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From: Peter Zijlstra <peterz@infradead.org>
To: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Marco Elver <elver@google.com>, Arnd Bergmann <arnd@arndb.de>,
	Florian Weimer <fweimer@redhat.com>,
	"David S. Miller" <davem@davemloft.net>,
	Ingo Molnar <mingo@kernel.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Peter Collingbourne <pcc@google.com>,
	Dmitry Vyukov <dvyukov@google.com>,
	Alexander Potapenko <glider@google.com>,
	sparclinux <sparclinux@vger.kernel.org>,
	linux-arch <linux-arch@vger.kernel.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Linux API <linux-api@vger.kernel.org>,
	kasan-dev <kasan-dev@googlegroups.com>
Subject: Re: [PATCH 7/3] signal: Deliver all of the perf_data in si_perf
Date: Mon, 3 May 2021 14:44:21 +0200	[thread overview]
Message-ID: <YI/wJSwQitisM8Xf@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <m1wnshm14b.fsf@fess.ebiederm.org>

On Sun, May 02, 2021 at 01:39:16PM -0500, Eric W. Biederman wrote:

> The one thing that this doesn't do is give you a 64bit field
> on 32bit architectures.
> 
> On 32bit builds the layout is:
> 
> 	int si_signo;
> 	int si_errno;
> 	int si_code;
> 	void __user *_addr;
>         
> So I believe if the first 3 fields were moved into the _sifields union
> si_perf could define a 64bit field as it's first member and it would not
> break anything else.
> 
> Given that the data field is 64bit that seems desirable.

The data field is fundamentally an address, it is internally a u64
because the perf ring buffer has u64 alignment and it saves on compat
crap etc.

So for the 32bit/compat case the high bits will always be 0 and
truncating into an unsigned long is fine.

  parent reply	other threads:[~2021-05-03 12:46 UTC|newest]

