- [Notes on multi-threading](#notes-on-multi-threading)
- [Notes on shared libraries](#notes-on-shared-libraries)
- [Notes on random number generation](#notes-on-random-number-generation)
+ - [Notes on assembler modules compilation](#notes-on-assembler-modules-compilation)
Prerequisites
=============
Build the OpenSSL libraries to support the API for the specified version.
If [no-deprecated](#no-deprecated) is also given, don't build with support
for deprecated APIs in or below the specified version number. For example,
-addding
+adding
--api=1.1.0 no-deprecated
The name of the directory under the top of the installation directory tree
(see the `--prefix` option) where libraries will be installed. By default
-this is `lib/`. Note that on Windows only static libraries (`*.lib`) will
+this is `lib`. Note that on Windows only static libraries (`*.lib`) will
be stored in this location. Shared libraries (`*.dll`) will always be
-installed to the `bin/` directory.
+installed to the `bin` directory.
+
+Some build targets have a multilib postfix set in the build configuration.
+For these targets the default libdir is `lib<multilib-postfix>`. Please use
+`--libdir=lib` to override the libdir if adding the postfix is undesirable.
### openssldir
gcc or clang and should be used in conjunction with the [no-shared](#no-shared)
option.
-### no-acvp_tests
+### enable-acvp-tests
-Do not build support for Automated Cryptographic Validation Protocol (ACVP)
+Build support for Automated Cryptographic Validation Protocol (ACVP)
tests.
This is required for FIPS validation purposes. Certain ACVP tests require
the C++ compiler. If not, the C++ build test will most likely break. As an
alternative, you can use the language specific variables, `CFLAGS` and `CXXFLAGS`.
+### --banner=text
+
+Use the specified text instead of the default banner at the end of
+configuration.
+
+### --w
+
+On platforms where the choice of 32-bit or 64-bit architecture
+is not explicitly specified, `Configure` will print a warning
+message and wait for a few seconds to let you interrupt the
+configuration. Using this flag skips the wait.
+
### no-bulk
Build only some minimal set of features.
Don't compile in filename and line number information (e.g. for errors and
memory allocation).
-### no-fips
+### enable-fips
-Don't compile the FIPS provider
+Build (and install) the FIPS provider
### no-fips-securitychecks
"audience" running such kernel, consider `no-sse2`. Both the `386` and `no-asm`
options imply `no-sse2`.
-### enable-ssl-trace
+### no-ssl-trace
-Build with the SSL Trace capabilities.
+Don't build with SSL Trace capabilities.
-This adds the `-trace` option to `s_client` and `s_server`.
+This removes the `-trace` option from `s_client` and `s_server`, and omits the
+`SSL_trace()` function from libssl.
+
+Disabling `ssl-trace` may provide a small reduction in libssl binary size.
### no-static-engine
### Automatic Configuration
-On some platform a `config` script is available which attempts to guess
-your operating system (and compiler, if necessary) and calls the `Configure`
-Perl script with appropriate target based on its guess. Further options can
-be supplied to the `config` script, which will be passed on to the `Configure`
-script.
+In previous version, the `config` script determined the platform type and
+compiler and then called `Configure`. Starting with this release, they are
+the same.
#### Unix / Linux / macOS
"--cross-compile-prefix" Configure flag described above. If both
are set then the Configure flag takes precedence.
+ HASHBANGPERL
+ The command string for the Perl executable to insert in the
+ #! line of perl scripts that will be publicly installed.
+ Default: /usr/bin/env perl
+ Note: the value of this variable is added to the same scripts
+ on all platforms, but it's only relevant on Unix-like platforms.
+
+ KERNEL_BITS
+ This can be the value `32` or `64` to specify the architecture
+ when it is not "obvious" to the configuration. It should generally
+ not be necessary to specify this environment variable.
+
NM
The name of the nm executable to use.
Only needed if builing should use a different Perl executable
than what is used to run the Configure script.
- HASHBANGPERL
- The command string for the Perl executable to insert in the
- #! line of perl scripts that will be publicly installed.
- Default: /usr/bin/env perl
- Note: the value of this variable is added to the same scripts
- on all platforms, but it's only relevant on Unix-like platforms.
+ RANLIB
+ The name of the ranlib executable to use.
RC
The name of the rc executable to use. The default will be as
variable is synonymous to this. If both are defined then RC
takes precedence.
- RANLIB
- The name of the ranlib executable to use.
-
WINDRES
See RC.
$ mms clean ! (or mmk) OpenVMS
$ nmake clean # Windows
-Assembler error messages can sometimes be sidestepped by using the
-`no-asm` configuration option.
+Assembler error messages can sometimes be sidestepped by using the `no-asm`
+configuration option. See also [notes](#notes-on-assembler-modules-compilation).
Compiling parts of OpenSSL with gcc and others with the system compiler will
result in unresolved symbols on some systems.
the CSPRNG manually. Please check out the manual pages for `RAND_add()`,
`RAND_bytes()`, `RAND_egd()`, and the FAQ for more information.
+Notes on assembler modules compilation
+--------------------------------------
+
+Compilation of some code paths in assembler modules might depend on whether the
+current assembler version supports certain ISA extensions or not. Code paths
+that use the AES-NI, PCLMULQDQ, SSSE3, and SHA extensions are always assembled.
+Apart from that, the minimum requirements for the assembler versions are shown
+in the table below:
+
+| ISA extension | GNU as | nasm | llvm |
+|---------------|--------|--------|---------|
+| AVX | 2.19 | 2.09 | 3.0 |
+| AVX2 | 2.22 | 2.10 | 3.1 |
+| ADCX/ADOX | 2.23 | 2.10 | 3.3 |
+| AVX512 | 2.25 | 2.11.8 | 3.6 (*) |
+| AVX512IFMA | 2.26 | 2.11.8 | 6.0 (*) |
+| VAES | 2.30 | 2.13.3 | 6.0 (*) |
+
+---
+
+(*) Even though AVX512 support was implemented in llvm 3.6, prior to version 7.0
+an explicit -march flag was apparently required to compile assembly modules. But
+then the compiler generates processor-specific code, which in turn contradicts
+the idea of performing dispatch at run-time, which is facilitated by the special
+variable `OPENSSL_ia32cap`. For versions older than 7.0, it is possible to work
+around the problem by forcing the build procedure to use the following script:
+
+ #!/bin/sh
+ exec clang -no-integrated-as "$@"
+
+instead of the real clang. In which case it doesn't matter what clang version
+is used, as it is the version of the GNU assembler that will be checked.
+
+---
+
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