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authorMax Filippov <jcmvbkbc@gmail.com>2022-06-17 02:40:11 -0700
committerWaldemar Brodkorb <wbx@openadk.org>2022-06-20 12:17:17 +0200
commit6561433a6680b34c04dd4581e340f96cc7dfb04c (patch)
tree256e5adccc7312c7cd54e4401c3d0a850d350852 /libc/sysdeps/linux/xtensa/swapcontext.S
parent6d45c0fe89e6de7d35a991051ec7f9feaaaf3729 (diff)
xtensa: implement user context manipulation functions
Implement getcontext, makecontext, setcontext and swapcontext. Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
Diffstat (limited to 'libc/sysdeps/linux/xtensa/swapcontext.S')
-rw-r--r--libc/sysdeps/linux/xtensa/swapcontext.S173
1 files changed, 173 insertions, 0 deletions
diff --git a/libc/sysdeps/linux/xtensa/swapcontext.S b/libc/sysdeps/linux/xtensa/swapcontext.S
new file mode 100644
index 000000000..a215edc6d
--- /dev/null
+++ b/libc/sysdeps/linux/xtensa/swapcontext.S
@@ -0,0 +1,173 @@
+/* Copyright (C) 2018 - 2022 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library 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
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, see
+ <http://www.gnu.org/licenses/>. */
+
+#include <sysdep.h>
+#include "ucontext_i.h"
+
+#if defined(__XTENSA_CALL0_ABI__)
+ENTRY(__swapcontext)
+ s32i a0, a2, MCONTEXT_SC_PC
+ s32i a1, a2, MCONTEXT_SC_A_0 + 4
+
+ /* save callee-saved registers in the context */
+ s32i a12, a2, MCONTEXT_SC_A_0 + 48
+ s32i a13, a2, MCONTEXT_SC_A_0 + 52
+ s32i a14, a2, MCONTEXT_SC_A_0 + 56
+ s32i a15, a2, MCONTEXT_SC_A_0 + 60
+
+ mov a12, a3
+ mov a13, a2
+
+ addi a3, a3, UCONTEXT_SIGMASK
+ addi a4, a2, UCONTEXT_SIGMASK
+ movi a2, SIG_SETMASK
+ movi a5, JUMPTARGET (sigprocmask)
+ callx0 a5
+ bnez a2, .Lerror
+
+ mov a2, a12
+ l32i a0, a2, MCONTEXT_SC_PC
+ l32i a1, a2, MCONTEXT_SC_A_0 + 4
+
+ /* load callee-saved registers from the context */
+ l32i a12, a2, MCONTEXT_SC_A_0 + 48
+ l32i a13, a2, MCONTEXT_SC_A_0 + 52
+ l32i a14, a2, MCONTEXT_SC_A_0 + 56
+ l32i a15, a2, MCONTEXT_SC_A_0 + 60
+
+ movi a2, 0
+ ret
+.Lerror:
+ l32i a0, a13, MCONTEXT_SC_PC
+ l32i a12, a13, MCONTEXT_SC_A_0 + 48
+ l32i a13, a13, MCONTEXT_SC_A_0 + 52
+ ret
+END(__swapcontext)
+#elif defined(__XTENSA_WINDOWED_ABI__)
+ENTRY(__swapcontext)
+ movi a4, __window_spill
+ callx4 a4
+ mov a9, a3
+ s32i a0, a2, MCONTEXT_SC_PC
+
+ /* copy registers a0..a3 from spill area */
+ addi a3, a1, -16
+ l32i a4, a3, 0
