Date: Fri, 7 Apr 2017 22:58:20 +0000 (UTC) From: Alexander Kabaev <kan@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r316624 - head/lib/libc/aarch64 Message-ID: <201704072258.v37MwKN3004884@repo.freebsd.org>
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Author: kan Date: Fri Apr 7 22:58:20 2017 New Revision: 316624 URL: https://svnweb.freebsd.org/changeset/base/316624 Log: Do not use b.cs instruction to jump to cerror. The conditional jump can only be performed to targets up to 1MB in either direction and does not work too well when linker places cerror further that that from the caller. In that case linker will complain about relocation overflows. Reviewed by: emaste, andrew Differential Revision: https://reviews.freebsd.org/D10305 Modified: head/lib/libc/aarch64/SYS.h Modified: head/lib/libc/aarch64/SYS.h ============================================================================== --- head/lib/libc/aarch64/SYS.h Fri Apr 7 21:06:50 2017 (r316623) +++ head/lib/libc/aarch64/SYS.h Fri Apr 7 22:58:20 2017 (r316624) @@ -45,12 +45,19 @@ ENTRY(__sys_##name); \ ret; \ END(__sys_##name) +/* + * Conditional jumps can only go up to one megabyte in either + * direction, and cerror can be located anywhere, so we have + * to jump around to use more capable unconditional branch + * instruction. + */ #define PSEUDO(name) \ ENTRY(__sys_##name); \ WEAK_REFERENCE(__sys_##name, _##name); \ _SYSCALL(name); \ - b.cs cerror; \ + b.cs 1f; \ ret; \ +1: b cerror; \ END(__sys_##name) #define RSYSCALL(name) \ @@ -58,6 +65,7 @@ ENTRY(__sys_##name); \ WEAK_REFERENCE(__sys_##name, name); \ WEAK_REFERENCE(__sys_##name, _##name); \ _SYSCALL(name); \ - b.cs cerror; \ + b.cs 1f; \ ret; \ +1: b cerror; \ END(__sys_##name)
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