powerpc/bpf: Enable bpf_probe_read{, str}() on powerpc again

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

diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 924c541..cb042a4 100644 (file)
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -126,6 +126,7 @@ 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