This is a note to let you know that I've just added the patch titled
riscv: Fix P4D_SHIFT definition for 3-level page table mode
to the 6.1-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
riscv-fix-p4d_shift-definition-for-3-level-page-tabl.patch
and it can be found in the queue-6.1 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 1677c97670044f94e648e061b909efccd31f4312
Author: Alexandre Ghiti <alexghiti@xxxxxxxxxxxx>
Date: Thu Dec 1 14:51:28 2022 +0100
riscv: Fix P4D_SHIFT definition for 3-level page table mode
[ Upstream commit 71fc3621efc38ace9640ee6a0db3300900689592 ]
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 <alexghiti@xxxxxxxxxxxx>
Reviewed-by: Palmer Dabbelt <palmer@xxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20221201135128.1482189-2-alexghiti@xxxxxxxxxxxx
Signed-off-by: Palmer Dabbelt <palmer@xxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/arch/riscv/include/asm/pgtable-64.h b/arch/riscv/include/asm/pgtable-64.h
index dc42375c2357..42a042c0e13e 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))
