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5186 commits

Author SHA1 Message Date
Richard Henderson 33f7f6f09a
tcg/i386: Fix dup_vec in non-AVX2 codepath
The VPUNPCKLD* instructions are all "non-destructive source",
indicated by "NDS" in the encoding string in the x86 ISA manual.
This means that they take two source operands, one of which is
encoded in the VEX.vvvv field. We were incorrectly treating them
as if they were destructive-source and passing 0 as the 'v'
argument of tcg_out_vex_modrm(). This meant we were always
using %xmm0 as one of the source operands, causing incorrect
results if the register allocator happened to want to use
something else. For instance the input AArch64 insn:
DUP v26.16b, w21
which becomes TCG IR ops:
dup_vec v128,e8,tmp2,x21
st_vec v128,e8,tmp2,env,$0xa40
was assembled to:
0x607c568c: c4 c1 7a 7e 86 e8 00 00 vmovq 0xe8(%r14), %xmm0
0x607c5694: 00
0x607c5695: c5 f9 60 c8 vpunpcklbw %xmm0, %xmm0, %xmm1
0x607c5699: c5 f9 61 c9 vpunpcklwd %xmm1, %xmm0, %xmm1
0x607c569d: c5 f9 70 c9 00 vpshufd $0, %xmm1, %xmm1
0x607c56a2: c4 c1 7a 7f 8e 40 0a 00 vmovdqu %xmm1, 0xa40(%r14)
0x607c56aa: 00

when the vpunpcklwd insn should be "%xmm1, %xmm1, %xmm1".
This resulted in our incorrectly setting the output vector to
q26=0000320000003200:0000320000003200
when given an input of x21 == 0000000002803200
rather than the expected all-zeroes.

Pass the correct source register number to tcg_out_vex_modrm()
for these insns.

Backports commit 7eb30ef0ba2eb59e7430d4848ae8d4bf4e50f768 from qemu
2018-05-11 11:22:38 -04:00
Richard Henderson 991683af73
target/m68k: Fix build Werror with gcc 8.0.1
The Werror stems from the compiler finding a path through the second
switch via a missing default case in which src1 is uninitialized, and
not being able to prove that the missing default case is unreachable
due to the first switch.

Simplify the second switch to merge default with OS_LONG,
which returns directly. This removes the unreachable path.

Backports commit 5cbc61110738accb16ff8ed1f08a32906d02790f from qemu.
2018-05-11 10:37:45 -04:00
Peter Maydell ca9b601d0d
target/arm: Implement v8M VLLDM and VLSTM
For v8M the instructions VLLDM and VLSTM support lazy saving
and restoring of the secure floating-point registers. Even
if the floating point extension is not implemented, these
instructions must act as NOPs in Secure state, so they can
be used as part of the secure-to-nonsecure call sequence.

Fixes: https://bugs.launchpad.net/qemu/+bug/1768295

Backports commit b1e5336a9899016c53d59eba53ebf6abcc21995c from qemu
2018-05-08 08:29:12 -04:00
Mathew Maidment 06da6ae3c8
target/arm: Correct MPUIR privilege level in register_cp_regs_for_features() conditional case
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
2018-05-08 08:27:40 -04:00
Richard Henderson 5940a36394
target/arm: Tidy condition in disas_simd_two_reg_misc
Path analysis shows that size == 3 && !is_q has been eliminated.

Fixes: Coverity CID1385853

Backports commit a8766e3172c1671cab297c1ef4566a3c5d094822 from qemu
2018-05-08 08:26:31 -04:00
Richard Henderson cb324fd039
target/arm: Tidy conditions in handle_vec_simd_shri
The (size > 3 && !is_q) condition is identical to the preceeding test
of bit 3 in immh; eliminate it. For the benefit of Coverity, assert
that size is within the bounds we expect.