Thread overview: 118+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-04-29  7:48 siginfo_t ABI break on sparc64 from si_addr_lsb move 3y ago Marco Elver
2021-04-29 17:23 ` Eric W. Biederman
2021-04-29 18:46   ` Marco Elver
2021-04-29 20:48   ` Arnd Bergmann
2021-04-30 17:08     ` Eric W. Biederman
2021-04-30 19:07       ` Marco Elver
2021-04-30 20:15         ` Eric W. Biederman
2021-04-30 23:50           ` Marco Elver
2021-04-30 22:49         ` [RFC][PATCH 0/3] signal: Move si_trapno into the _si_fault union Eric W. Biederman
2021-04-30 22:50           ` [PATCH 1/3] siginfo: Move si_trapno inside the union inside _si_fault Eric W. Biederman
2021-05-01 10:31             ` Marco Elver
2021-05-02 18:27               ` Eric W. Biederman
2021-04-30 22:54           ` [PATCH 2/3] signal: Implement SIL_FAULT_TRAPNO Eric W. Biederman
2021-04-30 23:19             ` Eric W. Biederman
2021-05-01 10:33             ` Marco Elver
2021-05-02 18:24               ` Eric W. Biederman
2021-04-30 22:55           ` [PATCH 3/3] signal: Use dedicated helpers to send signals with si_trapno set Eric W. Biederman
2021-05-01 10:33             ` Marco Elver
2021-04-30 22:56           ` [PATCH 4/3] signal: Remove __ARCH_SI_TRAPNO Eric W. Biederman
2021-04-30 23:23           ` Is perf_sigtrap synchronous? Eric W. Biederman
2021-05-01  0:28             ` Marco Elver
2021-04-30 23:42           ` [PATCH 5/3] signal: Rename SIL_PERF_EVENT SIL_FAULT_PERF_EVENT for consistency Eric W. Biederman
2021-05-01 10:35             ` Marco Elver
2021-04-30 23:43           ` [PATCH 6/3] signal: Factor force_sig_perf out of perf_sigtrap Eric W. Biederman
2021-05-01 10:45             ` Marco Elver
2021-04-30 23:43           ` [PATCH 7/3] signal: Deliver all of the perf_data in si_perf Eric W. Biederman
2021-05-01 10:47             ` Marco Elver
2021-05-02 18:39               ` Eric W. Biederman
2021-05-02 19:13                 ` Marco Elver
2021-05-03 12:44                 ` Peter Zijlstra [this message]
2021-05-03 19:38                   ` Eric W. Biederman
2021-05-03 19:53                     ` Marco Elver
2021-04-30 23:47           ` [RFC][PATCH 0/3] signal: Move si_trapno into the _si_fault union Eric W. Biederman
2021-05-01  0:37             ` Marco Elver
2021-05-01 15:16               ` Eric W. Biederman
2021-05-01 16:24                 ` Marco Elver
2021-05-03 20:25                   ` [PATCH 00/12] signal: sort out si_trapno and si_perf Eric W. Biederman
2021-05-03 20:38                     ` [PATCH 01/12] sparc64: Add compile-time asserts for siginfo_t offsets Eric W. Beiderman
2021-05-03 20:38                       ` [PATCH 02/12] arm: " Eric W. Beiderman
2021-05-03 20:38                       ` [PATCH 03/12] arm64: " Eric W. Beiderman
2021-05-03 20:38                       ` [PATCH 04/12] siginfo: Move si_trapno inside the union inside _si_fault Eric W. Beiderman
2021-05-03 20:38                       ` [PATCH 05/12] signal: Implement SIL_FAULT_TRAPNO Eric W. Beiderman
2021-05-03 20:38                       ` [PATCH 06/12] signal: Use dedicated helpers to send signals with si_trapno set Eric W. Beiderman
2021-05-03 20:38                       ` [PATCH 07/12] signal: Remove __ARCH_SI_TRAPNO Eric W. Beiderman
2021-05-03 20:38                       ` [PATCH 08/12] signal: Rename SIL_PERF_EVENT SIL_FAULT_PERF_EVENT for consistency Eric W. Beiderman
2021-05-03 20:38                       ` [PATCH 09/12] signal: Factor force_sig_perf out of perf_sigtrap Eric W. Beiderman
2021-05-03 20:38                       ` [PATCH 10/12] signal: Redefine signinfo so 64bit fields are possible Eric W. Beiderman
2021-05-03 21:04                         ` Eric W. Biederman
2021-05-03 22:47                           ` Marco Elver
2021-05-04  3:42                             ` Eric W. Biederman
2021-05-04  4:03                               ` Peter Collingbourne
2021-05-04  9:52                                 ` Marco Elver
2021-05-04 16:16                                   ` Eric W. Biederman
2021-05-03 20:38                       ` [PATCH 11/12] signal: Deliver all of the siginfo perf data in _perf Eric W. Beiderman
2021-05-03 20:38                       ` [PATCH 12/12] signalfd: Remove SIL_FAULT_PERF_EVENT fields from signalfd_siginfo Eric W. Beiderman
2021-05-04 21:13                     ` [PATCH v3 00/12] signal: sort out si_trapno and si_perf Eric W. Biederman
2021-05-04 22:05                       ` Marco Elver
2021-05-05 14:12                         ` Eric W. Biederman
2021-05-05 14:10                       ` [PATCH v3 01/12] sparc64: Add compile-time asserts for siginfo_t offsets Eric W. Beiderman
2021-05-05 14:10                         ` [PATCH v3 02/12] arm: " Eric W. Beiderman
2021-05-05 14:10                         ` [PATCH v3 03/12] arm64: " Eric W. Beiderman
2021-05-05 14:10                         ` [PATCH v3 04/12] signal: Verify the alignment and size of siginfo_t Eric W. Beiderman
