From: arnd@arndb.de (Arnd Bergmann)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v9 00/24] ILP32 for ARM64
Date: Sun, 14 Oct 2018 21:53:22 +0200 [thread overview]
Message-ID: <CAK8P3a1qUVoE0CYkCOU2N+-WkqMad15fFsakbwkpiiPPRFz-eA@mail.gmail.com> (raw)
In-Reply-To: <20181013020731.GD21972@asgard.redhat.com>
On Sat, Oct 13, 2018 at 4:07 AM Eugene Syromiatnikov <esyr@redhat.com> wrote:
>
> On Wed, Oct 10, 2018 at 03:39:07PM +0100, Szabolcs Nagy wrote:
> > On 10/10/18 15:10, Eugene Syromiatnikov wrote:
> > > * What's the reasoning behind capping syscall arguments to 32 bit? x32
> > > and MIPS N32 do not have such a restriction (and do not need special
> > > wrappers for syscalls that pass 64-bit values as a result, except
> > > when they do, as it is the case for preadv2 on x32); moreover, that
> > > would lead to insurmountable difficulties for AArch64 ILP32 tracers
> > > that try to trace LP64 tracees, as it would be impossible to pass
> > > 64-bit addresses to process_vm_{read,write} or ptrace PEEK/POKE.
> >
> > but that's necessarily the case for all ilp32 abis:
> > the userspace syscall function receives 32bit
> > arguments so even if the kernel abi takes 64bit
> > args you cannot use that from c code. (the libc
> > does not even know which args should be sign or
> > zero extended.)
>
> glibc's syscall() prototype has kernel_ulong_t as its arguments (more
> specifically, to __syscall_ulong_t, which is 64-bit wide on x32; it
> should also have kernel_long_t as its return type instead of long,
> but that's another story), so it works perfectly fine in case of x32.
>
> > process_vm_readv/writev is limited by the ilp32
> > iovec struct, not by the syscall arguments.
>
> Right, on x32/N32 this issue is worked around by the usage of the respective
> x86_64/N64 call, and it looks like another thing that is impossible
> with AArch64 ilp32.
>
> > ptrace is specified to take void* addr argument,
> > and void* is 32bit on all ilp32 targets.
> > so again on the c language level there is no
> > way around the 32bit limitation.
>
> Which is an issue.
I have no idea why you think this is a problem specific to aarch64-ilp32:
If we want to be able to debug 64-bit tasks from a 32-bit task on any
architecture that has compat mode, we should solve it once and
extend the ptrace interface to allow it on *all* of them. We certainly
don't need /more/ special cases for the x32 hack, there should really
be fewer of them.
Arnd
next prev parent reply other threads:[~2018-10-14 19:53 UTC|newest]
Thread overview: 73+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-05-16 8:18 [PATCH v9 00/24] ILP32 for ARM64 Yury Norov
2018-05-16 8:18 ` [PATCH 01/24] arm64: signal: Make parse_user_sigframe() independent of rt_sigframe layout Yury Norov
2018-05-16 8:18 ` [PATCH 02/24] ptrace: Add compat PTRACE_{G,S}ETSIGMASK handlers Yury Norov
2018-05-16 8:18 ` [PATCH 03/24] compat ABI: use non-compat openat and open_by_handle_at variants Yury Norov
2018-05-16 8:18 ` [PATCH 04/24] 32-bit userspace ABI: introduce ARCH_32BIT_OFF_T config option Yury Norov
2018-06-08 17:32 ` Catalin Marinas
2018-06-08 22:33 ` Palmer Dabbelt
2018-06-09 7:43 ` Yury Norov
2018-06-09 21:13 ` Adam Borowski
2018-06-09 7:42 ` Yury Norov
2018-06-11 7:48 ` Arnd Bergmann
2018-06-11 11:27 ` Yury Norov
2018-06-25 6:19 ` Yury Norov
2018-08-02 18:30 ` Palmer Dabbelt
2018-05-16 8:18 ` [PATCH 06/24] thread: move thread bits accessors to separated file Yury Norov
