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view src/os/unix/ngx_gcc_atomic_amd64.h @ 566:0161f3197817 NGINX_0_8_15
nginx 0.8.15
*) Security: a segmentation fault might occur in worker process while
specially crafted request handling.
Thanks to Chris Ries.
*) Bugfix: if names .domain.tld, .sub.domain.tld, and .domain-some.tld
were defined, then the name .sub.domain.tld was matched by
.domain.tld.
*) Bugfix: in transparency support in the ngx_http_image_filter_module.
*) Bugfix: in file AIO.
*) Bugfix: in X-Accel-Redirect usage; the bug had appeared in 0.8.11.
*) Bugfix: in embedded perl module; the bug had appeared in 0.8.11.
author | Igor Sysoev <http://sysoev.ru> |
---|---|
date | Mon, 14 Sep 2009 00:00:00 +0400 |
parents | 052a7b1d40e5 |
children |
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/* * Copyright (C) Igor Sysoev */ #if (NGX_SMP) #define NGX_SMP_LOCK "lock;" #else #define NGX_SMP_LOCK #endif /* * "cmpxchgq r, [m]": * * if (rax == [m]) { * zf = 1; * [m] = r; * } else { * zf = 0; * rax = [m]; * } * * * The "r" is any register, %rax (%r0) - %r16. * The "=a" and "a" are the %rax register. * Although we can return result in any register, we use "a" because it is * used in cmpxchgq anyway. The result is actually in %al but not in $rax, * however as the code is inlined gcc can test %al as well as %rax. * * The "cc" means that flags were changed. */ static ngx_inline ngx_atomic_uint_t ngx_atomic_cmp_set(ngx_atomic_t *lock, ngx_atomic_uint_t old, ngx_atomic_uint_t set) { u_char res; __asm__ volatile ( NGX_SMP_LOCK " cmpxchgq %3, %1; " " sete %0; " : "=a" (res) : "m" (*lock), "a" (old), "r" (set) : "cc", "memory"); return res; } /* * "xaddq r, [m]": * * temp = [m]; * [m] += r; * r = temp; * * * The "+r" is any register, %rax (%r0) - %r16. * The "cc" means that flags were changed. */ static ngx_inline ngx_atomic_int_t ngx_atomic_fetch_add(ngx_atomic_t *value, ngx_atomic_int_t add) { __asm__ volatile ( NGX_SMP_LOCK " xaddq %0, %1; " : "+r" (add) : "m" (*value) : "cc", "memory"); return add; } #define ngx_memory_barrier() __asm__ volatile ("" ::: "memory") #define ngx_cpu_pause() __asm__ ("pause")