Merge branch 'akpm' (patches from Andrew)

Merge more updates from Andrew Morton:
 "VM:
   - z3fold fixes and enhancements by Henry Burns and Vitaly Wool

   - more accurate reclaimed slab caches calculations by Yafang Shao

   - fix MAP_UNINITIALIZED UAPI symbol to not depend on config, by
     Christoph Hellwig

   - !CONFIG_MMU fixes by Christoph Hellwig

   - new novmcoredd parameter to omit device dumps from vmcore, by
     Kairui Song

   - new test_meminit module for testing heap and pagealloc
     initialization, by Alexander Potapenko

   - ioremap improvements for huge mappings, by Anshuman Khandual

   - generalize kprobe page fault handling, by Anshuman Khandual

   - device-dax hotplug fixes and improvements, by Pavel Tatashin

   - enable synchronous DAX fault on powerpc, by Aneesh Kumar K.V

   - add pte_devmap() support for arm64, by Robin Murphy

   - unify locked_vm accounting with a helper, by Daniel Jordan

   - several misc fixes

  core/lib:
   - new typeof_member() macro including some users, by Alexey Dobriyan

   - make BIT() and GENMASK() available in asm, by Masahiro Yamada

   - changed LIST_POISON2 on x86_64 to 0xdead000000000122 for better
     code generation, by Alexey Dobriyan

   - rbtree code size optimizations, by Michel Lespinasse

   - convert struct pid count to refcount_t, by Joel Fernandes

  get_maintainer.pl:
   - add --no-moderated switch to skip moderated ML's, by Joe Perches

  misc:
   - ptrace PTRACE_GET_SYSCALL_INFO interface

   - coda updates

   - gdb scripts, various"

[ Using merge message suggestion from Vlastimil Babka, with some editing - Linus ]

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (100 commits)
  fs/select.c: use struct_size() in kmalloc()
  mm: add account_locked_vm utility function
  arm64: mm: implement pte_devmap support
  mm: introduce ARCH_HAS_PTE_DEVMAP
  mm: clean up is_device_*_page() definitions
  mm/mmap: move common defines to mman-common.h
  mm: move MAP_SYNC to asm-generic/mman-common.h
  device-dax: "Hotremove" persistent memory that is used like normal RAM
  mm/hotplug: make remove_memory() interface usable
  device-dax: fix memory and resource leak if hotplug fails
  include/linux/lz4.h: fix spelling and copy-paste errors in documentation
  ipc/mqueue.c: only perform resource calculation if user valid
  include/asm-generic/bug.h: fix "cut here" for WARN_ON for __WARN_TAINT architectures
  scripts/gdb: add helpers to find and list devices
  scripts/gdb: add lx-genpd-summary command
  drivers/pps/pps.c: clear offset flags in PPS_SETPARAMS ioctl
  kernel/pid.c: convert struct pid count to refcount_t
  drivers/rapidio/devices/rio_mport_cdev.c: NUL terminate some strings
  select: shift restore_saved_sigmask_unless() into poll_select_copy_remaining()
  select: change do_poll() to return -ERESTARTNOHAND rather than -EINTR
  ...

1 files changed, 100 insertions, 1 deletions

diff --git a/kernel/ptrace.c b/kernel/ptrace.c
index 83a531cea2f3..cb9ddcc08119 100644
--- a/kernel/ptrace.c
+++ b/kernel/ptrace.c
@@ -32,6 +32,8 @@
 #include <linux/compat.h>
 #include <linux/sched/signal.h>
 
