I'm far from confident this handling here is correct. Hence
RFC. In particular not sure on what locks I should hold for this
to be even moderately safe.
The function already appears to be inconsistent in what it returns
as the CONFIG_ATOMIC64 block returns the endian converted 'eventual'
value of the cmpxchg whereas the TCG_OVERSIZED_GUEST case returns
the previous value.
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Message-id: 20240219161229.11776-1-Jonathan.Cameron@huawei.com
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
The Cortex-A53 r0p4 revision that QEMU emulates is affected by a CatA
erratum #843419 (i.e., the most severe), which requires workarounds in
the toolchain as well as the OS.
Since the emulation is obviously not affected in the same way, we can
indicate this via REVIDR bit #8, which on r0p4 has the meaning that no
workarounds for erratum #843419 are needed.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20240215160202.2803452-1-ardb+git@google.com
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Architecturally, the AArch32 MSR/MRS to/from banked register
instructions are UNPREDICTABLE for attempts to access a banked
register that the guest could access in a more direct way (e.g.
using this insn to access r8_fiq when already in FIQ mode). QEMU has
chosen to UNDEF on all of these.
However, for the case of accessing SPSR_hyp from hyp mode, it turns
out that real hardware permits this, with the same effect as if the
guest had directly written to SPSR. Further, there is some
guest code out there that assumes it can do this, because it
happens to work on hardware: an example Cortex-R52 startup code
fragment uses this, and it got copied into various other places,
including Zephyr. Zephyr was fixed to not use this:
https://github.com/zephyrproject-rtos/zephyr/issues/47330
but other examples are still out there, like the selftest
binary for the MPS3-AN536.
For convenience of being able to run guest code, permit
this UNPREDICTABLE access instead of UNDEFing it.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20240206132931.38376-5-peter.maydell@linaro.org
The Cortex-R52 implements the Configuration Base Address Register
(CBAR), as a read-only register. Add ARM_FEATURE_CBAR_RO to this CPU
type, so that our implementation provides the register and the
associated qdev property.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20240206132931.38376-3-peter.maydell@linaro.org
We support two different encodings for the AArch32 IMPDEF
CBAR register -- older cores like the Cortex A9, A7, A15
have this at 4, c15, c0, 0; newer cores like the
Cortex A35, A53, A57 and A72 have it at 1 c15 c0 0.
When we implemented this we picked which encoding to
use based on whether the CPU set ARM_FEATURE_AARCH64.
However this isn't right for three cases:
* the qemu-system-arm 'max' CPU, which is supposed to be
a variant on a Cortex-A57; it ought to use the same
encoding the A57 does and which the AArch64 'max'
exposes to AArch32 guest code
* the Cortex-R52, which is AArch32-only but has the CBAR
at the newer encoding (and where we incorrectly are
not yet setting ARM_FEATURE_CBAR_RO anyway)
* any possible future support for other v8 AArch32
only CPUs, or for supporting "boot the CPU into
AArch32 mode" on our existing cores like the A57 etc
Make the decision of the encoding be based on whether
the CPU implements the ARM_FEATURE_V8 flag instead.
This changes the behaviour only for the qemu-system-arm
'-cpu max'. We don't expect anybody to be relying on the
old behaviour because:
* it's not what the real hardware Cortex-A57 does
(and that's what our ID register claims we are)
* we don't implement the memory-mapped GICv3 support
which is the only thing that exists at the peripheral
base address pointed to by the register
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20240206132931.38376-2-peter.maydell@linaro.org
It doesn't make sense to read the value of MDCR_EL2 on a non-A-profile
CPU, and in fact if you try to do it we will assert:
#6 0x00007ffff4b95e96 in __GI___assert_fail
(assertion=0x5555565a8c70 "!arm_feature(env, ARM_FEATURE_M)", file=0x5555565a6e5c "../../target/arm/helper.c", line=12600, function=0x5555565a9560 <__PRETTY_FUNCTION__.0> "arm_security_space_below_el3") at ./assert/assert.c:101
#7 0x0000555555ebf412 in arm_security_space_below_el3 (env=0x555557bc8190) at ../../target/arm/helper.c:12600
#8 0x0000555555ea6f89 in arm_is_el2_enabled (env=0x555557bc8190) at ../../target/arm/cpu.h:2595
#9 0x0000555555ea942f in arm_mdcr_el2_eff (env=0x555557bc8190) at ../../target/arm/internals.h:1512
We might call pmu_counter_enabled() on an M-profile CPU (for example
from the migration pre/post hooks in machine.c); this should always
return false because these CPUs don't set ARM_FEATURE_PMU.
Avoid the assertion by not calling arm_mdcr_el2_eff() before we
have done the early return for "PMU not present".
This fixes an assertion failure if you try to do a loadvm or
savevm for an M-profile board.
Cc: qemu-stable@nongnu.org
Resolves: https://gitlab.com/qemu-project/qemu/-/issues/2155
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20240208153346.970021-1-peter.maydell@linaro.org
For user-only mode, use MMU_USER_IDX.
For system mode, use CPUClass.mmu_index.
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
In kernel commit 5d5b4e8c2d9ec ("arm64/sve: Report FEAT_SVE_B16B16 to
userspace") Linux added ID_AA64ZFR0_el1.B16B16 to the set of ID
register fields which it exposes to userspace. Update our
exported_bits mask to include this.
(This doesn't yet change any behaviour for us, because we don't yet
have any CPUs that implement this feature, which is part of SVE2.)
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20240125134304.1470404-1-peter.maydell@linaro.org
Akihiko OdakiandAlex Bennée
Jonathan CameronandPeter Maydell
Ard BiesheuvelandPeter Maydell
Richard HendersonandPeter Maydell
Jan KlötzkeandPeter Maydell
Anton JohanssonandRichard Henderson