2018-05-16 8:18 ` [PATCH 07/24] arm64: ilp32: add documentation on the ILP32 ABI for ARM64 Yury Norov
2018-05-23 14:06 ` Pavel Machek
2018-05-24 12:15 ` Yury Norov
2018-05-24 12:24 ` Dr. Philipp Tomsich
2018-05-16 8:18 ` [PATCH 08/24] arm64: rename COMPAT to AARCH32_EL0 in Kconfig Yury Norov
2018-05-16 8:18 ` [PATCH 09/24] arm64: rename functions that reference compat term Yury Norov
2018-05-16 8:18 ` [PATCH 10/24] arm64: uapi: set __BITS_PER_LONG correctly for ILP32 and LP64 Yury Norov
2018-05-16 8:18 ` [PATCH 11/24] arm64: introduce is_a32_task and is_a32_thread (for AArch32 compat) Yury Norov
2018-05-16 8:18 ` [PATCH 12/24] arm64: ilp32: add is_ilp32_compat_{task, thread} and TIF_32BIT_AARCH64 Yury Norov
2018-05-16 8:18 ` [PATCH 13/24] arm64: introduce binfmt_elf32.c Yury Norov
2018-05-16 8:18 ` [PATCH 14/24] arm64: change compat_elf_hwcap and compat_elf_hwcap2 prefix to a32 Yury Norov
2018-05-16 8:19 ` [PATCH 15/24] arm64: ilp32: introduce binfmt_ilp32.c Yury Norov
2018-05-16 8:19 ` [PATCH 16/24] arm64: ilp32: share aarch32 syscall handlers Yury Norov
2018-05-16 8:19 ` [PATCH 17/24] arm64: ilp32: add sys_ilp32.c and a separate table (in entry.S) to use it Yury Norov
2018-05-16 8:19 ` [PATCH 18/24] arm64: signal: share lp64 signal structures and routines to ilp32 Yury Norov
2018-05-16 8:19 ` [PATCH 19/24] arm64: signal32: move ilp32 and aarch32 common code to separated file Yury Norov
2018-05-16 8:19 ` [PATCH 20/24] arm64: ilp32: introduce ilp32-specific sigframe and ucontext Yury Norov
2018-05-16 8:19 ` [PATCH 21/24] arm64: ptrace: handle ptrace_request differently for aarch32 and ilp32 Yury Norov
2018-05-16 8:19 ` [PATCH 22/24] arm64:ilp32: add vdso-ilp32 and use for signal return Yury Norov
2019-09-30 7:24 ` Andreas Schwab
2018-05-16 8:19 ` [PATCH 23/24] arm64:ilp32: add ARM64_ILP32 to Kconfig Yury Norov
2018-05-16 8:19 ` [PATCH 24/24] arm64: ilp32: Make the Kconfig option default y Yury Norov
2018-07-24 17:39 ` [PATCH v9 00/24] ILP32 for ARM64 Yury Norov
2018-07-25 9:48 ` Andreas Schwab
2018-10-10 14:10 ` Eugene Syromiatnikov
2018-10-10 14:18 ` Arnd Bergmann
2018-10-10 14:39 ` Szabolcs Nagy
2018-10-13 2:07 ` Eugene Syromiatnikov
2018-10-13 9:20 ` Catalin Marinas
2018-10-14 19:53 ` Arnd Bergmann [this message]
2018-10-10 15:36 ` Catalin Marinas
2018-10-13 2:14 ` Eugene Syromiatnikov
2018-10-13 9:34 ` Catalin Marinas
2018-10-13 13:43 ` Yury Norov
2018-10-13 16:54 ` Andy Lutomirski
2018-11-13 10:04 ` Andreas Schwab
2018-11-13 10:57 ` Yury Norov
2018-11-15 0:51 ` Catalin Marinas
2018-11-15 8:54 ` Andreas Schwab
2018-11-15 20:27 ` Yury Norov
2018-11-19 9:57 ` Andreas Schwab
2018-10-13 19:36 ` Andy Lutomirski
2018-10-14 19:49 ` Arnd Bergmann
2018-10-18 11:14 ` Catalin Marinas
2018-11-19 21:29 ` Yury Norov
2019-01-07 15:50 ` Yuri Norov
[not found] ` <DC9A951E-B638-4820-8499-02D5322E7DF7@amacapital.net>
2019-01-07 20:43 ` Yuri Norov
2019-01-08 21:18 ` [PATCH] arm64: introduce AUDIT_ARCH_AARCH64ILP32 for ilp32 Yuri Norov
2019-03-05 20:56 ` [PATCH v9 00/24] ILP32 for ARM64 Yury Norov
2019-05-08 22:59 ` Yury Norov
2019-05-08 23:10 ` Yury Norov
2019-05-13 8:48 ` Andreas Schwab
2019-05-13 20:16 ` [EXT] " Yuri Norov
[not found] ` <20190514104311.GA24708@rei>
2019-05-14 23:01 ` [LTP] " Yury Norov
2019-05-14 23:41 ` Yury Norov
2019-07-09 22:42 ` Yury Norov
-- strict thread matches above, loose matches on Subject: below --
2018-05-15 19:11 Yury Norov
2018-05-15 19:40 ` Yury Norov
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