LKML Archive on lore.kernel.org
help / color / mirror / Atom feed
From: Nicholas Piggin <npiggin@gmail.com>
To: "Michal Suchánek" <msuchanek@suse.de>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>,
	Alexander Shishkin <alexander.shishkin@linux.intel.com>,
	Allison Randal <allison@lohutok.net>,
	Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
	Arnd Bergmann <arnd@arndb.de>,
	Thiago Jung Bauermann <bauerman@linux.ibm.com>,
	Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
	Claudio Carvalho <cclaudio@linux.ibm.com>,
	"David S. Miller" <davem@davemloft.net>,
	"Eric W. Biederman" <ebiederm@xmission.com>,
	Eric Richter <erichte@linux.ibm.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Gustavo Luiz Duarte <gustavold@linux.ibm.com>,
	Hari Bathini <hbathini@linux.ibm.com>,
	Jordan Niethe <jniethe5@gmail.com>, Jiri Olsa <jolsa@redhat.com>,
	Jonathan Cameron <Jonathan.Cameron@huawei.com>,
	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
	linuxppc-dev@lists.ozlabs.org,
	Mark Rutland <mark.rutland@arm.com>,
	Masahiro Yamada <masahiroy@kernel.org>,
	Mauro Carvalho Chehab <mchehab+huawei@kernel.org>,
	Michael Neuling <mikey@neuling.org>,
	Ingo Molnar <mingo@redhat.com>,
	Namhyung Kim <namhyung@kernel.org>,
	Nayna Jain <nayna@linux.ibm.com>,
	Paul Mackerras <paulus@samba.org>,
	Peter Zijlstra <peterz@infradead.org>,
	Rob Herring <robh@kernel.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Valentin Schneider <valentin.schneider@arm.com>,
	Alexander Viro <viro@zeniv.linux.org.uk>
Subject: Re: [PATCH v11 5/8] powerpc/64: make buildable without CONFIG_COMPAT
Date: Fri, 03 Apr 2020 17:16:43 +1000	[thread overview]
Message-ID: <1585898018.8y4vw9c8hc.astroid@bobo.none> (raw)
In-Reply-To: <20200324193055.GG25468@kitsune.suse.cz>

Michal Suchánek's on March 25, 2020 5:30 am:
> On Tue, Mar 24, 2020 at 06:54:20PM +1000, Nicholas Piggin wrote:
>> Michal Suchanek's on March 19, 2020 10:19 pm:
>> > diff --git a/arch/powerpc/kernel/signal.c b/arch/powerpc/kernel/signal.c
>> > index 4b0152108f61..a264989626fd 100644
>> > --- a/arch/powerpc/kernel/signal.c
>> > +++ b/arch/powerpc/kernel/signal.c
>> > @@ -247,7 +247,6 @@ static void do_signal(struct task_struct *tsk)
>> >  	sigset_t *oldset = sigmask_to_save();
>> >  	struct ksignal ksig = { .sig = 0 };
>> >  	int ret;
>> > -	int is32 = is_32bit_task();
>> >  
>> >  	BUG_ON(tsk != current);
>> >  
>> > @@ -277,7 +276,7 @@ static void do_signal(struct task_struct *tsk)
>> >  
>> >  	rseq_signal_deliver(&ksig, tsk->thread.regs);
>> >  
>> > -	if (is32) {
>> > +	if (is_32bit_task()) {
>> >          	if (ksig.ka.sa.sa_flags & SA_SIGINFO)
>> >  			ret = handle_rt_signal32(&ksig, oldset, tsk);
>> >  		else
>> 
>> Unnecessary?
>> 
>> > diff --git a/arch/powerpc/kernel/syscall_64.c b/arch/powerpc/kernel/syscall_64.c
>> > index 87d95b455b83..2dcbfe38f5ac 100644
>> > --- a/arch/powerpc/kernel/syscall_64.c
>> > +++ b/arch/powerpc/kernel/syscall_64.c
>> > @@ -24,7 +24,6 @@ notrace long system_call_exception(long r3, long r4, long r5,
>> >  				   long r6, long r7, long r8,
>> >  				   unsigned long r0, struct pt_regs *regs)
>> >  {
>> > -	unsigned long ti_flags;
>> >  	syscall_fn f;
>> >  
>> >  	if (IS_ENABLED(CONFIG_PPC_IRQ_SOFT_MASK_DEBUG))
>> > @@ -68,8 +67,7 @@ notrace long system_call_exception(long r3, long r4, long r5,
>> >  
>> >  	local_irq_enable();
>> >  
>> > -	ti_flags = current_thread_info()->flags;
>> > -	if (unlikely(ti_flags & _TIF_SYSCALL_DOTRACE)) {
>> > +	if (unlikely(current_thread_info()->flags & _TIF_SYSCALL_DOTRACE)) {
>> >  		/*
>> >  		 * We use the return value of do_syscall_trace_enter() as the
>> >  		 * syscall number. If the syscall was rejected for any reason
>> > @@ -94,7 +92,7 @@ notrace long system_call_exception(long r3, long r4, long r5,
>> >  	/* May be faster to do array_index_nospec? */
>> >  	barrier_nospec();
>> >  
>> > -	if (unlikely(ti_flags & _TIF_32BIT)) {
>> > +	if (unlikely(is_32bit_task())) {
>> 
>> Problem is, does this allow the load of ti_flags to be used for both
>> tests, or does test_bit make it re-load?
>> 
>> This could maybe be fixed by testing if(IS_ENABLED(CONFIG_COMPAT) &&
> Both points already discussed here:

