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

Add CFI start/end proc directives to arm64, i386, and ppc

2020-12-05T00:33:28Z

Follow-up to r353959 and r368070: do the same for other architectures. arm32 already seems to use its own .fnstart/.fnend directives, which appear to be ARM-specific variants of the same thing. Likewise, MIPS uses .frame directives. Reviewed by: arichardson Differential Revision: https://reviews.freebsd.org/D27387

[PowerPC64LE] Fix gdtoa configurations on LE.

2020-09-23T02:05:44Z

gdtoa wins the award for "most outdated endianness naming convention" with its IEEE_8087 vs IEEE_MC68k defines. I had a good chuckle. Update softfloat and arith.h to adjust to BE or LE automatically based on the low level preprocessor defines. Fixes printf/scanf on PowerPC64LE, although there is still a problem lurking regarding Signalling NaNs... Sponsored by: Tag1 Consulting, Inc.

[PowerPC] Implement VDSO timebase access on powerpc*

2020-09-08T03:00:31Z

Implement the remaining pieces needed to allow userland timestamp reading. Rewritten based on an intial essay into the problem by Justin Hibbits. (Copyright changed to my own on his request.) Tested on ppc64 (POWER9 Talos II), powerpcspe (e500v2 RB800), and powerpc (g4 PowerBook). Reviewed by: jhibbits (in irc) Sponsored by: Tag1 Consulting, Inc. Differential Revision: https://reviews.freebsd.org/D26347

[PowerPC] Fix typo in _ctx_start on ppc32

2019-11-23T23:41:21Z

Theoretically, this was breaking the size calculation for the symbol. Noticed when doing a readthrough. Reviewed by: imp Differential Revision: https://reviews.freebsd.org/D22525

powerpc: Transition to Secure-PLT, like most other OSs

2019-06-25T00:40:44Z

Summary: PowerPC has two PLT models: BSS-PLT and Secure-PLT. BSS-PLT uses runtime code generation to generate the PLT stubs. Secure-PLT was introduced with GCC 4.1 and Binutils 2.17 (base has GCC 4.2.1 and Binutils 2.17), and is a more secure PLT format, using a read-only linkage table, with the dynamic linker populating a non-executable index table. This is the libc, rtld, and kernel support only. The toolchain and build parts will be updated separately. Reviewed By: nwhitehorn, bdragon, pfg Differential Revision: https://reviews.freebsd.org/D20598 MFC after: 1 month

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

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

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

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