Fixes: Coverity CID1385846
Fixes: Coverity CID1385849
Fixes: Coverity CID1385852
Fixes: Coverity CID1385857

Backports commit 8dae46970532afcf93470b00e83ca9921980efc3 from qemu
2018-05-08 08:25:37 -04:00
Marc-André Lureau 0087625b7e
qobject: Modify qobject_ref() to return obj
For convenience and clarity, make it possible to call qobject_ref() at
the time when the reference is associated with a variable, or
argument, by making qobject_ref() return the same pointer as given.
Use that to simplify the callers.

Backports commit f5a74a5a50387c6f980b2e2f94f062487a1826da from qemu
2018-05-04 10:24:10 -04:00
Marc-André Lureau ab4528c1e4
qobject: Replace qobject_incref/QINCREF qobject_decref/QDECREF
Now that we can safely call QOBJECT() on QObject * as well as its
subtypes, we can have macros qobject_ref() / qobject_unref() that work
everywhere instead of having to use QINCREF() / QDECREF() for QObject
and qobject_incref() / qobject_decref() for its subtypes.

The replacement is mechanical, except I broke a long line, and added a
cast in monitor_qmp_cleanup_req_queue_locked(). Unlike
qobject_decref(), qobject_unref() doesn't accept void *.

Note that the new macros evaluate their argument exactly once, thus no
need to shout them.

Backports commit cb3e7f08aeaab0ab13e629ce8496dca150a449ba from qemu
2018-05-04 10:16:07 -04:00
Marc-André Lureau f4b3c5d0bd
qobject: use a QObjectBase_ struct
By moving the base fields to a QObjectBase_, QObject can be a type
which also has a 'base' field. This allows writing a generic QOBJECT()
macro that will work with any QObject type, including QObject
itself. The container_of() macro ensures that the object to cast has a
QObjectBase_ base field, giving some type safety guarantees. QObject
must have no members but QObjectBase_ base, or else QOBJECT() breaks.

QObjectBase_ is not a typedef and uses a trailing underscore to make
it obvious it is not for normal use and to avoid potential abuse.

Backports commit 3d3eacaeccaab718ea0e2ddaa578bfae9e311c59 from qemu
2018-05-04 10:11:24 -04:00
Marc-André Lureau 2ca916e106
qobject: Ensure base is at offset 0
All QObject types have the base QObject as their first field. This
allows the simplification of qobject_to().

Backports commit 7ee9edfdb117da47c86c9764d90f0be11a648666 from qemu
2018-05-04 09:54:36 -04:00
Laurent Vivier ec12091943
tcg: workaround branch instruction overflow in tcg_out_qemu_ld/st
ppc64 uses a BC instruction to call the tcg_out_qemu_ld/st
slow path. BC instruction uses a relative address encoded
on 14 bits.

The slow path functions are added at the end of the generated
instructions buffer, in the reverse order of the callers.
So more we have slow path functions more the distance between
the caller (BC) and the function increases.

This patch changes the behavior to generate the functions in
the same order of the callers.

Backports commit 6001f7729e12dd1d810291e4cbf83cee8e07441d from qemu
2018-05-03 15:09:07 -04:00
Richard Henderson 2150745db4
tcg: Improve TCGv_ptr support
Drop TCGV_PTR_TO_NAT and TCGV_NAT_TO_PTR internal macros.

Add tcg_temp_local_new_ptr, tcg_gen_brcondi_ptr, tcg_gen_ext_i32_ptr,
tcg_gen_trunc_i64_ptr, tcg_gen_extu_ptr_i64, tcg_gen_trunc_ptr_i32.

Use inlines instead of macros where possible.

Backports commit 5bfa803448638a45542441fd6b7cc1241403ea72 from qemu
2018-05-03 15:05:43 -04:00
Richard Henderson 4fa9ea2ae1
tcg: Allow wider vectors for cmp and mul
In db432672, we allow wide inputs for operations such as add.
However, in 212be173 and 3774030a we didn't do the same for
compare and multiply.

