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Diffstat (limited to 'arch/ppc64/kernel/vdso.c')
-rw-r--r--arch/ppc64/kernel/vdso.c614
1 files changed, 614 insertions, 0 deletions
diff --git a/arch/ppc64/kernel/vdso.c b/arch/ppc64/kernel/vdso.c
new file mode 100644
index 000000000000..8c4597224b71
--- /dev/null
+++ b/arch/ppc64/kernel/vdso.c
@@ -0,0 +1,614 @@
+/*
+ * linux/arch/ppc64/kernel/vdso.c
+ *
+ * Copyright (C) 2004 Benjamin Herrenschmidt, IBM Corp.
+ * <benh@kernel.crashing.org>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#include <linux/config.h>
+#include <linux/module.h>
+#include <linux/errno.h>
+#include <linux/sched.h>
+#include <linux/kernel.h>
+#include <linux/mm.h>
+#include <linux/smp.h>
+#include <linux/smp_lock.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/bootmem.h>
+
+#include <asm/pgtable.h>
+#include <asm/system.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/vdso.h>
+
+#undef DEBUG
+
+#ifdef DEBUG
+#define DBG(fmt...) printk(fmt)
+#else
+#define DBG(fmt...)
+#endif
+
+
+/*
+ * The vDSOs themselves are here
+ */
+extern char vdso64_start, vdso64_end;
+extern char vdso32_start, vdso32_end;
+
+static void *vdso64_kbase = &vdso64_start;
+static void *vdso32_kbase = &vdso32_start;
+
+unsigned int vdso64_pages;
+unsigned int vdso32_pages;
+
+/* Signal trampolines user addresses */
+
+unsigned long vdso64_rt_sigtramp;
+unsigned long vdso32_sigtramp;
+unsigned long vdso32_rt_sigtramp;
+
+/* Format of the patch table */
+struct vdso_patch_def
+{
+ u32 pvr_mask, pvr_value;
+ const char *gen_name;
+ const char *fix_name;
+};
+
+/* Table of functions to patch based on the CPU type/revision
+ *
+ * TODO: Improve by adding whole lists for each entry
+ */
+static struct vdso_patch_def vdso_patches[] = {
+ {
+ 0xffff0000, 0x003a0000, /* POWER5 */
+ "__kernel_sync_dicache", "__kernel_sync_dicache_p5"
+ },
+ {
+ 0xffff0000, 0x003b0000, /* POWER5 */
+ "__kernel_sync_dicache", "__kernel_sync_dicache_p5"
+ },
+};
+
+/*
+ * Some infos carried around for each of them during parsing at
+ * boot time.
+ */
+struct lib32_elfinfo
+{
+ Elf32_Ehdr *hdr; /* ptr to ELF */
+ Elf32_Sym *dynsym; /* ptr to .dynsym section */
+ unsigned long dynsymsize; /* size of .dynsym section */
+ char *dynstr; /* ptr to .dynstr section */
+ unsigned long text; /* offset of .text section in .so */
+};
+
+struct lib64_elfinfo
+{
+ Elf64_Ehdr *hdr;
+ Elf64_Sym *dynsym;
+ unsigned long dynsymsize;
+ char *dynstr;
+ unsigned long text;
+};
+
+
+#ifdef __DEBUG
+static void dump_one_vdso_page(struct page *pg, struct page *upg)
+{
+ printk("kpg: %p (c:%d,f:%08lx)", __va(page_to_pfn(pg) << PAGE_SHIFT),
+ page_count(pg),
+ pg->flags);
+ if (upg/* && pg != upg*/) {
+ printk(" upg: %p (c:%d,f:%08lx)", __va(page_to_pfn(upg) << PAGE_SHIFT),
+ page_count(upg),
+ upg->flags);
+ }
+ printk("\n");
+}
+
+static void dump_vdso_pages(struct vm_area_struct * vma)
+{
+ int i;
+
+ if (!vma || test_thread_flag(TIF_32BIT)) {
+ printk("vDSO32 @ %016lx:\n", (unsigned long)vdso32_kbase);
+ for (i=0; i<vdso32_pages; i++) {
+ struct page *pg = virt_to_page(vdso32_kbase + i*PAGE_SIZE);
+ struct page *upg = (vma && vma->vm_mm) ?
