From: "Michal Suchánek" <msuchanek@suse.de>
To: Nicholas Piggin <npiggin@gmail.com>
Cc: Mark Rutland <mark.rutland@arm.com>,
Gustavo Luiz Duarte <gustavold@linux.ibm.com>,
Alexander Shishkin <alexander.shishkin@linux.intel.com>,
Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
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>,
Eric Richter <erichte@linux.ibm.com>,
Masahiro Yamada <masahiroy@kernel.org>,
Nayna Jain <nayna@linux.ibm.com>,
Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@redhat.com>,
Hari Bathini <hbathini@linux.ibm.com>,
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>,
Allison Randal <allison@lohutok.net>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Claudio Carvalho <cclaudio@linux.ibm.com>,
Mauro Carvalho Chehab <mchehab+huawei@kernel.org>,
"Eric W. Biederman" <ebiederm@xmission.com>,
linux-fsdevel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
"David S. Miller" <davem@davemloft.net>,
Thiago Jung Bauermann <bauerman@linux.ibm.com>
Subject: Re: [PATCH v11 3/8] powerpc/perf: consolidate read_user_stack_32
Date: Mon, 6 Apr 2020 22:52:47 +0200 [thread overview]
Message-ID: <20200406205247.GE25468@kitsune.suse.cz> (raw)
In-Reply-To: <1585896170.ohti800w9v.astroid@bobo.none>
On Fri, Apr 03, 2020 at 05:13:25PM +1000, Nicholas Piggin wrote:
> Michal Suchánek's on March 25, 2020 5:38 am:
> > On Tue, Mar 24, 2020 at 06:48:20PM +1000, Nicholas Piggin wrote:
> >> Michal Suchanek's on March 19, 2020 10:19 pm:
> >> > There are two almost identical copies for 32bit and 64bit.
> >> >
> >> > The function is used only in 32bit code which will be split out in next
> >> > patch so consolidate to one function.
> >> >
> >> > Signed-off-by: Michal Suchanek <msuchanek@suse.de>
> >> > Reviewed-by: Christophe Leroy <christophe.leroy@c-s.fr>
> >> > ---
> >> > v6: new patch
> >> > v8: move the consolidated function out of the ifdef block.
> >> > v11: rebase on top of def0bfdbd603
> >> > ---
> >> > arch/powerpc/perf/callchain.c | 48 +++++++++++++++++------------------
> >> > 1 file changed, 24 insertions(+), 24 deletions(-)
> >> >
> >> > diff --git a/arch/powerpc/perf/callchain.c b/arch/powerpc/perf/callchain.c
> >> > index cbc251981209..c9a78c6e4361 100644
> >> > --- a/arch/powerpc/perf/callchain.c
> >> > +++ b/arch/powerpc/perf/callchain.c
> >> > @@ -161,18 +161,6 @@ static int read_user_stack_64(unsigned long __user *ptr, unsigned long *ret)
> >> > return read_user_stack_slow(ptr, ret, 8);
> >> > }
> >> >
> >> > -static int read_user_stack_32(unsigned int __user *ptr, unsigned int *ret)
> >> > -{
> >> > - if ((unsigned long)ptr > TASK_SIZE - sizeof(unsigned int) ||
> >> > - ((unsigned long)ptr & 3))
> >> > - return -EFAULT;
> >> > -
> >> > - if (!probe_user_read(ret, ptr, sizeof(*ret)))
> >> > - return 0;
> >> > -
> >> > - return read_user_stack_slow(ptr, ret, 4);
> >> > -}
> >> > -
> >> > static inline int valid_user_sp(unsigned long sp, int is_64)
> >> > {
> >> > if (!sp || (sp & 7) || sp > (is_64 ? TASK_SIZE : 0x100000000UL) - 32)
> >> > @@ -277,19 +265,9 @@ static void perf_callchain_user_64(struct perf_callchain_entry_ctx *entry,
> >> > }
> >> >
> >> > #else /* CONFIG_PPC64 */
> >> > -/*
> >> > - * On 32-bit we just access the address and let hash_page create a
> >> > - * HPTE if necessary, so there is no need to fall back to reading
> >> > - * the page tables. Since this is called at interrupt level,
> >> > - * do_page_fault() won't treat a DSI as a page fault.
