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    Subject[PATCH 5.6 173/177] powerpc/bpf: Enable bpf_probe_read{, str}() on powerpc again
    Date
    From: Petr Mladek <pmladek@suse.com>

    commit d195b1d1d1196681ac4775e0361e9cca70f740c2 upstream.

    The commit 0ebeea8ca8a4d1d453a ("bpf: Restrict bpf_probe_read{, str}() only
    to archs where they work") caused that bpf_probe_read{, str}() functions
    were not longer available on architectures where the same logical address
    might have different content in kernel and user memory mapping. These
    architectures should use probe_read_{user,kernel}_str helpers.

    For backward compatibility, the problematic functions are still available
    on architectures where the user and kernel address spaces are not
    overlapping. This is defined CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE.

    At the moment, these backward compatible functions are enabled only on x86_64,
    arm, and arm64. Let's do it also on powerpc that has the non overlapping
    address space as well.

    Fixes: 0ebeea8ca8a4 ("bpf: Restrict bpf_probe_read{, str}() only to archs where they work")
    Signed-off-by: Petr Mladek <pmladek@suse.com>
    Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
    Acked-by: Michael Ellerman <mpe@ellerman.id.au>
    Link: https://lore.kernel.org/lkml/20200527122844.19524-1-pmladek@suse.com
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

    ---
    arch/powerpc/Kconfig | 1 +
    1 file changed, 1 insertion(+)

    --- a/arch/powerpc/Kconfig
    +++ b/arch/powerpc/Kconfig
    @@ -125,6 +125,7 @@ config PPC
    select ARCH_HAS_MMIOWB if PPC64
    select ARCH_HAS_PHYS_TO_DMA
    select ARCH_HAS_PMEM_API
    + select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
    select ARCH_HAS_PTE_DEVMAP if PPC_BOOK3S_64
    select ARCH_HAS_PTE_SPECIAL
    select ARCH_HAS_MEMBARRIER_CALLBACKS

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