diff options
Diffstat (limited to 'arch/x86/kernel/sys_x86_64.c')
-rw-r--r-- | arch/x86/kernel/sys_x86_64.c | 81 |
1 files changed, 78 insertions, 3 deletions
diff --git a/arch/x86/kernel/sys_x86_64.c b/arch/x86/kernel/sys_x86_64.c index ff14a5044ce..aaa8d09c719 100644 --- a/arch/x86/kernel/sys_x86_64.c +++ b/arch/x86/kernel/sys_x86_64.c @@ -18,6 +18,72 @@ #include <asm/ia32.h> #include <asm/syscalls.h> +struct __read_mostly va_alignment va_align = { + .flags = -1, +}; + +/* + * Align a virtual address to avoid aliasing in the I$ on AMD F15h. + * + * @flags denotes the allocation direction - bottomup or topdown - + * or vDSO; see call sites below. + */ +unsigned long align_addr(unsigned long addr, struct file *filp, + enum align_flags flags) +{ + unsigned long tmp_addr; + + /* handle 32- and 64-bit case with a single conditional */ + if (va_align.flags < 0 || !(va_align.flags & (2 - mmap_is_ia32()))) + return addr; + + if (!(current->flags & PF_RANDOMIZE)) + return addr; + + if (!((flags & ALIGN_VDSO) || filp)) + return addr; + + tmp_addr = addr; + + /* + * We need an address which is <= than the original + * one only when in topdown direction. + */ + if (!(flags & ALIGN_TOPDOWN)) + tmp_addr += va_align.mask; + + tmp_addr &= ~va_align.mask; + + return tmp_addr; +} + +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) @@ -92,6 +158,9 @@ arch_get_unmapped_area(struct file *filp, unsigned long addr, start_addr = addr; full_search: + + addr = align_addr(addr, filp, 0); + for (vma = find_vma(mm, addr); ; vma = vma->vm_next) { /* At this point: (!vma || addr < vma->vm_end). */ if (end - len < addr) { @@ -117,6 +186,7 @@ full_search: mm->cached_hole_size = vma->vm_start - addr; addr = vma->vm_end; + addr = align_addr(addr, filp, 0); } } @@ -161,10 +231,13 @@ arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0, /* 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) + unsigned long tmp_addr = align_addr(addr - len, filp, + ALIGN_TOPDOWN); + + vma = find_vma(mm, tmp_addr); + if (!vma || tmp_addr + len <= vma->vm_start) /* remember the address as a hint for next time */ - return mm->free_area_cache = addr-len; + return mm->free_area_cache = tmp_addr; } if (mm->mmap_base < len) @@ -173,6 +246,8 @@ arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0, addr = mm->mmap_base-len; do { + addr = align_addr(addr, filp, ALIGN_TOPDOWN); + /* * Lookup failure means no vma is above this address, * else if new region fits below vma->vm_start, |