Messages in this thread | | | Date | Mon, 22 Nov 2021 21:13:30 +0530 | Subject | Re: [PATCHv4 2/2] arm64/io: Add a header for mmio access instrumentation | From | Sai Prakash Ranjan <> |
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On 11/22/2021 9:05 PM, Arnd Bergmann wrote: > On Mon, Nov 22, 2021 at 3:59 PM Sai Prakash Ranjan > <quic_saipraka@quicinc.com> wrote: >>>> And if we do move this instrumentation to asm-generic/io.h, how will >>>> that be executed since >>>> the arch specifc read{b,w,l,q} overrides this generic version? >>> As I understand it, your version also requires architecture specific >>> changes, so that would be the same: it only works for architectures >>> that get the definition of readl()/readl_relaxed()/inl()/... from >>> include/asm-generic/io.h and only override the __raw version. Arnd >> Sorry, I didn't get this part, so I am trying this on ARM64: >> >> arm64/include/asm/io.h has read{b,l,w,q} defined. >> include/asm-generic/io.h has below: >> #ifndef readl >> #define readl readl >> static inline u32 readl(const volatile void __iomem *addr) >> >> and we include asm-generic/io.h in arm64/include/asm/io.h at the end >> after the definitions for arm64 mmio accesors. >> So arch implementation here overrides generic ones as I see it, am I >> missing something? I even confirmed this >> with some trace_printk to generic and arch specific definitions of readl >> and I see arch specific ones being called. > Ah, you are right that the arm64 version currently has custom definitions > of the high-level interfaces. These predate the introduction of the > __io_{p,}{b,a}{r,w} macros and are currently only used on risc-v. > > I think in this case you should start by changing arm64 to use the > generic readl() etc definitions, by removing the extra definitions and > using > > #define __io_ar(v) __iormb(__v) > #define __io_bw() dma_wmb() > >
Sure, will do that.
Thanks, Sai
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