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linux-user: Provide new force_sig_fault() function

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In many places in the linux-user code we need to queue a signal for
the guest using the QEMU_SI_FAULT si_type.  This requires that the
caller sets up and passes us a target_siginfo, including setting the
appropriate part of the _sifields union for the si_type. In a number
of places the code forgets to set the _sifields union field.

Provide a new force_sig_fault() function, which does the same thing
as the Linux kernel function of that name -- it takes the signal
number, the si_code value and the address to use in
_sifields._sigfault, and assembles the target_siginfo itself.  This
makes the callsites simpler and means it's harder to forget to pass
in an address value.

We follow force_sig() and the kernel's force_sig_fault() in not
requiring the caller to pass in the CPU pointer but always acting
on the CPU of the current thread.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20210813131809.28655-6-peter.maydell@linaro.org>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
This commit is contained in:
Peter Maydell 2021-08-13 14:18:07 +01:00 committed by Laurent Vivier
parent 819121b9b0
commit af7969605e
2 changed files with 18 additions and 0 deletions
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1
linux-user/signal-common.h
View File

@ -40,6 +40,7 @@ void tswap_siginfo(target_siginfo_t *tinfo,
void set_sigmask(const sigset_t *set);
void force_sig(int sig);
void force_sigsegv(int oldsig);
void force_sig_fault(int sig, int code, abi_ulong addr);
#if defined(TARGET_ARCH_HAS_SETUP_FRAME)
void setup_frame(int sig, struct target_sigaction *ka,
target_sigset_t *set, CPUArchState *env);

17
linux-user/signal.c
View File

@ -651,6 +651,23 @@ void force_sig(int sig)
queue_signal(env, info.si_signo, QEMU_SI_KILL, &info);
}
/*
* Force a synchronously taken QEMU_SI_FAULT signal. For QEMU the
* 'force' part is handled in process_pending_signals().
*/
void force_sig_fault(int sig, int code, abi_ulong addr)
{
CPUState *cpu = thread_cpu;
CPUArchState *env = cpu->env_ptr;
target_siginfo_t info = {};
info.si_signo = sig;
info.si_errno = 0;
info.si_code = code;
info._sifields._sigfault._addr = addr;
queue_signal(env, sig, QEMU_SI_FAULT, &info);
}
/* Force a SIGSEGV if we couldn't write to memory trying to set
* up the signal frame. oldsig is the signal we were trying to handle
* at the point of failure.