[patch 09/18] entry: Remove syscall_enter_from_user_mode()

[Thomas Gleixner <tglx@kernel.org>]

All architecture use either:

    nr = enter_from_user_mode_randomize_stack(regs, nr);

or

    enter_from_user_mode_randomize_stack(regs);
    nr = syscall_enter_from_user_mode_work(regs, nr);

Remove the now unused function.

Signed-off-by: Thomas Gleixner <tglx@kernel.org>
---
 Documentation/core-api/entry.rst |   17 +++++++++-------
 include/linux/entry-common.h     |   40 +++------------------------------------
 include/linux/irq-entry-common.h |    6 ++---
 3 files changed, 17 insertions(+), 46 deletions(-)

--- a/Documentation/core-api/entry.rst
+++ b/Documentation/core-api/entry.rst
@@ -68,7 +68,7 @@ low-level C code must not be instrumente
   noinstr void syscall(struct pt_regs *regs, int nr)
   {
 	arch_syscall_enter(regs);
-	nr = syscall_enter_from_user_mode(regs, nr);
+	nr = syscall_enter_from_user_mode_randomize_stack(regs, nr);
 
 	instrumentation_begin();
 	if (!invoke_syscall(regs, nr) && nr != -1)
@@ -78,12 +78,14 @@ low-level C code must not be instrumente
 	syscall_exit_to_user_mode(regs);
   }
 
-syscall_enter_from_user_mode() first invokes enter_from_user_mode() which
-establishes state in the following order:
+syscall_enter_from_user_mode_randomize_stack() first invokes
+enter_from_user_mode_randomize_stack() which establishes state in the
+following order:
 
   * Lockdep
   * RCU / Context tracking
   * Tracing
+  * Apply stack randomization
 
 and then invokes the various entry work functions like ptrace, seccomp, audit,
 syscall tracing, etc. After all that is done, the instrumentable invoke_syscall
@@ -99,10 +101,11 @@ that it invokes exit_to_user_mode() whic
   * RCU / Context tracking
   * Lockdep
 
-syscall_enter_from_user_mode() and syscall_exit_to_user_mode() are also
-available as fine grained subfunctions in cases where the architecture code
-has to do extra work between the various steps. In such cases it has to
-ensure that enter_from_user_mode() is called first on entry and
+syscall_enter_from_user_mode_randomize_stack() and
+syscall_exit_to_user_mode() are also available as fine grained subfunctions
+in cases where the architecture code has to do extra work between the
+various steps. In such cases it has to ensure that
+enter_from_user_mode_randomize_stack() is called first on entry and
 exit_to_user_mode() is called last on exit.
 
 Do not nest syscalls. Nested syscalls will cause RCU and/or context tracking
--- a/include/linux/entry-common.h
+++ b/include/linux/entry-common.h
@@ -19,7 +19,7 @@
 #endif
 
 /*
- * SYSCALL_WORK flags handled in syscall_enter_from_user_mode()
+ * SYSCALL_WORK flags handled in syscall_enter_from_user_mode_work()
  */
 #define SYSCALL_WORK_ENTER	(SYSCALL_WORK_SECCOMP |			\
 				 SYSCALL_WORK_SYSCALL_TRACEPOINT |	\
@@ -205,42 +205,10 @@ do {									\
 	_ret;								\
 })
 
-/**
- * syscall_enter_from_user_mode - Establish state and check and handle work
- *				  before invoking a syscall
- * @regs:	Pointer to currents pt_regs
- * @syscall:	The syscall number
- *
- * Invoked from architecture specific syscall entry code with interrupts
- * disabled. The calling code has to be non-instrumentable. When the
- * function returns all state is correct, interrupts are enabled and the
- * subsequent functions can be instrumented.
- *
- * This is the combination of enter_from_user_mode() and
- * syscall_enter_from_user_mode_work() to be used when there is no
- * architecture specific work to be done between the two.
- *
- * Returns: The original or a modified syscall number. See
- * syscall_enter_from_user_mode_work() for further explanation.
- */
-static __always_inline long syscall_enter_from_user_mode(struct pt_regs *regs, long syscall)
-{
-	long ret;
-
-	enter_from_user_mode(regs);
-
-	instrumentation_begin();
-	local_irq_enable();
-	ret = syscall_enter_from_user_mode_work(regs, syscall);
-	instrumentation_end();
-
-	return ret;
-}
-
 /*
- * If SYSCALL_EMU is set, then the only reason to report is when
- * SINGLESTEP is set (i.e. PTRACE_SYSEMU_SINGLESTEP).  This syscall
- * instruction has been already reported in syscall_enter_from_user_mode().
+ * If SYSCALL_EMU is set, then the only reason to report is when SINGLESTEP is
+ * set (i.e. PTRACE_SYSEMU_SINGLESTEP).  This syscall instruction has been
+ * already reported in syscall_enter_from_user_mode_work().
  */
 static __always_inline bool report_single_step(unsigned long work)
 {
--- a/include/linux/irq-entry-common.h
+++ b/include/linux/irq-entry-common.h
@@ -49,9 +49,9 @@
  * Defaults to an empty implementation. Can be replaced by architecture
  * specific code.
  *
- * Invoked from syscall_enter_from_user_mode() in the non-instrumentable
- * section. Use __always_inline so the compiler cannot push it out of line
- * and make it instrumentable.
+ * Invoked from enter_from_user_mode_syscall_and_randomize_stack() in the
+ * non-instrumentable section. Use __always_inline so the compiler cannot push
+ * it out of line and make it instrumentable.
  */
 static __always_inline void arch_enter_from_user_mode(struct pt_regs *regs);