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Diffstat (limited to 'arch/x86/kernel/sys_x86_64.c')
-rw-r--r--arch/x86/kernel/sys_x86_64.c165
1 files changed, 73 insertions, 92 deletions
diff --git a/arch/x86/kernel/sys_x86_64.c b/arch/x86/kernel/sys_x86_64.c
index ff14a5044ce..30277e27431 100644
--- a/arch/x86/kernel/sys_x86_64.c
+++ b/arch/x86/kernel/sys_x86_64.c
@@ -14,10 +14,59 @@
#include <linux/personality.h>
#include <linux/random.h>
#include <linux/uaccess.h>
+#include <linux/elf.h>
#include <asm/ia32.h>
#include <asm/syscalls.h>
+/*
+ * Align a virtual address to avoid aliasing in the I$ on AMD F15h.
+ */
+static unsigned long get_align_mask(void)
+{
+ /* handle 32- and 64-bit case with a single conditional */
+ if (va_align.flags < 0 || !(va_align.flags & (2 - mmap_is_ia32())))
+ return 0;
+
+ if (!(current->flags & PF_RANDOMIZE))
+ return 0;
+
+ return va_align.mask;
+}
+
+unsigned long align_vdso_addr(unsigned long addr)
+{
+ unsigned long align_mask = get_align_mask();
+ return (addr + align_mask) & ~align_mask;
+}
+
+static int __init control_va_addr_alignment(char *str)
+{
+ /* guard against enabling this on other CPU families */
+ if (va_align.flags < 0)
+ return 1;
+
+ if (*str == 0)
+ return 1;
+
+ if (*str == '=')
+ str++;
+
+ if (!strcmp(str, "32"))
+ va_align.flags = ALIGN_VA_32;
+ else if (!strcmp(str, "64"))
+ va_align.flags = ALIGN_VA_64;
+ else if (!strcmp(str, "off"))
+ va_align.flags = 0;
+ else if (!strcmp(str, "on"))
+ va_align.flags = ALIGN_VA_32 | ALIGN_VA_64;
+ else
+ return 0;
+
+ return 1;
+}
+__setup("align_va_addr", control_va_addr_alignment);
+
SYSCALL_DEFINE6(mmap, unsigned long, addr, unsigned long, len,
unsigned long, prot, unsigned long, flags,
unsigned long, fd, unsigned long, off)
@@ -35,7 +84,7 @@ 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_ADDR32) && (flags & MAP_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
@@ -52,7 +101,7 @@ static void find_start_end(unsigned long flags, unsigned long *begin,
*begin = new_begin;
}
} else {
- *begin = TASK_UNMAPPED_BASE;
+ *begin = current->mm->mmap_legacy_base;
*end = TASK_SIZE;
}
}
@@ -63,7 +112,7 @@ arch_get_unmapped_area(struct file *filp, unsigned long addr,
{
struct mm_struct *mm = current->mm;
struct vm_area_struct *vma;
- unsigned long start_addr;
+ struct vm_unmapped_area_info info;
unsigned long begin, end;
if (flags & MAP_FIXED)
@@ -81,46 +130,16 @@ 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))
- && len <= mm->cached_hole_size) {
- mm->cached_hole_size = 0;
- mm->free_area_cache = begin;
- }
- addr = mm->free_area_cache;
- if (addr < begin)
- addr = begin;
- start_addr = addr;
-
-full_search:
- for (vma = find_vma(mm, addr); ; vma = vma->vm_next) {
- /* At this point: (!vma || addr < vma->vm_end). */
- if (end - len < addr) {
- /*
- * Start a new search - just in case we missed
- * some holes.
- */
- if (start_addr != begin) {
- start_addr = addr = begin;
- mm->cached_hole_size = 0;
- goto full_search;
- }
- return -ENOMEM;
- }
- if (!vma || addr + len <= vma->vm_start) {
- /*
- * Remember the place where we stopped the search:
- */
- mm->free_area_cache = addr + len;
- return addr;
- }
- if (addr + mm->cached_hole_size < vma->vm_start)
- mm->cached_hole_size = vma->vm_start - addr;
- addr = vma->vm_end;
- }
+ info.flags = 0;
+ info.length = len;
+ info.low_limit = begin;
+ info.high_limit = end;
+ info.align_mask = filp ? get_align_mask() : 0;
+ info.align_offset = pgoff << PAGE_SHIFT;
+ return vm_unmapped_area(&info);
}
-
unsigned long
arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
const unsigned long len, const unsigned long pgoff,
@@ -129,6 +148,7 @@ arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
struct vm_area_struct *vma;
struct mm_struct *mm = current->mm;
unsigned long addr = addr0;
+ struct vm_unmapped_area_info info;
/* requested length too big for entire address space */
if (len > TASK_SIZE)
@@ -137,8 +157,8 @@ 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 we force the legacy mmap base */
+ if (!test_thread_flag(TIF_ADDR32) && (flags & MAP_32BIT))
goto bottomup;
/* requesting a specific address */
@@ -150,46 +170,16 @@ arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
return addr;
}
- /* check if free_area_cache is useful for us */
- if (len <= mm->cached_hole_size) {
- mm->cached_hole_size = 0;
- mm->free_area_cache = mm->mmap_base;
- }
-
- /* either no address requested or can't fit in requested address hole */
- addr = mm->free_area_cache;
-
- /* make sure it can fit in the remaining address space */
- if (addr > len) {
- vma = find_vma(mm, addr-len);
- if (!vma || addr <= vma->vm_start)
- /* remember the address as a hint for next time */
- return mm->free_area_cache = addr-len;
- }
-
- if (mm->mmap_base < len)
- goto bottomup;
-
- addr = mm->mmap_base-len;
-
- do {
- /*
- * Lookup failure means no vma is above this address,
- * else if new region fits below vma->vm_start,
- * return with success:
- */
- vma = find_vma(mm, addr);
- if (!vma || addr+len <= vma->vm_start)
- /* remember the address as a hint for next time */
- return mm->free_area_cache = addr;
-
- /* remember the largest hole we saw so far */
- if (addr + mm->cached_hole_size < vma->vm_start)
- mm->cached_hole_size = vma->vm_start - addr;
-
- /* try just below the current vma->vm_start */
- addr = vma->vm_start-len;
- } while (len < vma->vm_start);
+ info.flags = VM_UNMAPPED_AREA_TOPDOWN;
+ info.length = len;
+ info.low_limit = PAGE_SIZE;
+ info.high_limit = mm->mmap_base;
+ info.align_mask = filp ? get_align_mask() : 0;
+ info.align_offset = pgoff << PAGE_SHIFT;
+ addr = vm_unmapped_area(&info);
+ if (!(addr & ~PAGE_MASK))
+ return addr;
+ VM_BUG_ON(addr != -ENOMEM);
bottomup:
/*
@@ -198,14 +188,5 @@ bottomup:
* can happen with large stack limits and large mmap()
* allocations.
*/
- mm->cached_hole_size = ~0UL;
- mm->free_area_cache = TASK_UNMAPPED_BASE;
- addr = arch_get_unmapped_area(filp, addr0, len, pgoff, flags);
- /*
- * Restore the topdown base:
- */
- mm->free_area_cache = mm->mmap_base;
- mm->cached_hole_size = ~0UL;
-
- return addr;
+ return arch_get_unmapped_area(filp, addr0, len, pgoff, flags);
}
generated by cgit v1.2.3-70-g09d2 (git 2.46.0) at 2025-11-09 20:53:56 +0000