+#include <asm/syscall.h>	/* for syscall_get_* */
+
 /*
  * Access another process' address space via ptrace.
  * Source/target buffer must be kernel space,
@@ -897,7 +899,100 @@ static int ptrace_regset(struct task_struct *task, int req, unsigned int type,
  * to ensure no machine forgets it.
  */
 EXPORT_SYMBOL_GPL(task_user_regset_view);
-#endif
+
+static unsigned long
+ptrace_get_syscall_info_entry(struct task_struct *child, struct pt_regs *regs,
+			      struct ptrace_syscall_info *info)
+{
+	unsigned long args[ARRAY_SIZE(info->entry.args)];
+	int i;
+
+	info->op = PTRACE_SYSCALL_INFO_ENTRY;
+	info->entry.nr = syscall_get_nr(child, regs);
+	syscall_get_arguments(child, regs, args);
+	for (i = 0; i < ARRAY_SIZE(args); i++)
+		info->entry.args[i] = args[i];
+
+	/* args is the last field in struct ptrace_syscall_info.entry */
+	return offsetofend(struct ptrace_syscall_info, entry.args);
+}
+
+static unsigned long
+ptrace_get_syscall_info_seccomp(struct task_struct *child, struct pt_regs *regs,
+				struct ptrace_syscall_info *info)
+{
+	/*
+	 * As struct ptrace_syscall_info.entry is currently a subset
+	 * of struct ptrace_syscall_info.seccomp, it makes sense to
+	 * initialize that subset using ptrace_get_syscall_info_entry().
+	 * This can be reconsidered in the future if these structures
+	 * diverge significantly enough.
+	 */
+	ptrace_get_syscall_info_entry(child, regs, info);
+	info->op = PTRACE_SYSCALL_INFO_SECCOMP;
+	info->seccomp.ret_data = child->ptrace_message;
+
+	/* ret_data is the last field in struct ptrace_syscall_info.seccomp */
+	return offsetofend(struct ptrace_syscall_info, seccomp.ret_data);
+}
+
+static unsigned long
+ptrace_get_syscall_info_exit(struct task_struct *child, struct pt_regs *regs,
+			     struct ptrace_syscall_info *info)
+{
+	info->op = PTRACE_SYSCALL_INFO_EXIT;
+	info->exit.rval = syscall_get_error(child, regs);
+	info->exit.is_error = !!info->exit.rval;
+	if (!info->exit.is_error)
+		info->exit.rval = syscall_get_return_value(child, regs);
+
+	/* is_error is the last field in struct ptrace_syscall_info.exit */
+	return offsetofend(struct ptrace_syscall_info, exit.is_error);
+}
+
+static int
+ptrace_get_syscall_info(struct task_struct *child, unsigned long user_size,
+			void __user *datavp)
+{
+	struct pt_regs *regs = task_pt_regs(child);
+	struct ptrace_syscall_info info = {
+		.op = PTRACE_SYSCALL_INFO_NONE,
+		.arch = syscall_get_arch(child),
+		.instruction_pointer = instruction_pointer(regs),
+		.stack_pointer = user_stack_pointer(regs),
+	};
+	unsigned long actual_size = offsetof(struct ptrace_syscall_info, entry);
+	unsigned long write_size;
+
+	/*
+	 * This does not need lock_task_sighand() to access
+	 * child->last_siginfo because ptrace_freeze_traced()
+	 * called earlier by ptrace_check_attach() ensures that
+	 * the tracee cannot go away and clear its last_siginfo.
+	 */
+	switch (child->last_siginfo ? child->last_siginfo->si_code : 0) {
+	case SIGTRAP | 0x80:
+		switch (child->ptrace_message) {
+		case PTRACE_EVENTMSG_SYSCALL_ENTRY:
+			actual_size = ptrace_get_syscall_info_entry(child, regs,
+								    &info);
+			break;
+		case PTRACE_EVENTMSG_SYSCALL_EXIT:
+			actual_size = ptrace_get_syscall_info_exit(child, regs,
+								   &info);
+			break;
+		}
+		break;
+	case SIGTRAP | (PTRACE_EVENT_SECCOMP << 8):
+		actual_size = ptrace_get_syscall_info_seccomp(child, regs,
+							      &info);
+		break;
+	}
+
+	write_size = min(actual_size, user_size);
+	return copy_to_user(datavp, &info, write_size) ? -EFAULT : actual_size;
+}
+#endif /* CONFIG_HAVE_ARCH_TRACEHOOK */
 
 int ptrace_request(struct task_struct *child, long request,
 		   unsigned long addr, unsigned long data)
@@ -1114,6 +1209,10 @@ int ptrace_request(struct task_struct *child, long request,
 			ret = __put_user(kiov.iov_len, &uiov->iov_len);
 		break;
 	}
+
+	case PTRACE_GET_SYSCALL_INFO:
+		ret = ptrace_get_syscall_info(child, addr, datavp);
+		break;
 #endif
 
 	case PTRACE_SECCOMP_GET_FILTER: