From: "H. Peter Anvin" <hpa@zytor.com>
To: Heiko Carstens <hca@linux.ibm.com>
Cc: "Thomas Gleixner" <tglx@kernel.org>,
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Subject: Re: [patch 00/18] entry: Consolidate and rework syscall entry handling
Date: Mon, 31 Aug 2026 12:57:32 -0700 [thread overview]
Message-ID: <1238a07e-ce04-47d9-b8ac-8b7f557b401f@zytor.com> (raw)
In-Reply-To: <20260831085056.34274A00-hca@linux.ibm.com>
On 2026-08-31 01:50, Heiko Carstens wrote:
> On Thu, Aug 27, 2026 at 03:22:35PM -0700, H. Peter Anvin wrote:
>> This isn't a hard thing to solve in any way: replacing the pointer argument
>> with a two-element structure return would do the trick. As far as I know,
>> *all* architectures that support Linux support returning structures with two
>> register-sized values in registers.
>
> That is unfortunately not true. The s390 ABI defines that structures,
> regardless of size, are returned in a return value buffer allocated by
> the caller.
*Groan*
You guys should use an improved ABI for the kernel like i386 does (different
from the standard ABI used in user space)...
That being said, perhaps s390(x) isn't affected by the underlying problem, and
passing a pointer to a structure isn't any more expensive than passing a
pointer to a variable...
-hpa
prev parent reply other threads:[~2026-08-31 20:01 UTC|newest]
Thread overview: 107+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-07-07 19:05 [patch 00/18] entry: Consolidate and rework syscall entry handling Thomas Gleixner
2026-07-07 19:05 ` [patch 01/18] powerpc: Move stack randomization after syscall_enter_from_user_mode() Thomas Gleixner
2026-07-08 14:07 ` Shrikanth Hegde
2026-07-08 17:22 ` Radu Rendec
2026-07-09 1:20 ` Jinjie Ruan
2026-07-09 11:12 ` Philippe Mathieu-Daudé
2026-07-09 18:32 ` Mukesh Kumar Chaurasiya
2026-07-07 19:06 ` [patch 02/18] randomize_kstack: Provide add_random_kstack_offset_irqsoff() Thomas Gleixner
2026-07-08 17:24 ` Radu Rendec
2026-07-09 2:13 ` Jinjie Ruan
2026-07-09 16:23 ` Kees Cook
2026-07-09 18:34 ` Mukesh Kumar Chaurasiya
2026-07-07 19:06 ` [patch 03/18] entry: Provide [syscall_]enter_from_user_mode_randomize_stack() Thomas Gleixner
2026-07-08 17:26 ` Radu Rendec
2026-07-09 2:34 ` Jinjie Ruan
2026-07-09 3:46 ` Jinjie Ruan
2026-07-09 11:15 ` Philippe Mathieu-Daudé
2026-07-09 20:16 ` Mukesh Kumar Chaurasiya
2026-08-27 22:46 ` H. Peter Anvin
2026-08-29 21:12 ` Thomas Gleixner
2026-07-07 19:06 ` [patch 04/18] loongarch/syscall: Use syscall_enter_from_user_mode_randomize_stack() Thomas Gleixner
2026-07-08 18:37 ` Radu Rendec
2026-07-09 2:37 ` Jinjie Ruan
2026-07-09 11:15 ` Philippe Mathieu-Daudé
2026-07-09 18:40 ` Mukesh Kumar Chaurasiya
2026-07-07 19:06 ` [patch 05/18] powerpc/syscall: " Thomas Gleixner
2026-07-08 18:35 ` Radu Rendec
2026-07-09 2:38 ` Jinjie Ruan
2026-07-09 11:16 ` Philippe Mathieu-Daudé
2026-07-09 18:41 ` Mukesh Kumar Chaurasiya
2026-07-07 19:06 ` [patch 06/18] riscv/syscall: " Thomas Gleixner
2026-07-08 20:57 ` Radu Rendec
2026-07-09 2:38 ` Jinjie Ruan
2026-07-09 11:16 ` Philippe Mathieu-Daudé
2026-07-09 18:42 ` Mukesh Kumar Chaurasiya
2026-07-13 7:06 ` Guo Ren
2026-07-07 19:06 ` [patch 07/18] s390/syscall: Use enter_from_user_mode_randomize_stack() Thomas Gleixner
2026-07-08 6:47 ` Sven Schnelle
2026-07-08 20:57 ` Radu Rendec
2026-07-09 2:39 ` Jinjie Ruan
