The exception return address for nios2 is the instruction
after the one that was executing at the time of the exception.
We have so far implemented this by advancing the pc during the
process of raising the exception. It is perhaps a little less
confusing to do this advance in the translator (and helpers)
when raising the exception in the first place, so that we may
more closely match kernel sources.
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Message-Id: <20220421151735.31996-58-richard.henderson@linaro.org>
Indirect branches, plus eret and bret optionally raise
an exception when branching to a misaligned address.
The exception is required when an mmu is enabled, but
enable it always because the fallback behaviour is not
documented (though presumably it discards low bits).
For the purposes of the linux-user cpu loop, if EXCP_UNALIGN
(misaligned data) were to arrive, it would be treated the
same as EXCP_UNALIGND (misaligned destination). See the
!defined(CONFIG_NIOS2_ALIGNMENT_TRAP) block in kernel/traps.c.
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20220421151735.31996-53-richard.henderson@linaro.org>
Drop the set of estatus in init_thread; it was clearly intended
to be setting the value of CR_STATUS for the application, but we
never actually performed that copy. However, the proper value is
set in nios2_cpu_reset so we don't need to do anything here.
We only initialize SP and EA in init_thread, there's no value in
copying other uninitialized data into ENV.
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20220421151735.31996-21-richard.henderson@linaro.org>
Note that this advance *should* be done by the translator, as
that's the pc value that's supposed to be generated by hardware.
However, that's a much larger change across sysemu as well.
In the meantime, produce the correct PC for any signals raised
by the trap instruction. Note the special case of TRAP_BRKPT,
which itself is special cased within the kernel.
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20220421151735.31996-2-richard.henderson@linaro.org>
The real kernel will talk about the user PC as EA,
because that's where the hardware will have copied it,
and where it expects to put it to then use ERET.
But qemu does not emulate all of the exception stuff
while emulating user-only. Manipulate PC directly.
This fixes signal entry and return, and eliminates
some slight confusion from target_cpu_copy_regs.
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Laurent Vivier <laurent@vivier.eu>
Message-Id: <20211221025012.1057923-6-richard.henderson@linaro.org>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
Do not confuse host and guest addresses. Lock and unlock
the target_rt_sigframe structure in setup_rt_sigframe.
Since rt_setup_ucontext always returns 0, drop the return
value entirely. This eliminates the only write to the err
variable in setup_rt_sigframe.
Always copy the siginfo structure.
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20211221025012.1057923-3-richard.henderson@linaro.org>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
Since the prctl constants are supposed to be generic, supply
any that are not provided by the host.
Split out subroutines for PR_GET_FP_MODE, PR_SET_FP_MODE,
PR_GET_VL, PR_SET_VL, PR_RESET_KEYS, PR_SET_TAGGED_ADDR_CTRL,
PR_GET_TAGGED_ADDR_CTRL. Return EINVAL for guests that do
not support these options rather than pass them on to the host.
Reviewed-by: Laurent Vivier <laurent@vivier.eu>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20211227150127.2659293-2-richard.henderson@linaro.org>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
