diff --git a/arch/x86/include/asm/vdso.h b/arch/x86/include/asm/vdso.h index 30be253dd283..8021bd28c0f1 100644 --- a/arch/x86/include/asm/vdso.h +++ b/arch/x86/include/asm/vdso.h @@ -18,15 +18,15 @@ struct vdso_image { unsigned long alt, alt_len; - unsigned long sym_end_mapping; /* Total size of the mapping */ + long sym_vvar_start; /* Negative offset to the vvar area */ - unsigned long sym_vvar_page; - unsigned long sym_hpet_page; - unsigned long sym_VDSO32_NOTE_MASK; - unsigned long sym___kernel_sigreturn; - unsigned long sym___kernel_rt_sigreturn; - unsigned long sym___kernel_vsyscall; - unsigned long sym_VDSO32_SYSENTER_RETURN; + long sym_vvar_page; + long sym_hpet_page; + long sym_VDSO32_NOTE_MASK; + long sym___kernel_sigreturn; + long sym___kernel_rt_sigreturn; + long sym___kernel_vsyscall; + long sym_VDSO32_SYSENTER_RETURN; }; #ifdef CONFIG_X86_64 diff --git a/arch/x86/vdso/vdso-layout.lds.S b/arch/x86/vdso/vdso-layout.lds.S index 9197544eea9a..de2c921025f5 100644 --- a/arch/x86/vdso/vdso-layout.lds.S +++ b/arch/x86/vdso/vdso-layout.lds.S @@ -18,6 +18,25 @@ SECTIONS { + /* + * User/kernel shared data is before the vDSO. This may be a little + * uglier than putting it after the vDSO, but it avoids issues with + * non-allocatable things that dangle past the end of the PT_LOAD + * segment. + */ + + vvar_start = . - 2 * PAGE_SIZE; + vvar_page = vvar_start; + + /* Place all vvars at the offsets in asm/vvar.h. */ +#define EMIT_VVAR(name, offset) vvar_ ## name = vvar_page + offset; +#define __VVAR_KERNEL_LDS +#include +#undef __VVAR_KERNEL_LDS +#undef EMIT_VVAR + + hpet_page = vvar_start + PAGE_SIZE; + . = SIZEOF_HEADERS; .hash : { *(.hash) } :text @@ -74,31 +93,6 @@ SECTIONS .altinstructions : { *(.altinstructions) } :text .altinstr_replacement : { *(.altinstr_replacement) } :text - /* - * The remainder of the vDSO consists of special pages that are - * shared between the kernel and userspace. It needs to be at the - * end so that it doesn't overlap the mapping of the actual - * vDSO image. - */ - - . = ALIGN(PAGE_SIZE); - vvar_page = .; - - /* Place all vvars at the offsets in asm/vvar.h. */ -#define EMIT_VVAR(name, offset) vvar_ ## name = vvar_page + offset; -#define __VVAR_KERNEL_LDS -#include -#undef __VVAR_KERNEL_LDS -#undef EMIT_VVAR - - . = vvar_page + PAGE_SIZE; - - hpet_page = .; - . = . + PAGE_SIZE; - - . = ALIGN(PAGE_SIZE); - end_mapping = .; - /DISCARD/ : { *(.discard) *(.discard.*) diff --git a/arch/x86/vdso/vdso2c.c b/arch/x86/vdso/vdso2c.c index 238dbe82776e..22c54d04bced 100644 --- a/arch/x86/vdso/vdso2c.c +++ b/arch/x86/vdso/vdso2c.c @@ -20,9 +20,9 @@ const char *outfilename; /* Symbols that we need in vdso2c. */ enum { + sym_vvar_start, sym_vvar_page, sym_hpet_page, - sym_end_mapping, sym_VDSO_FAKE_SECTION_TABLE_START, sym_VDSO_FAKE_SECTION_TABLE_END, }; @@ -38,9 +38,9 @@ struct vdso_sym { }; struct vdso_sym required_syms[] = { + [sym_vvar_start] = {"vvar_start", true}, [sym_vvar_page] = {"vvar_page", true}, [sym_hpet_page] = {"hpet_page", true}, - [sym_end_mapping] = {"end_mapping", true}, [sym_VDSO_FAKE_SECTION_TABLE_START] = { "VDSO_FAKE_SECTION_TABLE_START", false }, @@ -96,9 +96,11 @@ extern void bad_put_le(void); #define NSYMS (sizeof(required_syms) / sizeof(required_syms[0])) -#define BITSFUNC3(name, bits) name##bits -#define BITSFUNC2(name, bits) BITSFUNC3(name, bits) -#define BITSFUNC(name) BITSFUNC2(name, ELF_BITS) +#define BITSFUNC3(name, bits, suffix) name##bits##suffix +#define BITSFUNC2(name, bits, suffix) BITSFUNC3(name, bits, suffix) +#define BITSFUNC(name) BITSFUNC2(name, ELF_BITS, ) + +#define INT_BITS BITSFUNC2(int, ELF_BITS, _t) #define ELF_BITS_XFORM2(bits, x) Elf##bits##_##x #define ELF_BITS_XFORM(bits, x) ELF_BITS_XFORM2(bits, x) diff --git a/arch/x86/vdso/vdso2c.h b/arch/x86/vdso/vdso2c.h index 11b65d4f9414..2da32fbc46da 100644 --- a/arch/x86/vdso/vdso2c.h +++ b/arch/x86/vdso/vdso2c.h @@ -132,7 +132,7 @@ static void BITSFUNC(go)(void *addr, size_t len, *alt_sec = NULL; ELF(Dyn) *dyn = 0, *dyn_end = 0; const char *secstrings; - uint64_t syms[NSYMS] = {}; + INT_BITS syms[NSYMS] = {}; struct BITSFUNC(fake_sections) fake_sections = {}; @@ -209,6 +209,13 @@ static void BITSFUNC(go)(void *addr, size_t len, fail("duplicate symbol %s\n", required_syms[k].name); } + + /* + * Careful: we use negative addresses, but + * st_value is unsigned, so we rely + * on syms[k] being a signed type of the + * correct width. + */ syms[k] = GET_LE(&sym->st_value); } } @@ -263,15 +270,15 @@ static void BITSFUNC(go)(void *addr, size_t len, if (syms[i] % 4096) fail("%s must be a multiple of 4096\n", required_syms[i].name); - if (syms[i] < data_size) - fail("%s must be after the text mapping\n", + if (syms[sym_vvar_start] > syms[i] + 4096) + fail("%s underruns begin_vvar\n", required_syms[i].name); - if (syms[sym_end_mapping] < syms[i] + 4096) - fail("%s overruns end_mapping\n", + if (syms[i] + 4096 > 0) + fail("%s is on the wrong side of the vdso text\n", required_syms[i].name); } - if (syms[sym_end_mapping] % 4096) - fail("end_mapping must be a multiple of 4096\n"); + if (syms[sym_vvar_start] % 4096) + fail("vvar_begin must be a multiple of 4096\n"); if (!name) { fwrite(addr, load_size, 1, outfile); @@ -311,8 +318,8 @@ static void BITSFUNC(go)(void *addr, size_t len, } for (i = 0; i < NSYMS; i++) { if (required_syms[i].export && syms[i]) - fprintf(outfile, "\t.sym_%s = 0x%" PRIx64 ",\n", - required_syms[i].name, syms[i]); + fprintf(outfile, "\t.sym_%s = %" PRIi64 ",\n", + required_syms[i].name, (int64_t)syms[i]); } fprintf(outfile, "};\n"); } diff --git a/arch/x86/vdso/vma.c b/arch/x86/vdso/vma.c index 5a5176de8d0a..dbef622bb5af 100644 --- a/arch/x86/vdso/vma.c +++ b/arch/x86/vdso/vma.c @@ -93,7 +93,7 @@ static int map_vdso(const struct vdso_image *image, bool calculate_addr) { struct mm_struct *mm = current->mm; struct vm_area_struct *vma; - unsigned long addr; + unsigned long addr, text_start; int ret = 0; static struct page *no_pages[] = {NULL}; static struct vm_special_mapping vvar_mapping = { @@ -103,26 +103,28 @@ static int map_vdso(const struct vdso_image *image, bool calculate_addr) if (calculate_addr) { addr = vdso_addr(current->mm->start_stack, - image->sym_end_mapping); + image->size - image->sym_vvar_start); } else { addr = 0; } down_write(&mm->mmap_sem); - addr = get_unmapped_area(NULL, addr, image->sym_end_mapping, 0, 0); + addr = get_unmapped_area(NULL, addr, + image->size - image->sym_vvar_start, 0, 0); if (IS_ERR_VALUE(addr)) { ret = addr; goto up_fail; } - current->mm->context.vdso = (void __user *)addr; + text_start = addr - image->sym_vvar_start; + current->mm->context.vdso = (void __user *)text_start; /* * MAYWRITE to allow gdb to COW and set breakpoints */ vma = _install_special_mapping(mm, - addr, + text_start, image->size, VM_READ|VM_EXEC| VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC, @@ -134,8 +136,8 @@ static int map_vdso(const struct vdso_image *image, bool calculate_addr) } vma = _install_special_mapping(mm, - addr + image->size, - image->sym_end_mapping - image->size, + addr, + -image->sym_vvar_start, VM_READ, &vvar_mapping); @@ -146,7 +148,7 @@ static int map_vdso(const struct vdso_image *image, bool calculate_addr) if (image->sym_vvar_page) ret = remap_pfn_range(vma, - addr + image->sym_vvar_page, + text_start + image->sym_vvar_page, __pa_symbol(&__vvar_page) >> PAGE_SHIFT, PAGE_SIZE, PAGE_READONLY); @@ -157,7 +159,7 @@ static int map_vdso(const struct vdso_image *image, bool calculate_addr) #ifdef CONFIG_HPET_TIMER if (hpet_address && image->sym_hpet_page) { ret = io_remap_pfn_range(vma, - addr + image->sym_hpet_page, + text_start + image->sym_hpet_page, hpet_address >> PAGE_SHIFT, PAGE_SIZE, pgprot_noncached(PAGE_READONLY));