From: Paul Walmsley <paul.walmsley@sifive.com>
To: Palmer Dabbelt <palmer@rivosinc.com>
Cc: guoren@kernel.org, Arnd Bergmann <arnd@arndb.de>,
tglx@linutronix.de, peterz@infradead.org, luto@kernel.org,
Conor Dooley <conor.dooley@microchip.com>,
heiko@sntech.de, jszhang@kernel.org, chenhuacai@kernel.org,
apatel@ventanamicro.com, atishp@atishpatra.org,
Mark Rutland <mark.rutland@arm.com>,
bjorn@kernel.org, Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will@kernel.org>,
rppt@kernel.org, anup@brainfault.org, shihua@iscas.ac.cn,
jiawei@iscas.ac.cn, liweiwei@iscas.ac.cn, luxufan@iscas.ac.cn,
chunyu@iscas.ac.cn, tsu.yubo@gmail.com, wefu@redhat.com,
wangjunqiang@iscas.ac.cn, kito.cheng@sifive.com,
andy.chiu@sifive.com, vincent.chen@sifive.com,
greentime.hu@sifive.com, corbet@lwn.net, wuwei2016@iscas.ac.cn,
jrtc27@jrtc27.com, linux-arch@vger.kernel.org,
linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org,
guoren@linux.alibaba.com
Subject: Re: [RFC PATCH 00/22] riscv: s64ilp32: Running 32-bit Linux kernel on 64-bit supervisor mode
Date: Thu, 18 May 2023 17:14:36 -0700 (PDT) [thread overview]
Message-ID: <668be661-728d-b87f-b827-4345ad07cc61@sifive.com> (raw)
In-Reply-To: <mhng-24855381-7da8-4c77-bcaf-a3a53c8cb38b@palmer-ri-x1c9>
On Thu, 18 May 2023, Palmer Dabbelt wrote:
> On Thu, 18 May 2023 06:09:51 PDT (-0700), guoren@kernel.org wrote:
>
> > This patch series adds s64ilp32 support to riscv. The term s64ilp32
> > means smode-xlen=64 and -mabi=ilp32 (ints, longs, and pointers are all
> > 32-bit), i.e., running 32-bit Linux kernel on pure 64-bit supervisor
> > mode. There have been many 64ilp32 abis existing, such as mips-n32 [1],
> > arm-aarch64ilp32 [2], and x86-x32 [3], but they are all about userspace.
> > Thus, this should be the first time running a 32-bit Linux kernel with
> > the 64ilp32 ABI at supervisor mode (If not, correct me).
>
> Does anyone actually want this? At a bare minimum we'd need to add it to the
> psABI, which would presumably also be required on the compiler side of things.
>
> It's not even clear anyone wants rv64/ilp32 in userspace, the kernel seems
> like it'd be even less widely used.
We've certainly talked to folks who are interested in RV64 ILP32 userspace
with an LP64 kernel. The motivation is the usual one: to reduce data size
and therefore (ideally) BOM cost. I think this work, if it goes forward,
would need to go hand in hand with the RVIA psABI group.
The RV64 ILP32 kernel and ILP32 userspace approach implemented by this
patch is intriguing, but I guess for me, the question is whether it's
worth the extra hassle vs. a pure RV32 kernel & userspace.
- Paul
next prev parent reply other threads:[~2023-05-19 0:14 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-05-18 13:09 guoren
2023-05-18 13:09 ` [RFC PATCH 01/22] riscv: vdso: Unify vdso32 & compat_vdso into vdso/Makefile guoren
2023-05-18 13:09 ` [RFC PATCH 02/22] riscv: vdso: Remove compat_vdso/ guoren
2023-05-18 13:09 ` [RFC PATCH 03/22] riscv: vdso: Add time-related vDSO common flow for vdso32 guoren
2023-05-18 13:09 ` [RFC PATCH 04/22] clocksource: riscv: s64ilp32: Use __riscv_xlen instead of CONFIG_32BIT guoren
2023-05-18 13:09 ` [RFC PATCH 05/22] riscv: s64ilp32: Introduce xlen_t guoren
2023-05-18 13:09 ` [RFC PATCH 06/22] irqchip: riscv: s64ilp32: Use __riscv_xlen instead of CONFIG_32BIT guoren
2023-05-18 13:09 ` [RFC PATCH 07/22] riscv: s64ilp32: Add sbi support guoren
2023-05-18 13:09 ` [RFC PATCH 08/22] riscv: s64ilp32: Add asid support guoren
2023-05-18 13:10 ` [RFC PATCH 09/22] riscv: s64ilp32: Introduce PTR_L and PTR_S guoren
2023-05-18 13:10 ` [RFC PATCH 10/22] riscv: s64ilp32: Enable user space runtime environment guoren
2023-05-18 13:10 ` [RFC PATCH 11/22] riscv: s64ilp32: Add ebpf jit support guoren
2023-05-18 13:10 ` [RFC PATCH 12/22] riscv: s64ilp32: Add ELF32 support guoren
2023-05-18 13:10 ` [RFC PATCH 13/22] riscv: s64ilp32: Add ARCH RV64 ILP32 compiling framework guoren
2023-05-18 13:10 ` [RFC PATCH 14/22] riscv: s64ilp32: Add MMU_SV39 mode support for 32BIT guoren
2023-05-18 13:10 ` [RFC PATCH 15/22] riscv: s64ilp32: Enable native atomic64 guoren
2023-05-18 13:10 ` [RFC PATCH 16/22] riscv: s64ilp32: Add TImode (128 int) support guoren
2023-05-18 13:10 ` [RFC PATCH 17/22] riscv: s64ilp32: Implement cmpxchg_double guoren
2023-05-18 13:10 ` [RFC PATCH 18/22] riscv: s64ilp32: Disable KVM guoren
2023-05-18 13:10 ` [RFC PATCH 19/22] riscv: Cleanup rv32_defconfig guoren
2023-05-18 13:10 ` [RFC PATCH 20/22] riscv: s64ilp32: Add rv64ilp32_defconfig guoren
2023-05-18 13:10 ` [RFC PATCH 21/22] riscv: s64ilp32: Correct the rv64ilp32 stackframe layout guoren
2023-05-18 13:10 ` [RFC PATCH 22/22] riscv: s64ilp32: Temporary workaround solution to gcc problem guoren
2023-05-18 15:38 ` [RFC PATCH 00/22] riscv: s64ilp32: Running 32-bit Linux kernel on 64-bit supervisor mode Palmer Dabbelt
2023-05-18 18:29 ` Arnd Bergmann
2023-05-19 0:38 ` Paul Walmsley
2023-05-19 8:55 ` Arnd Bergmann
2023-05-19 15:31 ` Guo Ren
2023-05-19 16:53 ` Arnd Bergmann
2023-05-19 17:18 ` Palmer Dabbelt
2023-05-20 1:43 ` Guo Ren
2023-05-19 0:14 ` Paul Walmsley [this message]
2023-05-21 12:37 ` Guo Ren
2023-05-19 20:20 ` Arnd Bergmann
2023-05-20 2:53 ` Guo Ren
2023-05-20 10:13 ` Arnd Bergmann
2023-05-20 15:57 ` Guo Ren
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