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Message-Id: <b51b96090138aba1920d2cf7c0e0e348667f9a69.1566564560.git.christophe.leroy@c-s.fr>
From:   Christophe Leroy <christophe.leroy@c-s.fr>
Subject: [PATCH 1/2] powerpc/32s: automatically allocate BAT in setbat()
To:     Benjamin Herrenschmidt <benh@kernel.crashing.org>,
        Paul Mackerras <paulus@samba.org>,
        Michael Ellerman <mpe@ellerman.id.au>, oss@buserror.net,
        galak@kernel.crashing.org
Cc:     linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org
Date:   Fri, 23 Aug 2019 12:50:17 +0000 (UTC)
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

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

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
---
 arch/powerpc/mm/book3s32/mmu.c | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/mm/book3s32/mmu.c b/arch/powerpc/mm/book3s32/mmu.c
index 50a1991d257f..5f08b93ecffd 100644
--- 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;
-- 
2.13.3