riscv: fix overlap of allocated page and PTR_ERR

On riscv32, it is possible for the last page in virtual address space
(0xfffff000) to be allocated. This page overlaps with PTR_ERR, so that
shouldn't happen.

There is already some code to ensure memblock won't allocate the last page.
However, buddy allocator is left unchecked.

Fix this by reserving physical memory that would be mapped at virtual
addresses greater than 0xfffff000.

Reported-by: Björn Töpel <[email protected]>
Closes: https://lore.kernel.org/linux-riscv/[email protected]
Fixes: 76d2a0493a17 ("RISC-V: Init and Halt Code")
Signed-off-by: Nam Cao <[email protected]>
Cc: <[email protected]>
Tested-by: Björn Töpel <[email protected]>
Reviewed-by: Björn Töpel <[email protected]>
Reviewed-by: Mike Rapoport (IBM) <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Palmer Dabbelt <[email protected]>

0 files changed, 0 insertions, 0 deletions