pcre: fix instruction cache flush bug on ppc*

This commit is contained in:
Jake Hamby 2022-02-28 22:38:18 +01:00 committed by q66
parent c2b48f1ec4
commit 8e1eceec43
2 changed files with 103 additions and 1 deletions

View file

@ -0,0 +1,102 @@
GCC's version of __builtin___clear_cache() is a no-op on PowerPC.
Change to use an improved version of the existing ppc_cache_flush().
--- a/sljit/sljitConfigInternal.h 2022-02-12 21:42:26.812059103 -0800
+++ b/sljit/sljitConfigInternal.h 2022-02-12 21:42:57.508834803 -0800
@@ -284,7 +284,8 @@
/****************************/
#if (!defined SLJIT_CACHE_FLUSH && defined __has_builtin)
-#if __has_builtin(__builtin___clear_cache)
+#if __has_builtin(__builtin___clear_cache) && \
+ !(defined SLJIT_CONFIG_PPC && SLJIT_CONFIG_PPC)
#define SLJIT_CACHE_FLUSH(from, to) \
__builtin___clear_cache((char*)from, (char*)to)
--- a/sljit/sljitNativePPC_common.c 2022-02-12 21:42:26.816059204 -0800
+++ b/sljit/sljitNativePPC_common.c 2022-02-12 21:42:57.512834904 -0800
@@ -46,6 +46,39 @@
#define SLJIT_PASS_ENTRY_ADDR_TO_CALL 1
#endif
+#ifdef __linux__
+#include <sys/auxv.h>
+
+/* Return the instruction cache line size, in bytes. */
+static SLJIT_INLINE sljit_u32 get_icache_line_size()
+{
+ static sljit_u32 icache_line_size = 0;
+ if (SLJIT_UNLIKELY(!icache_line_size)) {
+ icache_line_size = (sljit_u32) getauxval(AT_ICACHEBSIZE);
+ SLJIT_ASSERT(icache_line_size != 0);
+ }
+ return icache_line_size;
+}
+
+/* Cache and return the first hardware capabilities word. */
+static SLJIT_INLINE unsigned long get_hwcap()
+{
+ static unsigned long hwcap = 0;
+ if (SLJIT_UNLIKELY(!hwcap)) {
+ hwcap = getauxval(AT_HWCAP);
+ SLJIT_ASSERT(hwcap != 0);
+ }
+ return hwcap;
+}
+
+/* Return non-zero if this CPU has the icache snoop feature. */
+static SLJIT_INLINE unsigned long has_feature_icache_snoop()
+{
+ return (get_hwcap() & PPC_FEATURE_ICACHE_SNOOP);
+}
+
+#endif /* __linux__ */
+
#if (defined SLJIT_CACHE_FLUSH_OWN_IMPL && SLJIT_CACHE_FLUSH_OWN_IMPL)
static void ppc_cache_flush(sljit_ins *from, sljit_ins *to)
@@ -68,14 +101,40 @@
# error "Cache flush is not implemented for PowerPC/POWER common mode."
# else
/* Cache flush for PowerPC architecture. */
- while (from < to) {
+ /* For POWER5 and up with icache snooping, only one icbi in the range
+ * is required. The sync flushes the store queue, and the icbi/isync
+ * kills the local prefetch.
+ */
+ if (has_feature_icache_snoop()) {
__asm__ volatile (
- "dcbf 0, %0\n"
"sync\n"
"icbi 0, %0\n"
- : : "r"(from)
+ "isync\n"
+ : : "r"(from) : "memory"
+ );
+ return;
+ }
+
+ sljit_u32 cache_line_bytes = get_icache_line_size();
+ sljit_u32 cache_line_words = cache_line_bytes / sizeof(sljit_ins);
+ uintptr_t cache_line_mask = ~(uintptr_t)(cache_line_bytes - 1);
+
+ /* Round down to start of cache line to simplify the end condition. */
+ sljit_ins* start = (sljit_ins*)((uintptr_t)(from) & cache_line_mask);
+
+ for (from = start; from < to; from += cache_line_words) {
+ __asm__ volatile (
+ "dcbf 0, %0"
+ : : "r"(from) : "memory"
+ );
+ }
+ __asm__ volatile ( "sync" );
+
+ for (from = start; from < to; from += cache_line_words) {
+ __asm__ volatile (
+ "icbi 0, %0"
+ : : "r"(from) : "memory"
);
- from++;
}
__asm__ volatile ( "isync" );
# endif

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@ -1,7 +1,7 @@
# Template file for 'pcre'
pkgname=pcre
version=8.45
revision=2
revision=3
build_style=gnu-configure
configure_args="--enable-utf8 --enable-unicode-properties --with-pic
--enable-pcregrep-libz --enable-pcregrep-libbz2 --enable-newline-is-anycrlf