+ l32i a5, a3, 4
+ l32i a6, a3, 8
+ l32i a7, a3, 12
+ s32i a4, a2, MCONTEXT_SC_A_0 + 0
+ s32i a5, a2, MCONTEXT_SC_A_0 + 4
+ s32i a6, a2, MCONTEXT_SC_A_0 + 8
+ s32i a7, a2, MCONTEXT_SC_A_0 + 12
+
+ /* if it was call4 then register saving is done */
+ extui a4, a0, 30, 2
+ bltui a4, 2, 1f
+
+ /* otherwise load spill overflow area address into a3 */
+ addi a3, a5, -16
+ l32i a3, a3, 4
+ addi a3, a3, -32
+ beqi a4, 2, 2f
+
+ /* copy registers a8..a11 from spill overflow area */
+ addi a3, a3, -16
+ l32i a4, a3, 16
+ l32i a5, a3, 20
+ l32i a6, a3, 24
+ l32i a7, a3, 28
+ s32i a4, a2, MCONTEXT_SC_A_0 + 32
+ s32i a5, a2, MCONTEXT_SC_A_0 + 36
+ s32i a6, a2, MCONTEXT_SC_A_0 + 40
+ s32i a7, a2, MCONTEXT_SC_A_0 + 44
+
+ /* copy registers a4..a7 from spill overflow area */
+2:
+ l32i a4, a3, 0
+ l32i a5, a3, 4
+ l32i a6, a3, 8
+ l32i a7, a3, 12
+ s32i a4, a2, MCONTEXT_SC_A_0 + 16
+ s32i a5, a2, MCONTEXT_SC_A_0 + 20
+ s32i a6, a2, MCONTEXT_SC_A_0 + 24
+ s32i a7, a2, MCONTEXT_SC_A_0 + 28
+1:
+ movi a6, SIG_SETMASK
+ addi a7, a9, UCONTEXT_SIGMASK
+ addi a8, a2, UCONTEXT_SIGMASK
+ mov a2, a9
+ movi a4, JUMPTARGET (sigprocmask)
+ callx4 a4
+ bnez a6, .Lerror
+
+ l32i a0, a2, MCONTEXT_SC_PC
+
+ /* copy registers a0..a3 to spill area */
+ addi a3, a1, -16
+ l32i a4, a2, MCONTEXT_SC_A_0 + 0
+ l32i a5, a2, MCONTEXT_SC_A_0 + 4
+ l32i a6, a2, MCONTEXT_SC_A_0 + 8
+ l32i a7, a2, MCONTEXT_SC_A_0 + 12
+ s32i a4, a3, 0
+ s32i a5, a3, 4
+ s32i a6, a3, 8
+ s32i a7, a3, 12
+
+ /* if it was call4 then register setup is done */
+ extui a4, a0, 30, 2
+ bltui a4, 2, 1f
+
+ /* otherwise load spill overflow area address into a3 */
+ addi a3, a5, -16
+ l32i a3, a3, 4
+ addi a3, a3, -32
+ beqi a4, 2, 2f
+
+ /* copy registers a8..a11 to spill overflow area */
+ addi a3, a3, -16
+ l32i a4, a2, MCONTEXT_SC_A_0 + 32
+ l32i a5, a2, MCONTEXT_SC_A_0 + 36
+ l32i a6, a2, MCONTEXT_SC_A_0 + 40
+ l32i a7, a2, MCONTEXT_SC_A_0 + 44
+ s32i a4, a3, 16
+ s32i a5, a3, 20
+ s32i a6, a3, 24
+ s32i a7, a3, 28
+
+ /* copy registers a4..a7 to spill overflow area */
+2:
+ l32i a4, a2, MCONTEXT_SC_A_0 + 16
+ l32i a5, a2, MCONTEXT_SC_A_0 + 20
+ l32i a6, a2, MCONTEXT_SC_A_0 + 24
+ l32i a7, a2, MCONTEXT_SC_A_0 + 28
+ s32i a4, a3, 0
+ s32i a5, a3, 4
+ s32i a6, a3, 8
+ s32i a7, a3, 12
+1:
+ movi a2, 0
+ retw
+.Lerror:
+ mov a2, a6
+ retw
+END(__swapcontext)
+#else
+#error Unsupported Xtensa ABI
+#endif
+
+weak_alias (__swapcontext, swapcontext)