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authorHelge Deller <deller@gmx.de>2014-01-31 22:19:52 +0100
committerHelge Deller <deller@gmx.de>2014-02-02 21:00:13 +0100
commit9dabf60dc4abe6e06bebcc2ee46b4d76ec8741f2 (patch)
tree93b98d806b1941b91ac3de04b7bd730103d3fab8
parentf5a408d53edef3af07ac7697b8bc54a755628450 (diff)
downloadlinux-sh-9dabf60dc4abe6e06bebcc2ee46b4d76ec8741f2.tar.gz
parisc: add flexible mmap memory layout support
Add support for the flexible mmap memory layout (as described in http://lwn.net/Articles/91829). This is especially very interesting on parisc since we currently only support 32bit userspace (even with a 64bit Linux kernel). Signed-off-by: Helge Deller <deller@gmx.de>
-rw-r--r--arch/parisc/include/asm/elf.h4
-rw-r--r--arch/parisc/include/asm/pgtable.h1
-rw-r--r--arch/parisc/include/asm/processor.h2
-rw-r--r--arch/parisc/include/asm/thread_info.h10
-rw-r--r--arch/parisc/kernel/process.c21
-rw-r--r--arch/parisc/kernel/sys_parisc.c238
6 files changed, 233 insertions, 43 deletions
diff --git a/arch/parisc/include/asm/elf.h b/arch/parisc/include/asm/elf.h
index ad2b50397894..3391d061eccc 100644
--- a/arch/parisc/include/asm/elf.h
+++ b/arch/parisc/include/asm/elf.h
@@ -348,4 +348,8 @@ struct pt_regs; /* forward declaration... */
#define ELF_HWCAP 0
+struct mm_struct;
+extern unsigned long arch_randomize_brk(struct mm_struct *);
+#define arch_randomize_brk arch_randomize_brk
+
#endif
diff --git a/arch/parisc/include/asm/pgtable.h b/arch/parisc/include/asm/pgtable.h
index 34899b5d959a..22b89d1edba7 100644
--- a/arch/parisc/include/asm/pgtable.h
+++ b/arch/parisc/include/asm/pgtable.h
@@ -511,6 +511,7 @@ static inline void ptep_set_wrprotect(struct mm_struct *mm, unsigned long addr,
/* We provide our own get_unmapped_area to provide cache coherency */
#define HAVE_ARCH_UNMAPPED_AREA
+#define HAVE_ARCH_UNMAPPED_AREA_TOPDOWN
#define __HAVE_ARCH_PTEP_TEST_AND_CLEAR_YOUNG
#define __HAVE_ARCH_PTEP_GET_AND_CLEAR
diff --git a/arch/parisc/include/asm/processor.h b/arch/parisc/include/asm/processor.h
index cc2290a3cace..198a86feb574 100644
--- a/arch/parisc/include/asm/processor.h
+++ b/arch/parisc/include/asm/processor.h
@@ -30,6 +30,8 @@
#endif
#define current_text_addr() ({ void *pc; current_ia(pc); pc; })
+#define HAVE_ARCH_PICK_MMAP_LAYOUT
+
#define TASK_SIZE_OF(tsk) ((tsk)->thread.task_size)
#define TASK_SIZE TASK_SIZE_OF(current)
#define TASK_UNMAPPED_BASE (current->thread.map_base)
diff --git a/arch/parisc/include/asm/thread_info.h b/arch/parisc/include/asm/thread_info.h
index d5f97ea3a4e1..4b9b10ce1f9d 100644
--- a/arch/parisc/include/asm/thread_info.h
+++ b/arch/parisc/include/asm/thread_info.h
@@ -76,6 +76,16 @@ struct thread_info {
#define _TIF_SYSCALL_TRACE_MASK (_TIF_SYSCALL_TRACE | _TIF_SINGLESTEP | \
_TIF_BLOCKSTEP | _TIF_SYSCALL_AUDIT)
+#ifdef CONFIG_64BIT
+# ifdef CONFIG_COMPAT
+# define is_32bit_task() (test_thread_flag(TIF_32BIT))
+# else
+# define is_32bit_task() (0)
+# endif
+#else
+# define is_32bit_task() (1)
+#endif
+
#endif /* __KERNEL__ */
#endif /* _ASM_PARISC_THREAD_INFO_H */
diff --git a/arch/parisc/kernel/process.c b/arch/parisc/kernel/process.c
index 55f92b614182..0bbbf0d3f608 100644
--- a/arch/parisc/kernel/process.c
