diff options
-rw-r--r-- | arch/tile/include/asm/stack.h | 1 | ||||
-rw-r--r-- | arch/tile/kernel/stack.c | 231 |
2 files changed, 112 insertions, 120 deletions
diff --git a/arch/tile/include/asm/stack.h b/arch/tile/include/asm/stack.h index 4d97a2d..0e9d382 100644 --- a/arch/tile/include/asm/stack.h +++ b/arch/tile/include/asm/stack.h @@ -25,7 +25,6 @@ struct KBacktraceIterator { BacktraceIterator it; struct task_struct *task; /* task we are backtracing */ - pte_t *pgtable; /* page table for user space access */ int end; /* iteration complete. */ int new_context; /* new context is starting */ int profile; /* profiling, so stop on async intrpt */ diff --git a/arch/tile/kernel/stack.c b/arch/tile/kernel/stack.c index 0be6b01..b2f44c2 100644 --- a/arch/tile/kernel/stack.c +++ b/arch/tile/kernel/stack.c @@ -21,9 +21,10 @@ #include <linux/stacktrace.h> #include <linux/uaccess.h> #include <linux/mmzone.h> +#include <linux/dcache.h> +#include <linux/fs.h> #include <asm/backtrace.h> #include <asm/page.h> -#include <asm/tlbflush.h> #include <asm/ucontext.h> #include <asm/switch_to.h> #include <asm/sigframe.h> @@ -45,72 +46,23 @@ static int in_kernel_stack(struct KBacktraceIterator *kbt, unsigned long sp) return sp >= kstack_base && sp < kstack_base + THREAD_SIZE; } -/* Is address valid for reading? */ -static int valid_address(struct KBacktraceIterator *kbt, unsigned long address) -{ - HV_PTE *l1_pgtable = kbt->pgtable; - HV_PTE *l2_pgtable; - unsigned long pfn; - HV_PTE pte; - struct page *page; - - if (l1_pgtable == NULL) - return 0; /* can't read user space in other tasks */ - -#ifdef CONFIG_64BIT - /* Find the real l1_pgtable by looking in the l0_pgtable. */ - pte = l1_pgtable[HV_L0_INDEX(address)]; - if (!hv_pte_get_present(pte)) - return 0; - pfn = hv_pte_get_pfn(pte); - if (pte_huge(pte)) { - if (!pfn_valid(pfn)) { - pr_err("L0 huge page has bad pfn %#lx\n", pfn); - return 0; - } - return hv_pte_get_present(pte) && hv_pte_get_readable(pte); - } - page = pfn_to_page(pfn); - BUG_ON(PageHighMem(page)); /* No HIGHMEM on 64-bit. */ - l1_pgtable = (HV_PTE *)pfn_to_kaddr(pfn); -#endif - pte = l1_pgtable[HV_L1_INDEX(address)]; - if (!hv_pte_get_present(pte)) - return 0; - pfn = hv_pte_get_pfn(pte); - if (pte_huge(pte)) { - if (!pfn_valid(pfn)) { - pr_err("huge page has bad pfn %#lx\n", pfn); - return 0; - } - return hv_pte_get_present(pte) && hv_pte_get_readable(pte); - } - - page = pfn_to_page(pfn); - if (PageHighMem(page)) { - pr_err("L2 page table not in LOWMEM (%#llx)\n", - HV_PFN_TO_CPA(pfn)); - return 0; - } - l2_pgtable = (HV_PTE *)pfn_to_kaddr(pfn); - pte = l2_pgtable[HV_L2_INDEX(address)]; - return hv_pte_get_present(pte) && hv_pte_get_readable(pte); -} - /* Callback for backtracer; basically a glorified memcpy */ static bool read_memory_func(void *result, unsigned long address, unsigned int size, void *vkbt) { int retval; struct KBacktraceIterator *kbt = (struct KBacktraceIterator *)vkbt; + + if (address == 0) + return 0; if (__kernel_text_address(address)) { /* OK to read kernel code. */ } else if (address >= PAGE_OFFSET) { /* We only tolerate kernel-space reads of this task's stack */ if (!in_kernel_stack(kbt, address)) return 0; - } else if (!valid_address(kbt, address)) { - return 0; /* invalid user-space address */ + } else if (!kbt->is_current) { + return 0; /* can't read from other user address spaces */ } pagefault_disable(); retval = __copy_from_user_inatomic(result, @@ -128,6 +80,8 @@ static struct pt_regs *valid_fault_handler(struct