> >> > - */
> >> > -static int read_user_stack_32(unsigned int __user *ptr, unsigned int *ret)
> >> > +static int read_user_stack_slow(void __user *ptr, void *buf, int nb)
> >> > {
> >> > - if ((unsigned long)ptr > TASK_SIZE - sizeof(unsigned int) ||
> >> > - ((unsigned long)ptr & 3))
> >> > - return -EFAULT;
> >> > -
> >> > - return probe_user_read(ret, ptr, sizeof(*ret));
> >> > + return 0;
> >> > }
> >> >
> >> > static inline void perf_callchain_user_64(struct perf_callchain_entry_ctx *entry,
> >> > @@ -312,6 +290,28 @@ static inline int valid_user_sp(unsigned long sp, int is_64)
> >> >
> >> > #endif /* CONFIG_PPC64 */
> >> >
> >> > +/*
> >> > + * On 32-bit we just access the address and let hash_page create a
> >> > + * HPTE if necessary, so there is no need to fall back to reading
> >> > + * the page tables. Since this is called at interrupt level,
> >> > + * do_page_fault() won't treat a DSI as a page fault.
> >> > + */
> >>
> >> The comment is actually probably better to stay in the 32-bit
> >> read_user_stack_slow implementation. Is that function defined
> >> on 32-bit purely so that you can use IS_ENABLED()? In that case
> > It documents the IS_ENABLED() and that's where it is. The 32bit
> > definition is only a technical detail.
>
> Sorry for the late reply, busy trying to fix bugs in the C rewrite
> series. I don't think it is the right place, it should be in the
> ppc32 implementation detail.
Which does not exist anymore after the 32bit and 64bit part is split.
> ppc64 has an equivalent comment at the top of its read_user_stack functions.
>
> >> I would prefer to put a BUG() there which makes it self documenting.
> > Which will cause checkpatch complaints about introducing new BUG() which
> > is frowned on.
>
> It's fine in this case, that warning is about not introducing
> runtime bugs, but this wouldn't be.
>
> But... I actually don't like adding read_user_stack_slow on 32-bit
> and especially not just to make IS_ENABLED work.
That's to not break build at this point. Later the function is removed.
>
> IMO this would be better if you really want to consolidate it
>
> ---
>
> diff --git a/arch/powerpc/perf/callchain.c b/arch/powerpc/perf/callchain.c
> index cbc251981209..ca3a599b3f54 100644
> --- a/arch/powerpc/perf/callchain.c
> +++ b/arch/powerpc/perf/callchain.c
> @@ -108,7 +108,7 @@ perf_callchain_kernel(struct perf_callchain_entry_ctx *entry, struct pt_regs *re
> * interrupt context, so if the access faults, we read the page tables
> * to find which page (if any) is mapped and access it directly.
> */
> -static int read_user_stack_slow(void __user *ptr, void *buf, int nb)
> +static int read_user_stack_slow(const void __user *ptr, void *buf, int nb)
> {
> int ret = -EFAULT;
> pgd_t *pgdir;
> @@ -149,28 +149,21 @@ static int read_user_stack_slow(void __user *ptr, void *buf, int nb)
> return ret;
> }
>
> -static int read_user_stack_64(unsigned long __user *ptr, unsigned long *ret)
> +static int __read_user_stack(const void __user *ptr, void *ret, size_t size)
> {
> - if ((unsigned long)ptr > TASK_SIZE - sizeof(unsigned long) ||
> - ((unsigned long)ptr & 7))
> + if ((unsigned long)ptr > TASK_SIZE - size ||
> + ((unsigned long)ptr & (size - 1)))
> return -EFAULT;
>
> - if (!probe_user_read(ret, ptr, sizeof(*ret)))
> + if (!probe_user_read(ret, ptr, size))
> return 0;
>
> - return read_user_stack_slow(ptr, ret, 8);
> + return read_user_stack_slow(ptr, ret, size);
> }
>
> -static int read_user_stack_32(unsigned int __user *ptr, unsigned int *ret)
> +static int read_user_stack_64(unsigned long __user *ptr, unsigned long *ret)
> {
> - if ((unsigned long)ptr > TASK_SIZE - sizeof(unsigned int) ||
> - ((unsigned long)ptr & 3))
> - return -EFAULT;
> -
> - if (!probe_user_read(ret, ptr, sizeof(*ret)))
> - return 0;
> -
> - return read_user_stack_slow(ptr, ret, 4);
> + return __read_user_stack(ptr, ret, sizeof(*ret));
> }
>
> static inline int valid_user_sp(unsigned long sp, int is_64)
> @@ -283,13 +276,13 @@ static void perf_callchain_user_64(struct perf_callchain_entry_ctx *entry,
> * the page tables. Since this is called at interrupt level,
> * do_page_fault() won't treat a DSI as a page fault.
