Messages in this thread | | | Date | Sun, 24 Apr 2022 08:28:19 -0700 | From | Guenter Roeck <> | Subject | Re: [PATCH v2 00/48] ARM: PXA multiplatform support |
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On 4/24/22 01:52, Arnd Bergmann wrote: > On Sun, Apr 24, 2022 at 4:09 AM Guenter Roeck <linux@roeck-us.net> wrote: >> On 4/23/22 12:55, Arnd Bergmann wrote: >>> On Sat, Apr 23, 2022 at 1:41 AM Guenter Roeck <linux@roeck-us.net> wrote: >>>> On Sat, Apr 23, 2022 at 12:04:31AM +0200, Arnd Bergmann wrote: >>> >>> Odd, I can't reproduce this at all. Do you get any console output at >>> all for this? >>> >>> Is this the plain omap1_defconfig, or something else? >>> >> >> No, it is my own sx1 specific configuration. >> >> https://github.com/groeck/linux-build-test/blob/master/rootfs/arm/qemu_sx1_defconfig >> >> I don't recall where I got it from but ... > > Ok, that explains it, thanks! > > I fixed all the defconfig files that come with the kernel, but for your own > ones you have to add > > # CONFIG_ARCH_MULTI_V7 is not set > > into the defconfig file, otherwise the multiplatform target defaults to > an ARMv7 instead of ARMv5 build. For an OMAP15xx as in the SX1, > you also need to enable CONFIG_ARCH_MULTI_V4T. > > This is slightly unfortunate, but I don't see any way to avoid it, and the > modified defconfig will still work fine with older kernel trees. >
Yes, that works. I changed it in my configuration.
>>> One thing I keep having to apply myself is this snippet: >>> >>> diff --git a/arch/arm/mm/proc-arm925.S b/arch/arm/mm/proc-arm925.S >>> index 0bfad62ea858..87c695703580 100644 >>> --- a/arch/arm/mm/proc-arm925.S >>> +++ b/arch/arm/mm/proc-arm925.S >>> @@ -441,7 +441,6 @@ __arm925_setup: >>> >>> #ifdef CONFIG_CPU_DCACHE_WRITETHROUGH >>> mov r0, #4 @ disable write-back >>> on caches explicitly >>> - mcr p15, 7, r0, c15, c0, 0 >>> #endif >> >> it does not have CONFIG_CPU_DCACHE_WRITETHROUGH enabled. > > Maybe it was disabled explicitly for the sx1_defconfig because of this > bug. I would think that this is required for actual sx1 hardware because the > option is default-enabled for ARM925T, and that CPU core is exclusively > used in OMAP15xx. >
That looks like a bug in qemu. ARM925T instruction support is limited to V4T instructions. qemu doesn't have explicit 5T support. It is either V4T or V5.
Guenter
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