/* * 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/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 <asm/pgtable.h> #include <asm/processor.h> #include <asm/mmu.h> #include <asm/mmu_context.h> #include <asm/prom.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> #undef DEBUG #ifdef DEBUG #define DBG(fmt...) printk(fmt) #else #define DBG(fmt...) #endif /* Max supported size for symbol names */ #define MAX_SYMNAME 64 /* The alignment of the vDSO */ #define VDSO_ALIGNMENT (1 << 16) static unsigned int vdso32_pages; static void *vdso32_kbase; static struct page **vdso32_pagelist; unsigned long vdso32_sigtramp; unsigned long vdso32_rt_sigtramp; #ifdef CONFIG_VDSO32 extern char vdso32_start, vdso32_end; #endif #ifdef CONFIG_PPC64 extern char vdso64_start, vdso64_end; static void *vdso64_kbase = &vdso64_start; static unsigned int vdso64_pages; static struct page **vdso64_pagelist; unsigned long vdso64_rt_sigtramp; #endif /* CONFIG_PPC64 */ static int vdso_ready; /* * 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_data data; u8 page[PAGE_SIZE]; } vdso_data_store __page_aligned_data; struct vdso_data *vdso_data = &vdso_data_store.data; /* Format of the patch table */ struct vdso_patch_def { unsigned long ftr_mask, ftr_value; const char *gen_name; const char *fix_name; }; /* Table of functions to patch based on the CPU type/revision * * Currently, we only change sync_dicache to do nothing on processors * with a coherent icache */ static struct vdso_patch_def vdso_patches[] = { { CPU_FTR_COHERENT_ICACHE, CPU_FTR_COHERENT_ICACHE, "__kernel_sync_dicache", "__kernel_sync_dicache_p5" }, { CPU_FTR_USE_TB, 0, "__kernel_gettimeofday", NULL }, { CPU_FTR_USE_TB, 0, "__kernel_clock_gettime", NULL }, { CPU_FTR_USE_TB, 0, "__kernel_clock_getres", NULL }, { CPU_FTR_USE_TB, 0, "__kernel_get_tbfreq", NULL }, { CPU_FTR_USE_TB, 0, "__kernel_time", NULL }, }; /* * 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; }; /* * 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 uses_interp) { struct mm_struct *mm = current->mm; struct page **vdso_pagelist; unsigned long vdso_pages; unsigned long vdso_base; int rc; if (!vdso_ready) return 0; #ifdef CONFIG_PPC64 if (is_32bit_task()) { vdso_pagelist = vdso32_pagelist; vdso_pages = vdso32_pages; vdso_base = VDSO32_MBASE; } else { vdso_pagelist = vdso64_pagelist; vdso_pages = vdso64_pages; /* * On 64bit we don't have a preferred map address. This * allows get_unmapped_area to find an area near other mmaps * and most likely share a SLB entry. */ vdso_base = 0; } #else vdso_pagelist = vdso32_pagelist; vdso_pages = vdso32_pages; vdso_base = VDSO32_MBASE; #endif current->mm->context.vdso_base = 0; /* vDSO has a problem and was disabled, just don't "enable" it for the * process */ if (vdso_pages == 0) return 0; /* Add a page to the vdso size for the data page */ vdso_pages ++; /* * pick a base address for the vDSO in process space. We try to put it * at vdso_base which is the "natural" base for it, but we might fail * and end up putting it elsewhere. * Add enough to the size so that the result can be aligned. */ if (down_write_killable(&mm->mmap_sem)) return -EINTR; vdso_base = get_unmapped_area(NULL, vdso_base, (vdso_pages << PAGE_SHIFT) + ((VDSO_ALIGNMENT - 1) & PAGE_MASK), 0, 0); if (IS_ERR_VALUE(vdso_base)) { rc = vdso_base; goto fail_mmapsem; } /* 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 (since arch_vma_name fails). */ current->mm->context.vdso_base = vdso_base; /* * 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. */ rc = install_special_mapping(mm, vdso_base, vdso_pages << PAGE_SHIFT, VM_READ|VM_EXEC| VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC, vdso_pagelist); if (rc) { current->mm->context.vdso_base = 0; goto fail_mmapsem; } up_write(&mm->mmap_sem); return 0; fail_mmapsem: up_write(&mm->mmap_sem); return rc; } const char *arch_vma_name(struct vm_area_struct *vma) { if (vma->vm_mm && vma->vm_start == vma->vm_mm->context.vdso_base) return "[vdso]"; return NULL; } #ifdef CONFIG_VDSO32 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 Elf32_Sym * __init find_symbol32(struct lib32_elfinfo *lib, const char *symname) { unsigned int i; char name[MAX_SYMNAME], *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, MAX_SYMNAME); 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; } static int __init 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; } if (fix == NULL) { sym32_gen->st_name = 0; return 0; } 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; } #else /* !CONFIG_VDSO32 */ static unsigned long __init find_function32(struct lib32_elfinfo *lib, const char *symname) { return 0; } static int __init vdso_do_func_patch32(struct lib32_elfinfo *v32, struct lib64_elfinfo *v64, const char *orig, const char *fix) { return 0; } #endif /* CONFIG_VDSO32 */ #ifdef CONFIG_PPC64 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 Elf64_Sym * __init find_symbol64(struct lib64_elfinfo *lib, const char *symname) { unsigned int i; char name[MAX_SYMNAME], *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, MAX_SYMNAME); 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_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 int __init 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; } if (fix == NULL) { sym64_gen->st_name = 0; return 0; } 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; } #endif /* CONFIG_PPC64 */ static __init int vdso_do_find_sections(struct lib32_elfinfo *v32, struct lib64_elfinfo *v64) { void *sect; /* * Locate symbol tables & text section */ #ifdef CONFIG_VDSO32 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: required symbol section 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; #endif #ifdef CONFIG_PPC64 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: required symbol section 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; #endif /* CONFIG_PPC64 */ return 0; } static __init void vdso_setup_trampolines(struct lib32_elfinfo *v32, struct lib64_elfinfo *v64) { /* * Find signal trampolines */ #ifdef CONFIG_PPC64 vdso64_rt_sigtramp = find_function64(v64, "__kernel_sigtramp_rt64"); #endif 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) { #ifdef CONFIG_VDSO32 Elf32_Sym *sym32; #endif #ifdef CONFIG_PPC64 Elf64_Sym *sym64; 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); #endif /* CONFIG_PPC64 */ #ifdef CONFIG_VDSO32 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); #endif return 0; } static __init int vdso_fixup_features(struct lib32_elfinfo *v32, struct lib64_elfinfo *v64) { unsigned long size; void *start; #ifdef CONFIG_PPC64 start = find_section64(v64->hdr, "__ftr_fixup", &size); if (start) do_feature_fixups(cur_cpu_spec->cpu_features, start, start + size); start = find_section64(v64->hdr, "__mmu_ftr_fixup", &size); if (start) do_feature_fixups(cur_cpu_spec->mmu_features, start, start + size); start = find_section64(v64->hdr, "__fw_ftr_fixup", &size); if (start) do_feature_fixups(powerpc_firmware_features, start, start + size); start = find_section64(v64->hdr, "__lwsync_fixup", &size); if (start) do_lwsync_fixups(cur_cpu_spec->cpu_features, start, start + size); #endif /* CONFIG_PPC64 */ #ifdef CONFIG_VDSO32 start = find_section32(v32->hdr, "__ftr_fixup", &size); if (start) do_feature_fixups(cur_cpu_spec->cpu_features, start, start + size); start = find_section32(v32->hdr, "__mmu_ftr_fixup", &size); if (start) do_feature_fixups(cur_cpu_spec->mmu_features, start, start + size); #ifdef CONFIG_PPC64 start = find_section32(v32->hdr, "__fw_ftr_fixup", &size); if (start) do_feature_fixups(powerpc_firmware_features, start, start + size); #endif /* CONFIG_PPC64 */ start = find_section32(v32->hdr, "__lwsync_fixup", &size); if (start) do_lwsync_fixups(cur_cpu_spec->cpu_features, start, start + size); #endif return 0; } static __init int vdso_fixup_alt_funcs(struct lib32_elfinfo *v32, struct lib64_elfinfo *v64) { int i; for (i = 0; i < ARRAY_SIZE(vdso_patches); i++) { struct vdso_patch_def *patch = &vdso_patches[i]; int match = (cur_cpu_spec->cpu_features & patch->ftr_mask) == patch->ftr_value; if (!match) continue; DBG("replacing %s with %s...