Re: [PATCH] riscv: correct pt_level name via pgtable_l5/4_enabled
From: Song Shuai
Date: Wed Jul 12 2023 - 21:25:09 EST
在 2023/7/12 21:58, Palmer Dabbelt 写道:
On Tue, 11 Jul 2023 04:14:10 PDT (-0700), alex@xxxxxxxx wrote:
Hi Song,
On 11/07/2023 12:52, Song Shuai wrote:
The pt_level uses CONFIG_PGTABLE_LEVELS to display page table names.
But if downgrading page mode from kernel cmdline in 64BIT, it will
give a wrong name.
Like, using no4lvl for sv39, ptdump named the 1G-mapping as "PUD"
that should be "PGD":
0xffffffd840000000-0xffffffd900000000 0x00000000c0000000
3G PUD D A G . . W R V
So select "P4D/PUD" or "PGD" via pgtable_l5/4_enabled to correct it.
Fixes: 26e7aacb83df ("riscv: Allow to downgrade paging mode from the
command line")
Signed-off-by: Song Shuai <suagrfillet@xxxxxxxxx>
---
arch/riscv/mm/ptdump.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/arch/riscv/mm/ptdump.c b/arch/riscv/mm/ptdump.c
index 20a9f991a6d7..cfdd327981ee 100644
--- a/arch/riscv/mm/ptdump.c
+++ b/arch/riscv/mm/ptdump.c
@@ -384,6 +384,11 @@ static int __init ptdump_init(void)
kernel_ptd_info.base_addr = KERN_VIRT_START;
+#ifdef CONFIG_64BIT
+ pg_level[1].name = pgtable_l5_enabled ? "P4D" : "PGD";
+ pg_level[2].name = pgtable_l4_enabled ? "PUD" : "PGD";
+#endif
You don't need the #ifdef here as pgtable_lX_enabled are always declared.
+
for (i = 0; i < ARRAY_SIZE(pg_level); i++)
for (j = 0; j < ARRAY_SIZE(pte_bits); j++)
pg_level[i].mask |= pte_bits[j].mask;
The Fixes tag is wrong to me, if satp mode is restricted by the hardware
itself (not from the command line), the same problem happens. Maybe that
should be the sv48 introduction patch? Or the sv57? It will be more
cumbersome to backport with the sv48 introduction though as this patch
won't apply as-is.
Sometimes it's easier to base the fix on the original offending commit
and then forward-port it via a merge, I haven't looked at this one to
know for sure though.
Otherwise, you can add:
Reviewed-by: Alexandre Ghiti <alexghiti@xxxxxxxxxxxx>
Thanks.
Song: do you have a v2 that addresses the comments?
Here is V2 :
https://lore.kernel.org/linux-riscv/20230712115740.943324-1-suagrfillet@xxxxxxxxx/
Thanks,
Alex
--
Thanks
Song Shuai