+ follow_page(vma->vm_mm, vma->vm_start + i*PAGE_SIZE, 0)
+ : NULL;
+ dump_one_vdso_page(pg, upg);
+ }
+ }
+ if (!vma || !test_thread_flag(TIF_32BIT)) {
+ printk("vDSO64 @ %016lx:\n", (unsigned long)vdso64_kbase);
+ for (i=0; i<vdso64_pages; i++) {
+ struct page *pg = virt_to_page(vdso64_kbase + i*PAGE_SIZE);
+ struct page *upg = (vma && vma->vm_mm) ?
+ follow_page(vma->vm_mm, vma->vm_start + i*PAGE_SIZE, 0)
+ : NULL;
+ dump_one_vdso_page(pg, upg);
+ }
+ }
+}
+#endif /* DEBUG */
+
+/*
+ * Keep a dummy vma_close for now, it will prevent VMA merging.
+ */
+static void vdso_vma_close(struct vm_area_struct * vma)
+{
+}
+
+/*
+ * Our nopage() function, maps in the actual vDSO kernel pages, they will
+ * be mapped read-only by do_no_page(), and eventually COW'ed, either
+ * right away for an initial write access, or by do_wp_page().
+ */
+static struct page * vdso_vma_nopage(struct vm_area_struct * vma,
+ unsigned long address, int *type)
+{
+ unsigned long offset = address - vma->vm_start;
+ struct page *pg;
+ void *vbase = test_thread_flag(TIF_32BIT) ? vdso32_kbase : vdso64_kbase;
+
+ DBG("vdso_vma_nopage(current: %s, address: %016lx, off: %lx)\n",
+ current->comm, address, offset);
+
+ if (address < vma->vm_start || address > vma->vm_end)
+ return NOPAGE_SIGBUS;
+
+ /*
+ * Last page is systemcfg, special handling here, no get_page() a
+ * this is a reserved page
+ */
+ if ((vma->vm_end - address) <= PAGE_SIZE)
+ return virt_to_page(systemcfg);
+
+ pg = virt_to_page(vbase + offset);
+ get_page(pg);
+ DBG(" ->page count: %d\n", page_count(pg));
+
+ return pg;
+}
+
+static struct vm_operations_struct vdso_vmops = {
+ .close = vdso_vma_close,
+ .nopage = vdso_vma_nopage,
+};
+
+/*
+ * This is called from binfmt_elf, we create the special vma for the
+ * vDSO and insert it into the mm struct tree
+ */
+int arch_setup_additional_pages(struct linux_binprm *bprm, int executable_stack)
+{
+ struct mm_struct *mm = current->mm;
+ struct vm_area_struct *vma;
+ unsigned long vdso_pages;
+ unsigned long vdso_base;
+
+ if (test_thread_flag(TIF_32BIT)) {
+ vdso_pages = vdso32_pages;
+ vdso_base = VDSO32_MBASE;
+ } else {
+ vdso_pages = vdso64_pages;
+ vdso_base = VDSO64_MBASE;
+ }
+
+ /* vDSO has a problem and was disabled, just don't "enable" it for the
+ * process
+ */
+ if (vdso_pages == 0) {
+ current->thread.vdso_base = 0;
+ return 0;
+ }
+ vma = kmem_cache_alloc(vm_area_cachep, SLAB_KERNEL);
+ if (vma == NULL)
+ return -ENOMEM;
+ if (security_vm_enough_memory(vdso_pages)) {
+ kmem_cache_free(vm_area_cachep, vma);
+ return -ENOMEM;
+ }
+ memset(vma, 0, sizeof(*vma));
+
+ /*
+ * pick a base address for the vDSO in process space. We have a default
+ * base of 1Mb on which we had a random offset up to 1Mb.