+++ b/arch/parisc/kernel/process.c
@@ -13,7 +13,7 @@
* Copyright (C) 2000 Grant Grundler <grundler with parisc-linux.org>
* Copyright (C) 2001 Alan Modra <amodra at parisc-linux.org>
* Copyright (C) 2001-2002 Ryan Bradetich <rbrad at parisc-linux.org>
- * Copyright (C) 2001-2007 Helge Deller <deller at parisc-linux.org>
+ * Copyright (C) 2001-2014 Helge Deller <deller@gmx.de>
* Copyright (C) 2002 Randolph Chung <tausq with parisc-linux.org>
*
*
@@ -49,6 +49,7 @@
#include <linux/kallsyms.h>
#include <linux/uaccess.h>
#include <linux/rcupdate.h>
+#include <linux/random.h>
#include <asm/io.h>
#include <asm/asm-offsets.h>
@@ -286,3 +287,21 @@ void *dereference_function_descriptor(void *ptr)
return ptr;
}
#endif
+
+static inline unsigned long brk_rnd(void)
+{
+ /* 8MB for 32bit, 1GB for 64bit */
+ if (is_32bit_task())
+ return (get_random_int() & 0x7ffUL) << PAGE_SHIFT;
+ else
+ return (get_random_int() & 0x3ffffUL) << PAGE_SHIFT;
+}
+
+unsigned long arch_randomize_brk(struct mm_struct *mm)
+{
+ unsigned long ret = PAGE_ALIGN(mm->brk + brk_rnd());
+
+ if (ret < mm->brk)
+ return mm->brk;
+ return ret;
+}
diff --git a/arch/parisc/kernel/sys_parisc.c b/arch/parisc/kernel/sys_parisc.c
index 0d3a9d4927b5..b7cadc4a06cd 100644
--- a/arch/parisc/kernel/sys_parisc.c
+++ b/arch/parisc/kernel/sys_parisc.c
@@ -5,6 +5,7 @@
* Copyright (C) 1999-2003 Matthew Wilcox <willy at parisc-linux.org>
* Copyright (C) 2000-2003 Paul Bame <bame at parisc-linux.org>
* Copyright (C) 2001 Thomas Bogendoerfer <tsbogend at parisc-linux.org>
+ * Copyright (C) 1999-2014 Helge Deller <deller@gmx.de>
*
*
* This program is free software; you can redistribute it and/or modify
@@ -23,6 +24,7 @@
*/
#include <asm/uaccess.h>
+#include <asm/elf.h>
#include <linux/file.h>
#include <linux/fs.h>
#include <linux/linkage.h>
@@ -32,78 +34,230 @@
#include <linux/syscalls.h>
#include <linux/utsname.h>
#include <linux/personality.h>
+#include <linux/random.h>
-static unsigned long get_unshared_area(unsigned long addr, unsigned long len)
+/* we construct an artificial offset for the mapping based on the physical
+ * address of the kernel mapping variable */
+#define GET_LAST_MMAP(filp) \
+ (filp ? ((unsigned long) filp->f_mapping) >> 8 : 0UL)
+#define SET_LAST_MMAP(filp, val) \
+ { /* nothing */ }
+
+static int get_offset(unsigned int last_mmap)
{
- struct vm_unmapped_area_info info;
+ return (last_mmap & (SHMLBA-1)) >> PAGE_SHIFT;
+}
- info.flags = 0;
- info.length = len;
- info.low_limit = PAGE_ALIGN(addr);
- info.high_limit = TASK_SIZE;
- info.align_mask = 0;
- info.align_offset = 0;
- return vm_unmapped_area(&info);
+static unsigned long shared_align_offset(unsigned int last_mmap,
+ unsigned long pgoff)
+{
+ return (get_offset(last_mmap) + pgoff) << PAGE_SHIFT;
}
-/*
- * We need to know the offset to use. Old scheme was to look for
- * existing mapping and use the same offset. New scheme is to use the
- * address of the kernel data structure as the seed for the offset.
- * We'll see how that works...
- *
- * The mapping is cacheline aligned, so there's no information in the bottom
- * few bits of the address. We're looking for 10 bits (4MB / 4k), so let's
- * drop the bottom 8 bits and use bits 8-17.
