[PATCH 5.6 173/177] powerpc/bpf: Enable bpf_probe_read{, str}() on powerpc again

[Greg Kroah-Hartman]

From: Petr Mladek <pmladek@xxxxxxxx>

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@xxxxxxxx>
Signed-off-by: Daniel Borkmann <daniel@xxxxxxxxxxxxx>
Acked-by: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Link: https://lore.kernel.org/lkml/20200527122844.19524-1-pmladek@xxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 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