+ * XXX: Add possibility for a program header to specify that location
+ */
+ current->thread.vdso_base = vdso_base;
+ /* + ((unsigned long)vma & 0x000ff000); */
+
+ vma->vm_mm = mm;
+ vma->vm_start = current->thread.vdso_base;
+
+ /*
+ * the VMA size is one page more than the vDSO since systemcfg
+ * is mapped in the last one
+ */
+ vma->vm_end = vma->vm_start + ((vdso_pages + 1) << PAGE_SHIFT);
+
+ /*
+ * 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->vm_flags = VM_READ | VM_EXEC | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC;
+ vma->vm_flags |= mm->def_flags;
+ vma->vm_page_prot = protection_map[vma->vm_flags & 0x7];
+ vma->vm_ops = &vdso_vmops;
+
+ down_write(&mm->mmap_sem);
+ insert_vm_struct(mm, vma);
+ mm->total_vm += (vma->vm_end - vma->vm_start) >> PAGE_SHIFT;
+ up_write(&mm->mmap_sem);
+
+ return 0;
+}
+
+static void * __init find_section32(Elf32_Ehdr *ehdr, const char *secname,
+ unsigned long *size)
+{
+ Elf32_Shdr *sechdrs;
+ unsigned int i;
+ char *secnames;
+
+ /* Grab section headers and strings so we can tell who is who */
+ sechdrs = (void *)ehdr + ehdr->e_shoff;
+ secnames = (void *)ehdr + sechdrs[ehdr->e_shstrndx].sh_offset;
+
+ /* Find the section they want */
+ for (i = 1; i < ehdr->e_shnum; i++) {
+ if (strcmp(secnames+sechdrs[i].sh_name, secname) == 0) {
+ if (size)
+ *size = sechdrs[i].sh_size;
+ return (void *)ehdr + sechdrs[i].sh_offset;
+ }
+ }
+ *size = 0;
+ return NULL;
+}
+
+static void * __init find_section64(Elf64_Ehdr *ehdr, const char *secname,
+ unsigned long *size)
+{
+ Elf64_Shdr *sechdrs;
+ unsigned int i;
+ char *secnames;
+
+ /* Grab section headers and strings so we can tell who is who */
+ sechdrs = (void *)ehdr + ehdr->e_shoff;
+ secnames = (void *)ehdr + sechdrs[ehdr->e_shstrndx].sh_offset;
+
+ /* Find the section they want */
+ for (i = 1; i < ehdr->e_shnum; i++) {
+ if (strcmp(secnames+sechdrs[i].sh_name, secname) == 0) {
+ if (size)
+ *size = sechdrs[i].sh_size;
+ return (void *)ehdr + sechdrs[i].sh_offset;
+ }
+ }
+ if (size)
+ *size = 0;
+ return NULL;
+}
+
+static Elf32_Sym * __init find_symbol32(struct lib32_elfinfo *lib, const char *symname)
+{
+ unsigned int i;
+ char name[32], *c;
+
+ for (i = 0; i < (lib->dynsymsize / sizeof(Elf32_Sym)); i++) {
+ if (lib->dynsym[i].st_name == 0)
+ continue;
+ strlcpy(name, lib->dynstr + lib->dynsym[i].st_name, 32);
+ c = strchr(name, '@');
+ if (c)
+ *c = 0;
+ if (strcmp(symname, name) == 0)
+ return &lib->dynsym[i];
+ }
+ return NULL;
+}
+
+static Elf64_Sym * __init find_symbol64(struct lib64_elfinfo *lib, const char *symname)
+{
+ unsigned int i;
+ char name[32], *c;
+
+ for (i = 0; i < (lib->dynsymsize / sizeof(Elf64_Sym)); i++) {
+ if (lib->dynsym[i].st_name == 0)
+ continue;
+ strlcpy(name, lib->dynstr + lib->dynsym[i].st_name, 32);
+ c = strchr(name, '@');
+ if (c)
+ *c = 0;
+ if (strcmp(symname, name) == 0)
+ return &lib->dynsym[i];
+ }
+ return NULL;
+}
+
+/* Note that we assume the section is .text and the symbol is relative to
+ * the library base
+ */
+static unsigned long __init find_function32(struct lib32_elfinfo *lib, const char *symname)
+{
+ Elf32_Sym *sym = find_symbol32(lib, symname);
+
+ if (sym == NULL) {
+ printk(KERN_WARNING "vDSO32: function %s not found !\n", symname);
+ return 0;
+ }
+ return sym->st_value - VDSO32_LBASE;
+}
+