Agh, I'm hopeless.

I don't think it really resolves this issue. But probably don't have time
to look at generated asm, and might never because it won't really hit
LE unless we add a 32-bit ABI. It's pretty minor though either way.

Sorry for being difficult, I really do like your patches :)

Thanks,
Nick

  reply	other threads:[~2020-04-03  7:16 UTC|newest]

Thread overview: 53+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20200225173541.1549955-1-npiggin@gmail.com>
2020-03-19 12:19 ` [PATCH v11 0/8] Disable compat cruft on ppc64le v11 Michal Suchanek
2020-03-19 12:19   ` [PATCH v11 1/8] powerpc: Add back __ARCH_WANT_SYS_LLSEEK macro Michal Suchanek
2020-03-19 12:19   ` [PATCH v11 2/8] powerpc: move common register copy functions from signal_32.c to signal.c Michal Suchanek
2020-03-19 12:19   ` [PATCH v11 3/8] powerpc/perf: consolidate read_user_stack_32 Michal Suchanek
2020-03-24  8:48     ` Nicholas Piggin
2020-03-24 19:38       ` Michal Suchánek
2020-04-03  7:13         ` Nicholas Piggin
2020-04-03 10:52           ` Michal Suchánek
2020-04-03 11:26             ` Nicholas Piggin
2020-04-03 11:51               ` Michal Suchánek
2020-04-06 20:52           ` Michal Suchánek
2020-04-06 21:00           ` [PATCH] powerpcs: perf: consolidate perf_callchain_user_64 and perf_callchain_user_32 Michal Suchanek
2020-04-07  5:21             ` Christophe Leroy
2020-04-09 11:22               ` Michal Suchánek
2020-03-19 12:19   ` [PATCH v11 4/8] powerpc/perf: consolidate valid_user_sp Michal Suchanek
2020-03-19 12:19   ` [PATCH v11 5/8] powerpc/64: make buildable without CONFIG_COMPAT Michal Suchanek
2020-03-24  8:54     ` Nicholas Piggin
2020-03-24 19:30       ` Michal Suchánek
2020-04-03  7:16         ` Nicholas Piggin [this message]
2020-03-19 12:19   ` [PATCH v11 6/8] powerpc/64: Make COMPAT user-selectable disabled on littleendian by default Michal Suchanek
2020-03-19 12:19   ` [PATCH v11 7/8] powerpc/perf: split callchain.c by bitness Michal Suchanek
2020-03-19 12:19   ` [PATCH v11 8/8] MAINTAINERS: perf: Add pattern that matches ppc perf to the perf entry Michal Suchanek
2020-03-19 13:37     ` Andy Shevchenko
2020-03-19 14:00       ` Michal Suchánek
2020-03-19 14:26         ` Andy Shevchenko
2020-03-19 17:03     ` Joe Perches
2020-03-19 12:36   ` [PATCH v11 0/8] Disable compat cruft on ppc64le v11 Christophe Leroy
2020-03-19 14:01     ` Michal Suchánek
2020-04-03  7:25   ` Nicholas Piggin
2020-04-03  7:26     ` Christophe Leroy
2020-04-03  9:43       ` Nicholas Piggin
2020-04-05  0:40         ` Michael Ellerman
2020-03-20 10:20 ` [PATCH v12 0/8] Disable compat cruft on ppc64le v12 Michal Suchanek
2020-03-20 10:20   ` [PATCH v12 1/8] powerpc: Add back __ARCH_WANT_SYS_LLSEEK macro Michal Suchanek
2020-03-20 10:20   ` [PATCH v12 2/8] powerpc: move common register copy functions from signal_32.c to signal.c Michal Suchanek
2020-03-20 10:20   ` [PATCH v12 3/8] powerpc/perf: consolidate read_user_stack_32 Michal Suchanek
2020-03-20 10:20   ` [PATCH v12 4/8] powerpc/perf: consolidate valid_user_sp -> invalid_user_sp Michal Suchanek
2020-03-20 10:20   ` [PATCH v12 5/8] powerpc/64: make buildable without CONFIG_COMPAT Michal Suchanek
2020-04-07  5:50     ` Christophe Leroy
2020-04-07  9:57       ` Michal Suchánek
2020-03-20 10:20   ` [PATCH v12 6/8] powerpc/64: Make COMPAT user-selectable disabled on littleendian by default Michal Suchanek
2020-03-20 10:20   ` [PATCH v12 7/8] powerpc/perf: split callchain.c by bitness Michal Suchanek
2020-03-20 10:20   ` [PATCH v12 8/8] MAINTAINERS: perf: Add pattern that matches ppc perf to the perf entry Michal Suchanek
2020-03-20 10:33     ` Andy Shevchenko
2020-03-20 11:23       ` Michal Suchánek
2020-03-20 12:42         ` Andy Shevchenko
2020-03-20 14:42           ` Joe Perches
2020-03-20 16:28             ` Michal Suchánek
2020-03-20 16:31             ` Andy Shevchenko
2020-03-20 16:42               ` Michal Suchánek
2020-03-20 16:47                 ` Andy Shevchenko
2020-03-20 21:36               ` Joe Perches
2020-03-19 11:52 [PATCH v11 0/8] Disable compat cruft on ppc64le v11 Michal Suchanek
2020-03-19 11:52 ` [PATCH v11 5/8] powerpc/64: make buildable without CONFIG_COMPAT Michal Suchanek

