From: Alexandre Ghiti alexghiti@rivosinc.com
commit c3bcc65d4d2e8292c435322cbc34c318d06b8b6c upstream.
So that we do not end up mapping the whole linear mapping using 4K pages, which is slow at boot time, and also very likely at runtime.
So make sure we align the start of DRAM on a PMD boundary.
Signed-off-by: Alexandre Ghiti alexghiti@rivosinc.com Reported-by: Song Shuai suagrfillet@gmail.com Fixes: 3335068f8721 ("riscv: Use PUD/P4D/PGD pages for the linear mapping") Tested-by: Song Shuai suagrfillet@gmail.com Link: https://lore.kernel.org/r/20230704121837.248976-1-alexghiti@rivosinc.com Cc: stable@vger.kernel.org Signed-off-by: Palmer Dabbelt palmer@rivosinc.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/riscv/mm/init.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c index 9ce504737d18..ad845c3aa9b2 100644 --- a/arch/riscv/mm/init.c +++ b/arch/riscv/mm/init.c @@ -214,8 +214,13 @@ static void __init setup_bootmem(void) memblock_reserve(vmlinux_start, vmlinux_end - vmlinux_start);
phys_ram_end = memblock_end_of_DRAM(); + + /* + * Make sure we align the start of the memory on a PMD boundary so that + * at worst, we map the linear mapping with PMD mappings. + */ if (!IS_ENABLED(CONFIG_XIP_KERNEL)) - phys_ram_base = memblock_start_of_DRAM(); + phys_ram_base = memblock_start_of_DRAM() & PMD_MASK;
/* * In 64-bit, any use of __va/__pa before this point is wrong as we