[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [XEN PATCH v2 6/7] xen/arm: vcpreg: address violation of MISRA C Rule 2.1
There is no path that reaches the call to 'advance_pc', thus violating MISRA C Rule 2.1. A call to ASSERT_UNREACHABLE() is added after the switch, despite this being useful to detect errors only in debug builds; if that marker is ever reached, a domain crash is triggered, as a defensive coding measure. No functional change. Signed-off-by: Julien Grall <julien@xxxxxxx> Signed-off-by: Nicola Vetrini <nicola.vetrini@xxxxxxxxxxx> --- The code changes (including the comment) were made by Julien in [1]; I added the commit text and all other informations. All the switch clauses, when expanded, end with a return statement and the default clause has an unconditional return, therefore advance_pc() is never reached. However, it has been deemed safer to crash the domain if the switch is ever exited. [1] https://lore.kernel.org/xen-devel/alpine.DEB.2.22.394.2312151232580.3175268@ubuntu-linux-20-04-desktop/T/#maa91d8025532455a6317119a1e4affa00a99e1ce --- xen/arch/arm/vcpreg.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/xen/arch/arm/vcpreg.c b/xen/arch/arm/vcpreg.c index 39aeda9dab62..a2d050070473 100644 --- a/xen/arch/arm/vcpreg.c +++ b/xen/arch/arm/vcpreg.c @@ -707,8 +707,14 @@ void do_cp10(struct cpu_user_regs *regs, const union hsr hsr) inject_undef_exception(regs, hsr); return; } - - advance_pc(regs, hsr); + + /* + * All the cases in the switch should return. If this is not the + * case, then something went wrong and it is best to crash the + * domain. + */ + ASSERT_UNREACHABLE(); + domain_crash(current->domain); } void do_cp(struct cpu_user_regs *regs, const union hsr hsr) -- 2.34.1
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