Date: Mon, 7 Oct 2019 12:53:27 +0000 (UTC) From: Andriy Gapon <avg@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r353270 - head/sys/cddl/contrib/opensolaris/common/atomic/i386 Message-ID: <201910071253.x97CrRcF015960@repo.freebsd.org>
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Author: avg Date: Mon Oct 7 12:53:27 2019 New Revision: 353270 URL: https://svnweb.freebsd.org/changeset/base/353270 Log: fix up r353168, add atomic_swap_64 to i386 version of opensolaris_atomic.S The compatibility code for the atomic operations in ZFS code is a bit messy. In some cases the native definitions are directly made available, in some cases there are emulated operations in opensolaris_atomic.c and in yet other cases there are atomic operations implemented in assembly that were obtained from OpenSolaris / illumos. This commit adds atomic_swap_64 for use with i386 userland. The code is copied from illumos. I am not sure why FreeBSD does not provide that operation natively. Maybe because we try (or pretend) to support processors that did not have the necessary instructions. While here I also added atomic_load_64 for the same reasons. This is original code based on iilumos atomic_swap_64 and FreeBSD atomic_load_acq_64_i586. Pointyhat to: avg MFC after: 1 week Modified: head/sys/cddl/contrib/opensolaris/common/atomic/i386/opensolaris_atomic.S Modified: head/sys/cddl/contrib/opensolaris/common/atomic/i386/opensolaris_atomic.S ============================================================================== --- head/sys/cddl/contrib/opensolaris/common/atomic/i386/opensolaris_atomic.S Mon Oct 7 12:51:36 2019 (r353269) +++ head/sys/cddl/contrib/opensolaris/common/atomic/i386/opensolaris_atomic.S Mon Oct 7 12:53:27 2019 (r353270) @@ -126,6 +126,34 @@ ret SET_SIZE(atomic_cas_64) + ENTRY(atomic_swap_64) + pushl %esi + pushl %ebx + movl 12(%esp), %esi + movl 16(%esp), %ebx + movl 20(%esp), %ecx + movl (%esi), %eax + movl 4(%esi), %edx // %edx:%eax = old value +1: + lock + cmpxchg8b (%esi) + jne 1b + popl %ebx + popl %esi + ret + SET_SIZE(atomic_swap_64) + + ENTRY(atomic_load_64) + pushl %esi + movl 8(%esp), %esi + movl %ebx, %eax // make old and new values equal, so that + movl %ecx, %edx // destination is never changed + lock + cmpxchg8b (%esi) + popl %esi + ret + SET_SIZE(atomic_load_64) + ENTRY(membar_producer) lock xorl $0, (%esp)
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