Mercurial > pub > dyncall > dyncall
annotate doc/manual/callconvs/callconv_ppc64.tex @ 356:2f64957d6a46
- fix to dynload to build with musl libc (latter has dlinfo but not RTLD_SELF, so fallback to dl_iterate_phdr if on ELF targets)
author | Tassilo Philipp |
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date | Tue, 25 Feb 2020 16:07:45 +0100 |
parents | c607d67cd6b8 |
children | b47168dacba6 |
rev | line source |
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0 | 1 %////////////////////////////////////////////////////////////////////////////// |
2 % | |
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3 % Copyright (c) 2007-2019 Daniel Adler <dadler@uni-goettingen.de>, |
0 | 4 % Tassilo Philipp <tphilipp@potion-studios.com> |
5 % | |
6 % Permission to use, copy, modify, and distribute this software for any | |
7 % purpose with or without fee is hereby granted, provided that the above | |
8 % copyright notice and this permission notice appear in all copies. | |
9 % | |
10 % THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES | |
11 % WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF | |
12 % MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR | |
13 % ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES | |
14 % WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN | |
15 % ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF | |
16 % OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. | |
17 % | |
18 %////////////////////////////////////////////////////////////////////////////// | |
19 | |
20 % ================================================== | |
21 % PowerPC 64 | |
22 % ================================================== | |
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23 \subsection{PowerPC (64bit) Calling Conventions} |
0 | 24 |
25 \paragraph{Overview} | |
26 | |
27 \begin{itemize} | |
331 | 28 \item Word size is 32 bits for historical reasons |
0 | 29 \item Big endian (MSB) and litte endian (LSB) operating modes. |
30 \item Apple Mac OS X/Darwin PPC is specified in "Mac OS X ABI Function Call Guide"\cite{ppcMacOSX}. It uses Big Endian (MSB). | |
31 \item Linux PPC 64-bit ABI is specified in "64-bit PowerPC ELF Application Binary Interface Supplement"\cite{ppcelf64abi} which is based on "System V ABI". | |
32 \end{itemize} | |
33 | |
34 \paragraph{\product{dyncall} support} | |
35 | |
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36 \product{Dyncall} and \product{dyncallback} are supported for PowerPC (64bit) |
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37 Big Endian and Little Endian ELF ABIs on System V systems. Mac OS X is not |
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38 supported.\\ |
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39 \product{Dyncall} can also be used to issue syscalls by using the syscall |
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40 number as target parameter and selecting the correct mode. |
0 | 41 |
42 | |
43 \subsubsection{PPC64 ELF ABI} | |
44 | |
45 \paragraph{Registers and register usage} | |
46 | |
331 | 47 \begin{table}[h] |
48 \begin{tabular*}{0.95\textwidth}{3 B} | |
49 Name & Brief description\\ | |
50 \hline | |
51 {\bf gpr0} & scratch\\ | |
52 {\bf gpr1} & stack pointer\\ | |
53 {\bf gpr2} & TOC base ptr (offset table and data for position independent code), scratch\\ | |
54 {\bf gpr3} & return value, parameter 0 for integer or pointer, scratch\\ | |
55 {\bf gpr4-gpr10} & parameter 1-7 for integer or pointer parameters, scratch\\ | |
0 | 56 |
331 | 57 {\bf gpr11} & env pointer if needed, scratch\\ |
58 {\bf gpr12} & used for exception handling and glink code, scratch\\ | |
59 {\bf gpr13} & used for system thread ID, preserve\\ | |
60 {\bf gpr14-31} & preserve\\ | |
61 {\bf fpr0} & scratch\\ | |
62 {\bf fpr1-fpr4} & floating point return value, floating point parameter 0-3 (always double precision)\\ | |
63 {\bf fpr5-fpr13} & floating point parameters 4-12 (always double precision)\\ | |
64 {\bf fpr14-fpr31} & preserve\\ | |
65 {\bf v0-v1} & scratch\\ | |
66 {\bf v2-v13} & vector parameters\\ | |
67 {\bf v14-v19} & scratch\\ | |
68 {\bf v20-v31} & preserve\\ | |
69 {\bf lr} & link-register, scratch\\ | |
70 {\bf ctr} & count-register, scratch\\ | |
71 {\bf xer} & fixed point exception register, scratch\\ | |
72 {\bf fpscr} & floating point status and control register, scratch\\ | |
73 {\bf cr0-cr7} & conditional register fields, each 4-bit wide (cr0-cr1 and cr5-cr7 are scratch)\\ | |
74 \end{tabular*} | |
75 \caption{Register usage on PowerPC 64-Bit ELF ABI} | |
76 \end{table} | |
0 | 77 |
78 \paragraph{Parameter passing} | |
79 | |
123 | 80 \begin{itemize} |
331 | 81 \item stack grows down |
82 \item stack parameter order: right-to-left | |
83 \item caller cleans up the stack | |
84 \item stack is always 16 byte aligned | |
85 \item the stack pointer must be atomically updated (to avoid any timing window in which an interrupt can occur with a partially updated stack), usually with the stdu (store doubleword with update) instruction | |
86 \item the first 8 integer parameters are passed in registers gpr3-gpr10 | |
87 \item the first 13 floating point parameters are passed in registers fpr1-fpr13 | |
88 \item preserved registers are saved using a defined order (from high to low addresses): | |
89 fpr* (64bit aligned), | |
90 gpr*, | |
91 VRSAVE save word (32 bits), | |
92 padding for alignment (4 or 12 bytes), | |
93 v* (128bit aligned) | |
94 \item if a floating point parameter is passed via a register, a gpr registers is skipped for subsequent integer parameters | |
95 \item the caller pushes subsequent parameters onto the stack | |
96 \item single precision floating point values use the second word in a doubleword | |
97 \item a quad precision floating point argument is passed as two consecutive double precision ones | |
98 \item integer types \textless\ 64 bit are sign or zero extended and use a doubleword | |
99 \item ellipsis calls take floating point values in int and float registers (single precision floats are promoted to double precision as | |
100 required by ellipsis calls) | |
101 \item space for all potential gpr* register passed arguments is reserved in the stack parameter area (in order to spill the parameters if | |
102 needed - e.g. varargs), meaning a minimum of 64 bytes to hold gpr3-gpr10 | |
103 \item all nonvector parameters are aligned on 8-byte boundaries | |
104 \item vector parameters are aligned on 16-byte boundaries | |
125 | 105 \item integer parameters \textless\ 64 bit are right-justified (meaning occupy higher-address bytes) in their 8-byte slot on the stack, requiring extra-care for big-endian targets |
123 | 106 \end{itemize} |
0 | 107 |
108 | |
109 \paragraph{Return values} | |
110 | |
331 | 111 \begin{itemize} |
112 \item return values of integer \textless=\ 32bit or pointer type use gpr3 and are zero or sign extended depending on their type | |
113 \item 64 bit integers use gpr3 | |
114 \item floating point values are returned via fpr1 | |
115 \item character arrays \textless=\ 8 bytes use gpr3, and are right justified | |
116 \item for all structs/unions (regardless of size) or character arrays \textgreater\ 8 bytes, a secret first parameter with an address to a caller allocated space is passed as first argument to the function (meaning in gpr3), which is written to by the callee | |
117 \end{itemize} | |
0 | 118 |
119 | |
120 \paragraph{Stack layout} | |
121 | |
331 | 122 Stack frame is always 16-byte aligned. |
123 % verified/amended: TP nov 2019 (see also doc/disas_examples/ppc64.elfabi.disas) | |
124 Stack directly after function prolog:\\ | |
0 | 125 |
331 | 126 \begin{figure}[h] |
127 \begin{tabular}{5|3|1 1} | |
128 & \vdots & & \\ | |
129 \hhline{~=~~} | |
130 register save area & \hspace{4cm} & & \mrrbrace{14}{caller's frame} \\ | |
131 \hhline{~-~~} | |
132 local data & & & \\ | |
133 \hhline{~-~~} | |
134 \mrlbrace{6}{parameter area} & last arg & \mrrbrace{3}{stack parameters} & \\ | |
135 & \ldots & & \\ | |
136 & arg 8 & & \\ | |
137 & gpr10 & \mrrbrace{3}{spill area (as needed)} & \\ | |
138 & \ldots & & \\ | |
139 & gpr3 & & \\ | |
140 \hhline{~-~~} | |
141 \mrlbrace{6}{linkage area} & TOC ptr reg & & \\ | |
142 & reserved & & \\ | |
143 & reserved & & \\ | |
144 & return address (callee saved) & & \\ | |
145 & condition reg (callee saved) & & \\ | |
146 & parent stack frame pointer & & \\ | |
147 \hhline{~=~~} | |
148 register save area & & & \mrrbrace{4}{current frame} \\ | |
149 \hhline{~-~~} | |
150 local data & & & \\ | |
151 \hhline{~-~~} | |
152 parameter area & & & \\ | |
153 \hhline{~-~~} | |
154 linkage area & \vdots & & \\ | |
155 \end{tabular} | |
156 \caption{Stack layout on ppc64 ELF ABI} | |
157 \end{figure} | |
158 | |
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159 |
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160 \newpage |
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161 |
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162 \subsubsection{System V syscalls} |
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163 |
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164 \paragraph{Parameter passing} |
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165 |
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166 \begin{itemize} |
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167 \item syscall is issued via the {\em sc} instruction |
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168 \item kernel destroys registers r13 |
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169 \item syscall number is set in r0 |
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170 \item params are passed in registers r3 through r10 |
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171 \item no stack in use, meaning syscalls are in theory limited to eight arguments |
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172 \item register r3 holds the return value, overflow flag in conditional register cr0 signals errors in syscall |
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173 \end{itemize} |
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174 |