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-rw-r--r--arch/x86/include/asm/vdso.h18
-rw-r--r--arch/x86/vdso/vdso-layout.lds.S44
-rw-r--r--arch/x86/vdso/vdso2c.c12
-rw-r--r--arch/x86/vdso/vdso2c.h25
-rw-r--r--arch/x86/vdso/vma.c20
5 files changed, 62 insertions, 57 deletions
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 */
-
- 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_start; /* Negative offset to the vvar area */
+
+ 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 <asm/vvar.h>
+#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 <asm/vvar.h>
-#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));
generated by cgit (git 2.34.1) at 2024-06-12 11:04:52 +0000