src-test/lib/libc/i386, branch main

remove obsolete i386 MD memchr implementation

2019-09-25T16:49:22Z

bde reports (in a reply to r351700 commit mail): This uses scasb, which was last optimal on the 8086, or perhaps the original i386. On freefall, it is several times slower than the naive translation of the naive C code. Reported by: bde Reviewed by: kib, markj Sponsored by: The FreeBSD Foundation Differential Revision: https://reviews.freebsd.org/D21785

Fix initial exec TLS mode for dynamically loaded shared objects.

2019-03-29T17:52:57Z

If dso uses initial exec TLS mode, rtld tries to allocate TLS in static space. If there is no space left, the dlopen(3) fails. If space if allocated, initial content from PT_TLS segment is distributed to all threads' pcbs, which was missed and caused un-initialized TLS segment for such dso after dlopen(3). The mode is auto-detected either due to the relocation used, or if the DF_STATIC_TLS dynamic flag is set. In the later case, the TLS segment is tried to allocate earlier, which increases chance of the dlopen(3) to succeed. LLD was recently fixed to properly emit the flag, ld.bdf did it always. Initial test by: dumbbell Tested by: emaste (amd64), ian (arm) Tested by: Gerald Aryeetey (arm64) Sponsored by: The FreeBSD Foundation MFC after: 2 weeks Differential revision: https://reviews.freebsd.org/D19072

Add usermode helpers for for Intel userspace protection keys feature.

2019-02-20T09:56:23Z

Reviewed by: markj Tested by: pho Sponsored by: The FreeBSD Foundation MFC after: 2 weeks Differential revision: https://reviews.freebsd.org/D18893

Unify i386 and amd64 getcontextx.c, and use ifuncs while there.

2019-02-14T14:02:33Z

In particular, use ifuncs for __getcontextx_size(), also calculate the size of the extended save area in resolver. Same for __fillcontextx2(). Sponsored by: The FreeBSD Foundation MFC after: 1 week

Remove MD __sys_* private symbols.

2018-12-05T00:46:09Z

No references to any of these exist in the tree. The list was also erratic with different architectures exporting different things (arm64 and riscv exported none). Reviewed by: kib Sponsored by: DARPA, AFRL Differential Revision: https://reviews.freebsd.org/D18425

amd64: depessimize userspace memcpy/memmove/bcopy

2018-09-17T15:49:35Z

The change resembles what was done in r334537 for kernel routines. While here take care of i386 variants. Note that primitives remain suboptimal. Reviewed by: kib (previous version) Approved by: re (gjb) Differential Revision: https://reviews.freebsd.org/D17167

Reimplement brk() and sbrk() to avoid the use of _end.

2018-06-04T19:35:15Z

Previously, libc.so would initialize its notion of the break address using _end, a special symbol emitted by the static linker following the bss section. Compatibility issues between lld and ld.bfd could cause the wrong definition of _end (libc.so's definition rather than that of the executable) to be used, breaking the brk()/sbrk() interface. Avoid this problem and future interoperability issues by simply not relying on _end. Instead, modify the break() system call to return the kernel's view of the current break address, and have libc initialize its state using an extra syscall upon the first use of the interface. As a side effect, this appears to fix brk()/sbrk() usage in executables run with rtld direct exec, since the kernel and libc.so no longer maintain separate views of the process' break address. PR: 228574 Reviewed by: kib (previous version) MFC after: 2 months Differential Revision: https://reviews.freebsd.org/D15663

Remove support for SYS_sys_exit in favor of SYS_exit.

2018-06-01T22:09:27Z

SYS_exit has been defined in the repo since 1994 except for a brief window when SYS_sys_exit was defined in 2000.

Replace MD assembly exect() with a portable version.

2018-04-12T18:23:14Z

Originally, on the VAX exect() enable tracing once the new executable image was loaded. This was possible because tracing was controllable through user space code by setting the PSL_T flag. The following instruction is a system call that activated tracing (as all instructions do) by copying PSL_T to PSL_TP (trace pending). The first instruction of the new executable image would trigger a trace fault. This is not portable to all platforms and the behavior was replaced with ptrace(PT_TRACE_ME, ...) since FreeBSD forked off of the CSRG repository. Platforms either incorrectly call execve(), trigger trace faults inside the original executable, or do contain an implementation of this function. The exect() interfaces is deprecated or removed on NetBSD and OpenBSD. Submitted by: Ali Mashtizadeh Reviewed by: kib Differential Revision: https://reviews.freebsd.org/D14989

Remove caching from getlogin(2).

2018-04-06T17:17:34Z

This caching has existed since the CSRG import, but serves no obvious purpose. Sure, setlogin() is called rarely, but calls to getlogin() should also be infrequent. The required invalidation was not implemented on aarch64, arm, mips, amd riscv so updates would never occur if getlogin() was called before setlogin(). Reported by: Ali Mashtizadeh Reviewed by: kib Sponsored by: DARPA, AFRL Differential Revision: https://reviews.freebsd.org/D14965