1/*
2    Copyright (c) 2001-2006 by Tensilica Inc.
3
4    Permission is hereby granted, free of charge, to any person obtaining
5    a copy of this software and associated documentation files (the
6    "Software"), to deal in the Software without restriction, including
7    without limitation the rights to use, copy, modify, merge, publish,
8    distribute, sublicense, and/or sell copies of the Software, and to
9    permit persons to whom the Software is furnished to do so, subject to
10    the following conditions:
11
12    The above copyright notice and this permission notice shall be included
13    in all copies or substantial portions of the Software.
14
15    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
16    EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
17    MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
18    IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
19    CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
20    TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
21    SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
22*/
23
24/*
25  This file contains a modified version of the original Xtensa longjmp implementation.
26  In this modified version, setting WINDOWSTART = 1 << WINDOWBASE is done inside a critical section.
27  This is necessary because after a FreeRTOS context switch in IDF, the values of WINDOWBASE and WINDOWSTART
28  are not guaranteed to be the same as before the context switch.
29*/
30
31#include <xtensa/corebits.h>
32#include <sdkconfig.h>
33
34/* void longjmp (jmp_buf env, int val) */
35
36    .align  4
37    .literal_position
38    .global __wrap_longjmp
39    .type   __wrap_longjmp, @function
40__wrap_longjmp:
41    entry   sp, 16
42
43    /* Deactivate interrupts in order to modify WINDOWBASE and WINDOWSTART. */
44    rsr     a7, PS                     /* to be restored after SPILL_ALL_WINDOWS */
45    movi    a5, PS_EXCM                /* PS_INTLEVEL_MASK */
46    or      a5, a7, a5                 /* get the current INTLEVEL */
47    wsr     a5, PS
48
49    /* Invalidate all but the current window;
50       set WindowStart to (1 << WindowBase).  */
51    rsr a5, WINDOWBASE
52    movi    a4, 1
53    ssl a5
54    sll a4, a4
55    wsr a4, WINDOWSTART
56    rsync
57
58    /* Activate interrupts again after modifying WINDOWBASE and WINDOWSTART. */
59    wsr     a7, PS
60
61#if !CONFIG_IDF_TARGET_ESP32S3
62
63    /*
64        If not on S3, replacement of only the first instructions,
65        then jump back to original longjmp implementation.
66        The jump target is the instrucion
67    	    l32i	a0, a2, 64
68        of the original code. Hence, the original code's entry instruction and windowstart modification are left
69        out.
70     */
71    movi a0, __real_longjmp + 20
72    jx a0
73
74    .size   __wrap_longjmp, . - __wrap_longjmp
75
76#else /* CONFIG_IDF_TARGET_ESP32S3 */
77    /*
78       If on S3, we replace the whole function for simplicity. The placement of longjmp in ROM is ECO-dependent
79       on S3.
80    */
81
82    /*
83	   Return to the return address of the setjmp, using the
84	   window size bits from the setjmp call so that the caller
85	   will be able to find the return value that we put in a2.  */
86
87	l32i	a0, a2, 64
88
89	/* Copy the first 4 saved registers from jmp_buf into the save area
90	   at the current sp so that the values will be restored to registers
91	   when longjmp returns.  */
92
93	addi	a7, a1, -16
94	l32i	a4, a2, 0
95	l32i	a5, a2, 4
96	s32i	a4, a7, 0
97	s32i	a5, a7, 4
98	l32i	a4, a2, 8
99	l32i	a5, a2, 12
100	s32i	a4, a7, 8
101	s32i	a5, a7, 12
102
103	/* Copy the remaining 0-8 saved registers.  */
104	extui	a7, a0, 30, 2
105	blti	a7, 2, .Lendlj
106	l32i	a8, a2, 52
107	slli	a4, a7, 4
108	sub	a6, a8, a4
109	addi	a5, a2, 16
110	addi	a8, a8, -16		// a8 = end of register overflow area
111.Lljloop:
112	l32i	a7, a5, 0
113	l32i	a4, a5, 4
114	s32i	a7, a6, 0
115	s32i	a4, a6, 4
116	l32i	a7, a5, 8
117	l32i	a4, a5, 12
118	s32i	a7, a6, 8
119	s32i	a4, a6, 12
120	addi	a5, a5, 16
121	addi	a6, a6, 16
122	blt	a6, a8, .Lljloop
123.Lendlj:
124
125	/* The 4 words saved from the register save area at the target's
126	   sp are copied back to the target procedure's save area.  The
127	   only point of this is to prevent a catastrophic failure in
128	   case the contents were moved by an alloca after calling
129	   setjmp.  This is a bit paranoid but it doesn't cost much.  */
130
131	l32i	a7, a2, 4		// load the target stack pointer
132	addi	a7, a7, -16		// find the destination save area
133	l32i	a4, a2, 48
134	l32i	a5, a2, 52
135	s32i	a4, a7, 0
136	s32i	a5, a7, 4
137	l32i	a4, a2, 56
138	l32i	a5, a2, 60
139	s32i	a4, a7, 8
140	s32i	a5, a7, 12
141
142	/* Return val ? val : 1.  */
143	movi	a2, 1
144	movnez	a2, a3, a3
145
146	retw
147    .size   __wrap_longjmp, . - __wrap_longjmp
148
149#endif /* CONFIG_IDF_TARGET_ESP32S3 */
150