riscv: fix overlap of allocated page and PTR_ERR

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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 <bjorn@kernel.org>
Closes: https://lore.kernel.org/linux-riscv/878r1ibpdn.fsf@all.your.base.are.belong.to.us
Fixes: 76d2a0493a ("RISC-V: Init and Halt Code")
Signed-off-by: Nam Cao <namcao@linutronix.de>
Cc: <stable@vger.kernel.org>
Tested-by: Björn Töpel <bjorn@rivosinc.com>
Reviewed-by: Björn Töpel <bjorn@rivosinc.com>
Reviewed-by: Mike Rapoport (IBM) <rppt@kernel.org>
Link: https://lore.kernel.org/r/20240425115201.3044202-1-namcao@linutronix.de
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>

...

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Nam Cao 2024-04-25 13:52:01 +02:00 • committed by Palmer Dabbelt

parent c3f38fa61a

commit 994af1825a

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arch/riscv/mm/init.c

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