Backports commit 9a938d86b04025ac605db0ea9819e5896bf576ec from qemu
2018-05-03 14:42:57 -04:00
Henry Wertz 090e2e9d0e
tcg/arm: Fix memory barrier encoding
I found with qemu 2.11.x or newer that I would get an illegal instruction
error running some Intel binaries on my ARM chromebook. On investigation,
I found it was quitting on memory barriers.

qemu instruction:
mb $0x31
was translating as:
0x604050cc: 5bf07ff5 blpl #0x600250a8

After patch it gives:
0x604050cc: f57ff05b dmb ish

In short, I found INSN_DMB_ISH (memory barrier for ARMv7) appeared to be
correct based on online docs, but due to some endian-related shenanigans it
had to be byte-swapped to suit qemu; it appears INSN_DMB_MCR (memory
barrier for ARMv6) also should be byte swapped (and this patch does so).
I have not checked for correctness of aarch64's barrier instruction.

Backports commit 3f814b803797c007abfe5c4041de754e01723031 from qemu
2018-05-03 14:41:36 -04:00
Richard Henderson 16a55143dc
tcg: Document INDEX_mul[us]h_*
Backports commit d103021269ca9307ed7ca0d845d2b9e6c387509a from qemu
2018-05-03 14:40:49 -04:00
Laurent Vivier 97c8507f00
m68k: remove dead code (Coverity CID1390617)
floatx80_sin() and floatx80_cos() are derived from one
sincos() function. They have both unused code coming from
their common origin. Remove it.

Backports commit 6361d2984ce88912976a34e1797a5ad5139c649b from qemu
2018-05-01 11:44:18 -04:00
Laurent Vivier ebf0c8f9ca
m68k: Fix floatx80_lognp1 (Coverity CID1390587)
return the result of packFloatx80() instead of
dropping it.

Backports commit 981348af5c3c72335d95f6877abf702d80176eb3 from qemu
2018-05-01 11:41:07 -04:00
Pavel Dovgalyuk bf16c6daee
m68k: fix subx mem, mem instruction
This patch fixes decrement of the pointers for subx mem, mem instructions.
Without the patch pointers are decremented by OS_* constant value instead of
retrieving the corresponding data size and using it as a decrement.

Backports commit 355d4d1c00e708907ff391c24ca708f1c9c06bf0 from qemu
2018-05-01 11:40:00 -04:00
Aaron Lindsay d3e7bbffea
target/arm: Make PMOVSCLR and PMUSERENR 64 bits wide
This is a bug fix to ensure 64-bit reads of these registers don't read
adjacent data.

Backports commit e4e91a217c17fff4045dd4b423cdcb471b3d6a0e from qemu
2018-04-26 09:25:09 -04:00
Aaron Lindsay 4ed7524444
target/arm: Fix bitmask for PMCCFILTR writes
It was shifted to the left one bit too few.

Backports commit ac57fd24cd864d42e7551f82266bc0930bd39547 from qemu
2018-04-26 09:23:04 -04:00
Aaron Lindsay 99a0be89a8
target/arm: Add pre-EL change hooks
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
2018-04-26 09:21:54 -04:00
Aaron Lindsay 8caf217d26
target/arm: Support multiple EL change hooks
Backports commit 08267487c99e8150382420936ab72c1e0ad74ce3 from qemu
2018-04-26 09:16:09 -04:00
Aaron Lindsay dfe1f54920
target/arm: Fetch GICv3 state directly from CPUARMState
This eliminates the need for fetching it from el_change_hook_opaque, and
allows for supporting multiple el_change_hooks without having to hack
something together to find the registered opaque belonging to GICv3.

