From: esyr@redhat.com (Eugene Syromiatnikov)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v9 00/24] ILP32 for ARM64
Date: Sat, 13 Oct 2018 04:14:16 +0200 [thread overview]
Message-ID: <20181013021416.GE21972@asgard.redhat.com> (raw)
In-Reply-To: <20181010153655.GA212880@arrakis.emea.arm.com>
On Wed, Oct 10, 2018 at 04:36:56PM +0100, Catalin Marinas wrote:
> On Wed, Oct 10, 2018 at 04:10:21PM +0200, Eugene Syromiatnikov wrote:
> > I have some questions regarding AArch64 ILP32 implementation for which I
> > failed to find an answer myself:
> > * How ptrace() tracer is supposed to distinguish between ILP32 and LP64
> > tracees? For MIPS N32 and x32 this is possible based on syscall
> > number, but for AArch64 ILP32 I do not see such a sign. There's also
> > ARM_ip is employed for signalling entering/exiting, I wonder whether
> > it's possible to employ it also for signalling tracee's personality.
>
> With the current implementation, I don't think you can distinguish. From
> the kernel perspective, the register set is the same. What is the
> use-case for this?
Err, a ptrace()-based tracer trying to trace a process, for example?
> We could add a new regset to expose the ILP32 state (NT_ARM_..., I can't
> think of a name now but probably not PER* as this implies PER_LINUX_...
> which is independent from TIF_32BIT_*).
So that would require an additional ptrace() call on each syscall stop,
is that correct?
> > * 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.
>
> We've attempted in earlier versions to allow a mix of 32 and 64-bit
> register values from ILP32 but it got pretty complicated. The entry code
> would need to know which registers need zeroing of the top 32-bit
If kernel specifies 64-bit wide registers for syscalls, then it's the
caller's (libc's) responsibility to properly sign-extend arguments when
needed, and glibc, for example, already has proper type definitions that
aimed to handle this.
> and the generic unistd.h wrapper hacks were not very nice.
They are already implemented in glibc during x32 introduction period.
> Some past discussions:
>
> https://www.mail-archive.com/linux-kernel at vger.kernel.org/msg1211716.html
>
> --
> Catalin
next prev parent reply other threads:[~2018-10-13 2:14 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
2018-10-10 15:36 ` Catalin Marinas
2018-10-13 2:14 ` Eugene Syromiatnikov [this message]
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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