powerpc/603: Fix boot failure with DEBUG_PAGEALLOC and KFENCE

Allthough kernel text is always mapped with BATs, we still have
inittext mapped with pages, so TLB miss handling is required
when CONFIG_DEBUG_PAGEALLOC or CONFIG_KFENCE is set.

The final solution should be to set a BAT that also maps inittext
but that BAT then needs to be cleared at end of init, and it will
require more changes to be able to do it properly.

As DEBUG_PAGEALLOC or KFENCE are debugging, performance is not a big
deal so let's fix it simply for now to enable easy stable application.

Fixes: 035b19a15a98 ("powerpc/32s: Always map kernel text and rodata with BATs")
Cc: stable@vger.kernel.org # v5.11+
Reported-by: Maxime Bizon <mbizon@freebox.fr>
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/aea33b4813a26bdb9378b5f273f00bd5d4abe240.1638857364.git.christophe.leroy@csgroup.eu

diff --git a/arch/powerpc/kernel/head_book3s_32.S b/arch/powerpc/kernel/head_book3s_32.S
index fa84744d6b2486edbfc47613658e2b0a0a8f2564..b876ef8c70a7dac50960e3a0d65b69bcbd6707e1 100644 (file)
--- a/arch/powerpc/kernel/head_book3s_32.S
+++ b/arch/powerpc/kernel/head_book3s_32.S
@@ -421,14 +421,14 @@ InstructionTLBMiss:
  */
        /* Get PTE (linux-style) and check access */
        mfspr   r3,SPRN_IMISS
-#ifdef CONFIG_MODULES
+#if defined(CONFIG_MODULES) || defined(CONFIG_DEBUG_PAGEALLOC) || defined(CONFIG_KFENCE)
        lis     r1, TASK_SIZE@h         /* check if kernel address */
        cmplw   0,r1,r3
 #endif
        mfspr   r2, SPRN_SDR1
        li      r1,_PAGE_PRESENT | _PAGE_ACCESSED | _PAGE_EXEC | _PAGE_USER
        rlwinm  r2, r2, 28, 0xfffff000
-#ifdef CONFIG_MODULES
+#if defined(CONFIG_MODULES) || defined(CONFIG_DEBUG_PAGEALLOC) || defined(CONFIG_KFENCE)
        bgt-    112f
        lis     r2, (swapper_pg_dir - PAGE_OFFSET)@ha   /* if kernel address, use */
        li      r1,_PAGE_PRESENT | _PAGE_ACCESSED | _PAGE_EXEC