Backports commit d5a5e4c93dae0dc3feb402cf7ee78d846da1a7e1 from qemu
2018-04-26 09:10:32 -04:00
Aaron Lindsay 1228bcf45d
target/arm: Mask PMU register writes based on PMCR_EL0.N
This is in preparation for enabling counters other than PMCCNTR

Backports commit 7ece99b17e832065236c07a158dfac62619ef99b from qemu
2018-04-26 09:09:12 -04:00
Aaron Lindsay e1d021ad74
target/arm: Treat PMCCNTR as alias of PMCCNTR_EL0
They share the same underlying state

Backports commit 169c893874977eee8303a6dad4a3f25c5464858f from qemu
2018-04-26 09:07:50 -04:00
Aaron Lindsay e1bffbf7df
target/arm: Check PMCNTEN for whether PMCCNTR is enabled
Backports commit ccbc0e338486b21cb0eb52e52cd309bbbe6a7507 from qemu
2018-04-26 09:07:02 -04:00
Peter Maydell 43e7478d3f
target/arm: Use v7m_stack_read() for reading the frame signature
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
2018-04-26 09:02:11 -04:00
Peter Maydell bec50934ad
target/arm: Remove stale TODO comment
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
2018-04-26 09:00:08 -04:00
Richard Henderson 76e343ef55
fpu: Bound increment for scalbn
Without bounding the increment, we can overflow exp either here
in scalbn_decomposed or when adding the bias in round_canonical.
This can result in e.g. underflowing to 0 instead of overflowing
to infinity.

The old softfloat code did bound the increment.

Backports commit ce8d4082054519f2eaac39958edde502860a7fc6 from qemu
2018-04-18 09:21:03 -04:00
Alex Bennée af6a0b7c14
fpu/softfloat: check for Inf / x or 0 / x before /0
The re-factoring of div_floats changed the order of checking meaning
an operation like -inf/0 erroneously raises the divbyzero flag.
IEEE-754 (2008) specifies this should only occur for operations on
finite operands.

We fix this by moving the check on the dividend being Inf/0 to before
the divisor is zero check.

Backports commit 9cb4e398c2f95c1e837fe9c570e124a55259f725 from qemu
2018-04-18 09:19:28 -04:00
Pavel Dovgalyuk fe353764e9
m68k: fix exception stack frame for 68000
68000 CPUs do not save format in the exception stack frame.
This patch adds feature checking to prevent format saving for 68000.
m68k_ret() already includes this modification, this patch fixes
the exception processing function too.

Backports commit 000761dc0c97d70e7314db3e8f52783880325a22 from qemu
2018-04-16 13:49:56 -04:00
Alex Bennée 9517a002da
fpu/softfloat: raise float_invalid for NaN/Inf in round_to_int_and_pack
The re-factor broke the raising of INVALID when NaN/Inf is passed to
the float_to_int conversion functions. round_to_uint_and_pack got this
right for NaN but also missed out the Inf handling.

Fixes https://bugs.launchpad.net/qemu/+bug/1759264

Backports commit 801bc56336a127d9b351b3a2cc0336e4d0cb2686 from qemu
2018-04-16 13:48:17 -04:00
Emilio G. Cota 74b7fe484c
softfloat: fix {min, max}nummag for same-abs-value inputs
Before 8936006 ("fpu/softfloat: re-factor minmax", 2018-02-21),
we used to return +Zero for maxnummag(-Zero,+Zero); after that
commit, we return -Zero.

Fix it by making {min,max}nummag consistent with {min,max}num,
deferring to the latter when the absolute value of the operands
is the same.

With this fix we now pass fp-test.

Backports commit 6245327a367292b354489c54e965646823023919 from qemu
2018-04-16 13:46:29 -04:00
Peter Maydell 778d0c47df
tcg/mips: Handle large offsets from target env to tlb_table
The MIPS TCG target makes the assumption that the offset from the
target env pointer to the tlb_table is less than about 64K. This
used to be true, but gradual addition of features to the Arm
target means that it's no longer true there. This results in
the build-time assertion failing:

In file included from /home/pm215/qemu/include/qemu/osdep.h:36:0,
from /home/pm215/qemu/tcg/tcg.c:28:
/home/pm215/qemu/tcg/mips/tcg-target.inc.c: In function ‘tcg_out_tlb_load’:
/home/pm215/qemu/include/qemu/compiler.h:90:36: error: static assertion failed: "not expecting: offsetof(CPUArchState, tlb_table[NB_MMU_MODES - 1][1]) > 0x7ff0 + 0x7fff"
^
/home/pm215/qemu/include/qemu/compiler.h:98:30: note: in expansion of macro ‘QEMU_BUILD_BUG_MSG’
^
/home/pm215/qemu/tcg/mips/tcg-target.inc.c:1236:9: note: in expansion of macro ‘QEMU_BUILD_BUG_ON’
QEMU_BUILD_BUG_ON(offsetof(CPUArchState,
^
/home/pm215/qemu/rules.mak:66: recipe for target 'tcg/tcg.o' failed

An ideal long term approach would be to rearrange the CPU state
so that the tlb_table was not so far along it, but this is tricky
because it would move it from the "not cleared on CPU reset" part
of the struct to the "cleared on CPU reset" part. As a simple fix
for the 2.12 release, make the MIPS TCG target handle an arbitrary
offset by emitting more add instructions. This will mean an extra
instruction in the fastpath for TCG loads and stores for the
affected guests (currently just aarch64-softmmu)

Backports commit 161dfd1e7fad1203840c0390f235030eba3fd23c from qemu
2018-04-16 13:44:39 -04:00
Pavel Dovgalyuk b4bf3c776b
icount: fix cpu_restore_state_from_tb for non-tb-exit cases
In icount mode, instructions that access io memory spaces in the middle
of the translation block invoke TB recompilation. After recompilation,
such instructions become last in the TB and are allowed to access io
memory spaces.

When the code includes instruction like i386 'xchg eax, 0xffffd080'
which accesses APIC, QEMU goes into an infinite loop of the recompilation.

This instruction includes two memory accesses - one read and one write.
After the first access, APIC calls cpu_report_tpr_access, which restores
the CPU state to get the current eip. But cpu_restore_state_from_tb
resets the cpu->can_do_io flag which makes the second memory access invalid.
Therefore the second memory access causes a recompilation of the block.
Then these operations repeat again and again.

This patch moves resetting cpu->can_do_io flag from
cpu_restore_state_from_tb to cpu_loop_exit* functions.

It also adds a parameter for cpu_restore_state which controls restoring
icount. There is no need to restore icount when we only query CPU state
without breaking the TB. Restoring it in such cases leads to the
incorrect flow of the virtual time.

In most cases new parameter is true (icount should be recalculated).
But there are two cases in i386 and openrisc when the CPU state is only
queried without the need to break the TB. This patch fixes both of
these cases.

Backports commit afd46fcad2dceffda35c0586f5723c127b6e09d8 from qemu
2018-04-11 20:05:40 -04:00
Alex Bennée 4074587775
accel/tcg/translate-all: expand cpu_restore_state addr check
We are still seeing signals during translation time when we walk over
a page protection boundary. This expands the check to ensure the host
PC is inside the code generation buffer. The original suggestion was
to check versus tcg_ctx.code_gen_ptr but as we now segment the
translation buffer we have to settle for just a general check for
being inside.

I've also fixed up the declaration to make it clear it can deal with
invalid addresses. A later patch will fix up the call sites.

Backports commit d25f2a72272b9ffe0d06710d6217d1169bc2cc7d from qemu
2018-04-11 19:53:57 -04:00
Richard Henderson bc8e85a1c5
fpu: Fix rounding mode for floatN_to_uintM_round_to_zero
We incorrectly passed in the current rounding mode
instead of float_round_to_zero.

Backports commit bd49e6027cbc207c87633c7add3ebd7d3474cd35 from qemu
2018-04-11 19:36:12 -04:00
Richard Henderson 49476ebf5e
tcg: Introduce tcg_set_insn_start_param
The parameters for tcg_gen_insn_start are target_ulong, which may be split
into two TCGArg parameters for storage in the opcode on 32-bit hosts.

Fixes the ARM target and its direct use of tcg_set_insn_param, which would
set the wrong argument in the 64-on-32 case.

