arm64: implement TASK_SIZE_OF

commit fa2ec3ea10bd377f9d55772b1dab65178425a1a2 upstream.

include/linux/sched.h implements TASK_SIZE_OF as TASK_SIZE if it
is not set by the architecture headers.  TASK_SIZE uses the
current task to determine the size of the virtual address space.
On a 64-bit kernel this will cause reading /proc/pid/pagemap of a
64-bit process from a 32-bit process to return EOF when it reads
past 0xffffffff.

Implement TASK_SIZE_OF exactly the same as TASK_SIZE with
test_tsk_thread_flag instead of test_thread_flag.

Signed-off-by: Colin Cross <ccross@android.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/arch/arm64/include/asm/memory.h b/arch/arm64/include/asm/memory.h
index 9dc5dc3..11ad59b 100644 (file)
--- a/arch/arm64/include/asm/memory.h
+++ b/arch/arm64/include/asm/memory.h
@@ -56,6 +56,8 @@
 #define TASK_SIZE_32           UL(0x100000000)
 #define TASK_SIZE              (test_thread_flag(TIF_32BIT) ? \
                                TASK_SIZE_32 : TASK_SIZE_64)
+#define TASK_SIZE_OF(tsk)      (test_tsk_thread_flag(tsk, TIF_32BIT) ? \
+                               TASK_SIZE_32 : TASK_SIZE_64)
 #else
 #define TASK_SIZE              TASK_SIZE_64
 #endif /* CONFIG_COMPAT */