// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Copyright (C) 2004 Benjamin Herrenschmidt, IBM Corp.
* <[email protected]>
*/
#include <linux/errno.h>
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/smp.h>
#include <linux/stddef.h>
#include <linux/unistd.h>
#include <linux/slab.h>
#include <linux/user.h>
#include <linux/elf.h>
#include <linux/security.h>
#include <linux/memblock.h>
#include <linux/syscalls.h>
#include <linux/time_namespace.h>
#include <vdso/datapage.h>
#include <asm/syscall.h>
#include <asm/processor.h>
#include <asm/mmu.h>
#include <asm/mmu_context.h>
#include <asm/machdep.h>
#include <asm/cputable.h>
#include <asm/sections.h>
#include <asm/firmware.h>
#include <asm/vdso.h>
#include <asm/vdso_datapage.h>
#include <asm/setup.h>
/* The alignment of the vDSO */
#define VDSO_ALIGNMENT (1 << 16)
extern char vdso32_start, vdso32_end;
extern char vdso64_start, vdso64_end;
long sys_ni_syscall(void);
/*
* The vdso data page (aka. systemcfg for old ppc64 fans) is here.
* Once the early boot kernel code no longer needs to muck around
* with it, it will become dynamically allocated
*/
static union {
struct vdso_arch_data data;
u8 page[PAGE_SIZE];
} vdso_data_store __page_aligned_data;
struct vdso_arch_data *vdso_data = &vdso_data_store.data;
enum vvar_pages {
VVAR_DATA_PAGE_OFFSET,
VVAR_TIMENS_PAGE_OFFSET,
VVAR_NR_PAGES,
};
static int vdso_mremap(const struct vm_special_mapping *sm, struct vm_area_struct *new_vma,
unsigned long text_size)
{
unsigned long new_size = new_vma->vm_end - new_vma->vm_start;
if (new_size != text_size)
return -EINVAL;
current->mm->context.vdso = (void __user *)new_vma->vm_start;
return 0;
}
static int vdso32_mremap(const struct vm_special_mapping *sm, struct vm_area_struct *new_vma)
{
return vdso_mremap(sm, new_vma, &vdso32_end - &vdso32_start);
}
static int vdso64_mremap(const struct vm_special_mapping *sm, struct vm_area_struct *new_vma)
{
return vdso_mremap(sm, new_vma, &vdso64_end - &vdso64_start);
}
static vm_fault_t vvar_fault(const struct vm_special_mapping *sm,
struct vm_area_struct *vma, struct vm_fault *vmf);
static struct vm_special_mapping vvar_spec __ro_after_init = {
.name = "[vvar]",
.fault = vvar_fault,
};
static struct vm_special_mapping vdso32_spec __ro_after_init = {
.name = "[vdso]",
.mremap = vdso32_mremap,
};
static struct vm_special_mapping vdso64_spec __ro_after_init = {
.name = "[vdso]",
.mremap = vdso64_mremap,
};
#ifdef CONFIG_TIME_NS
struct vdso_data *arch_get_vdso_data(void *vvar_page)
{
return ((struct vdso_arch_data *)vvar_page)->data;
}
/*
* The vvar mapping contains data for a specific time namespace, so when a task
* changes namespace we must unmap its vvar data for the old namespace.
* Subsequent faults will map in data for the new namespace.
*
* For more details see timens_setup_vdso_data().
*/
int vdso_join_timens(struct task_struct *task, struct time_namespace *ns)
{
struct mm_struct *mm = task->mm;
VMA_ITERATOR(vmi, mm, 0);
struct vm_area_struct *vma;
mmap_read_lock(mm);
for_each_vma(vmi, vma) {
if (vma_is_special_mapping(vma, &vvar_spec))
zap_vma_pages(vma);
}
mmap_read_unlock(mm);
return 0;
}
#endif
static vm_fault_t vvar_fault(const struct vm_special_mapping *sm,
struct vm_area_struct *vma, struct vm_fault *vmf)
{
struct page *timens_page = find_timens_vvar_page(vma);
unsigned long pfn;
switch (vmf->pgoff) {
case VVAR_DATA_PAGE_OFFSET:
if (timens_page)
pfn = page_to_pfn(timens_page);
else
pfn = virt_to_pfn(vdso_data);
break;
#ifdef CONFIG_TIME_NS
case VVAR_TIMENS_PAGE_OFFSET:
/*
* If a task belongs to a time namespace then a namespace
* specific VVAR is mapped with the VVAR_DATA_PAGE_OFFSET and
* the real VVAR page is mapped with the VVAR_TIMENS_PAGE_OFFSET
* offset.