- */
-static int get_offset(struct address_space *mapping)
+static inline unsigned long COLOR_ALIGN(unsigned long addr,
+ unsigned int last_mmap, unsigned long pgoff)
{
- return (unsigned long) mapping >> 8;
+ unsigned long base = (addr+SHMLBA-1) & ~(SHMLBA-1);
+ unsigned long off = (SHMLBA-1) &
+ (shared_align_offset(last_mmap, pgoff) << PAGE_SHIFT);
+
+ return base + off;
}
-static unsigned long shared_align_offset(struct file *filp, unsigned long pgoff)
+/*
+ * Top of mmap area (just below the process stack).
+ */
+
+static unsigned long mmap_upper_limit(void)
{
- struct address_space *mapping = filp ? filp->f_mapping : NULL;
+ unsigned long stack_base;
- return (get_offset(mapping) + pgoff) << PAGE_SHIFT;
+ /* Limit stack size to 1GB - see setup_arg_pages() in fs/exec.c */
+ stack_base = rlimit_max(RLIMIT_STACK);
+ if (stack_base > (1 << 30))
+ stack_base = 1 << 30;
+
+ return PAGE_ALIGN(STACK_TOP - stack_base);
}
-static unsigned long get_shared_area(struct file *filp, unsigned long addr,
- unsigned long len, unsigned long pgoff)
+
+unsigned long arch_get_unmapped_area(struct file *filp, unsigned long addr,
+ unsigned long len, unsigned long pgoff, unsigned long flags)
{
+ struct mm_struct *mm = current->mm;
+ struct vm_area_struct *vma;
+ unsigned long task_size = TASK_SIZE;
+ int do_color_align, last_mmap;
struct vm_unmapped_area_info info;
+ if (len > task_size)
+ return -ENOMEM;
+
+ do_color_align = 0;
+ if (filp || (flags & MAP_SHARED))
+ do_color_align = 1;
+ last_mmap = GET_LAST_MMAP(filp);
+
+ if (flags & MAP_FIXED) {
+ if ((flags & MAP_SHARED) && last_mmap &&
+ (addr - shared_align_offset(last_mmap, pgoff))
+ & (SHMLBA - 1))
+ return -EINVAL;
+ goto found_addr;
+ }
+
+ if (addr) {
+ if (do_color_align && last_mmap)
+ addr = COLOR_ALIGN(addr, last_mmap, pgoff);
+ else
+ addr = PAGE_ALIGN(addr);
+
+ vma = find_vma(mm, addr);
+ if (task_size - len >= addr &&
+ (!vma || addr + len <= vma->vm_start))
+ goto found_addr;
+ }
+
info.flags = 0;
info.length = len;
- info.low_limit = PAGE_ALIGN(addr);
- info.high_limit = TASK_SIZE;
- info.align_mask = PAGE_MASK & (SHMLBA - 1);
- info.align_offset = shared_align_offset(filp, pgoff);
- return vm_unmapped_area(&info);
+ info.low_limit = mm->mmap_legacy_base;
+ info.high_limit = mmap_upper_limit();
+ info.align_mask = last_mmap ? (PAGE_MASK & (SHMLBA - 1)) : 0;
+ info.align_offset = shared_align_offset(last_mmap, pgoff);
+ addr = vm_unmapped_area(&info);
+
+found_addr:
+ if (do_color_align && !last_mmap && !(addr & ~PAGE_MASK))
+ SET_LAST_MMAP(filp, addr - (pgoff << PAGE_SHIFT));
+
+ return addr;
}
-unsigned long arch_get_unmapped_area(struct file *filp, unsigned long addr,
- unsigned long len, unsigned long pgoff, unsigned long flags)
+unsigned long
+arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
+ const unsigned long len, const unsigned long pgoff,
+ const unsigned long flags)
{
+ struct vm_area_struct *vma;
+ struct mm_struct *mm = current->mm;
+ unsigned long addr = addr0;
+ int do_color_align, last_mmap;
+ struct vm_unmapped_area_info info;
+
+#ifdef CONFIG_64BIT
+ /* This should only ever run for 32-bit processes. */
+ BUG_ON(!test_thread_flag(TIF_32BIT));