2026-07-09 2:46 ` Jinjie Ruan
2026-07-09 11:17 ` Philippe Mathieu-Daudé
2026-07-09 18:43 ` Mukesh Kumar Chaurasiya
2026-07-07 19:06 ` [patch 08/18] x86/syscall: Use [syscall_]enter_from_user_mode_randomize_stack() Thomas Gleixner
2026-07-08 20:59 ` Radu Rendec
2026-07-09 2:44 ` Jinjie Ruan
2026-07-09 11:18 ` Philippe Mathieu-Daudé
2026-07-09 18:45 ` Mukesh Kumar Chaurasiya
2026-07-07 19:06 ` [patch 09/18] entry: Remove syscall_enter_from_user_mode() Thomas Gleixner
2026-07-08 21:21 ` Radu Rendec
2026-07-08 22:08 ` Thomas Gleixner
2026-07-09 2:49 ` Jinjie Ruan
2026-07-09 18:49 ` Mukesh Kumar Chaurasiya
2026-07-07 19:06 ` [patch 10/18] entry: Use syscall number instead of rereading it Thomas Gleixner
2026-07-08 21:39 ` Radu Rendec
2026-07-09 2:55 ` Jinjie Ruan
2026-07-09 11:20 ` Philippe Mathieu-Daudé
2026-07-09 11:22 ` Philippe Mathieu-Daudé
2026-07-09 18:50 ` Mukesh Kumar Chaurasiya
2026-07-07 19:06 ` [patch 11/18] seccomp, treewide: Rename and convert __secure_computing() to return boolean Thomas Gleixner
2026-07-08 1:43 ` Jinjie Ruan
2026-07-08 9:15 ` Thomas Gleixner
2026-07-08 16:04 ` Oleg Nesterov
2026-07-08 21:49 ` Thomas Gleixner
2026-07-09 16:22 ` Kees Cook
2026-07-09 19:10 ` Mukesh Kumar Chaurasiya
2026-07-07 19:06 ` [patch 12/18] ptrace, treewide: Rename ptrace_report_syscall_entry() to ptrace_report_syscall_permit_entry() Thomas Gleixner
2026-07-08 15:46 ` Oleg Nesterov
2026-07-09 1:41 ` Jinjie Ruan
2026-07-09 8:41 ` Geert Uytterhoeven
2026-07-09 17:03 ` Radu Rendec
2026-07-09 19:22 ` Mukesh Kumar Chaurasiya
2026-07-10 10:42 ` Michal Suchánek
2026-07-10 11:16 ` Oleg Nesterov
2026-07-07 19:06 ` [patch 13/18] entry: Make trace_syscall_enter() return type bool Thomas Gleixner
2026-07-08 15:52 ` Michal Suchánek
2026-07-08 20:34 ` Thomas Gleixner
2026-07-08 23:14 ` Thomas Gleixner
2026-07-09 16:26 ` David Laight
2026-07-10 11:01 ` Michal Suchánek
2026-07-10 11:40 ` Oleg Nesterov
2026-07-10 12:32 ` Michal Suchánek
2026-07-10 12:52 ` Oleg Nesterov
2026-07-10 15:20 ` Michal Suchánek
2026-07-11 20:33 ` Thomas Gleixner
2026-07-14 8:20 ` Michal Suchánek
2026-07-07 19:06 ` [patch 14/18] entry: Make return type of syscall_trace_enter() bool Thomas Gleixner
2026-07-09 19:36 ` Mukesh Kumar Chaurasiya
2026-07-07 19:06 ` [patch 15/18] x86/entry: Make syscall functions static Thomas Gleixner
2026-07-09 1:47 ` Jinjie Ruan
2026-07-09 19:43 ` Mukesh Kumar Chaurasiya
2026-07-07 19:07 ` [patch 16/18] x86/entry: Get rid of the sys_ni_syscall() indirection Thomas Gleixner
2026-07-09 2:03 ` Jinjie Ruan
2026-07-07 19:07 ` [patch 17/18] x86/entry: Simplify the syscall number logic Thomas Gleixner
2026-07-07 19:07 ` [patch 18/18] entry, treewide: Make syscall_enter_from_user_mode[_work]() indicate syscall execution Thomas Gleixner
2026-07-08 5:21 ` Shrikanth Hegde
2026-07-08 9:16 ` Thomas Gleixner
2026-07-09 19:49 ` Mukesh Kumar Chaurasiya
2026-07-09 20:15 ` [patch 00/18] entry: Consolidate and rework syscall entry handling Mukesh Kumar Chaurasiya
2026-07-11 12:29 ` Magnus Lindholm
2026-07-19 11:25 ` Magnus Lindholm
2026-07-20 19:21 ` Thomas Gleixner
2026-07-20 22:01 ` Magnus Lindholm
2026-07-21 8:17 ` Thomas Gleixner
2026-08-27 22:22 ` H. Peter Anvin
2026-08-31 8:50 ` Heiko Carstens
2026-08-31 19:57 ` H. Peter Anvin [this message]
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