[ Upstream commit 71fc3621ef ]
RISC-V kernels support 3,4,5-level page tables at runtime by folding
upper levels.
In case of a 3-level page table, PGDIR is folded into P4D which in turn
is folded into PUD: PGDIR_SHIFT value is correctly set to the same value
as PUD_SHIFT, but P4D_SHIFT is not, then any use of P4D_SHIFT will access
invalid address bits (all set to 1).
Fix this by dynamically defining P4D_SHIFT value, like we already do for
PGDIR_SHIFT.
Fixes: d10efa21a9 ("riscv: mm: Control p4d's folding by pgtable_l5_enabled")
Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Reviewed-by: Palmer Dabbelt <palmer@rivosinc.com>
Link: https://lore.kernel.org/r/20221201135128.1482189-2-alexghiti@rivosinc.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
6392d71b4b