sh: Initial vsyscall page support.

This implements initial support for the vsyscall page on SH.
At the moment we leave it configurable due to having nommu
to support from the same code base. We hook it up for the
signal trampoline return at present, with more to be added
later, once uClibc catches up.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>

1 files changed, 13 insertions, 0 deletions

diff --git a/arch/sh/mm/Kconfig b/arch/sh/mm/Kconfig
index b445d02075e8..9dd606464d23 100644
--- a/arch/sh/mm/Kconfig
+++ b/arch/sh/mm/Kconfig
@@ -223,6 +223,19 @@ config 32BIT
           32-bits through the SH-4A PMB. If this is not set, legacy
           29-bit physical addressing will be used.
 
+config VSYSCALL
+        bool "Support vsyscall page"
+        depends on MMU
+        default y
+        help
+          This will enable support for the kernel mapping a vDSO page
+          in process space, and subsequently handing down the entry point
+          to the libc through the ELF auxiliary vector.
+
+          From the kernel side this is used for the signal trampoline.
+          For systems with an MMU that can afford to give up a page,
+          (the default value) say Y.
+
 choice
         prompt "HugeTLB page size"
         depends on HUGETLB_PAGE && CPU_SH4 && MMU