> */
> -static int read_user_stack_32(unsigned int __user *ptr, unsigned int *ret)
> +static int __read_user_stack(const void __user *ptr, void *ret, size_t size)
> {
> - if ((unsigned long)ptr > TASK_SIZE - sizeof(unsigned int) ||
> - ((unsigned long)ptr & 3))
> + if ((unsigned long)ptr > TASK_SIZE - size ||
> + ((unsigned long)ptr & (size - 1)))
> return -EFAULT;
>
> - return probe_user_read(ret, ptr, sizeof(*ret));
> + return probe_user_read(ret, ptr, size);
> }
>
> static inline void perf_callchain_user_64(struct perf_callchain_entry_ctx *entry,
> @@ -312,6 +305,11 @@ static inline int valid_user_sp(unsigned long sp, int is_64)
>
> #endif /* CONFIG_PPC64 */
>
> +static int read_user_stack_32(unsigned int __user *ptr, unsigned int *ret)
> +{
> + return __read_user_stack(ptr, ret, sizeof(*ret));
> +}
> +
> /*
> * Layout for non-RT signal frames
> */
next prev parent reply other threads:[~2020-04-06 20:54 UTC|newest]
Thread overview: 109+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-25 17:35 [PATCH v3 00/32] powerpc/64: interrupts and syscalls series Nicholas Piggin
2020-02-25 17:35 ` [PATCH v3 01/32] powerpc/64s/exception: Introduce INT_DEFINE parameter block for code generation Nicholas Piggin
2020-04-01 12:53 ` Michael Ellerman
2020-02-25 17:35 ` [PATCH v3 02/32] powerpc/64s/exception: Add GEN_COMMON macro that uses INT_DEFINE parameters Nicholas Piggin
2020-02-25 17:35 ` [PATCH v3 03/32] powerpc/64s/exception: Add GEN_KVM " Nicholas Piggin
2020-02-25 17:35 ` [PATCH v3 04/32] powerpc/64s/exception: Expand EXC_COMMON and EXC_COMMON_ASYNC macros Nicholas Piggin
2020-02-25 17:35 ` [PATCH v3 05/32] powerpc/64s/exception: Move all interrupt handlers to new style code gen macros Nicholas Piggin
2020-02-25 17:35 ` [PATCH v3 06/32] powerpc/64s/exception: Remove old INT_ENTRY macro Nicholas Piggin
2020-02-25 17:35 ` [PATCH v3 07/32] powerpc/64s/exception: Remove old INT_COMMON macro Nicholas Piggin
2020-02-25 17:35 ` [PATCH v3 08/32] powerpc/64s/exception: Remove old INT_KVM_HANDLER Nicholas Piggin
2020-02-25 17:35 ` [PATCH v3 09/32] powerpc/64s/exception: Add ISIDE option Nicholas Piggin
2020-02-25 17:35 ` [PATCH v3 10/32] powerpc/64s/exception: move real->virt switch into the common handler Nicholas Piggin
2020-02-25 17:35 ` [PATCH v3 11/32] powerpc/64s/exception: move soft-mask test to common code Nicholas Piggin
2020-02-25 17:35 ` [PATCH v3 12/32] powerpc/64s/exception: move KVM " Nicholas Piggin
2020-02-25 17:35 ` [PATCH v3 13/32] powerpc/64s/exception: remove confusing IEARLY option Nicholas Piggin
2020-02-25 17:35 ` [PATCH v3 14/32] powerpc/64s/exception: remove the SPR saving patch code macros Nicholas Piggin
2020-02-25 17:35 ` [PATCH v3 15/32] powerpc/64s/exception: trim unused arguments from KVMTEST macro Nicholas Piggin
2020-02-25 17:35 ` [PATCH v3 16/32] powerpc/64s/exception: hdecrementer avoid touching the stack Nicholas Piggin