Backports commit 9743cd5736263e90d312b2c33bd739ffe1eae70d from qemu
2018-04-11 19:34:18 -04:00
Peter Maydell 8f26d8e556
target/arm: Report unsupported MPU region sizes more clearly
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
2018-04-11 19:32:16 -04:00
Onur Sahin 18e6b1549f
target-arm: Check undefined opcodes for SWP in A32 decoder
Make sure we are not treating architecturally Undefined instructions
as a SWP, by verifying the opcodes as per section A8.8.229 of ARMv7-A
specification. Bits [21:20] must be zero for this to be a SWP or SWPB.
We also choose to UNDEF for the architecturally UNPREDICTABLE case of
bits [11:8] not being zero.

Backports commit c4869ca630a57f4269bb932ec7f719cef5bc79b8 from qemu
2018-04-11 19:30:50 -04:00
Eugene Minibaev 87180dd231
Add missing bit for SSE instr in VEX decoding
The 2-byte VEX prefix imples a leading 0Fh opcode byte.

Backports commit e0014d4b3a955cfd8d517674703bfa87f340290a from qemu
2018-04-10 08:49:15 -04:00
Alexandro Sanchez Bach 4a1de154ef
target/i386: Fix andn instruction
In commit 7073fbada733c8d10992f00772c9b9299d740e9b, the `andn` instruction
was implemented via `tcg_gen_andc` but passes the operands in the wrong
order:
- X86 defines `andn dest,src1,src2` as: dest = ~src1 & src2
- TCG defines `andc dest,src1,src2` as: dest = src1 & ~src2

The following simple test shows the issue:

int main(void) {
uint32_t ret = 0;
__asm (
"mov $0xFF00, %%ecx\n"
"mov $0x0F0F, %%eax\n"
"andn %%ecx, %%eax, %%ecx\n"
"mov %%ecx, %0\n"
: "=r" (ret));
printf("%08X\n", ret);
return 0;
}

This patch fixes the problem by simply swapping the order of the two last
arguments in `tcg_gen_andc_tl`.

Backports commit 5cd10051c2e02b7a86eae49919d6c65a87dbea46 from qemu
2018-04-10 08:48:05 -04:00
Richard Henderson e0903adacf
tcg: Fix out-of-line generic vector compares
A mistake in the type passed to sizeof, that happens to work
when the out-of-line fallback itself is using host vectors,
but fails when using only the base types.

Backports commit 6cb1d3b8517572031a22675280ec642972cdb395 from qemu
2018-04-07 23:05:19 -04:00
Laurent Vivier b25de410a9
tcg: fix 16-byte vector operations detection
configure tries to detect if the compiler
supports 16-byte vector operations.

As stated in the comment of the detection
program, there is a problem with the system
compiler on GCC on Centos 7.

This program doesn't actually detect the problem
with GCC on RHEL7 on PPC64LE (Red Hat 4.8.5-28).

This patch updates the test to look more like
it is in QEMU helpers, and now detects the problem.

The error reported is:

CC ppc64-softmmu/accel/tcg/tcg-runtime-gvec.o
..//accel/tcg/tcg-runtime-gvec.c: In function ‘helper_gvec_shl8i’:
../accel/tcg/tcg-runtime-gvec.c:558:26: internal compiler error: in emit_move_insn, at expr.c:3495
*(vec8 *)(d + i) = *(vec8 *)(a + i) << shift;
^
Fixes: db43267 "tcg: Add generic vector expanders"

Backports commit 74912f6dad207bfdd5bfa8c6012c364ea9405fc7 from qemu
2018-04-07 23:03:11 -04:00
Richard Henderson c2e46f2931
tcg: Mark muluh_i64 and mulsh_i64 as 64-bit ops
Failure to do so results in the tcg optimizer sign-extending
any constant fold from 32-bits. This turns out to be visible
in the RISC-V testsuite using a host that emits these opcodes
(e.g. any non-x86_64).

