc0b4322da858 from qemu
Despite the fact that the text for the call to gen_exception_insn
is identical for aarch64 and aarch32, the implementation inside
gen_exception_insn is totally different.
This fixes exceptions raised from aarch64.
This reverts commit fb2d3c9a9a.
Separate shift + extract low will result in one extra insn
for hosts like RISC-V, MIPS, and Sparc.
Backports commit 664b7e3b97d6376f3329986c465b3782458b0f8b from qemu
All of the inputs to these instructions are 32-bits. Rather than
extend each input to 64-bits and then extract the high 32-bits of
the output, use tcg_gen_muls2_i32 and other 32-bit generator functions.
Backports commit 5f8cd06ebcf57420be8fea4574de2e074de46709 from qemu
Rotate is the more compact and obvious way to swap 16-bit
elements of a 32-bit word.
Backports commit adefba76e8bf10dfb342094d2f5debfeedb1a74d from qemu
The helper function is more documentary, and also already
handles the case of rotate by zero.
Backports commit dd861b3f29be97a9e3cdb9769dcbc0c7d7825185 from qemu
The immediate shift generator functions already test for,
and eliminate, the case of a shift by zero.
Backports commit 464eaa9571fae5867d9aea7d7209c091c8a50223 from qemu
Replace x = double_saturate(y) with x = add_saturate(y, y).
There is no need for a separate more specialized helper.
Backports commit 640581a06d14e2d0d3c3ba79b916de6bc43578b0 from qemu
Promote this function from aarch64 to fully general use.
Use it to unify the code sequences for generating illegal
opcode exceptions.
Backports commit 3cb36637157088892e9e33ddb1034bffd1251d3b from qemu
Unlike the other more generic gen_exception{,_internal}_insn
interfaces, breakpoints always refer to the current instruction.
Backports commit 06bcbda3f64d464b6ecac789bce4bd69f199cd68 from qemu
The offset is variable depending on the instruction set.
Passing in the actual value is clearer in intent.
Backpors commit aee828e7541a5895669ade3a4b6978382b6b094a from qemu
We must update s->base.pc_next when we return from the translate_insn
hook to the main translator loop. By incrementing s->base.pc_next
immediately after reading the insn word, "pc_next" contains the address
of the next instruction throughout translation.
All remaining uses of s->pc are referencing the address of the next insn,
so this is now a simple global replacement. Remove the "s->pc" field.
Backports commit a04159166b880b505ccadc16f2fe84169806883d from qemu
Provide a common routine for the places that require ALIGN(PC, 4)
as the base address as opposed to plain PC. The two are always
the same for A32, but the difference is meaningful for thumb mode.
Backports commit 16e0d8234ef9291747332d2c431e46808a060472 from qemu
We currently have 3 different ways of computing the architectural
value of "PC" as seen in the ARM ARM.
The value of s->pc has been incremented past the current insn,
but that is all. Thus for a32, PC = s->pc + 4; for t32, PC = s->pc;
for t16, PC = s->pc + 2. These differing computations make it
impossible at present to unify the various code paths.
With the newly introduced s->pc_curr, we can compute the correct
value for all cases, using the formula given in the ARM ARM.
This changes the behaviour for load_reg() and load_reg_var()
when called with reg==15 from a 32-bit Thumb instruction:
previously they would have returned the incorrect value
of pc_curr + 6, and now they will return the architecturally
correct value of PC, which is pc_curr + 4. This will not
affect well-behaved guest software, because all of the places
we call these functions from T32 code are instructions where
using r15 is UNPREDICTABLE. Using the architectural PC value
here is more consistent with the T16 and A32 behaviour.
Backports commit fdbcf6329d0c2984c55d7019419a72bf8e583c36 from qemu
Add a new field to retain the address of the instruction currently
being translated. The 32-bit uses are all within subroutines used
by a32 and t32. This will become less obvious when t16 support is
merged with a32+t32, and having a clear definition will help.
Convert aarch64 as well for consistency. Note that there is one
instance of a pre-assert fprintf that used the wrong value for the
address of the current instruction.