2021-05-05 17:24                           ` Marco Elver
2021-05-05 14:10                         ` [PATCH v3 05/12] siginfo: Move si_trapno inside the union inside _si_fault Eric W. Beiderman
2021-05-05 14:10                         ` [PATCH v3 06/12] signal: Implement SIL_FAULT_TRAPNO Eric W. Beiderman
2021-05-05 17:25                           ` Marco Elver
2021-05-05 14:10                         ` [PATCH v3 07/12] signal: Use dedicated helpers to send signals with si_trapno set Eric W. Beiderman
2021-05-05 17:25                           ` Marco Elver
2021-05-05 14:10                         ` [PATCH v3 08/12] signal: Remove __ARCH_SI_TRAPNO Eric W. Beiderman
2021-05-05 17:25                           ` Marco Elver
2021-05-05 14:10                         ` [PATCH v3 09/12] signal: Rename SIL_PERF_EVENT SIL_FAULT_PERF_EVENT for consistency Eric W. Beiderman
2021-05-05 17:26                           ` Marco Elver
2021-05-05 14:10                         ` [PATCH v3 10/12] signal: Factor force_sig_perf out of perf_sigtrap Eric W. Beiderman
2021-05-05 17:26                           ` Marco Elver
2021-05-06 10:54                           ` Peter Zijlstra
2021-05-05 14:11                         ` [PATCH v3 11/12] signal: Deliver all of the siginfo perf data in _perf Eric W. Beiderman
2021-05-05 17:27                           ` Marco Elver
2021-05-05 14:11                         ` [PATCH v3 12/12] signalfd: Remove SIL_FAULT_PERF_EVENT fields from signalfd_siginfo Eric W. Beiderman
2021-05-05 17:27                           ` Marco Elver
2021-05-05 17:28                       ` [PATCH v3 00/12] signal: sort out si_trapno and si_perf Marco Elver
2021-05-06  7:00                       ` Geert Uytterhoeven
2021-05-06 10:43                         ` Marco Elver
2021-05-06 15:28                           ` Eric W. Biederman
2021-05-06 15:14                         ` Eric W. Biederman
2021-05-14  4:54                       ` [GIT PULL] siginfo: ABI fixes for v5.13-rc2 Eric W. Biederman
2021-05-14 19:14                         ` Linus Torvalds
2021-05-14 21:15                           ` Eric W. Biederman
2021-05-14 22:38                             ` Eric W. Biederman
2021-05-16  7:40                         ` Ingo Molnar
2021-05-17 15:29                           ` Eric W. Biederman
2021-05-21 14:59                         ` [GIT PULL] siginfo: ABI fixes for v5.13-rc3 Eric W. Biederman
2021-05-21 16:34                           ` pr-tracker-bot
2021-05-17 19:56                       ` [PATCH v4 0/5] siginfo: ABI fixes for TRAP_PERF Eric W. Biederman
2021-05-17 19:57                         ` [PATCH v4 1/5] siginfo: Move si_trapno inside the union inside _si_fault Eric W. Beiderman
2021-05-17 19:57                           ` [PATCH v4 2/5] signal: Implement SIL_FAULT_TRAPNO Eric W. Beiderman
2021-05-17 19:57                           ` [PATCH v4 3/5] signal: Factor force_sig_perf out of perf_sigtrap Eric W. Beiderman
2021-05-17 19:57                           ` [PATCH v4 4/5] signal: Deliver all of the siginfo perf data in _perf Eric W. Beiderman
2021-05-17 19:57                           ` [PATCH v4 5/5] signalfd: Remove SIL_PERF_EVENT fields from signalfd_siginfo Eric W. Beiderman
2021-05-17 20:53                         ` [PATCH v4 0/5] siginfo: ABI fixes for TRAP_PERF Marco Elver
2021-05-18  3:46                           ` Eric W. Biederman
2021-05-18  6:44                             ` Marco Elver
2021-05-01 16:26               ` [RFC][PATCH 0/3] signal: Move si_trapno into the _si_fault union Marco Elver
2021-07-15 18:09           ` [PATCH 0/6] Final si_trapno bits Eric W. Biederman
2021-07-15 18:11             ` [PATCH 1/6] sparc64: Add compile-time asserts for siginfo_t offsets Eric W. Biederman
2021-07-15 18:11             ` [PATCH 2/6] arm: " Eric W. Biederman
2021-07-15 18:11             ` [PATCH 3/6] arm64: " Eric W. Biederman
2021-07-15 18:12             ` [PATCH 4/6] signal/sparc: si_trapno is only used with SIGILL ILL_ILLTRP Eric W. Biederman
2021-07-16 11:49               ` Marco Elver
2021-07-15 18:12             ` [PATCH 5/6] signal/alpha: si_trapno is only used with SIGFPE and SIGTRAP TRAP_UNK Eric W. Biederman
2021-07-16 11:48               ` Marco Elver
2021-07-15 18:13             ` [PATCH 6/6] signal: Remove the generic __ARCH_SI_TRAPNO support Eric W. Biederman
2021-07-16 11:48               ` Marco Elver
2021-07-16 11:50             ` [PATCH 0/6] Final si_trapno bits Marco Elver
2021-07-16 16:08               ` Eric W. Biederman
2021-07-16 17:15                 ` Marco Elver
2021-07-16 16:06             ` [PATCH 7/7] signal: Verify the alignment and size of siginfo_t Eric W. Biederman
2021-07-16 16:07             ` [PATCH 8/6] signal: Rename SIL_PERF_EVENT SIL_FAULT_PERF_EVENT for consistency Eric W. Biederman
2021-04-30 20:43       ` siginfo_t ABI break on sparc64 from si_addr_lsb move 3y ago Arnd Bergmann

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