2020-02-25 17:35 ` [PATCH v3 17/32] powerpc/64s/exception: re-inline some handlers Nicholas Piggin
2020-02-25 17:35 ` [PATCH v3 18/32] powerpc/64s/exception: Clean up SRR specifiers Nicholas Piggin
2020-02-25 17:35 ` [PATCH v3 19/32] powerpc/64s/exception: add more comments for interrupt handlers Nicholas Piggin
2020-02-25 17:35 ` [PATCH v3 20/32] powerpc/64s/exception: only test KVM in SRR interrupts when PR KVM is supported Nicholas Piggin
2020-02-25 17:35 ` [PATCH v3 21/32] powerpc/64s/exception: sreset interrupts reconcile fix Nicholas Piggin
2020-02-25 17:35 ` [PATCH v3 22/32] powerpc/64s/exception: soft nmi interrupt should not use ret_from_except Nicholas Piggin
2020-02-25 17:35 ` [PATCH v3 23/32] powerpc/64: system call remove non-volatile GPR save optimisation Nicholas Piggin
2020-02-25 17:35 ` [PATCH v3 24/32] powerpc/64: sstep ifdef the deprecated fast endian switch syscall Nicholas Piggin
2020-02-25 17:35 ` [PATCH v3 25/32] powerpc/64: system call implement entry/exit logic in C Nicholas Piggin
2020-03-19 9:18 ` Christophe Leroy
2020-03-20 3:39 ` Nicholas Piggin
2020-02-25 17:35 ` [PATCH v3 26/32] powerpc/64: system call zero volatile registers when returning Nicholas Piggin
2020-02-25 21:20 ` Segher Boessenkool
2020-02-26 3:39 ` Nicholas Piggin
2020-03-07 0:54 ` [PATCH] Fix " Nicholas Piggin
2020-02-25 17:35 ` [PATCH v3 27/32] powerpc/64: implement soft interrupt replay in C Nicholas Piggin
2020-02-25 17:35 ` [PATCH v3 28/32] powerpc/64s: interrupt implement exit logic " Nicholas Piggin
2021-01-27 8:54 ` Christophe Leroy
2021-01-28 0:09 ` Nicholas Piggin
2021-02-03 16:25 ` Christophe Leroy
2021-02-04 3:27 ` Nicholas Piggin
2021-02-04 8:03 ` Christophe Leroy
2021-02-04 8:53 ` Nicholas Piggin
2021-02-05 0:22 ` Michael Ellerman
2021-02-05 2:16 ` Nicholas Piggin
2021-02-05 6:04 ` Christophe Leroy
2021-02-06 2:28 ` Nicholas Piggin
2021-02-27 10:07 ` Christophe Leroy
2021-03-01 0:47 ` Nicholas Piggin
2021-03-15 13:41 ` Christophe Leroy
2021-03-16 7:36 ` Nicholas Piggin
2021-03-19 11:44 ` Michael Ellerman
2020-02-25 17:35 ` [PATCH v3 29/32] powerpc/64s/exception: remove lite interrupt return Nicholas Piggin
2020-02-25 17:35 ` [PATCH v3 30/32] powerpc/64: system call reconcile interrupts Nicholas Piggin
2020-02-25 17:35 ` [PATCH v3 31/32] powerpc/64s/exception: treat NIA below __end_interrupts as soft-masked Nicholas Piggin
2020-02-25 17:35 ` [PATCH v3 32/32] powerpc/64s: system call support for scv/rfscv instructions Nicholas Piggin
2020-03-01 12:20 ` kbuild test robot
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 [this message]
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
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
2020-04-06 13:05 ` Michael Ellerman
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 3/8] powerpc/perf: consolidate read_user_stack_32 Michal Suchanek
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