xtensa: nommu support
Add support for !CONFIG_MMU setups.
Signed-off-by: Johannes Weiner <jw@emlix.com>
Signed-off-by: Chris Zankel <chris@zankel.net>
diff --git a/arch/xtensa/include/asm/cacheflush.h b/arch/xtensa/include/asm/cacheflush.h
index 94c4c53..8fc1c0c 100644
--- a/arch/xtensa/include/asm/cacheflush.h
+++ b/arch/xtensa/include/asm/cacheflush.h
@@ -65,13 +65,17 @@
# define __flush_invalidate_dcache_range(p,s) __invalidate_dcache_range(p,s)
#endif
-#if (DCACHE_WAY_SIZE > PAGE_SIZE)
+#if defined(CONFIG_MMU) && (DCACHE_WAY_SIZE > PAGE_SIZE)
extern void __flush_invalidate_dcache_page_alias(unsigned long, unsigned long);
+#else
+static inline void __flush_invalidate_dcache_page_alias(unsigned long virt,
+ unsigned long phys) { }
#endif
-#if (ICACHE_WAY_SIZE > PAGE_SIZE)
+#if defined(CONFIG_MMU) && (ICACHE_WAY_SIZE > PAGE_SIZE)
extern void __invalidate_icache_page_alias(unsigned long, unsigned long);
#else
-# define __invalidate_icache_page_alias(v,p) do { } while(0)
+static inline void __invalidate_icache_page_alias(unsigned long virt,
+ unsigned long phys) { }
#endif
/*
diff --git a/arch/xtensa/include/asm/dma.h b/arch/xtensa/include/asm/dma.h
index e30f3ab..137ca39 100644
--- a/arch/xtensa/include/asm/dma.h
+++ b/arch/xtensa/include/asm/dma.h
@@ -44,8 +44,9 @@
* the value desired).
*/
+#ifndef MAX_DMA_ADDRESS
#define MAX_DMA_ADDRESS (PAGE_OFFSET + XCHAL_KIO_SIZE - 1)
-
+#endif
/* Reserve and release a DMA channel */
extern int request_dma(unsigned int dmanr, const char * device_id);
diff --git a/arch/xtensa/include/asm/io.h b/arch/xtensa/include/asm/io.h
index 07b7299..d04cd3a 100644
--- a/arch/xtensa/include/asm/io.h
+++ b/arch/xtensa/include/asm/io.h
@@ -69,21 +69,28 @@
static inline void *ioremap(unsigned long offset, unsigned long size)
{
+#ifdef CONFIG_MMU
if (offset >= XCHAL_KIO_PADDR
&& offset < XCHAL_KIO_PADDR + XCHAL_KIO_SIZE)
return (void*)(offset-XCHAL_KIO_PADDR+XCHAL_KIO_BYPASS_VADDR);
-
else
BUG();
+#else
+ return (void *)offset;
+#endif
}
static inline void *ioremap_nocache(unsigned long offset, unsigned long size)
{
+#ifdef CONFIG_MMU
if (offset >= XCHAL_KIO_PADDR
&& offset < XCHAL_KIO_PADDR + XCHAL_KIO_SIZE)
return (void*)(offset-XCHAL_KIO_PADDR+XCHAL_KIO_CACHED_VADDR);
else
BUG();
+#else
+ return (void *)offset;
+#endif
}
static inline void iounmap(void *addr)
diff --git a/arch/xtensa/include/asm/mmu.h b/arch/xtensa/include/asm/mmu.h
index 44c5bb0..04890d6 100644
--- a/arch/xtensa/include/asm/mmu.h
+++ b/arch/xtensa/include/asm/mmu.h
@@ -11,7 +11,12 @@
#ifndef _XTENSA_MMU_H
#define _XTENSA_MMU_H
+#ifndef CONFIG_MMU
+#include <asm/nommu.h>
+#else
+
/* Default "unsigned long" context */
typedef unsigned long mm_context_t;
+#endif /* CONFIG_MMU */
#endif /* _XTENSA_MMU_H */
diff --git a/arch/xtensa/include/asm/mmu_context.h b/arch/xtensa/include/asm/mmu_context.h
