arm64: Fix kcore macros after 52-bit virtual addressing fallout

We export the entire kernel address space (i.e. the whole of the TTBR1
address range) via /proc/kcore. The kc_vaddr_to_offset() and
kc_offset_to_vaddr() macros are intended to convert between a kernel
virtual address and its offset relative to the start of the TTBR1
address space.

Prior to commit:

  14c127c957c1c607 ("arm64: mm: Flip kernel VA space")

... the offset was calculated relative to VA_START, which at the time
was the start of the TTBR1 address space. At this time, PAGE_OFFSET
pointed to the high half of the TTBR1 address space where arm64's
linear map lived.

That commit swapped the position of VA_START and PAGE_OFFSET, but
failed to update kc_vaddr_to_offset() or kc_offset_to_vaddr(), so
since then the two macros behave incorrectly.

Note that VA_START was subsequently renamed to PAGE_END in commit:

  77ad4ce69321abbe ("arm64: memory: rename VA_START to PAGE_END")

As the generic implementations of the two macros calculate the offset
relative to PAGE_OFFSET (which is now the start of the TTBR1 address
space), we can delete the arm64 implementation and use those.

Fixes: 14c127c957c1c607 ("arm64: mm: Flip kernel VA space")
Reviewed-by: James Morse <james.morse@arm.com>
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Chris von Recklinghausen <crecklin@redhat.com>
Signed-off-by: Will Deacon <will@kernel.org>

diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h
index 7576df00eb50e8f7109d711846f758369a50eb85..8330810f699e31bd01794f8dc5ad17dd419646f6 100644 (file)
--- a/arch/arm64/include/asm/pgtable.h
+++ b/arch/arm64/include/asm/pgtable.h
@@ -876,9 +876,6 @@ static inline void update_mmu_cache(struct vm_area_struct *vma,
 
 #define update_mmu_cache_pmd(vma, address, pmd) do { } while (0)
 
-#define kc_vaddr_to_offset(v)  ((v) & ~PAGE_END)
-#define kc_offset_to_vaddr(o)  ((o) | PAGE_END)
-
 #ifdef CONFIG_ARM64_PA_BITS_52
 #define phys_to_ttbr(addr)     (((addr) | ((addr) >> 46)) & TTBR_BADDR_MASK_52)
 #else