3 files changed, 108 insertions, 1 deletions

diff --git a/include/linux/elf.h b/include/linux/elf.h
index a8c4af073ce9..d8e6e61ad9ff 100644
--- a/include/linux/elf.h
+++ b/include/linux/elf.h
@@ -349,7 +349,11 @@ typedef struct elf64_shdr {
 #define ELF_OSABI ELFOSABI_NONE
 #endif
 
-/* Notes used in ET_CORE */
+/*
+ * Notes used in ET_CORE. Architectures export some of the arch register sets
+ * using the corresponding note types via the PTRACE_GETREGSET and
+ * PTRACE_SETREGSET requests.
+ */
 #define NT_PRSTATUS     1
 #define NT_PRFPREG      2
 #define NT_PRPSINFO     3
diff --git a/include/linux/ptrace.h b/include/linux/ptrace.h
index 56f2d63a5cbb..dbfa821d5a6e 100644
--- a/include/linux/ptrace.h
+++ b/include/linux/ptrace.h
@@ -27,6 +27,21 @@
 #define PTRACE_GETSIGINFO       0x4202
 #define PTRACE_SETSIGINFO       0x4203
 
+/*
+ * Generic ptrace interface that exports the architecture specific regsets
+ * using the corresponding NT_* types (which are also used in the core dump).
+ *
+ * This interface usage is as follows:
+ *      struct iovec iov = { buf, len};
+ *
+ *      ret = ptrace(PTRACE_GETREGSET/PTRACE_SETREGSET, pid, NT_XXX_TYPE, &iov);
+ *
+ * On the successful completion, iov.len will be updated by the kernel,
+ * specifying how much the kernel has written/read to/from the user's iov.buf.
+ */
+#define PTRACE_GETREGSET        0x4204
+#define PTRACE_SETREGSET        0x4205
+
 /* options set using PTRACE_SETOPTIONS */
 #define PTRACE_O_TRACESYSGOOD   0x00000001
 #define PTRACE_O_TRACEFORK      0x00000002
diff --git a/kernel/ptrace.c b/kernel/ptrace.c
index 23bd09cd042e..13b4554d8fbb 100644
--- a/kernel/ptrace.c
+++ b/kernel/ptrace.c
@@ -22,6 +22,7 @@
 #include <linux/pid_namespace.h>
 #include <linux/syscalls.h>
 #include <linux/uaccess.h>
+#include <linux/regset.h>
 
 
 /*
@@ -511,6 +512,47 @@ static int ptrace_resume(struct task_struct *child, long request, long data)
         return 0;
 }
 
+#ifdef CONFIG_HAVE_ARCH_TRACEHOOK
+
+static const struct user_regset *
+find_regset(const struct user_regset_view *view, unsigned int type)
+{
+        const struct user_regset *regset;
+        int n;
+
+        for (n = 0; n < view->n; ++n) {
+                regset = view->regsets + n;
+                if (regset->core_note_type == type)
+                        return regset;
+        }
+
+        return NULL;
+}
+
+static int ptrace_regset(struct task_struct *task, int req, unsigned int type,
+                         struct iovec *kiov)
+{
+        const struct user_regset_view *view = task_user_regset_view(task);
+        const struct user_regset *regset = find_regset(view, type);
+        int regset_no;
+
+        if (!regset || (kiov->iov_len % regset->size) != 0)
+                return -EIO;
+
+        regset_no = regset - view->regsets;
+        kiov->iov_len = min(kiov->iov_len,
+                            (__kernel_size_t) (regset->n * regset->size));
+
+        if (req == PTRACE_GETREGSET)
+                return copy_regset_to_user(task, view, regset_no, 0,
+                                           kiov->iov_len, kiov->iov_base);
+        else
+                return copy_regset_from_user(task, view, regset_no, 0,
+                                             kiov->iov_len, kiov->iov_base);
+}
+
+#endif
+
 int ptrace_request(struct task_struct *child, long request,
                    long addr, long data)
 {
@@ -573,6 +615,26 @@ int ptrace_request(struct task_struct *child, long request,
                         return 0;
                 return ptrace_resume(child, request, SIGKILL);
 
+#ifdef CONFIG_HAVE_ARCH_TRACEHOOK
+        case PTRACE_GETREGSET:
+        case PTRACE_SETREGSET:
+        {
+                struct iovec kiov;
+                struct iovec __user *uiov = (struct iovec __user *) data;
+
+                if (!access_ok(VERIFY_WRITE, uiov, sizeof(*uiov)))
+                        return -EFAULT;
+
+                if (__get_user(kiov.iov_base, &uiov->iov_base) ||
+                    __get_user(kiov.iov_len, &uiov->iov_len))
+                        return -EFAULT;
+
+                ret = ptrace_regset(child, request, addr, &kiov);
+                if (!ret)
+                        ret = __put_user(kiov.iov_len, &uiov->iov_len);
+                break;
+        }
+#endif
         default:
                 break;
         }
@@ -711,6 +773,32 @@ int compat_ptrace_request(struct task_struct *child, compat_long_t request,
                 else
                         ret = ptrace_setsiginfo(child, &siginfo);
                 break;
+#ifdef CONFIG_HAVE_ARCH_TRACEHOOK
+        case PTRACE_GETREGSET:
+        case PTRACE_SETREGSET:
+        {
+                struct iovec kiov;
+                struct compat_iovec __user *uiov =
+                        (struct compat_iovec __user *) datap;
+                compat_uptr_t ptr;
+                compat_size_t len;
+
+                if (!access_ok(VERIFY_WRITE, uiov, sizeof(*uiov)))
+                        return -EFAULT;
+
+                if (__get_user(ptr, &uiov->iov_base) ||
+                    __get_user(len, &uiov->iov_len))
+                        return -EFAULT;
+
+                kiov.iov_base = compat_ptr(ptr);
+                kiov.iov_len = len;
+
+                ret = ptrace_regset(child, request, addr, &kiov);
+                if (!ret)
+                        ret = __put_user(kiov.iov_len, &uiov->iov_len);
+                break;
+        }
+#endif
 
         default:
                 ret = ptrace_request(child, request, addr, data);