[SRU][K][PATCH 1/1] UBUNTU: SAUCE: riscv: mm: Force disable sv57

[Emil Renner Berthing]

From: Alexandre Ghiti <alexandre.ghiti at canonical.com>

BugLink: https://launchpad.net/bugs/1991790

The Kinetic userspace is not yet ready for 5-level page tables. Eg. Go
programs use too many of the higher bits for pointer tagging.
So force disable sv57 even on Qemu which advertices support for it.

Signed-off-by: Alexandre Ghiti <alexandre.ghiti at canonical.com>
Signed-off-by: Emil Renner Berthing <emil.renner.berthing at canonical.com>
---
 arch/riscv/mm/init.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c
index 2c4a64e97aec..18a0c70ed313 100644
--- a/arch/riscv/mm/init.c
+++ b/arch/riscv/mm/init.c
@@ -775,6 +775,10 @@ static __init void set_satp_mode(void)
 		disable_pgtable_l4();
 	}
 
+	/* UBUNTU: Force disable sv57 and fallback to sv48 */
+	if (pgtable_l5_enabled)
+		disable_pgtable_l5();
+
 	memset(early_pg_dir, 0, PAGE_SIZE);
 	memset(early_p4d, 0, PAGE_SIZE);
 	memset(early_pud, 0, PAGE_SIZE);
-- 
2.37.2