Backports commit 43722a6d4f0c92f7e7e1e291580039b0f9789df1 from qemu
This function is used in two different contexts, and it will be
clearer if the function is given the address to which it applies.
Backports commit 331b1ca616cb708db30dab68e3262d286e687f24 from qemu
When generating an architectural single-step exception we were
routing it to the "default exception level", which is to say
the same exception level we execute at except that EL0 exceptions
go to EL1. This is incorrect because the debug exception level
can be configured by the guest for situations such as single
stepping of EL0 and EL1 code by EL2.
We have to track the target debug exception level in the TB
flags, because it is dependent on CPU state like HCR_EL2.TGE
and MDCR_EL2.TDE. (That we were previously calling the
arm_debug_target_el() function to determine dc->ss_same_el
is itself a bug, though one that would only have manifested
as incorrect syndrome information.) Since we are out of TB
flag bits unless we want to expand into the cs_base field,
we share some bits with the M-profile only HANDLER and
STACKCHECK bits, since only A-profile has this singlestep.
Fixes: https://bugs.launchpad.net/qemu/+bug/1838913
Backports commit 8bd587c1066f4456ddfe611b571d9439a947d74c from qemu
Factor out code to 'generate a singlestep exception', which is
currently repeated in four places.
To do this we need to also pull the identical copies of the
gen-exception() function out of translate-a64.c and translate.c
into translate.h.
(There is a bug in the code: we're taking the exception to the wrong
target EL. This will be simpler to fix if there's only one place to
do it.)
Backports commit c1d5f50f094ab204accfacc2ee6aafc9601dd5c4 from qemu
An attempt to do an exception-return (branch to one of the magic
addresses) in linux-user mode for M-profile should behave like
a normal branch, because linux-user mode is always going to be
in 'handler' mode. This used to work, but we broke it when we added
support for the M-profile security extension in commit d02a8698d7ae2bfed.
In that commit we allowed even handler-mode calls to magic return
values to be checked for and dealt with by causing an
EXCP_EXCEPTION_EXIT exception to be taken, because this is
needed for the FNC_RETURN return-from-non-secure-function-call
handling. For system mode we added a check in do_v7m_exception_exit()
to make any spurious calls from Handler mode behave correctly, but
forgot that linux-user mode would also be affected.
How an attempted return-from-non-secure-function-call in linux-user
mode should be handled is not clear -- on real hardware it would
result in return to secure code (not to the Linux kernel) which
could then handle the error in any way it chose. For QEMU we take
the simple approach of treating this erroneous return the same way
it would be handled on a CPU without the security extensions --
treat it as a normal branch.
The upshot of all this is that for linux-user mode we should never
do any of the bx_excret magic, so the code change is simple.
This ought to be a weird corner case that only affects broken guest
code (because Linux user processes should never be attempting to do
exception returns or NS function returns), except that the code that
assigns addresses in RAM for the process and stack in our linux-user
code does not attempt to avoid this magic address range, so
legitimate code attempting to return to a trampoline routine on the
stack can fall into this case. This change fixes those programs,
but we should also look at restricting the range of memory we
use for M-profile linux-user guests to the area that would be
real RAM in hardware.
Backports commit 9027d3fba605d8f6093342ebe4a1da450d374630 from qemu
Thumb instructions in an IT block are set up to be conditionally
executed depending on a set of condition bits encoded into the IT
bits of the CPSR/XPSR. The architecture specifies that if the
condition bits are 0b1111 this means "always execute" (like 0b1110),
not "never execute"; we were treating it as "never execute". (See
the ConditionHolds() pseudocode in both the A-profile and M-profile
Arm ARM.)
This is a bit of an obscure corner case, because the only legal
way to get to an 0b1111 set of condbits is to do an exception
return which sets the XPSR/CPSR up that way. An IT instruction
which encodes a condition sequence that would include an 0b1111 is
UNPREDICTABLE, and for v8A the CONSTRAINED UNPREDICTABLE choices
for such an IT insn are to NOP, UNDEF, or treat 0b1111 like 0b1110.
Add a comment noting that we take the latter option.
Backports commit 5529de1e5512c05276825fa8b922147663fd6eac from qemu
