From: Hajime Tazaki <thehajime at gmail.com>
This commit adds memory operations on UML under !MMU environment.
Some part of the original UML code relying on CONFIG_MMU are excluded
from compilation when !CONFIG_MMU. Additionally, generic functions such as
uaccess, futex, memcpy/strnlen/strncpy can be used as user- and
kernel-space share the address space in !CONFIG_MMU mode.
Signed-off-by: Hajime Tazaki <thehajime at gmail.com>
Signed-off-by: Ricardo Koller <ricarkol at google.com>
[drop unnecessary bits]
Signed-off-by: Johannes Berg <johannes.berg at intel.com>
---
arch/um/include/asm/futex.h | 4 ++++
arch/um/include/asm/mmu.h | 3 +++
arch/um/include/asm/mmu_context.h | 2 ++
arch/um/include/asm/uaccess.h | 6 ++++--
arch/um/kernel/mem.c | 3 ++-
5 files changed, 15 insertions(+), 3 deletions(-)
diff --git a/arch/um/include/asm/futex.h b/arch/um/include/asm/futex.h
index 780aa6bfc050..785fd6649aa2 100644
--- a/arch/um/include/asm/futex.h
+++ b/arch/um/include/asm/futex.h
@@ -7,8 +7,12 @@
#include <asm/errno.h>
+#ifdef CONFIG_MMU
int arch_futex_atomic_op_inuser(int op, u32 oparg, int *oval, u32 __user *uaddr);
int futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,
u32 oldval, u32 newval);
+#else
+#include <asm-generic/futex.h>
+#endif
#endif
diff --git a/arch/um/include/asm/mmu.h b/arch/um/include/asm/mmu.h
index 82a919132aff..c0b9ce3215c4 100644
--- a/arch/um/include/asm/mmu.h
+++ b/arch/um/include/asm/mmu.h
@@ -22,10 +22,13 @@ typedef struct mm_context {
unsigned long sync_tlb_range_from;
unsigned long sync_tlb_range_to;
+#ifndef CONFIG_MMU
+ unsigned long end_brk;
#ifdef CONFIG_BINFMT_ELF_FDPIC
unsigned long exec_fdpic_loadmap;
unsigned long interp_fdpic_loadmap;
#endif
+#endif /* !CONFIG_MMU */
} mm_context_t;
#define INIT_MM_CONTEXT(mm) \
diff --git a/arch/um/include/asm/mmu_context.h b/arch/um/include/asm/mmu_context.h
index c727e56ba116..528b217da285 100644
--- a/arch/um/include/asm/mmu_context.h
+++ b/arch/um/include/asm/mmu_context.h
@@ -18,11 +18,13 @@ static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next,
{
}
+#ifdef CONFIG_MMU
#define init_new_context init_new_context
extern int init_new_context(struct task_struct *task, struct mm_struct *mm);
#define destroy_context destroy_context
extern void destroy_context(struct mm_struct *mm);
+#endif
#include <asm-generic/mmu_context.h>
diff --git a/arch/um/include/asm/uaccess.h b/arch/um/include/asm/uaccess.h
index 4417c8b1d37a..e493596f6663 100644
--- a/arch/um/include/asm/uaccess.h
+++ b/arch/um/include/asm/uaccess.h
@@ -18,6 +18,7 @@
#define __addr_range_nowrap(addr, size) \
((unsigned long) (addr) <= ((unsigned long) (addr) + (size)))
+#ifdef CONFIG_MMU
extern unsigned long raw_copy_from_user(void *to, const void __user *from, unsigned long n);
extern unsigned long raw_copy_to_user(void __user *to, const void *from, unsigned long n);
extern unsigned long __clear_user(void __user *mem, unsigned long len);
@@ -29,8 +30,6 @@ static inline int __access_ok(const void __user *ptr, unsigned long size);
#define INLINE_COPY_USER
-#include <asm-generic/uaccess.h>
-
static inline int __access_ok(const void __user *ptr, unsigned long size)
{
unsigned long addr = (unsigned long)ptr;
@@ -62,5 +61,8 @@ do { \
barrier(); \
current->thread.segv_continue = NULL; \
} while (0)
+#endif
+
+#include <asm-generic/uaccess.h>
#endif
diff --git a/arch/um/kernel/mem.c b/arch/um/kernel/mem.c
index 4b84760b5e55..bc03bf3d114d 100644
--- a/arch/um/kernel/mem.c
+++ b/arch/um/kernel/mem.c
@@ -64,7 +64,8 @@ void __init arch_mm_preinit(void)
* to be turned on.
*/
brk_end = PAGE_ALIGN((unsigned long) sbrk(0));
- map_memory(brk_end, __pa(brk_end), uml_reserved - brk_end, 1, 1, 0);
+ map_memory(brk_end, __pa(brk_end), uml_reserved - brk_end, 1, 1,
+ !IS_ENABLED(CONFIG_MMU));
memblock_free((void *)brk_end, uml_reserved - brk_end);
uml_reserved = brk_end;
min_low_pfn = PFN_UP(__pa(uml_reserved));
--
2.53.0