+#endif
+
+ /* requested length too big for entire address space */
if (len > TASK_SIZE)
return -ENOMEM;
+
+ do_color_align = 0;
+ if (filp || (flags & MAP_SHARED))
+ do_color_align = 1;
+ last_mmap = GET_LAST_MMAP(filp);
+
if (flags & MAP_FIXED) {
- if ((flags & MAP_SHARED) &&
- (addr - shared_align_offset(filp, pgoff)) & (SHMLBA - 1))
+ if ((flags & MAP_SHARED) && last_mmap &&
+ (addr - shared_align_offset(last_mmap, pgoff))
+ & (SHMLBA - 1))
return -EINVAL;
- return addr;
+ goto found_addr;
}
- if (!addr)
- addr = TASK_UNMAPPED_BASE;
- if (filp || (flags & MAP_SHARED))
- addr = get_shared_area(filp, addr, len, pgoff);
- else
- addr = get_unshared_area(addr, len);
+ /* requesting a specific address */
+ if (addr) {
+ if (do_color_align && last_mmap)
+ addr = COLOR_ALIGN(addr, last_mmap, pgoff);
+ else
+ addr = PAGE_ALIGN(addr);
+ vma = find_vma(mm, addr);
+ if (TASK_SIZE - len >= addr &&
+ (!vma || addr + len <= vma->vm_start))
+ goto found_addr;
+ }
+
+ info.flags = VM_UNMAPPED_AREA_TOPDOWN;
+ info.length = len;
+ info.low_limit = PAGE_SIZE;
+ info.high_limit = mm->mmap_base;
+ info.align_mask = last_mmap ? (PAGE_MASK & (SHMLBA - 1)) : 0;
+ info.align_offset = shared_align_offset(last_mmap, pgoff);
+ addr = vm_unmapped_area(&info);
+ if (!(addr & ~PAGE_MASK))
+ goto found_addr;
+ VM_BUG_ON(addr != -ENOMEM);
+
+ /*
+ * A failed mmap() very likely causes application failure,
+ * so fall back to the bottom-up function here. This scenario
+ * can happen with large stack limits and large mmap()
+ * allocations.
+ */
+ return arch_get_unmapped_area(filp, addr0, len, pgoff, flags);
+
+found_addr:
+ if (do_color_align && !last_mmap && !(addr & ~PAGE_MASK))
+ SET_LAST_MMAP(filp, addr - (pgoff << PAGE_SHIFT));
return addr;
}
+static int mmap_is_legacy(void)
+{
+ if (current->personality & ADDR_COMPAT_LAYOUT)
+ return 1;
+
+ /* parisc stack always grows up - so a unlimited stack should
+ * not be an indicator to use the legacy memory layout.
+ * if (rlimit(RLIMIT_STACK) == RLIM_INFINITY)
+ * return 1;
+ */
+
+ return sysctl_legacy_va_layout;
+}
+
+static unsigned long mmap_rnd(void)
+{
+ unsigned long rnd = 0;
+
+ /*
+ * 8 bits of randomness in 32bit mmaps, 20 address space bits
+ * 28 bits of randomness in 64bit mmaps, 40 address space bits
+ */
+ if (current->flags & PF_RANDOMIZE) {
+ if (is_32bit_task())
+ rnd = get_random_int() % (1<<8);
+ else
+ rnd = get_random_int() % (1<<28);
+ }
+ return rnd << PAGE_SHIFT;
+}
+
+static unsigned long mmap_legacy_base(void)
+{
+ return TASK_UNMAPPED_BASE + mmap_rnd();
+}
+
+/*
+ * This function, called very early during the creation of a new
+ * process VM image, sets up which VM layout function to use:
+ */
+void arch_pick_mmap_layout(struct mm_struct *mm)
+{
+ mm->mmap_legacy_base = mmap_legacy_base();
+ mm->mmap_base = mmap_upper_limit();
+
+ if (mmap_is_legacy()) {
+ mm->mmap_base = mm->mmap_legacy_base;
+ mm->get_unmapped_area = arch_get_unmapped_area;
+ } else {
+ mm->get_unmapped_area = arch_get_unmapped_area_topdown;
+ }
+}
+
+
asmlinkage unsigned long sys_mmap2(unsigned long addr, unsigned long len,
unsigned long prot, unsigned long flags, unsigned long fd,
unsigned long pgoff)