riscv: Do not restrict memory size because of linear mapping on nommu

It makes no sense to restrict physical memory size because of linear
mapping size constraints when there is no linear mapping, so only do
that when mmu is enabled.

Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
Closes: https://lore.kernel.org/linux-riscv/CAMuHMdW0bnJt5GMRtOZGkTiM7GK4UaLJCDMF_Ouq++fnDKi3_A@mail.gmail.com/
Fixes: 3b6564427aea ("riscv: Fix linear mapping checks for non-contiguous memory regions")
Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/20240827065230.145021-1-alexghiti@rivosinc.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>

diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c
index eb0649a61b4c1f3249967f893cf32cfdbadfb2d5..1785782c2e5542e4495b6d502e0e73cc2ff0610c 100644 (file)
--- a/arch/riscv/mm/init.c
+++ b/arch/riscv/mm/init.c
@@ -252,7 +252,7 @@ static void __init setup_bootmem(void)
         * The size of the linear page mapping may restrict the amount of
         * usable RAM.
         */
-       if (IS_ENABLED(CONFIG_64BIT)) {
+       if (IS_ENABLED(CONFIG_64BIT) && IS_ENABLED(CONFIG_MMU)) {
                max_mapped_addr = __pa(PAGE_OFFSET) + KERN_VIRT_SIZE;
                memblock_cap_memory_range(phys_ram_base,
                                          max_mapped_addr - phys_ram_base);