[ARM] 4185/2: entry: introduce get_irqnr_preamble and arch_ret_to_user

get_irqnr_preamble allows machines to take some action before entering the
get_irqnr_and_base loop.  On iop we enable cp6 access.

arch_ret_to_user is added to the userspace return path to allow individual
architectures to take actions, like disabling coprocessor access, before
the final return to userspace.

Per Nicolas Pitre's note, there is no need to cp_wait on the return to user
as the latency to return is sufficient.

Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

1 files changed, 7 insertions, 0 deletions

diff --git a/arch/arm/kernel/entry-common.S b/arch/arm/kernel/entry-common.S
index 6f5e7c50d42f..c589dc3ecd1a 100644
--- a/arch/arm/kernel/entry-common.S
+++ b/arch/arm/kernel/entry-common.S
@@ -9,6 +9,7 @@
  */
 
 #include <asm/unistd.h>
+#include <asm/arch/entry-macro.S>
 
 #include "entry-header.S"
 
@@ -25,6 +26,9 @@ ret_fast_syscall:
         tst     r1, #_TIF_WORK_MASK
         bne     fast_work_pending
 
+        /* perform architecture specific actions before user return */
+        arch_ret_to_user r1, lr
+
         @ fast_restore_user_regs
         ldr     r1, [sp, #S_OFF + S_PSR]        @ get calling cpsr
         ldr     lr, [sp, #S_OFF + S_PC]!        @ get pc
@@ -61,6 +65,9 @@ ret_slow_syscall:
         tst     r1, #_TIF_WORK_MASK
         bne     work_pending
 no_work_pending:
+        /* perform architecture specific actions before user return */
+        arch_ret_to_user r1, lr
+
         @ slow_restore_user_regs
         ldr     r1, [sp, #S_PSR]                @ get calling cpsr
         ldr     lr, [sp, #S_PC]!                @ get pc