[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, 12 insertions, 6 deletions

diff --git a/include/asm-arm/arch-iop13xx/entry-macro.S b/include/asm-arm/arch-iop13xx/entry-macro.S
index 94c50283dc56..a624a7870c64 100644
--- a/include/asm-arm/arch-iop13xx/entry-macro.S
+++ b/include/asm-arm/arch-iop13xx/entry-macro.S
@@ -19,21 +19,27 @@
         .macro  disable_fiq
         .endm
 
+        .macro get_irqnr_preamble, base, tmp
+        mrc     p15, 0, \tmp, c15, c1, 0
+        orr     \tmp, \tmp, #(1 << 6)
+        mcr     p15, 0, \tmp, c15, c1, 0        @ Enable cp6 access
+        .endm
+
         /*
          * Note: a 1-cycle window exists where iintvec will return the value
          * of iintbase, so we explicitly check for "bad zeros"
          */
         .macro  get_irqnr_and_base, irqnr, irqstat, base, tmp
-        mrc     p15, 0, \tmp, c15, c1, 0
-        orr     \tmp, \tmp, #(1 << 6)
-        mcr     p15, 0, \tmp, c15, c1, 0        @ Enable cp6 access
-
         mrc     p6, 0, \irqnr, c3, c2, 0        @ Read IINTVEC
         cmp     \irqnr, #0
         mrceq   p6, 0, \irqnr, c3, c2, 0        @ Re-read on potentially bad zero
         adds    \irqstat, \irqnr, #1            @ Check for 0xffffffff
         movne   \irqnr, \irqnr, lsr #2          @ Convert to irqnr
+        .endm
 
-        biceq   \tmp, \tmp, #(1 << 6)
-        mcreq   p15, 0, \tmp, c15, c1, 0        @ Disable cp6 access if no more interrupts
+        .macro arch_ret_to_user, tmp1, tmp2
+        mrc     p15, 0, \tmp1, c15, c1, 0
+        ands    \tmp2, \tmp1, #(1 << 6)
+        bicne   \tmp1, \tmp1, #(1 << 6)
+        mcrne   p15, 0, \tmp1, c15, c1, 0       @ Disable cp6 access
         .endm