index 6b7c19c..dbd8731 100644
--- a/arch/xtensa/include/asm/mmu_context.h
+++ b/arch/xtensa/include/asm/mmu_context.h
@@ -13,6 +13,10 @@
#ifndef _XTENSA_MMU_CONTEXT_H
#define _XTENSA_MMU_CONTEXT_H
+#ifndef CONFIG_MMU
+#include <asm/nommu_context.h>
+#else
+
#include <linux/stringify.h>
#include <linux/sched.h>
@@ -133,4 +137,5 @@
}
+#endif /* CONFIG_MMU */
#endif /* _XTENSA_MMU_CONTEXT_H */
diff --git a/arch/xtensa/include/asm/nommu.h b/arch/xtensa/include/asm/nommu.h
new file mode 100644
index 0000000..dce2c43
--- /dev/null
+++ b/arch/xtensa/include/asm/nommu.h
@@ -0,0 +1,3 @@
+typedef struct {
+ unsigned long end_brk;
+} mm_context_t;
diff --git a/arch/xtensa/include/asm/nommu_context.h b/arch/xtensa/include/asm/nommu_context.h
new file mode 100644
index 0000000..599e7a2
--- /dev/null
+++ b/arch/xtensa/include/asm/nommu_context.h
@@ -0,0 +1,25 @@
+static inline void enter_lazy_tlb(struct mm_struct *mm, struct task_struct *tsk)
+{
+}
+
+static inline int init_new_context(struct task_struct *tsk, struct mm_struct *mm)
+{
+ return 0;
+}
+
+static inline void destroy_context(struct mm_struct *mm)
+{
+}
+
+static inline void activate_mm(struct mm_struct *prev, struct mm_struct *next)
+{
+}
+
+static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next,
+ struct task_struct *tsk)
+{
+}
+
+static inline void deactivate_mm(struct task_struct *tsk, struct mm_struct *mm)
+{
+}
diff --git a/arch/xtensa/include/asm/page.h b/arch/xtensa/include/asm/page.h
index a5a5d33..17e0c53 100644
--- a/arch/xtensa/include/asm/page.h
+++ b/arch/xtensa/include/asm/page.h
@@ -33,8 +33,14 @@
#define PAGE_SIZE (__XTENSA_UL_CONST(1) << PAGE_SHIFT)
#define PAGE_MASK (~(PAGE_SIZE-1))
+#ifdef CONFIG_MMU
#define PAGE_OFFSET XCHAL_KSEG_CACHED_VADDR
#define MAX_MEM_PFN XCHAL_KSEG_SIZE
+#else
+#define PAGE_OFFSET 0
+#define MAX_MEM_PFN (PLATFORM_DEFAULT_MEM_START + PLATFORM_DEFAULT_MEM_SIZE)
+#endif
+
#define PGTABLE_START 0x80000000
/*
@@ -165,8 +171,9 @@
#define virt_addr_valid(kaddr) pfn_valid(__pa(kaddr) >> PAGE_SHIFT)
#define page_to_phys(page) (page_to_pfn(page) << PAGE_SHIFT)
+#ifdef CONFIG_MMU
#define WANT_PAGE_VIRTUAL
-
+#endif
#endif /* __ASSEMBLY__ */
diff --git a/arch/xtensa/include/asm/pgtable.h b/arch/xtensa/include/asm/pgtable.h
index 8014d96..a138770 100644
--- a/arch/xtensa/include/asm/pgtable.h
+++ b/arch/xtensa/include/asm/pgtable.h
@@ -183,7 +183,15 @@
#define ZERO_PAGE(vaddr) (virt_to_page(empty_zero_page))
+#ifdef CONFIG_MMU
extern pgd_t swapper_pg_dir[PAGE_SIZE/sizeof(pgd_t)];
+extern void paging_init(void);
+extern void pgtable_cache_init(void);
+#else
+# define swapper_pg_dir NULL
+static inline void paging_init(void) { }
+static inline void pgtable_cache_init(void) { }
+#endif
/*
* The pmd contains the kernel virtual address of the pte page.
