From: "Michal Suchánek" <msuchanek@suse•de>
To: Christophe Leroy <christophe.leroy@c-s•fr>
Cc: Mark Rutland <mark.rutland@arm•com>,
Gustavo Luiz Duarte <gustavold@linux•ibm.com>,
Peter Zijlstra <peterz@infradead•org>,
Sebastian Andrzej Siewior <bigeasy@linutronix•de>,
Linux Kernel Mailing List <linux-kernel@vger•kernel.org>,
Paul Mackerras <paulus@samba•org>, Jiri Olsa <jolsa@redhat•com>,
Rob Herring <robh@kernel•org>,
Michael Neuling <mikey@neuling•org>,
Mauro Carvalho Chehab <mchehab+huawei@kernel•org>,
Masahiro Yamada <masahiroy@kernel•org>,
Nayna Jain <nayna@linux•ibm.com>,
"linux-fsdevel @ vger . kernel . org --in-reply-to="
<20200225173541.1549955-1-npiggin@gmail•com>,
Alexander Shishkin <alexander.shishkin@linux•intel.com>,
Andy Shevchenko <andy.shevchenko@gmail•com>,
Ingo Molnar <mingo@redhat•com>,
Allison Randal <allison@lohutok•net>,
Jordan Niethe <jniethe5@gmail•com>,
Valentin Schneider <valentin.schneider@arm•com>,
Arnd Bergmann <arnd@arndb•de>,
Arnaldo Carvalho de Melo <acme@kernel•org>,
Alexander Viro <viro@zeniv•linux.org.uk>,
Jonathan Cameron <Jonathan.Cameron@huawei•com>,
Namhyung Kim <namhyung@kernel•org>,
Thomas Gleixner <tglx@linutronix•de>,
Andy Shevchenko <andriy.shevchenko@linux•intel.com>,
Hari Bathini <hbathini@linux•ibm.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation•org>,
Nicholas Piggin <npiggin@gmail•com>,
Claudio Carvalho <cclaudio@linux•ibm.com>,
Eric Richter <erichte@linux•ibm.com>,
"Eric W. Biederman" <ebiederm@xmission•com>,
"open list:LINUX FOR POWERPC PA SEMI PWRFICIENT"
<linuxppc-dev@lists•ozlabs.org>,
"David S. Miller" <davem@davemloft•net>,
Thiago Jung Bauermann <bauerman@linux•ibm.com>
Subject: Re: [PATCH v11 4/8] powerpc/perf: consolidate valid_user_sp
Date: Thu, 19 Mar 2020 15:46:42 +0100 [thread overview]
Message-ID: <20200319144642.GL25468@kitsune.suse.cz> (raw)
In-Reply-To: <8775f299-be1b-3457-c59d-e4f61d8223e5@c-s.fr>
On Thu, Mar 19, 2020 at 03:16:03PM +0100, Christophe Leroy wrote:
>
>
> Le 19/03/2020 à 14:35, Andy Shevchenko a écrit :
> > On Thu, Mar 19, 2020 at 1:54 PM Michal Suchanek <msuchanek@suse•de> wrote:
> > >
> > > Merge the 32bit and 64bit version.
> > >
> > > Halve the check constants on 32bit.
> > >
> > > Use STACK_TOP since it is defined.
> > >
> > > Passing is_64 is now redundant since is_32bit_task() is used to
> > > determine which callchain variant should be used. Use STACK_TOP and
> > > is_32bit_task() directly.
> > >
> > > This removes a page from the valid 32bit area on 64bit:
> > > #define TASK_SIZE_USER32 (0x0000000100000000UL - (1 * PAGE_SIZE))
> > > #define STACK_TOP_USER32 TASK_SIZE_USER32
> >
> > ...
> >
> > > +static inline int valid_user_sp(unsigned long sp)
> > > +{
> > > + bool is_64 = !is_32bit_task();
> > > +
> > > + if (!sp || (sp & (is_64 ? 7 : 3)) || sp > STACK_TOP - (is_64 ? 32 : 16))
> > > + return 0;
> > > + return 1;
> > > +}
> >
> > Other possibility:
>
> I prefer this one.
>
> >
> > unsigned long align = is_32bit_task() ? 3 : 7;
>
> I would call it mask instead of align
>
> > unsigned long top = STACK_TOP - (is_32bit_task() ? 16 : 32);
> >
> > return !(!sp || (sp & align) || sp > top);
And we can avoid the inversion here as well as in !valid_user_sp(sp) by
changing to invalid_user_sp.
Thanks
Michal
next prev parent reply other threads:[~2020-03-19 15:12 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-19 11:52 [PATCH v11 0/8] Disable compat cruft on ppc64le v11 Michal Suchanek
2020-03-19 11:52 ` [PATCH v11 1/8] powerpc: Add back __ARCH_WANT_SYS_LLSEEK macro Michal Suchanek
2020-03-19 11:52 ` [PATCH v11 2/8] powerpc: move common register copy functions from signal_32.c to signal.c Michal Suchanek
2020-03-19 11:52 ` [PATCH v11 3/8] powerpc/perf: consolidate read_user_stack_32 Michal Suchanek
2020-03-19 11:52 ` [PATCH v11 4/8] powerpc/perf: consolidate valid_user_sp Michal Suchanek
2020-03-19 13:35 ` Andy Shevchenko
2020-03-19 14:04 ` Michal Suchánek
2020-03-19 14:16 ` Christophe Leroy
2020-03-19 14:46 ` Michal Suchánek [this message]
2020-03-19 11:52 ` [PATCH v11 5/8] powerpc/64: make buildable without CONFIG_COMPAT Michal Suchanek
2020-03-19 11:52 ` [PATCH v11 6/8] powerpc/64: Make COMPAT user-selectable disabled on littleendian by default Michal Suchanek
2020-03-19 11:52 ` [PATCH v11 7/8] powerpc/perf: split callchain.c by bitness Michal Suchanek
2020-03-19 11:52 ` [PATCH v11 8/8] MAINTAINERS: perf: Add pattern that matches ppc perf to the perf entry Michal Suchanek
2020-03-19 12:20 ` [PATCH v11 0/8] Disable compat cruft on ppc64le v11 Michal Suchánek
-- strict thread matches above, loose matches on Subject: below --
2020-02-25 17:35 [PATCH v3 00/32] powerpc/64: interrupts and syscalls series Nicholas Piggin
2020-03-19 12:19 ` [PATCH v11 0/8] Disable compat cruft on ppc64le v11 Michal Suchanek
2020-03-19 12:19 ` [PATCH v11 4/8] powerpc/perf: consolidate valid_user_sp Michal Suchanek
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