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[PATCH] riscv: Fix Stage2 SV32 page table walk
From: |
Anup Patel |
Subject: |
[PATCH] riscv: Fix Stage2 SV32 page table walk |
Date: |
Mon, 30 Mar 2020 13:57:24 +0530 |
As-per RISC-V H-Extension v0.5 draft, the Stage2 SV32 page table has
12bits of VPN[1] and 10bits of VPN[0]. The additional 2bits in VPN[1]
is required to handle the 34bit intermediate physical address coming
from Stage1 SV32 page table. The 12bits of VPN[1] implies that Stage2
SV32 level-0 page table will be 16KB in size with total 4096 enteries
where each entry maps 4MB of memory (same as Stage1 SV32 page table).
The get_physical_address() function is broken for Stage2 SV32 level-0
page table because it incorrectly computes output physical address for
Stage2 SV32 level-0 page table entry.
The root cause of the issue is that get_physical_address() uses the
"widened" variable to compute level-0 physical address mapping which
changes level-0 mapping size (instead of 4MB). We should use the
"widened" variable only for computing index of Stage2 SV32 level-0
page table.
Signed-off-by: Anup Patel <address@hidden>
---
target/riscv/cpu_helper.c | 7 +------
1 file changed, 1 insertion(+), 6 deletions(-)
diff --git a/target/riscv/cpu_helper.c b/target/riscv/cpu_helper.c
index 50e13a064f..bc80aa87cf 100644
--- a/target/riscv/cpu_helper.c
+++ b/target/riscv/cpu_helper.c
@@ -559,12 +559,7 @@ restart:
/* for superpage mappings, make a fake leaf PTE for the TLB's
benefit. */
target_ulong vpn = addr >> PGSHIFT;
- if (i == 0) {
- *physical = (ppn | (vpn & ((1L << (ptshift + widened)) - 1)))
<<
- PGSHIFT;
- } else {
- *physical = (ppn | (vpn & ((1L << ptshift) - 1))) << PGSHIFT;
- }
+ *physical = (ppn | (vpn & ((1L << ptshift) - 1))) << PGSHIFT;
/* set permissions on the TLB entry */
if ((pte & PTE_R) || ((pte & PTE_X) && mxr)) {
--
2.17.1
- [PATCH] riscv: Fix Stage2 SV32 page table walk,
Anup Patel <=