@@ -383,8 +391,6 @@
#else
-extern void paging_init(void);
-
#define kern_addr_valid(addr) (1)
extern void update_mmu_cache(struct vm_area_struct * vma,
@@ -398,9 +404,6 @@
#define io_remap_pfn_range(vma,from,pfn,size,prot) \
remap_pfn_range(vma, from, pfn, size, prot)
-
-extern void pgtable_cache_init(void);
-
typedef pte_t *pte_addr_t;
#endif /* !defined (__ASSEMBLY__) */
diff --git a/arch/xtensa/include/asm/processor.h b/arch/xtensa/include/asm/processor.h
index fba8b7e..0ea4937 100644
--- a/arch/xtensa/include/asm/processor.h
+++ b/arch/xtensa/include/asm/processor.h
@@ -13,6 +13,7 @@
#include <variant/core.h>
#include <asm/coprocessor.h>
+#include <platform/hardware.h>
#include <linux/compiler.h>
#include <asm/ptrace.h>
@@ -35,7 +36,12 @@
* the 1 GB requirement applies to the stack as well.
*/
+#ifdef CONFIG_MMU
#define TASK_SIZE __XTENSA_UL_CONST(0x40000000)
+#else
+#define TASK_SIZE (PLATFORM_DEFAULT_MEM_START + PLATFORM_DEFAULT_MEM_SIZE)
+#endif
+
#define STACK_TOP TASK_SIZE
#define STACK_TOP_MAX STACK_TOP
diff --git a/arch/xtensa/kernel/entry.S b/arch/xtensa/kernel/entry.S
index a51d36a..80d24c4 100644
--- a/arch/xtensa/kernel/entry.S
+++ b/arch/xtensa/kernel/entry.S
@@ -1463,6 +1463,7 @@
callx0 a0 # should not return
1: j 1b
+#ifdef CONFIG_MMU
/*
* We should never get here. Bail out!
*/
@@ -1775,7 +1776,7 @@
bbsi.l a2, PS_UM_BIT, 1f
j _kernel_exception
1: j _user_exception
-
+#endif /* CONFIG_MMU */
/*
* System Calls.
diff --git a/arch/xtensa/kernel/head.S b/arch/xtensa/kernel/head.S
index 67e6913..d092c22 100644
--- a/arch/xtensa/kernel/head.S
+++ b/arch/xtensa/kernel/head.S
@@ -235,8 +235,9 @@
*/
.section ".bss.page_aligned", "w"
+#ifdef CONFIG_MMU
ENTRY(swapper_pg_dir)
.fill PAGE_SIZE, 1, 0
+#endif
ENTRY(empty_zero_page)
.fill PAGE_SIZE, 1, 0
-
diff --git a/arch/xtensa/kernel/setup.c b/arch/xtensa/kernel/setup.c
index 4ec1633..1e5a034 100644
--- a/arch/xtensa/kernel/setup.c
+++ b/arch/xtensa/kernel/setup.c
@@ -84,7 +84,13 @@
int initrd_is_mapped;
#endif
+#ifdef CONFIG_MMU
extern void init_mmu(void);
+#else
+static inline void init_mmu(void) { }
+#endif
+
+extern void zones_init(void);
/*
* Boot parameter parsing.
