[PATCH 3/3] powerpc/32: Remove __map_without_ltlbs

From: Christophe Leroy
Date: Tue Jun 14 2022 - 06:33:03 EST


__map_without_ltlbs is used only for 40x, and only when
STRICT_KERNEL_RWX, KFENCE or DEBUG_PAGEALLOC is active.

Do the verification directly in 40x version of mmu_mapin_ram()
and remove __map_without_ltlbs from core ppc32.

Signed-off-by: Christophe Leroy <christophe.leroy@xxxxxxxxxx>
---
arch/powerpc/mm/init_32.c | 23 -----------------------
arch/powerpc/mm/nohash/40x.c | 9 +++++++--
2 files changed, 7 insertions(+), 25 deletions(-)

diff --git a/arch/powerpc/mm/init_32.c b/arch/powerpc/mm/init_32.c
index 6f2e6210c273..62d9af6606cd 100644
--- a/arch/powerpc/mm/init_32.c
+++ b/arch/powerpc/mm/init_32.c
@@ -69,29 +69,9 @@ EXPORT_SYMBOL(agp_special_page);

void MMU_init(void);

-int __map_without_ltlbs;
-
/* max amount of low RAM to map in */
unsigned long __max_low_memory = MAX_LOW_MEM;

-/*
- * Check for command-line options that affect what MMU_init will do.
- */
-static void __init MMU_setup(void)
-{
- if (IS_ENABLED(CONFIG_PPC_8xx))
- return;
-
- if (IS_ENABLED(CONFIG_KFENCE))
- __map_without_ltlbs = 1;
-
- if (debug_pagealloc_enabled())
- __map_without_ltlbs = 1;
-
- if (strict_kernel_rwx_enabled())
- __map_without_ltlbs = 1;
-}
-
/*
* MMU_init sets up the basic memory mappings for the kernel,
* including both RAM and possibly some I/O regions,
@@ -102,9 +82,6 @@ void __init MMU_init(void)
if (ppc_md.progress)
ppc_md.progress("MMU:enter", 0x111);

- /* parse args from command line */
- MMU_setup();
-
/*
* Reserve gigantic pages for hugetlb. This MUST occur before
* lowmem_end_addr is initialized below.
diff --git a/arch/powerpc/mm/nohash/40x.c b/arch/powerpc/mm/nohash/40x.c
index b32e465a3d52..3684d6e570fb 100644
--- a/arch/powerpc/mm/nohash/40x.c
+++ b/arch/powerpc/mm/nohash/40x.c
@@ -43,7 +43,6 @@

#include <mm/mmu_decl.h>

-extern int __map_without_ltlbs;
/*
* MMU_init_hw does the chip-specific initialization of the MMU hardware.
*/
@@ -94,7 +93,13 @@ unsigned long __init mmu_mapin_ram(unsigned long base, unsigned long top)
p = 0;
s = total_lowmem;

- if (__map_without_ltlbs)
+ if (IS_ENABLED(CONFIG_KFENCE))
+ return 0;
+
+ if (debug_pagealloc_enabled())
+ return 0;
+
+ if (strict_kernel_rwx_enabled())
return 0;

while (s >= LARGE_PAGE_SIZE_16M) {
--
2.36.1