powerpc/32s: Always map kernel text and rodata with BATs

Since commit 2b279c0348af ("powerpc/32s: Allow mapping with BATs with
DEBUG_PAGEALLOC"), there is no real situation where mapping without
BATs is required.

In order to simplify memory handling, always map kernel text
and rodata with BATs even when "nobats" kernel parameter is set.

Also fix the 603 TLB miss exceptions that don't require anymore
kernel page table if DEBUG_PAGEALLOC.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/da51f7ec632825a4ce43290a904aad61648408c0.1606285013.git.christophe.leroy@csgroup.eu

diff --git a/arch/powerpc/kernel/head_book3s_32.S b/arch/powerpc/kernel/head_book3s_32.S
index bbcc84c..757aed0 100644 (file)
--- a/arch/powerpc/kernel/head_book3s_32.S
+++ b/arch/powerpc/kernel/head_book3s_32.S
@@ -457,13 +457,13 @@ InstructionTLBMiss:
  */
        /* Get PTE (linux-style) and check access */
        mfspr   r3,SPRN_IMISS
-#if defined(CONFIG_MODULES) || defined(CONFIG_DEBUG_PAGEALLOC)
+#ifdef CONFIG_MODULES
        lis     r1, TASK_SIZE@h         /* check if kernel address */
        cmplw   0,r1,r3
 #endif
        mfspr   r2, SPRN_SPRG_PGDIR
        li      r1,_PAGE_PRESENT | _PAGE_ACCESSED | _PAGE_EXEC
-#if defined(CONFIG_MODULES) || defined(CONFIG_DEBUG_PAGEALLOC)
+#ifdef CONFIG_MODULES
        bgt-    112f
        lis     r2, (swapper_pg_dir - PAGE_OFFSET)@ha   /* if kernel address, use */
        addi    r2, r2, (swapper_pg_dir - PAGE_OFFSET)@l        /* kernel page table */

diff --git a/arch/powerpc/mm/book3s32/mmu.c b/arch/powerpc/mm/book3s32/mmu.c
index a59e7ec..5c60dca 100644 (file)
--- a/arch/powerpc/mm/book3s32/mmu.c
+++ b/arch/powerpc/mm/book3s32/mmu.c
@@ -157,11 +157,9 @@ unsigned long __init mmu_mapin_ram(unsigned long base, unsigned long top)
        unsigned long done;
        unsigned long border = (unsigned long)__init_begin - PAGE_OFFSET;
 
-       if (__map_without_bats) {
-               pr_debug("RAM mapped without BATs\n");
-               return base;
-       }
-       if (debug_pagealloc_enabled()) {
+
+       if (debug_pagealloc_enabled() || __map_without_bats) {
+               pr_debug_once("Read-Write memory mapped without BATs\n");
                if (base >= border)
                        return base;
                if (top >= border)