diff options
| -rw-r--r-- | arch/x86/oprofile/backtrace.c | 56 | ||||
| -rw-r--r-- | arch/x86/oprofile/nmi_int.c | 14 |
2 files changed, 57 insertions, 13 deletions
diff --git a/arch/x86/oprofile/backtrace.c b/arch/x86/oprofile/backtrace.c index a5b64ab4cd6..32f78eb4674 100644 --- a/arch/x86/oprofile/backtrace.c +++ b/arch/x86/oprofile/backtrace.c @@ -11,10 +11,12 @@ #include <linux/oprofile.h> #include <linux/sched.h> #include <linux/mm.h> +#include <linux/compat.h> +#include <linux/highmem.h> + #include <asm/ptrace.h> #include <asm/uaccess.h> #include <asm/stacktrace.h> -#include <linux/compat.h> static int backtrace_stack(void *data, char *name) { @@ -36,17 +38,53 @@ static struct stacktrace_ops backtrace_ops = { .walk_stack = print_context_stack, }; +/* from arch/x86/kernel/cpu/perf_event.c: */ + +/* + * best effort, GUP based copy_from_user() that assumes IRQ or NMI context + */ +static unsigned long +copy_from_user_nmi(void *to, const void __user *from, unsigned long n) +{ + unsigned long offset, addr = (unsigned long)from; + unsigned long size, len = 0; + struct page *page; + void *map; + int ret; + + do { + ret = __get_user_pages_fast(addr, 1, 0, &page); + if (!ret) + break; + + offset = addr & (PAGE_SIZE - 1); + size = min(PAGE_SIZE - offset, n - len); + + map = kmap_atomic(page); + memcpy(to, map+offset, size); + kunmap_atomic(map); + put_page(page); + + len += size; + to += size; + addr += size; + + } while (len < n); + + return len; +} + #ifdef CONFIG_COMPAT static struct stack_frame_ia32 * dump_user_backtrace_32(struct stack_frame_ia32 *head) { + /* Also check accessibility of one struct frame_head beyond: */ struct stack_frame_ia32 bufhead[2]; struct stack_frame_ia32 *fp; + unsigned long bytes; - /* Also check accessibility of one struct frame_head beyond */ - if (!access_ok(VERIFY_READ, head, sizeof(bufhead))) - return NULL; - if (__copy_from_user_inatomic(bufhead, head, sizeof(bufhead))) + bytes = copy_from_user_nmi(bufhead, head, sizeof(bufhead)); + if (bytes != sizeof(bufhead)) return NULL; fp = (struct stack_frame_ia32 *) compat_ptr(bufhead[0].next_frame); @@ -87,12 +125,12 @@ x86_backtrace_32(struct pt_regs * const regs, unsigned int depth) static struct stack_frame *dump_user_backtrace(struct stack_frame *head) { + /* Also check accessibility of one struct frame_head beyond: */ struct stack_frame bufhead[2]; + unsigned long bytes; - /* Also check accessibility of one struct stack_frame beyond */ - if (!access_ok(VERIFY_READ, head, sizeof(bufhead))) - return NULL; - if (__copy_from_user_inatomic(bufhead, head, sizeof(bufhead))) + bytes = copy_from_user_nmi(bufhead, head, sizeof(bufhead)); + if (bytes != sizeof(bufhead)) return NULL; oprofile_add_trace(bufhead[0].return_address); diff --git a/arch/x86/oprofile/nmi_int.c b/arch/x86/oprofile/nmi_int.c index cf9750004a0..68894fdc034 100644 --- a/arch/x86/oprofile/nmi_int.c +++ b/arch/x86/oprofile/nmi_int.c @@ -112,8 +112,10 @@ static void nmi_cpu_start(void *dummy) static int nmi_start(void) { get_online_cpus(); - on_each_cpu(nmi_cpu_start, NULL, 1); ctr_running = 1; + /* make ctr_running visible to the nmi handler: */ + smp_mb(); + on_each_cpu(nmi_cpu_start, NULL, 1); put_online_cpus(); return 0; } @@ -504,15 +506,18 @@ static int nmi_setup(void) nmi_enabled = 0; ctr_running = 0; - barrier(); + /* make variables visible to the nmi handler: */ + smp_mb(); err = register_die_notifier(&profile_exceptions_nb); if (err) goto fail; get_online_cpus(); register_cpu_notifier(&oprofile_cpu_nb); - on_each_cpu(nmi_cpu_setup, NULL, 1); nmi_enabled = 1; + /* make nmi_enabled visible to the nmi handler: */ + smp_mb(); + on_each_cpu(nmi_cpu_setup, NULL, 1); put_online_cpus(); return 0; @@ -531,7 +536,8 @@ static void nmi_shutdown(void) nmi_enabled = 0; ctr_running = 0; put_online_cpus(); - barrier(); + /* make variables visible to the nmi handler: */ + smp_mb(); unregister_die_notifier(&profile_exceptions_nb); msrs = &get_cpu_var(cpu_msrs); model->shutdown(msrs); |