libbb: add and use infrastructure for fixed page size optimization

function                                             old     new   delta
procps_scan                                         1121    1118      -3
getpagesize                                            6       -      -6
rpm_main                                            1037    1027     -10
rpm2cpio_main                                        120     110     -10
ptok                                                  38      21     -17
time_main                                           1282    1261     -21
mkswap_main                                          317     278     -39
------------------------------------------------------------------------------
(add/remove: 0/2 grow/shrink: 0/6 up/down: 0/-106)           Total: -106 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

3 files changed, 10 insertions, 13 deletions

diff --git a/miscutils/devmem.c b/miscutils/devmem.c
index e8dce52..f9f0276 100644
--- a/miscutils/devmem.c
+++ b/miscutils/devmem.c
@@ -75,7 +75,7 @@ int devmem_main(int argc UNUSED_PARAM, char **argv)
 		bb_show_usage(); /* one of bb_strtouXX failed */
 
 	fd = xopen("/dev/mem", argv[3] ? (O_RDWR | O_SYNC) : (O_RDONLY | O_SYNC));
-	mapped_size = page_size = getpagesize();
+	mapped_size = page_size = bb_getpagesize();
 	offset_in_page = (unsigned)target & (page_size - 1);
 	if (offset_in_page + width > page_size) {
 		/* This access spans pages.
diff --git a/miscutils/hexedit.c b/miscutils/hexedit.c
index 898d773..f8ff9b6 100644
--- a/miscutils/hexedit.c
+++ b/miscutils/hexedit.c
@@ -31,7 +31,8 @@ struct globals {
 	int fd;
 	unsigned height;
 	unsigned row;
-	unsigned pagesize;
+	IF_VARIABLE_ARCH_PAGESIZE(unsigned pagesize;)
+#define G_pagesize cached_pagesize(G.pagesize)
 	uint8_t *baseaddr;
 	uint8_t *current_byte;
 	uint8_t *eof_byte;
@@ -46,15 +47,6 @@ struct globals {
 	SET_PTR_TO_GLOBALS(xzalloc(sizeof(G))); \
 } while (0)
 
-//TODO: move to libbb
-#if defined(__x86_64__) || defined(i386)
-# define G_pagesize 4096
-# define INIT_PAGESIZE() ((void)0)
-#else
-# define G_pagesize (G.pagesize)
-# define INIT_PAGESIZE() ((void)(G.pagesize = getpagesize()))
-#endif
-
 /* hopefully there aren't arches with PAGE_SIZE > 64k */
 #define G_mapsize  (64*1024)
 
@@ -262,7 +254,7 @@ int hexedit_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 int hexedit_main(int argc UNUSED_PARAM, char **argv)
 {
 	INIT_G();
-	INIT_PAGESIZE();
+	INIT_PAGESIZE(G.pagesize);
 
 	get_terminal_width_height(-1, NULL, &G.height);
 	if (1) {
diff --git a/miscutils/time.c b/miscutils/time.c
index d15d363..0006c59 100644
--- a/miscutils/time.c
+++ b/miscutils/time.c
@@ -111,6 +111,10 @@ static void printargv(char *const *argv)
    This is funky since the pagesize could be less than 1K.
    Note: Some machines express getrusage statistics in terms of K,
    others in terms of pages.  */
+#ifdef BB_ARCH_FIXED_PAGESIZE
+# define pagesize BB_ARCH_FIXED_PAGESIZE
+# define ptok(pagesize, pages) ptok(pages)
+#endif
 static unsigned long ptok(const unsigned pagesize, const unsigned long pages)
 {
 	unsigned long tmp;
@@ -124,6 +128,7 @@ static unsigned long ptok(const unsigned pagesize, const unsigned long pages)
 	tmp = pages * pagesize; /* Larger first, */
 	return tmp / 1024;      /* then smaller.  */
 }
+#undef pagesize
 
 /* summarize: Report on the system use of a command.
 
@@ -177,7 +182,7 @@ static void summarize(const char *fmt, char **command, resource_t *resp)
 {
 	unsigned vv_ms;     /* Elapsed virtual (CPU) milliseconds */
 	unsigned cpu_ticks; /* Same, in "CPU ticks" */
-	unsigned pagesize = getpagesize();
+	unsigned pagesize = bb_getpagesize();
 
 	/* Impossible: we do not use WUNTRACED flag in wait()...
 	if (WIFSTOPPED(resp->waitstatus))