Date: Fri, 7 Nov 2014 20:10:10 +0000 (UTC) From: Konstantin Belousov <kib@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r274250 - head/sys/dev/random Message-ID: <201411072010.sA7KAAkp026433@svn.freebsd.org>
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Author: kib Date: Fri Nov 7 20:10:09 2014 New Revision: 274250 URL: https://svnweb.freebsd.org/changeset/base/274250 Log: Simplify assembler in ivy.c. Move the copying of the random bits into buffer from asm to C, which reduces amount of arguments for inline asm and simplifies constraints. Use unsigned types consistently. Submitted by: bde Approved by: secteam (delphij) Reviewed by: markm MFC after: 1 week Modified: head/sys/dev/random/ivy.c Modified: head/sys/dev/random/ivy.c ============================================================================== --- head/sys/dev/random/ivy.c Fri Nov 7 19:34:10 2014 (r274249) +++ head/sys/dev/random/ivy.c Fri Nov 7 20:10:09 2014 (r274250) @@ -61,42 +61,41 @@ static struct live_entropy_source random }; static inline int -ivy_rng_store(long *buf) +ivy_rng_store(u_long *buf) { #ifdef __GNUCLIKE_ASM - long tmp; + u_long rndval; int retry; retry = RETRY_COUNT; __asm __volatile( "1:\n\t" - "rdrand %2\n\t" /* read randomness into tmp */ - "jb 2f\n\t" /* CF is set on success, exit retry loop */ + "rdrand %1\n\t" /* read randomness into tmp */ + "jc 2f\n\t" /* CF is set on success, exit retry loop */ "dec %0\n\t" /* otherwise, retry-- */ "jne 1b\n\t" /* and loop if retries are not exhausted */ - "jmp 3f\n" /* failure, retry is 0, used as return value */ - "2:\n\t" - "mov %2,%1\n\t" /* *buf = tmp */ - "3:" - : "+q" (retry), "=m" (*buf), "+q" (tmp) : : "cc"); + "2:" + : "+r" (retry), "=r" (rndval) : : "cc"); + *buf = rndval; return (retry); #else /* __GNUCLIKE_ASM */ return (0); #endif } -/* It is specifically allowed that buf is a multiple of sizeof(long) */ +/* It is required that buf length is a multiple of sizeof(u_long). */ static u_int random_ivy_read(void *buf, u_int c) { - long *b; + u_long *b, rndval; u_int count; KASSERT(c % sizeof(*b) == 0, ("partial read %d", c)); b = buf; for (count = c; count > 0; count -= sizeof(*b)) { - if (ivy_rng_store(b++) == 0) + if (ivy_rng_store(&rndval) == 0) break; + *b++ = rndval; } return (c - count); }
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