+/* Note that we assume the section is .text and the symbol is relative to
+ * the library base
+ */
+static unsigned long __init find_function64(struct lib64_elfinfo *lib, const char *symname)
+{
+ Elf64_Sym *sym = find_symbol64(lib, symname);
+
+ if (sym == NULL) {
+ printk(KERN_WARNING "vDSO64: function %s not found !\n", symname);
+ return 0;
+ }
+#ifdef VDS64_HAS_DESCRIPTORS
+ return *((u64 *)(vdso64_kbase + sym->st_value - VDSO64_LBASE)) - VDSO64_LBASE;
+#else
+ return sym->st_value - VDSO64_LBASE;
+#endif
+}
+
+
+static __init int vdso_do_find_sections(struct lib32_elfinfo *v32,
+ struct lib64_elfinfo *v64)
+{
+ void *sect;
+
+ /*
+ * Locate symbol tables & text section
+ */
+
+ v32->dynsym = find_section32(v32->hdr, ".dynsym", &v32->dynsymsize);
+ v32->dynstr = find_section32(v32->hdr, ".dynstr", NULL);
+ if (v32->dynsym == NULL || v32->dynstr == NULL) {
+ printk(KERN_ERR "vDSO32: a required symbol section was not found\n");
+ return -1;
+ }
+ sect = find_section32(v32->hdr, ".text", NULL);
+ if (sect == NULL) {
+ printk(KERN_ERR "vDSO32: the .text section was not found\n");
+ return -1;
+ }
+ v32->text = sect - vdso32_kbase;
+
+ v64->dynsym = find_section64(v64->hdr, ".dynsym", &v64->dynsymsize);
+ v64->dynstr = find_section64(v64->hdr, ".dynstr", NULL);
+ if (v64->dynsym == NULL || v64->dynstr == NULL) {
+ printk(KERN_ERR "vDSO64: a required symbol section was not found\n");
+ return -1;
+ }
+ sect = find_section64(v64->hdr, ".text", NULL);
+ if (sect == NULL) {
+ printk(KERN_ERR "vDSO64: the .text section was not found\n");
+ return -1;
+ }
+ v64->text = sect - vdso64_kbase;
+
+ return 0;
+}
+
+static __init void vdso_setup_trampolines(struct lib32_elfinfo *v32,
+ struct lib64_elfinfo *v64)
+{
+ /*
+ * Find signal trampolines
+ */
+
+ vdso64_rt_sigtramp = find_function64(v64, "__kernel_sigtramp_rt64");
+ vdso32_sigtramp = find_function32(v32, "__kernel_sigtramp32");
+ vdso32_rt_sigtramp = find_function32(v32, "__kernel_sigtramp_rt32");
+}
+
+static __init int vdso_fixup_datapage(struct lib32_elfinfo *v32,
+ struct lib64_elfinfo *v64)
+{
+ Elf32_Sym *sym32;
+ Elf64_Sym *sym64;
+
+ sym32 = find_symbol32(v32, "__kernel_datapage_offset");
+ if (sym32 == NULL) {
+ printk(KERN_ERR "vDSO32: Can't find symbol __kernel_datapage_offset !\n");
+ return -1;
+ }
+ *((int *)(vdso32_kbase + (sym32->st_value - VDSO32_LBASE))) =
+ (vdso32_pages << PAGE_SHIFT) - (sym32->st_value - VDSO32_LBASE);
+
+ sym64 = find_symbol64(v64, "__kernel_datapage_offset");
+ if (sym64 == NULL) {
+ printk(KERN_ERR "vDSO64: Can't find symbol __kernel_datapage_offset !\n");
+ return -1;
+ }
+ *((int *)(vdso64_kbase + sym64->st_value - VDSO64_LBASE)) =
+ (vdso64_pages << PAGE_SHIFT) - (sym64->st_value - VDSO64_LBASE);
+
+ return 0;
+}
+
+static int vdso_do_func_patch32(struct lib32_elfinfo *v32,
+ struct lib64_elfinfo *v64,
+ const char *orig, const char *fix)
+{
+ Elf32_Sym *sym32_gen, *sym32_fix;
+
+ sym32_gen = find_symbol32(v32, orig);
+ if (sym32_gen == NULL) {
+ printk(KERN_ERR "vDSO32: Can't find symbol %s !\n", orig);
+ return -1;
+ }
+ sym32_fix = find_symbol32(v32, fix);
+ if (sym32_fix == NULL) {
+ printk(KERN_ERR "vDSO32: Can't find symbol %s !\n", fix);
+ return -1;
+ }
+ sym32_gen->st_value = sym32_fix->st_value;
+ sym32_gen->st_size = sym32_fix->st_size;
+ sym32_gen->st_info = sym32_fix->st_info;
