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authorAlexandre Ghiti <alexghiti@rivosinc.com>2023-11-08 08:59:29 +0100
committerPalmer Dabbelt <palmer@rivosinc.com>2023-11-08 07:08:32 -0800
commit629db01c64ff6cea08fc61b52426362689ef8618 (patch)
tree2fb8971e08ada522c0becc8e1c2943536dbdd71f /arch/riscv
parent0bb80ecc33a8fb5a682236443c1e740d5c917d1d (diff)
downloadlwn-629db01c64ff6cea08fc61b52426362689ef8618.tar.gz
lwn-629db01c64ff6cea08fc61b52426362689ef8618.zip
riscv: Don't use PGD entries for the linear mapping
Propagating changes at this level is cumbersome as we need to go through all the page tables when that happens (either when changing the permissions or when splitting the mapping). Note that this prevents the use of 4MB mapping for sv32 and 1GB mapping for sv39 in the linear mapping. Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com> Link: https://lore.kernel.org/r/20231108075930.7157-2-alexghiti@rivosinc.com Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
Diffstat (limited to 'arch/riscv')
-rw-r--r--arch/riscv/mm/init.c12
1 files changed, 6 insertions, 6 deletions
diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c
index 0798bd861dcb..6dc61d3c392f 100644
--- a/arch/riscv/mm/init.c
+++ b/arch/riscv/mm/init.c
@@ -664,16 +664,16 @@ void __init create_pgd_mapping(pgd_t *pgdp,
static uintptr_t __init best_map_size(phys_addr_t pa, uintptr_t va,
phys_addr_t size)
{
- if (!(pa & (PGDIR_SIZE - 1)) && !(va & (PGDIR_SIZE - 1)) && size >= PGDIR_SIZE)
- return PGDIR_SIZE;
-
- if (!(pa & (P4D_SIZE - 1)) && !(va & (P4D_SIZE - 1)) && size >= P4D_SIZE)
+ if (pgtable_l5_enabled &&
+ !(pa & (P4D_SIZE - 1)) && !(va & (P4D_SIZE - 1)) && size >= P4D_SIZE)
return P4D_SIZE;
- if (!(pa & (PUD_SIZE - 1)) && !(va & (PUD_SIZE - 1)) && size >= PUD_SIZE)
+ if (pgtable_l4_enabled &&
+ !(pa & (PUD_SIZE - 1)) && !(va & (PUD_SIZE - 1)) && size >= PUD_SIZE)
return PUD_SIZE;
- if (!(pa & (PMD_SIZE - 1)) && !(va & (PMD_SIZE - 1)) && size >= PMD_SIZE)
+ if (IS_ENABLED(CONFIG_64BIT) &&
+ !(pa & (PMD_SIZE - 1)) && !(va & (PMD_SIZE - 1)) && size >= PMD_SIZE)
return PMD_SIZE;
return PAGE_SIZE;