@@ -286,6 +292,7 @@
paging_init();
+ zones_init();
#ifdef CONFIG_VT
# if defined(CONFIG_VGA_CONSOLE)
diff --git a/arch/xtensa/kernel/traps.c b/arch/xtensa/kernel/traps.c
index 6b4a9d7..9f0b711 100644
--- a/arch/xtensa/kernel/traps.c
+++ b/arch/xtensa/kernel/traps.c
@@ -104,6 +104,7 @@
#endif
{ EXCCAUSE_UNALIGNED, KRNL, fast_unaligned },
#endif
+#ifdef CONFIG_MMU
{ EXCCAUSE_ITLB_MISS, 0, do_page_fault },
{ EXCCAUSE_ITLB_MISS, USER|KRNL, fast_second_level_miss},
{ EXCCAUSE_ITLB_MULTIHIT, 0, do_multihit },
@@ -118,6 +119,7 @@
{ EXCCAUSE_STORE_CACHE_ATTRIBUTE, USER|KRNL, fast_store_prohibited },
{ EXCCAUSE_STORE_CACHE_ATTRIBUTE, 0, do_page_fault },
{ EXCCAUSE_LOAD_CACHE_ATTRIBUTE, 0, do_page_fault },
+#endif /* CONFIG_MMU */
/* XCCHAL_EXCCAUSE_FLOATING_POINT unhandled */
#if XTENSA_HAVE_COPROCESSOR(0)
COPROCESSOR(0),
diff --git a/arch/xtensa/kernel/vectors.S b/arch/xtensa/kernel/vectors.S
index eb2d7bb..74a7518 100644
--- a/arch/xtensa/kernel/vectors.S
+++ b/arch/xtensa/kernel/vectors.S
@@ -309,6 +309,7 @@
* All other exceptions are unexpected and thus unrecoverable!
*/
+#ifdef CONFIG_MMU
.extern fast_second_level_miss_double_kernel
.Lksp: /* a0: a0, a1: a1, a2: a2, a3: trashed, depc: depc, excsave: a3 */
@@ -319,6 +320,9 @@
bnez a3, .Lunrecoverable
1: movi a3, fast_second_level_miss_double_kernel
jx a3
+#else
+.equ .Lksp, .Lunrecoverable
+#endif
/* Critical! We can't handle this situation. PANIC! */
diff --git a/arch/xtensa/mm/Makefile b/arch/xtensa/mm/Makefile
index 64e304a..f0b646d 100644
--- a/arch/xtensa/mm/Makefile
+++ b/arch/xtensa/mm/Makefile
@@ -2,4 +2,5 @@
# Makefile for the Linux/Xtensa-specific parts of the memory manager.
#
-obj-y := init.o fault.o tlb.o misc.o cache.o
+obj-y := init.o cache.o misc.o
+obj-$(CONFIG_MMU) += fault.o mmu.o tlb.o
diff --git a/arch/xtensa/mm/init.c b/arch/xtensa/mm/init.c
index 6190988..427e14f 100644
--- a/arch/xtensa/mm/init.c
+++ b/arch/xtensa/mm/init.c
@@ -24,15 +24,8 @@
#include <linux/mm.h>
#include <linux/slab.h>
-#include <asm/pgtable.h>
#include <asm/bootparam.h>
-#include <asm/mmu_context.h>
-#include <asm/tlb.h>
#include <asm/page.h>
-#include <asm/pgalloc.h>
-
-
-DEFINE_PER_CPU(struct mmu_gather, mmu_gathers);
/* References to section boundaries */
@@ -160,7 +153,7 @@
}
-void __init paging_init(void)
+void __init zones_init(void)
{
unsigned long zones_size[MAX_NR_ZONES];
int i;
@@ -175,43 +168,10 @@
zones_size[ZONE_HIGHMEM] = max_pfn - max_low_pfn;
#endif
- /* Initialize the kernel's page tables. */
-
- memset(swapper_pg_dir, 0, PAGE_SIZE);
-
free_area_init_node(0, zones_size, ARCH_PFN_OFFSET, NULL);
}
/*
- * Flush the mmu and reset associated register to default values.
- */
-
-void __init init_mmu (void)
-{
- /* Writing zeros to the <t>TLBCFG special registers ensure
- * that valid values exist in the register. For existing
- * PGSZID<w> fields, zero selects the first element of the
- * page-size array. For nonexistent PGSZID<w> fields, zero is
- * the best value to write. Also, when changing PGSZID<w>
- * fields, the corresponding TLB must be flushed.
- */
- set_itlbcfg_register (0);
- set_dtlbcfg_register (0);
- flush_tlb_all ();
-
- /* Set rasid register to a known value. */
-
- set_rasid_register (ASID_USER_FIRST);
-
- /* Set PTEVADDR special register to the start of the page
- * table, which is in kernel mappable space (ie. not
- * statically mapped). This register's value is undefined on
- * reset.
