arm64: 32-bit (compat) applications support

[~andy/linux] / arch / arm64 / kernel / kuser32.S

diff --git a/arch/arm64/kernel/kuser32.S b/arch/arm64/kernel/kuser32.S
new file mode 100644 (file)
index 0000000..8b69ecb
--- /dev/null
+++ b/arch/arm64/kernel/kuser32.S
@@ -0,0 +1,77 @@
+/*
+ * Low-level user helpers placed in the vectors page for AArch32.
+ * Based on the kuser helpers in arch/arm/kernel/entry-armv.S.
+ *
+ * Copyright (C) 2005-2011 Nicolas Pitre <nico@fluxnic.net>
+ * Copyright (C) 2012 ARM Ltd.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ *
+ * AArch32 user helpers.
+ *
+ * Each segment is 32-byte aligned and will be moved to the top of the high
+ * vector page.  New segments (if ever needed) must be added in front of
+ * existing ones.  This mechanism should be used only for things that are
+ * really small and justified, and not be abused freely.
+ *
+ * See Documentation/arm/kernel_user_helpers.txt for formal definitions.
+ */
+       .align  5
+       .globl  __kuser_helper_start
+__kuser_helper_start:
+
+__kuser_cmpxchg64:                     // 0xffff0f60
+       .inst   0xe92d00f0              //      push            {r4, r5, r6, r7}
+       .inst   0xe1c040d0              //      ldrd            r4, r5, [r0]
+       .inst   0xe1c160d0              //      ldrd            r6, r7, [r1]
+       .inst   0xf57ff05f              //      dmb             sy
+       .inst   0xe1b20f9f              // 1:   ldrexd          r0, r1, [r2]
+       .inst   0xe0303004              //      eors            r3, r0, r4
+       .inst   0x00313005              //      eoreqs          r3, r1, r5
+       .inst   0x01a23f96              //      strexdeq        r3, r6, [r2]
+       .inst   0x03330001              //      teqeq           r3, #1
+       .inst   0x0afffff9              //      beq             1b
+       .inst   0xf57ff05f              //      dmb             sy
+       .inst   0xe2730000              //      rsbs            r0, r3, #0
+       .inst   0xe8bd00f0              //      pop             {r4, r5, r6, r7}
+       .inst   0xe12fff1e              //      bx              lr
+
+       .align  5
+__kuser_memory_barrier:                        // 0xffff0fa0
+       .inst   0xf57ff05f              //      dmb             sy
+       .inst   0xe12fff1e              //      bx              lr
+
+       .align  5
+__kuser_cmpxchg:                       // 0xffff0fc0
+       .inst   0xf57ff05f              //      dmb             sy
+       .inst   0xe1923f9f              // 1:   ldrex           r3, [r2]
+       .inst   0xe0533000              //      subs            r3, r3, r0
+       .inst   0x01823f91              //      strexeq r3, r1, [r2]
+       .inst   0x03330001              //      teqeq           r3, #1
+       .inst   0x0afffffa              //      beq             1b
+       .inst   0xe2730000              //      rsbs            r0, r3, #0
+       .inst   0xeaffffef              //      b               <__kuser_memory_barrier>
+
+       .align  5
+__kuser_get_tls:                       // 0xffff0fe0
+       .inst   0xee1d0f70              //      mrc             p15, 0, r0, c13, c0, 3
+       .inst   0xe12fff1e              //      bx              lr
+       .rep    5
+       .word   0
+       .endr
+
+__kuser_helper_version:                        // 0xffff0ffc
+       .word   ((__kuser_helper_end - __kuser_helper_start) >> 5)
+       .globl  __kuser_helper_end
+__kuser_helper_end: