> On 07.01.2019, at 10:13, Lokesh Vutla <lokeshvu...@ti.com> wrote: > > Hi All, > I am trying to enable CONFIG_USE_ARCH_MEMSET/MEMCPY on arm64 platforms > and realized that there is no arm64 specific memcpy available in u-boot. So I > tried porting arm64 specific memcpy from kernel[1]. Memcpy stopped working > after that and observed that if destination address is unaligned then system > hangs. > > After doing a bit more research, understood that unaligned access to device > or strongly ordered memories will fail. And the memory system (even normal > RAM) behaves like strongly ordered memory when the MMU is disabled[2]. In > u-boot MMU is enabled very late after relocation and SPL doesn't enable MMU > at all.
ARMv8 does not allow unaligned accesses in privileged (i.e. except in EL0) modes. > Before I proceed any further wanted to hear from others if anyone have > already tried and have any working solution. If not should we update the > kernel memcpy to use unaligned destination address and use it in u-boot? > > [1] > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/arch/arm64/lib/memcpy.S > [2] > https://community.arm.com/processors/f/discussions/7557/when-and-where-will-the-ldp-instruction-trigger-an-exception > > Thanks and regards, > Lokesh > _______________________________________________ > U-Boot mailing list > U-Boot@lists.denx.de > https://lists.denx.de/listinfo/u-boot _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de https://lists.denx.de/listinfo/u-boot