* See also the comment near timens_setup_vdso_data().
*/
if (!timens_page)
return VM_FAULT_SIGBUS;
pfn = virt_to_pfn(vdso_data);
break;
#endif /* CONFIG_TIME_NS */
default:
return VM_FAULT_SIGBUS;
}
return vmf_insert_pfn(vma, vmf->address, pfn);
}
/*
* This is called from binfmt_elf, we create the special vma for the
* vDSO and insert it into the mm struct tree
*/
static int __arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
{
unsigned long vdso_size, vdso_base, mappings_size;
struct vm_special_mapping *vdso_spec;
unsigned long vvar_size = VVAR_NR_PAGES * PAGE_SIZE;
struct mm_struct *mm = current->mm;
struct vm_area_struct *vma;
if (is_32bit_task()) {
vdso_spec = &vdso32_spec;
vdso_size = &vdso32_end - &vdso32_start;
} else {
vdso_spec = &vdso64_spec;
vdso_size = &vdso64_end - &vdso64_start;
}
mappings_size = vdso_size + vvar_size;
mappings_size += (VDSO_ALIGNMENT - 1) & PAGE_MASK;
/*
* Pick a base address for the vDSO in process space.
* Add enough to the size so that the result can be aligned.
*/
vdso_base = get_unmapped_area(NULL, 0, mappings_size, 0, 0);
if (IS_ERR_VALUE(vdso_base))
return vdso_base;
/* Add required alignment. */
vdso_base = ALIGN(vdso_base, VDSO_ALIGNMENT);
/*
* Put vDSO base into mm struct. We need to do this before calling
* install_special_mapping or the perf counter mmap tracking code
* will fail to recognise it as a vDSO.
*/
mm->context.vdso = (void __user *)vdso_base + vvar_size;
vma = _install_special_mapping(mm, vdso_base, vvar_size,
VM_READ | VM_MAYREAD | VM_IO |
VM_DONTDUMP | VM_PFNMAP, &vvar_spec);
if (IS_ERR(vma))
return PTR_ERR(vma);
/*
* our vma flags don't have VM_WRITE so by default, the process isn't
* allowed to write those pages.
* gdb can break that with ptrace interface, and thus trigger COW on
* those pages but it's then your responsibility to never do that on
* the "data" page of the vDSO or you'll stop getting kernel updates
* and your nice userland gettimeofday will be totally dead.
* It's fine to use that for setting breakpoints in the vDSO code
* pages though.
*/
vma = _install_special_mapping(mm, vdso_base + vvar_size, vdso_size,
VM_READ | VM_EXEC | VM_MAYREAD |
VM_MAYWRITE | VM_MAYEXEC, vdso_spec);
if (IS_ERR(vma))
do_munmap(mm, vdso_base, vvar_size, NULL);
return PTR_ERR_OR_ZERO(vma);
}
int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
{
struct mm_struct *mm = current->mm;
int rc;
mm->context.vdso = NULL;
if (mmap_write_lock_killable(mm))
return -EINTR;
rc = __arch_setup_additional_pages(bprm, uses_interp);
if (rc)
mm->context.vdso = NULL;
mmap_write_unlock(mm);
return rc;
}
#define VDSO_DO_FIXUPS(type, value, bits, sec) do { \
void *__start = (void *)VDSO##bits##_SYMBOL(&vdso##bits##_start, sec##_start); \
void *__end = (void *)VDSO##bits##_SYMBOL(&vdso##bits##_start, sec##_end); \
\
do_##type##_fixups((value), __start, __end); \
} while (0)
static void __init vdso_fixup_features(void)
{
#ifdef CONFIG_PPC64
VDSO_DO_FIXUPS(feature, cur_cpu_spec->cpu_features, 64, ftr_fixup);
VDSO_DO_FIXUPS(feature, cur_cpu_spec->mmu_features, 64, mmu_ftr_fixup);
VDSO_DO_FIXUPS(feature, powerpc_firmware_features, 64, fw_ftr_fixup);
VDSO_DO_FIXUPS(lwsync, cur_cpu_spec->cpu_features, 64, lwsync_fixup);