Backports commit f2f1dde75160cac6ede330f3db50dc817d01a2d6 from qemu
2018-03-29 14:03:00 -04:00
Peter Maydell 92b5817d92
target/arm: Always set FAR to a known unknown value for debug exceptions
For debug exceptions due to breakpoints or the BKPT instruction which
are taken to AArch32, the Fault Address Register is architecturally
UNKNOWN. We were using that as license to simply not set
env->exception.vaddress, but this isn't correct, because it will
expose to the guest whatever old value was in that field when
arm_cpu_do_interrupt_aarch32() writes it to the guest IFSR. That old
value might be a FAR for a previous guest EL2 or secure exception, in
which case we shouldn't show it to an EL1 or non-secure exception
handler. It might also be a non-deterministic value, which is bad
for record-and-replay.

Clear env->exception.vaddress before taking breakpoint debug
exceptions, to avoid this minor information leak.

Backports commit 548f514cf89dd9ab39c0cb4c063097bccf141fdd from qemu
2018-03-25 16:38:14 -04:00
Peter Maydell d6eafe5982
target/arm: Set FSR for BKPT, BRK when raising exception
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
2018-03-25 16:36:51 -04:00
Peter Maydell 16c0c2d253
target/arm: Factor out code to calculate FSR for debug exceptions
When a debug exception is taken to AArch32, it appears as a Prefetch
Abort, and the Instruction Fault Status Register (IFSR) must be set.
The IFSR has two possible formats, depending on whether LPAE is in
use. Factor out the code in arm_debug_excp_handler() which picks
an FSR value into its own utility function, update it to use
arm_fi_to_lfsc() and arm_fi_to_sfsc() rather than hard-coded constants,
and use the correct condition to select long or short format.

In particular this fixes a bug where we could select the short
format because we're at EL0 and the EL1 translation regime is
not using LPAE, but then route the debug exception to EL2 because
of MDCR_EL2.TDE and hand EL2 the wrong format FSR.

Backports commit 81621d9ab8a0f07956e67850b15eebf6d6992eec from qemu
2018-03-25 16:35:27 -04:00
Peter Maydell 7a3ee5fd95
target/arm: Honour MDCR_EL2.TDE when routing exceptions due to BKPT/BRK
The MDCR_EL2.TDE bit allows the exception level targeted by debug
exceptions to be set to EL2 for code executing at EL0. We handle
this in the arm_debug_target_el() function, but this is only used for
hardware breakpoint and watchpoint exceptions, not for the exception
generated when the guest executes an AArch32 BKPT or AArch64 BRK
instruction. We don't have enough information for a translate-time
equivalent of arm_debug_target_el(), so instead make BKPT and BRK
call a special purpose helper which can do the routing, rather than
the generic exception_with_syndrome helper.

Backports commit c900a2e62dd6dde11c8f5249b638caad05bb15be from qemu
2018-03-25 16:33:04 -04:00
Victor Kamensky ecd2ecb590
arm/translate-a64: treat DISAS_UPDATE as variant of DISAS_EXIT
In OE project 4.15 linux kernel boot hang was observed under
single cpu aarch64 qemu. Kernel code was in a loop waiting for
vtimer arrival, spinning in TC generated blocks, while interrupt
was pending unprocessed. This happened because when qemu tried to
handle vtimer interrupt target had interrupts disabled, as
result flag indicating TCG exit, cpu->icount_decr.u16.high,
was cleared but arm_cpu_exec_interrupt function did not call
arm_cpu_do_interrupt to process interrupt. Later when target
reenabled interrupts, it happened without exit into main loop, so
following code that waited for result of interrupt execution
run in infinite loop.

To solve the problem instructions that operate on CPU sys state
(i.e enable/disable interrupt), and marked as DISAS_UPDATE,
should be considered as DISAS_EXIT variant, and should be
forced to exit back to main loop so qemu will have a chance
processing pending CPU state updates, including pending
interrupts.

This change brings consistency with how DISAS_UPDATE is treated
in aarch32 case.

Backports commit a75a52d62418dafe462be4fe30485501d1010bb9 from qemu
2018-03-25 16:27:27 -04:00