From mboxrd@z Thu Jan 1 00:00:00 1970 From: Catalin Marinas Subject: Re: [PATCH] parisc: compat Fix siginfo_t -> compat_siginfo_t conversion on big endian Date: Tue, 17 Mar 2015 17:13:33 +0000 Message-ID: <20150317171333.GA14408@e104818-lin.cambridge.arm.com> References: <20150315200041.GA10927@ls3530.box> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: "linux-parisc@vger.kernel.org" , James Bottomley , John David Anglin , Bamvor Jian Zhang To: Helge Deller Return-path: In-Reply-To: <20150315200041.GA10927@ls3530.box> List-ID: List-Id: linux-parisc.vger.kernel.org On Sun, Mar 15, 2015 at 08:00:41PM +0000, Helge Deller wrote: > This patch is basically the same as commit 9d42d48 from Catalin Marinas > but adopted to the parisc architecture. > > The native (64-bit) sigval_t union contains sival_int (32-bit) and sival_ptr > (64-bit). When a compat application invokes a syscall that takes a sigval_t > value (as part of a larger structure, e.g. compat_sys_mq_notify, > compat_sys_timer_create), the compat_sigval_t union is converted to the native > sigval_t with sival_int overlapping with either the least or the most > significant half of sival_ptr, depending on endianness. When the corresponding > signal is delivered to a compat application, on big endian the current > (compat_uptr_t)sival_ptr cast always returns 0 since sival_int corresponds to > the top part of sival_ptr. This patch fixes copy_siginfo_to_user32() so that > sival_int is copied to the compat_siginfo_t structure. Se below, I don't think this patch is needed. > diff --git a/arch/parisc/kernel/signal32.c b/arch/parisc/kernel/signal32.c > index 984abbe..d1f1fcd 100644 > --- a/arch/parisc/kernel/signal32.c > +++ b/arch/parisc/kernel/signal32.c > @@ -322,7 +322,6 @@ int > copy_siginfo_to_user32 (compat_siginfo_t __user *to, const siginfo_t *from) > { > compat_uptr_t addr; > - compat_int_t val; > int err; > > if (!access_ok(VERIFY_WRITE, to, sizeof(compat_siginfo_t))) > @@ -361,15 +360,13 @@ copy_siginfo_to_user32 (compat_siginfo_t __user *to, const siginfo_t *from) > case __SI_TIMER >> 16: > err |= __put_user(from->si_tid, &to->si_tid); > err |= __put_user(from->si_overrun, &to->si_overrun); > - val = (compat_int_t)from->si_int; > - err |= __put_user(val, &to->si_int); > + err |= __put_user(from->si_int, &to->si_int); Is there any actual change here? The native si_int is 32-bit already, same as compat_int_t. I didn't think parisc needed fixing (only if it was using si_ptr which is 64-bit on a 64-bit architecture). > break; > case __SI_RT >> 16: /* Not generated by the kernel as of now. */ > case __SI_MESGQ >> 16: > err |= __put_user(from->si_uid, &to->si_uid); > err |= __put_user(from->si_pid, &to->si_pid); > - val = (compat_int_t)from->si_int; > - err |= __put_user(val, &to->si_int); > + err |= __put_user(from->si_int, &to->si_int); Same here. -- Catalin