[PATCH v2 44/45] powerpc/32s: Allow mapping with BATs with DEBUG_PAGEALLOC

[Christophe Leroy]

DEBUG_PAGEALLOC only manages RW data.

Text and RO data can still be mapped with BATs.

In order to map with BATs, also enforce data alignment. Set
by default to 256M which is a good compromise for keeping
enough BATs for also KASAN and IMMR.

Signed-off-by: Christophe Leroy <christophe.le...@csgroup.eu>
---
 arch/powerpc/Kconfig           | 1 +
 arch/powerpc/mm/book3s32/mmu.c | 6 ++++++
 arch/powerpc/mm/init_32.c      | 5 ++---
 3 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 9d94e8b178d8..5c1fcfe9be74 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -796,6 +796,7 @@ config DATA_SHIFT
        range 17 28 if (STRICT_KERNEL_RWX || DEBUG_PAGEALLOC) && PPC_BOOK3S_32
        range 19 23 if (STRICT_KERNEL_RWX || DEBUG_PAGEALLOC) && PPC_8xx
        default 22 if STRICT_KERNEL_RWX && PPC_BOOK3S_32
+       default 18 if DEBUG_PAGEALLOC && PPC_BOOK3S_32
        default 23 if STRICT_KERNEL_RWX && PPC_8xx
        default 23 if DEBUG_PAGEALLOC && PPC_8xx && PIN_TLB_DATA
        default 19 if DEBUG_PAGEALLOC && PPC_8xx
diff --git a/arch/powerpc/mm/book3s32/mmu.c b/arch/powerpc/mm/book3s32/mmu.c
index a9b2cbc74797..a6dcc708eee3 100644
--- a/arch/powerpc/mm/book3s32/mmu.c
+++ b/arch/powerpc/mm/book3s32/mmu.c
@@ -170,6 +170,12 @@ unsigned long __init mmu_mapin_ram(unsigned long base, 
unsigned long top)
                pr_debug("RAM mapped without BATs\n");
                return base;
        }
+       if (debug_pagealloc_enabled()) {
+               if (base >= border)
+                       return base;
+               if (top >= border)
+                       top = border;
+       }
 
        if (!strict_kernel_rwx_enabled() || base >= border || top <= border)
                return __mmu_mapin_ram(base, top);
diff --git a/arch/powerpc/mm/init_32.c b/arch/powerpc/mm/init_32.c
index 8977a7c2543d..36c39bd37256 100644
--- a/arch/powerpc/mm/init_32.c
+++ b/arch/powerpc/mm/init_32.c
@@ -99,10 +99,9 @@ static void __init MMU_setup(void)
        if (IS_ENABLED(CONFIG_PPC_8xx))
                return;
 
-       if (debug_pagealloc_enabled()) {
-               __map_without_bats = 1;
+       if (debug_pagealloc_enabled())
                __map_without_ltlbs = 1;
-       }
+
        if (strict_kernel_rwx_enabled())
                __map_without_ltlbs = 1;
 }
-- 
2.25.0