KBacktraceIterator* kbt) unsigned long sp = kbt->it.sp; struct pt_regs *p; + if (sp % sizeof(long) != 0) + return NULL; if (!in_kernel_stack(kbt, sp)) return NULL; if (!in_kernel_stack(kbt, sp + C_ABI_SAVE_AREA_SIZE + PTREGS_SIZE-1)) @@ -170,27 +124,27 @@ static int is_sigreturn(unsigned long pc) } /* Return a pt_regs pointer for a valid signal handler frame */ -static struct pt_regs *valid_sigframe(struct KBacktraceIterator* kbt) +static struct pt_regs *valid_sigframe(struct KBacktraceIterator* kbt, + struct rt_sigframe* kframe) { BacktraceIterator *b = &kbt->it; - if (b->pc == VDSO_BASE) { - struct rt_sigframe *frame; - unsigned long sigframe_top = - b->sp + sizeof(struct rt_sigframe) - 1; - if (!valid_address(kbt, b->sp) || - !valid_address(kbt, sigframe_top)) { - if (kbt->verbose) - pr_err(" (odd signal: sp %#lx?)\n", - (unsigned long)(b->sp)); + if (b->pc == VDSO_BASE && b->sp < PAGE_OFFSET && + b->sp % sizeof(long) == 0) { + int retval; + pagefault_disable(); + retval = __copy_from_user_inatomic( + kframe, (void __user __force *)b->sp, + sizeof(*kframe)); + pagefault_enable(); + if (retval != 0 || + (unsigned int)(kframe->info.si_signo) >= _NSIG) return NULL; - } - frame = (struct rt_sigframe *)b->sp; if (kbt->verbose) { pr_err(" <received signal %d>\n", - frame->info.si_signo); + kframe->info.si_signo); } - return (struct pt_regs *)&frame->uc.uc_mcontext; + return (struct pt_regs *)&kframe->uc.uc_mcontext; } return NULL; } @@ -203,10 +157,11 @@ static int KBacktraceIterator_is_sigreturn(struct KBacktraceIterator *kbt) static int KBacktraceIterator_restart(struct KBacktraceIterator *kbt) { struct pt_regs *p; + struct rt_sigframe kframe; p = valid_fault_handler(kbt); if (p == NULL) - p = valid_sigframe(kbt); + p = valid_sigframe(kbt, &kframe); if (p == NULL) return 0; backtrace_init(&kbt->it, read_memory_func, kbt, @@ -266,41 +221,19 @@ void KBacktraceIterator_init(struct KBacktraceIterator *kbt, /* * Set up callback information. We grab the kernel stack base - * so we will allow reads of that address range, and if we're - * asking about the current process we grab the page table - * so we can check user accesses before trying to read them. - * We flush the TLB to avoid any weird skew issues. + * so we will allow reads of that address range. */ - is_current = (t == NULL); + is_current = (t == NULL || t == current); kbt->is_current = is_current; if (is_current) t = validate_current(); kbt->task = t; - kbt->pgtable = NULL; kbt->verbose = 0; /* override in caller if desired */ kbt->profile = 0; /* override in caller if desired */ kbt->end = KBT_ONGOING; - kbt->new_context = 0; - if (is_current) { - HV_PhysAddr pgdir_pa = hv_inquire_context().page_table; - if (pgdir_pa == (unsigned long)swapper_pg_dir - PAGE_OFFSET) { - /* - * Not just an optimization: this also allows - * this to work at all before va/pa mappings - * are set up. - */ - kbt->pgtable = swapper_pg_dir; - } else { - struct page *page = pfn_to_page(PFN_DOWN(pgdir_pa)); - if (!PageHighMem(page)) - kbt->pgtable = __va(pgdir_pa); - else - pr_err("page table not in LOWMEM" - " (%#llx)\n", pgdir_pa); - } - local_flush_tlb_all(); + kbt->new_context = 1; + if (is_current) validate_stack(regs); - } if (regs == NULL) { if (is_current || t->state == TASK_RUNNING) { @@ -346,6 +279,78 @@ void KBacktraceIterator_next(struct KBacktraceIterator *kbt) } EXPORT_SYMBOL(KBacktraceIterator_next); +static void describe_addr(struct KBacktraceIterator *kbt, + unsigned long address, + int have_mmap_sem, char *buf, size_t bufsize) +{ + struct vm_area_struct *vma; + size_t namelen, remaining; + unsigned long size, offset, adjust; + char *p, *modname; + const char *name; + int rc; + + /* + * Look one byte back for every caller frame (i.e. those that + * aren't a new context) so we look up symbol data for the + * call itself, not the following instruction, which may be on + * a different line (or in a different function). + */ + adjust = !kbt->new_context; + address -= adjust; + + if (address >= PAGE_OFFSET) { + /* Handle kernel symbols. */ + BUG_ON(bufsize < KSYM_NAME_LEN); + name = kallsyms_lookup(address, &size, &offset, + &modname, buf); + if (name == NULL) { + buf[0] = '\0'; + return; + } + namelen = strlen(buf); + remaining = (bufsize - 1) - namelen; + p = buf + namelen; + rc = snprintf(p, remaining, "+%#lx/%#lx ", + offset + adjust, size); + if (modname && rc < remaining) + snprintf(p + rc, remaining - rc, "[%s] ", modname); + buf[bufsize-1] = '\0'; + return; + } + + /* If we don't have the mmap_sem, we can't show any more info. */ + buf[0] = '\0'; + if (!have_mmap_sem) + return; + + /* Find vma info. */ + vma = find_vma(kbt->task->mm, address); + if (vma == NULL || address < vma->vm_start) { + snprintf(buf, bufsize, "[unmapped address] "); + return; + } + + if (vma->vm_file) { + char *s; + p = d_path(&vma->vm_file->f_path, buf, bufsize); + if (IS_ERR(p)) + p = "?"; + s = strrchr(p, '/'); + if (s) + p = s+1; + } else { + p = "anon"; + } + + /* Generate a string description of the vma info. */ + namelen = strlen(p); + remaining = (bufsize - 1) - namelen; + memmove(buf, p, namelen); + snprintf(buf + namelen, remaining, "[%lx+%lx] ", + vma->vm_start, vma->vm_end - vma->vm_start); +} + /* * This method wraps the backtracer's more generic support. * It is only invoked from the architecture-specific code; show_stack() @@ -354,6 +359,7 @@ EXPORT_SYMBOL(KBacktraceIterator_next); void tile_show_stack(struct KBacktraceIterator *kbt, int headers) { int i; + int have_mmap_sem = 0; if (headers) { /* @@ -370,31 +376,16 @@ void tile_show_stack(struct KBacktraceIterator *kbt, int headers) kbt->verbose = 1; i = 0; for (; !KBacktraceIterator_end(kbt); KBacktraceIterator_next(kbt)) { - char *modname; - const char *name; - unsigned long address = kbt->it.pc; - unsigned long offset, size; char namebuf[KSYM_NAME_LEN+100]; + unsigned long address = kbt->it.pc; - if (address >= PAGE_OFFSET) - name = kallsyms_lookup(address, &size, &offset, - &modname, namebuf); - else - name = NULL; - - if (!name) - namebuf[0] = '\0'; - else { - size_t namelen = strlen(namebuf); - size_t remaining = (sizeof(namebuf) - 1) - namelen; - char *p = namebuf + namelen; - int rc = snprintf(p, remaining, "+%#lx/%#lx ", - offset, size); - if (modname && rc < remaining) - snprintf(p + rc, remaining - rc, - "[%s] ", modname); - namebuf[sizeof(namebuf)-1] = '\0'; - } + /* Try to acquire the mmap_sem as we pass into userspace. */ + if (address < PAGE_OFFSET && !have_mmap_sem && kbt->task->mm) + have_mmap_sem = + down_read_trylock(&kbt->task->mm->mmap_sem); + + describe_addr(kbt, address, have_mmap_sem, + namebuf, sizeof(namebuf)); pr_err(" frame %d: 0x%lx %s(sp 0x%lx)\n", i++, address, namebuf, (unsigned long)(kbt->it.sp)); @@ -409,6 +400,8 @@ void tile_show_stack(struct KBacktraceIterator *kbt, int headers) pr_err("Stack dump stopped; next frame identical to this one\n"); if (headers) pr_err("Stack dump complete\n"); + if (have_mmap_sem) + up_read(&kbt->task->mm->mmap_sem); } EXPORT_SYMBOL(tile_show_stack); |