From 71fc3621efc38ace9640ee6a0db3300900689592 Mon Sep 17 00:00:00 2001 From: Alexandre Ghiti Date: Thu, 1 Dec 2022 14:51:28 +0100 Subject: [PATCH] riscv: Fix P4D_SHIFT definition for 3-level page table mode 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: d10efa21a937 ("riscv: mm: Control p4d's folding by pgtable_l5_enabled") Signed-off-by: Alexandre Ghiti Reviewed-by: Palmer Dabbelt Link: https://lore.kernel.org/r/20221201135128.1482189-2-alexghiti@rivosinc.com Signed-off-by: Palmer Dabbelt --- arch/riscv/include/asm/pgtable-64.h | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/arch/riscv/include/asm/pgtable-64.h b/arch/riscv/include/asm/pgtable-64.h index dc42375c..42a042c 100644 --- a/arch/riscv/include/asm/pgtable-64.h +++ b/arch/riscv/include/asm/pgtable-64.h @@ -25,7 +25,11 @@ extern bool pgtable_l5_enabled; #define PGDIR_MASK (~(PGDIR_SIZE - 1)) /* p4d is folded into pgd in case of 4-level page table */ -#define P4D_SHIFT 39 +#define P4D_SHIFT_L3 30 +#define P4D_SHIFT_L4 39 +#define P4D_SHIFT_L5 39 +#define P4D_SHIFT (pgtable_l5_enabled ? P4D_SHIFT_L5 : \ + (pgtable_l4_enabled ? P4D_SHIFT_L4 : P4D_SHIFT_L3)) #define P4D_SIZE (_AC(1, UL) << P4D_SHIFT) #define P4D_MASK (~(P4D_SIZE - 1)) -- 2.7.4