powerpc/32s: automatically allocate BAT in setbat()

If no BAT is given to setbat(), select an available BAT.

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/a212bd36fbd6179e0929b6c727febc35132ac25c.1568665466.git.christophe.leroy@c-s.fr

diff --git a/arch/powerpc/mm/book3s32/mmu.c b/arch/powerpc/mm/book3s32/mmu.c
index 84d5fab..69b2419 100644 (file)
--- a/arch/powerpc/mm/book3s32/mmu.c
+++ b/arch/powerpc/mm/book3s32/mmu.c
@@ -251,9 +251,18 @@ void __init setbat(int index, unsigned long virt, phys_addr_t phys,
 {
        unsigned int bl;
        int wimgxpp;
-       struct ppc_bat *bat = BATS[index];
+       struct ppc_bat *bat;
        unsigned long flags = pgprot_val(prot);
 
+       if (index == -1)
+               index = find_free_bat();
+       if (index == -1) {
+               pr_err("%s: no BAT available for mapping 0x%llx\n", __func__,
+                      (unsigned long long)phys);
+               return;
+       }
+       bat = BATS[index];
+
        if ((flags & _PAGE_NO_CACHE) ||
            (cpu_has_feature(CPU_FTR_NEED_COHERENT) == 0))
                flags &= ~_PAGE_COHERENT;