#endif /* CONFIG_PPC64 */
#ifdef CONFIG_VDSO32
VDSO_DO_FIXUPS(feature, cur_cpu_spec->cpu_features, 32, ftr_fixup);
VDSO_DO_FIXUPS(feature, cur_cpu_spec->mmu_features, 32, mmu_ftr_fixup);
#ifdef CONFIG_PPC64
VDSO_DO_FIXUPS(feature, powerpc_firmware_features, 32, fw_ftr_fixup);
#endif /* CONFIG_PPC64 */
VDSO_DO_FIXUPS(lwsync, cur_cpu_spec->cpu_features, 32, lwsync_fixup);
#endif
}
/*
* Called from setup_arch to initialize the bitmap of available
* syscalls in the systemcfg page
*/
static void __init vdso_setup_syscall_map(void)
{
unsigned int i;
for (i = 0; i < NR_syscalls; i++) {
if (sys_call_table[i] != (void *)&sys_ni_syscall)
vdso_data->syscall_map[i >> 5] |= 0x80000000UL >> (i & 0x1f);
if (IS_ENABLED(CONFIG_COMPAT) &&
compat_sys_call_table[i] != (void *)&sys_ni_syscall)
vdso_data->compat_syscall_map[i >> 5] |= 0x80000000UL >> (i & 0x1f);
}
}
#ifdef CONFIG_PPC64
int vdso_getcpu_init(void)
{
unsigned long cpu, node, val;
/*
* SPRG_VDSO contains the CPU in the bottom 16 bits and the NUMA node
* in the next 16 bits. The VDSO uses this to implement getcpu().
*/
cpu = get_cpu();
WARN_ON_ONCE(cpu > 0xffff);
node = cpu_to_node(cpu);
WARN_ON_ONCE(node > 0xffff);
val = (cpu & 0xffff) | ((node & 0xffff) << 16);
mtspr(SPRN_SPRG_VDSO_WRITE, val);
get_paca()->sprg_vdso = val;
put_cpu();
return 0;
}
/* We need to call this before SMP init */
early_initcall(vdso_getcpu_init);
#endif
static struct page ** __init vdso_setup_pages(void *start, void *end)
{
int i;
struct page **pagelist;
int pages = (end - start) >> PAGE_SHIFT;
pagelist = kcalloc(pages + 1, sizeof(struct page *), GFP_KERNEL);
if (!pagelist)
panic("%s: Cannot allocate page list for VDSO", __func__);
for (i = 0; i < pages; i++)
pagelist[i] = virt_to_page(start + i * PAGE_SIZE);
return pagelist;
}
static int __init vdso_init(void)
{
#ifdef CONFIG_PPC64
/*
* Fill up the "systemcfg" stuff for backward compatibility
*/
strcpy((char *)vdso_data->eye_catcher, "SYSTEMCFG:PPC64");
vdso_data->version.major = SYSTEMCFG_MAJOR;
vdso_data->version.minor = SYSTEMCFG_MINOR;
vdso_data->processor = mfspr(SPRN_PVR);
/*
* Fake the old platform number for pSeries and add
* in LPAR bit if necessary
*/
vdso_data->platform = 0x100;
if (firmware_has_feature(FW_FEATURE_LPAR))
vdso_data->platform |= 1;
vdso_data->physicalMemorySize = memblock_phys_mem_size();
vdso_data->dcache_size = ppc64_caches.l1d.size;
vdso_data->dcache_line_size = ppc64_caches.l1d.line_size;
vdso_data->icache_size = ppc64_caches.l1i.size;
vdso_data->icache_line_size = ppc64_caches.l1i.line_size;
vdso_data->dcache_block_size = ppc64_caches.l1d.block_size;
vdso_data->icache_block_size = ppc64_caches.l1i.block_size;
vdso_data->dcache_log_block_size = ppc64_caches.l1d.log_block_size;
vdso_data->icache_log_block_size = ppc64_caches.l1i.log_block_size;
#endif /* CONFIG_PPC64 */
vdso_setup_syscall_map();
vdso_fixup_features();
if (IS_ENABLED(CONFIG_VDSO32))
vdso32_spec.pages = vdso_setup_pages(&vdso32_start, &vdso32_end);
if (IS_ENABLED(CONFIG_PPC64))
vdso64_spec.pages = vdso_setup_pages(&vdso64_start, &vdso64_end);
smp_wmb();
return 0;
}
arch_initcall(vdso_init);
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