From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pg1-f194.google.com ([209.85.215.194]:39321 "EHLO mail-pg1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726056AbfBMV5x (ORCPT ); Wed, 13 Feb 2019 16:57:53 -0500 Received: by mail-pg1-f194.google.com with SMTP id r11so1802506pgp.6 for ; Wed, 13 Feb 2019 13:57:52 -0800 (PST) Date: Wed, 13 Feb 2019 13:57:50 -0800 (PST) Subject: Re: [PATCH 1/2] asm-generic/io: Pass result on inX() accessor to __io_par() In-Reply-To: From: Palmer Dabbelt Message-ID: Mime-Version: 1.0 (MHng) Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Sender: linux-arch-owner@vger.kernel.org List-ID: To: Arnd Bergmann Cc: Will Deacon , linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org, andrew.murray@arm.com, catalin.marinas@arm.com, linux-riscv@lists.infradead.org, aou@eecs.berkeley.edu Message-ID: <20190213215750.UlFQI9tYZXEnpPgUcY8oWNpoz1hVmm9rH0GJdP3eYgM@z> On Wed, 13 Feb 2019 12:59:28 PST (-0800), Arnd Bergmann wrote: > On Wed, Feb 13, 2019 at 6:46 PM Will Deacon wrote: > >> On Tue, Feb 12, 2019 at 12:55:17PM +0100, Arnd Bergmann wrote: >> >> > For all I can see, this should not conflict with the usage of the >> > same macros on RISC-V, though it does make add a significant >> > difference, so I'd like to see an Ack from the RISC-V folks as >> > well (added to Cc), or possibly a change to arch/riscv/include/asm/io.h >> > to do a corresponding change. Thanks, the original patches didn't make it through my filters. >> There's already a comment in that header which says that the accesses are >> ordered wrt timer reads, so I don't think anything needs to change there. >> For consistency with the macro arguments, I could augment their __io_par to >> take the read value as an unused argument, if that's what you mean? FWIW, we don't really have a way to mandate this in the ISA yet as there's no formal model for either CSR orderings or the IO memory space. > Yes, that's what I meant, I should have been clearer there. That sounds reasonable to me. It looks like we can also go ahead and delete a bunch of arch/riscv/include/asm/io.h now that this stuff is in asm-generic, which would cause us to actually start using these things. I didn't know this had all been moved to asm-generic otherwise I would have cleaned this up earlier. I think this should do it, but this does bring up a bit of an issue: the RISC-V versions of reads and friends put barriers outside the loop, while the asm-generic version don't. What are these actually supposed to do? Either way that resolves, feel free to consider something like diff --git a/arch/riscv/include/asm/io.h b/arch/riscv/include/asm/io.h index b269451e7e85..378975f180a7 100644 --- a/arch/riscv/include/asm/io.h +++ b/arch/riscv/include/asm/io.h @@ -198,20 +198,20 @@ static inline u64 __raw_readq(const volatile void __iomem *addr) * writes. */ #define __io_pbr() __asm__ __volatile__ ("fence io,i" : : : "memory"); -#define __io_par() __asm__ __volatile__ ("fence i,ior" : : : "memory"); +#define __io_par(v) __asm__ __volatile__ ("fence i,ior" : : : "memory"); #define __io_pbw() __asm__ __volatile__ ("fence iow,o" : : : "memory"); #define __io_paw() __asm__ __volatile__ ("fence o,io" : : : "memory"); -#define inb(c) ({ u8 __v; __io_pbr(); __v = readb_cpu((void*)(PCI_IOBASE + (c))); __io_par(); __v; }) -#define inw(c) ({ u16 __v; __io_pbr(); __v = readw_cpu((void*)(PCI_IOBASE + (c))); __io_par(); __v; }) -#define inl(c) ({ u32 __v; __io_pbr(); __v = readl_cpu((void*)(PCI_IOBASE + (c))); __io_par(); __v; }) +#define inb(c) ({ u8 __v; __io_pbr(); __v = readb_cpu((void*)(PCI_IOBASE + (c))); __io_par(__v); __v; }) +#define inw(c) ({ u16 __v; __io_pbr(); __v = readw_cpu((void*)(PCI_IOBASE + (c))); __io_par(__v); __v; }) +#define inl(c) ({ u32 __v; __io_pbr(); __v = readl_cpu((void*)(PCI_IOBASE + (c))); __io_par(__v); __v; }) #define outb(v,c) ({ __io_pbw(); writeb_cpu((v),(void*)(PCI_IOBASE + (c))); __io_paw(); }) #define outw(v,c) ({ __io_pbw(); writew_cpu((v),(void*)(PCI_IOBASE + (c))); __io_paw(); }) #define outl(v,c) ({ __io_pbw(); writel_cpu((v),(void*)(PCI_IOBASE + (c))); __io_paw(); }) #ifdef CONFIG_64BIT -#define inq(c) ({ u64 __v; __io_pbr(); __v = readq_cpu((void*)(c)); __io_par(); __v; }) +#define inq(c) ({ u64 __v; __io_pbr(); __v = readq_cpu((void*)(c)); __io_par(__v); __v; }) #define outq(v,c) ({ __io_pbw(); writeq_cpu((v),(void*)(c)); __io_paw(); }) #endif @@ -261,9 +261,9 @@ __io_reads_ins(reads, u32, l, __io_br(), __io_ar()) #define readsw(addr, buffer, count) __readsw(addr, buffer, count) #define readsl(addr, buffer, count) __readsl(addr, buffer, count) -__io_reads_ins(ins, u8, b, __io_pbr(), __io_par()) -__io_reads_ins(ins, u16, w, __io_pbr(), __io_par()) -__io_reads_ins(ins, u32, l, __io_pbr(), __io_par()) +__io_reads_ins(ins, u8, b, __io_pbr(), __io_par(addr)) +__io_reads_ins(ins, u16, w, __io_pbr(), __io_par(addr)) +__io_reads_ins(ins, u32, l, __io_pbr(), __io_par(addr)) #define insb(addr, buffer, count) __insb((void __iomem *)(long)addr, buffer, count) #define insw(addr, buffer, count) __insw((void __iomem *)(long)addr, buffer, count) #define insl(addr, buffer, count) __insl((void __iomem *)(long)addr, buffer, count) as Revewied-by: Palmer Dabbelt when included along with the other diff. That way we can at least keep the macro signatures matching, the cleanup can come later... Thanks!