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Subject[PATCH] x86_64: Implement personality ADDR_LIMIT_32BIT
Date
Signed-off-by: Kirill A. Shutemov <kirill@shutemov.name>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
---
arch/x86/kernel/sys_x86_64.c | 16 ++++++++++++----
include/asm-x86/elf.h | 4 +++-
include/asm-x86/processor.h | 6 ++++--
3 files changed, 19 insertions(+), 7 deletions(-)
diff --git a/arch/x86/kernel/sys_x86_64.c b/arch/x86/kernel/sys_x86_64.c
index 3b360ef..7f8672d 100644
--- a/arch/x86/kernel/sys_x86_64.c
+++ b/arch/x86/kernel/sys_x86_64.c
@@ -48,7 +48,9 @@ out:
static void find_start_end(unsigned long flags, unsigned long *begin,
unsigned long *end)
{
- if (!test_thread_flag(TIF_IA32) && (flags & MAP_32BIT)) {
+ if (!test_thread_flag(TIF_IA32) &&
+ ((flags & MAP_32BIT) ||
+ (current->personality & ADDR_LIMIT_32BIT))) {
unsigned long new_begin;
/* This is usually used needed to map code in small
model, so it needs to be in the first 31bit. Limit
@@ -94,7 +96,8 @@ arch_get_unmapped_area(struct file *filp, unsigned long addr,
(!vma || addr + len <= vma->vm_start))
return addr;
}
- if (((flags & MAP_32BIT) || test_thread_flag(TIF_IA32))
+ if (((flags & MAP_32BIT) || test_thread_flag(TIF_IA32) ||
+ (current->personality & ADDR_LIMIT_32BIT))
&& len <= mm->cached_hole_size) {
mm->cached_hole_size = 0;
mm->free_area_cache = begin;
@@ -150,8 +153,13 @@ arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
if (flags & MAP_FIXED)
return addr;

- /* for MAP_32BIT mappings we force the legact mmap base */
- if (!test_thread_flag(TIF_IA32) && (flags & MAP_32BIT))
+ /*
+ * for MAP_32BIT mappings and ADDR_LIMIT_32BIT personality we force the
+ * legacy mmap base
+ */
+ if (!test_thread_flag(TIF_IA32) &&
+ ((flags & MAP_32BIT) ||
+ (current->personality & ADDR_LIMIT_32BIT)))
goto bottomup;

/* requesting a specific address */
diff --git a/include/asm-x86/elf.h b/include/asm-x86/elf.h
index 7be4733..fa39e10 100644
--- a/include/asm-x86/elf.h
+++ b/include/asm-x86/elf.h
@@ -298,7 +298,9 @@ do { \
#define VDSO_HIGH_BASE 0xffffe000U /* CONFIG_COMPAT_VDSO address */

/* 1GB for 64bit, 8MB for 32bit */
-#define STACK_RND_MASK (test_thread_flag(TIF_IA32) ? 0x7ff : 0x3fffff)
+#define STACK_RND_MASK ((test_thread_flag(TIF_IA32) || \
+ current->personality & ADDR_LIMIT_32BIT ) ? \
+ 0x7ff : 0x3fffff)

#define ARCH_DLINFO \
do { \
diff --git a/include/asm-x86/processor.h b/include/asm-x86/processor.h
index 4df3e2f..6d7f2f9 100644
--- a/include/asm-x86/processor.h
+++ b/include/asm-x86/processor.h
@@ -904,7 +904,8 @@ extern unsigned long thread_saved_pc(struct task_struct *tsk);
#define TASK_SIZE_OF(child) ((test_tsk_thread_flag(child, TIF_IA32)) ? \
IA32_PAGE_OFFSET : TASK_SIZE64)

-#define STACK_TOP TASK_SIZE
+#define STACK_TOP (current->personality & ADDR_LIMIT_32BIT ? \
+ 0x80000000 : TASK_SIZE)
#define STACK_TOP_MAX TASK_SIZE64

#define INIT_THREAD { \
@@ -932,7 +933,8 @@ extern void start_thread(struct pt_regs *regs, unsigned long new_ip,
* This decides where the kernel will search for a free chunk of vm
* space during mmap's.
*/
-#define TASK_UNMAPPED_BASE (PAGE_ALIGN(TASK_SIZE / 3))
+#define TASK_UNMAPPED_BASE (current->personality & ADDR_LIMIT_32BIT ? \
+ 0x40000000 : PAGE_ALIGN(TASK_SIZE / 3))

#define KSTK_EIP(task) (task_pt_regs(task)->ip)

--
1.5.6.5.GIT


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