- */
- set_ptevaddr_register (PGTABLE_START);
-}
-
-/*
* Initialize memory pages.
*/
@@ -281,23 +241,3 @@
printk("Freeing unused kernel memory: %dk freed\n",
(&__init_end - &__init_begin) >> 10);
}
-
-struct kmem_cache *pgtable_cache __read_mostly;
-
-static void pgd_ctor(void* addr)
-{
- pte_t* ptep = (pte_t*)addr;
- int i;
-
- for (i = 0; i < 1024; i++, ptep++)
- pte_clear(NULL, 0, ptep);
-
-}
-
-void __init pgtable_cache_init(void)
-{
- pgtable_cache = kmem_cache_create("pgd",
- PAGE_SIZE, PAGE_SIZE,
- SLAB_HWCACHE_ALIGN,
- pgd_ctor);
-}
diff --git a/arch/xtensa/mm/misc.S b/arch/xtensa/mm/misc.S
index c885664..b048406 100644
--- a/arch/xtensa/mm/misc.S
+++ b/arch/xtensa/mm/misc.S
@@ -84,6 +84,7 @@
retw
+#ifdef CONFIG_MMU
/*
* If we have to deal with cache aliasing, we use temporary memory mappings
* to ensure that the source and destination pages have the same color as
@@ -311,6 +312,7 @@
/* End of special treatment in tlb miss exception */
ENTRY(__tlbtemp_mapping_end)
+#endif /* CONFIG_MMU
/*
* void __invalidate_icache_page(ulong start)
diff --git a/arch/xtensa/mm/mmu.c b/arch/xtensa/mm/mmu.c
new file mode 100644
index 0000000..4bb91a9
--- /dev/null
+++ b/arch/xtensa/mm/mmu.c
@@ -0,0 +1,70 @@
+/*
+ * xtensa mmu stuff
+ *
+ * Extracted from init.c
+ */
+#include <linux/percpu.h>
+#include <linux/init.h>
+#include <linux/string.h>
+#include <linux/slab.h>
+#include <linux/cache.h>
+
+#include <asm/tlb.h>
+#include <asm/tlbflush.h>
+#include <asm/mmu_context.h>
+#include <asm/page.h>
+
+DEFINE_PER_CPU(struct mmu_gather, mmu_gathers);
+
+void __init paging_init(void)
+{
+ memset(swapper_pg_dir, 0, PAGE_SIZE);
+}
+
+/*
+ * Flush the mmu and reset associated register to default values.
+ */
+void __init init_mmu(void)
+{
+ /* Writing zeros to the <t>TLBCFG special registers ensure
+ * that valid values exist in the register. For existing
+ * PGSZID<w> fields, zero selects the first element of the
+ * page-size array. For nonexistent PGSZID<w> fields, zero is
+ * the best value to write. Also, when changing PGSZID<w>
+ * fields, the corresponding TLB must be flushed.
+ */
+ set_itlbcfg_register(0);
+ set_dtlbcfg_register(0);
+ flush_tlb_all();
+
+ /* Set rasid register to a known value. */
+
+ set_rasid_register(ASID_USER_FIRST);
+
+ /* Set PTEVADDR special register to the start of the page
+ * table, which is in kernel mappable space (ie. not
+ * statically mapped). This register's value is undefined on
+ * reset.
+ */
+ set_ptevaddr_register(PGTABLE_START);
+}
+
+struct kmem_cache *pgtable_cache __read_mostly;
+
+static void pgd_ctor(void *addr)
+{
+ pte_t *ptep = (pte_t *)addr;
+ int i;
+
+ for (i = 0; i < 1024; i++, ptep++)
+ pte_clear(NULL, 0, ptep);
+
+}
+
+void __init pgtable_cache_init(void)
+{
+ pgtable_cache = kmem_cache_create("pgd",
+ PAGE_SIZE, PAGE_SIZE,
+ SLAB_HWCACHE_ALIGN,
+ pgd_ctor);
+}