\n", patch->gen_name, patch->fix_name ? "NONE" : 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); #ifdef CONFIG_PPC64 vdso_do_func_patch64(v32, v64, patch->gen_name, patch->fix_name); #endif /* CONFIG_PPC64 */ } return 0; } static __init int vdso_setup(void) { struct lib32_elfinfo v32; struct lib64_elfinfo v64; v32.hdr = vdso32_kbase; #ifdef CONFIG_PPC64 v64.hdr = vdso64_kbase; #endif if (vdso_do_find_sections(&v32, &v64)) return -1; if (vdso_fixup_datapage(&v32, &v64)) return -1; if (vdso_fixup_features(&v32, &v64)) return -1; if (vdso_fixup_alt_funcs(&v32, &v64)) return -1; vdso_setup_trampolines(&v32, &v64); return 0; } /* * 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; extern unsigned long *sys_call_table; extern unsigned long sys_ni_syscall; for (i = 0; i < NR_syscalls; i++) { #ifdef CONFIG_PPC64 if (sys_call_table[i*2] != sys_ni_syscall) vdso_data->syscall_map_64[i >> 5] |= 0x80000000UL >> (i & 0x1f); if (sys_call_table[i*2+1] != sys_ni_syscall) vdso_data->syscall_map_32[i >> 5] |= 0x80000000UL >> (i & 0x1f); #else /* CONFIG_PPC64 */ if (sys_call_table[i] != sys_ni_syscall) vdso_data->syscall_map_32[i >> 5] |= 0x80000000UL >> (i & 0x1f); #endif /* CONFIG_PPC64 */ } } #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 & 0xfff) | ((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 int __init vdso_init(void) { int i; #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.dsize; vdso_data->dcache_line_size = ppc64_caches.dline_size; vdso_data->icache_size = ppc64_caches.isize; vdso_data->icache_line_size = ppc64_caches.iline_size; /* XXXOJN: Blocks should be added to ppc64_caches and used instead */ vdso_data->dcache_block_size = ppc64_caches.dline_size; vdso_data->icache_block_size = ppc64_caches.iline_size; vdso_data->dcache_log_block_size = ppc64_caches.log_dline_size; vdso_data->icache_log_block_size = ppc64_caches.log_iline_size; /* * Calculate the size of the 64 bits vDSO */ vdso64_pages = (&vdso64_end - &vdso64_start) >> PAGE_SHIFT; DBG("vdso64_kbase: %p, 0x%x pages\n", vdso64_kbase, vdso64_pages); #else vdso_data->dcache_block_size = L1_CACHE_BYTES; vdso_data->dcache_log_block_size = L1_CACHE_SHIFT; vdso_data->icache_block_size = L1_CACHE_BYTES; vdso_data->icache_log_block_size = L1_CACHE_SHIFT; #endif /* CONFIG_PPC64 */ #ifdef CONFIG_VDSO32 vdso32_kbase = &vdso32_start; /* * Calculate the size of the 32 bits vDSO */ vdso32_pages = (&vdso32_end - &vdso32_start) >> PAGE_SHIFT; DBG("vdso32_kbase: %p, 0x%x pages\n", vdso32_kbase, vdso32_pages); #endif /* * Setup the syscall map in the vDOS */ vdso_setup_syscall_map(); /* * 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"); vdso32_pages = 0; #ifdef CONFIG_PPC64 vdso64_pages = 0; #endif return 0; } #ifdef CONFIG_VDSO32 /* Make sure pages are in the correct state */ vdso32_pagelist = kzalloc(sizeof(struct page *) * (vdso32_pages + 2), GFP_KERNEL); BUG_ON(vdso32_pagelist == NULL); for (i = 0; i < vdso32_pages; i++) { struct page *pg = virt_to_page(vdso32_kbase + i*PAGE_SIZE); ClearPageReserved(pg); get_page(pg); vdso32_pagelist[i] = pg; } vdso32_pagelist[i++] = virt_to_page(vdso_data); vdso32_pagelist[i] = NULL; #endif #ifdef CONFIG_PPC64 vdso64_pagelist = kzalloc(sizeof(struct page *) * (vdso64_pages + 2), GFP_KERNEL); BUG_ON(vdso64_pagelist == NULL); for (i = 0; i < vdso64_pages; i++) { struct page *pg = virt_to_page(vdso64_kbase + i*PAGE_SIZE); ClearPageReserved(pg); get_page(pg); vdso64_pagelist[i] = pg; } vdso64_pagelist[i++] = virt_to_page(vdso_data); vdso64_pagelist[i] = NULL; #endif /* CONFIG_PPC64 */ get_page(virt_to_page(vdso_data)); smp_wmb(); vdso_ready = 1; return 0; } arch_initcall(vdso_init);