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=1585898018.8y4vw9c8hc.astroid@bobo.none \
    --to=npiggin@gmail.com \
    --cc=Jonathan.Cameron@huawei.com \
    --cc=acme@kernel.org \
    --cc=alexander.shishkin@linux.intel.com \
    --cc=allison@lohutok.net \
    --cc=andriy.shevchenko@linux.intel.com \
    --cc=arnd@arndb.de \
    --cc=bauerman@linux.ibm.com \
    --cc=bigeasy@linutronix.de \
    --cc=cclaudio@linux.ibm.com \
    --cc=davem@davemloft.net \
    --cc=ebiederm@xmission.com \
    --cc=erichte@linux.ibm.com \
    --cc=gregkh@linuxfoundation.org \
    --cc=gustavold@linux.ibm.com \
    --cc=hbathini@linux.ibm.com \
    --cc=jniethe5@gmail.com \
    --cc=jolsa@redhat.com \
    --cc=linux-fsdevel@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linuxppc-dev@lists.ozlabs.org \
    --cc=mark.rutland@arm.com \
    --cc=masahiroy@kernel.org \
    --cc=mchehab+huawei@kernel.org \
    --cc=mikey@neuling.org \
    --cc=mingo@redhat.com \
    --cc=msuchanek@suse.de \
    --cc=namhyung@kernel.org \
    --cc=nayna@linux.ibm.com \
    --cc=paulus@samba.org \
    --cc=peterz@infradead.org \
    --cc=robh@kernel.org \
    --cc=tglx@linutronix.de \
    --cc=valentin.schneider@arm.com \
    --cc=viro@zeniv.linux.org.uk \
    --subject='Re: [PATCH v11 5/8] powerpc/64: make buildable without CONFIG_COMPAT' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).