+ sym32_gen->st_other = sym32_fix->st_other;
+ sym32_gen->st_shndx = sym32_fix->st_shndx;
+
+ return 0;
+}
+
+static int vdso_do_func_patch64(struct lib32_elfinfo *v32,
+ struct lib64_elfinfo *v64,
+ const char *orig, const char *fix)
+{
+ Elf64_Sym *sym64_gen, *sym64_fix;
+
+ sym64_gen = find_symbol64(v64, orig);
+ if (sym64_gen == NULL) {
+ printk(KERN_ERR "vDSO64: Can't find symbol %s !\n", orig);
+ return -1;
+ }
+ sym64_fix = find_symbol64(v64, fix);
+ if (sym64_fix == NULL) {
+ printk(KERN_ERR "vDSO64: Can't find symbol %s !\n", fix);
+ return -1;
+ }
+ sym64_gen->st_value = sym64_fix->st_value;
+ sym64_gen->st_size = sym64_fix->st_size;
+ sym64_gen->st_info = sym64_fix->st_info;
+ sym64_gen->st_other = sym64_fix->st_other;
+ sym64_gen->st_shndx = sym64_fix->st_shndx;
+
+ return 0;
+}
+
+static __init int vdso_fixup_alt_funcs(struct lib32_elfinfo *v32,
+ struct lib64_elfinfo *v64)
+{
+ u32 pvr;
+ int i;
+
+ pvr = mfspr(SPRN_PVR);
+ for (i = 0; i < ARRAY_SIZE(vdso_patches); i++) {
+ struct vdso_patch_def *patch = &vdso_patches[i];
+ int match = (pvr & patch->pvr_mask) == patch->pvr_value;
+
+ DBG("patch %d (mask: %x, pvr: %x) : %s\n",
+ i, patch->pvr_mask, patch->pvr_value, match ? "match" : "skip");
+
+ if (!match)
+ continue;
+
+ DBG("replacing %s with %s...\n", patch->gen_name, patch->fix_name);
+
+ /*
+ * Patch the 32 bits and 64 bits symbols. Note that we do not patch
+ * the "." symbol on 64 bits. It would be easy to do, but doesn't
+ * seem to be necessary, patching the OPD symbol is enough.
+ */
+ vdso_do_func_patch32(v32, v64, patch->gen_name, patch->fix_name);
+ vdso_do_func_patch64(v32, v64, patch->gen_name, patch->fix_name);
+ }
+
+ return 0;
+}
+
+
+static __init int vdso_setup(void)
+{
+ struct lib32_elfinfo v32;
+ struct lib64_elfinfo v64;
+
+ v32.hdr = vdso32_kbase;
+ v64.hdr = vdso64_kbase;
+
+ if (vdso_do_find_sections(&v32, &v64))
+ return -1;
+
+ if (vdso_fixup_datapage(&v32, &v64))
+ return -1;
+
+ if (vdso_fixup_alt_funcs(&v32, &v64))
+ return -1;
+
+ vdso_setup_trampolines(&v32, &v64);
+
+ return 0;
+}
+
+void __init vdso_init(void)
+{
+ int i;
+
+ vdso64_pages = (&vdso64_end - &vdso64_start) >> PAGE_SHIFT;
+ vdso32_pages = (&vdso32_end - &vdso32_start) >> PAGE_SHIFT;
+
+ DBG("vdso64_kbase: %p, 0x%x pages, vdso32_kbase: %p, 0x%x pages\n",
+ vdso64_kbase, vdso64_pages, vdso32_kbase, vdso32_pages);
+
+ /*
+ * Initialize the vDSO images in memory, that is do necessary
+ * fixups of vDSO symbols, locate trampolines, etc...
+ */
+ if (vdso_setup()) {
+ printk(KERN_ERR "vDSO setup failure, not enabled !\n");
+ /* XXX should free pages here ? */
+ vdso64_pages = vdso32_pages = 0;
+ return;
+ }
+
+ /* Make sure pages are in the correct state */
+ for (i = 0; i < vdso64_pages; i++) {
+ struct page *pg = virt_to_page(vdso64_kbase + i*PAGE_SIZE);
+ ClearPageReserved(pg);
+ get_page(pg);
+ }
+ for (i = 0; i < vdso32_pages; i++) {
+ struct page *pg = virt_to_page(vdso32_kbase + i*PAGE_SIZE);
+ ClearPageReserved(pg);
+ get_page(pg);
+ }
+}
+
+int in_gate_area_no_task(unsigned long addr)
+{
+ return 0;
+}
+
+int in_gate_area(struct task_struct *task, unsigned long addr)
+{
+ return 0;
+}
+
+struct vm_area_struct *get_gate_vma(struct task_struct *tsk)
+{
+ return NULL;
+}
+
generated by cgit v1.2.3 (git 2.0.4) at 2024-11-08 01:07:17 +0000