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authorGravatar Denis Vlasenko <vda.linux@googlemail.com>2008-02-27 18:41:59 +0000
committerGravatar Denis Vlasenko <vda.linux@googlemail.com>2008-02-27 18:41:59 +0000
commit574f2f43948bb21d6e4187936ba5a5afccba25f6 (patch)
tree0b39aca564149e5ad30b3cc791228655ff1b1827 /shell
parentfe66a0eca1bfeae0abc0fc1e7d3709f271e05e82 (diff)
downloadbusybox-574f2f43948bb21d6e4187936ba5a5afccba25f6.tar.gz
busybox-574f2f43948bb21d6e4187936ba5a5afccba25f6.tar.bz2
*: add optimization barrier to all "G trick" locations
Diffstat (limited to 'shell')
-rw-r--r--shell/Kbuild7
-rw-r--r--shell/ash.c24
-rw-r--r--shell/ash_ptr_hack.c16
-rw-r--r--shell/hush.c5
-rw-r--r--shell/msh.c2
5 files changed, 36 insertions, 18 deletions
diff --git a/shell/Kbuild b/shell/Kbuild
index 36a8ffd3a..deedc24f3 100644
--- a/shell/Kbuild
+++ b/shell/Kbuild
@@ -5,8 +5,7 @@
# Licensed under the GPL v2, see the file LICENSE in this tarball.
lib-y:=
-lib-$(CONFIG_ASH) += ash.o
-lib-$(CONFIG_HUSH) += hush.o
-lib-$(CONFIG_MSH) += msh.o
-
+lib-$(CONFIG_ASH) += ash.o ash_ptr_hack.o
+lib-$(CONFIG_HUSH) += hush.o
+lib-$(CONFIG_MSH) += msh.o
lib-$(CONFIG_CTTYHACK) += cttyhack.o
diff --git a/shell/ash.c b/shell/ash.c
index 9c762e2ed..9b1a73024 100644
--- a/shell/ash.c
+++ b/shell/ash.c
@@ -202,9 +202,8 @@ struct globals_misc {
/* indicates specified signal received */
char gotsig[NSIG - 1];
};
-/* Make it reside in writable memory, yet make compiler understand that it is not going to change. */
-static struct globals_misc *const ptr_to_globals_misc __attribute__ ((section (".data")));
-#define G_misc (*ptr_to_globals_misc)
+extern struct globals_misc *const ash_ptr_to_globals_misc;
+#define G_misc (*ash_ptr_to_globals_misc)
#define rootpid (G_misc.rootpid )
#define shlvl (G_misc.shlvl )
#define minusc (G_misc.minusc )
@@ -223,7 +222,8 @@ static struct globals_misc *const ptr_to_globals_misc __attribute__ ((section ("
#define sigmode (G_misc.sigmode )
#define gotsig (G_misc.gotsig )
#define INIT_G_misc() do { \
- (*(struct globals_misc**)&ptr_to_globals_misc) = xzalloc(sizeof(G_misc)); \
+ (*(struct globals_misc**)&ash_ptr_to_globals_misc) = xzalloc(sizeof(G_misc)); \
+ barrier(); \
curdir = nullstr; \
physdir = nullstr; \
} while (0)
@@ -1147,9 +1147,8 @@ struct globals_memstack {
int herefd; // = -1;
struct stack_block stackbase;
};
-/* Make it reside in writable memory, yet make compiler understand that it is not going to change. */
-static struct globals_memstack *const ptr_to_globals_memstack __attribute__ ((section (".data")));
-#define G_memstack (*ptr_to_globals_memstack)
+extern struct globals_memstack *const ash_ptr_to_globals_memstack;
+#define G_memstack (*ash_ptr_to_globals_memstack)
#define g_stackp (G_memstack.g_stackp )
#define markp (G_memstack.markp )
#define g_stacknxt (G_memstack.g_stacknxt )
@@ -1158,7 +1157,8 @@ static struct globals_memstack *const ptr_to_globals_memstack __attribute__ ((se
#define herefd (G_memstack.herefd )
#define stackbase (G_memstack.stackbase )
#define INIT_G_memstack() do { \
- (*(struct globals_memstack**)&ptr_to_globals_memstack) = xzalloc(sizeof(G_memstack)); \
+ (*(struct globals_memstack**)&ash_ptr_to_globals_memstack) = xzalloc(sizeof(G_memstack)); \
+ barrier(); \
g_stackp = &stackbase; \
g_stacknxt = stackbase.space; \
g_stacknleft = MINSIZE; \
@@ -1778,9 +1778,8 @@ struct globals_var {
struct var *vartab[VTABSIZE];
struct var varinit[ARRAY_SIZE(varinit_data)];
};
-/* Make it reside in writable memory, yet make compiler understand that it is not going to change. */
-static struct globals_var *const ptr_to_globals_var __attribute__ ((section (".data")));
-#define G_var (*ptr_to_globals_var)
+extern struct globals_var *const ash_ptr_to_globals_var;
+#define G_var (*ash_ptr_to_globals_var)
#define shellparam (G_var.shellparam )
#define redirlist (G_var.redirlist )
#define g_nullredirs (G_var.g_nullredirs )
@@ -1789,7 +1788,8 @@ static struct globals_var *const ptr_to_globals_var __attribute__ ((section (".d
#define varinit (G_var.varinit )
#define INIT_G_var() do { \
int i; \
- (*(struct globals_var**)&ptr_to_globals_var) = xzalloc(sizeof(G_var)); \
+ (*(struct globals_var**)&ash_ptr_to_globals_var) = xzalloc(sizeof(G_var)); \
+ barrier(); \
for (i = 0; i < ARRAY_SIZE(varinit_data); i++) { \
varinit[i].flags = varinit_data[i].flags; \
varinit[i].text = varinit_data[i].text; \
diff --git a/shell/ash_ptr_hack.c b/shell/ash_ptr_hack.c
new file mode 100644
index 000000000..490b73b6d
--- /dev/null
+++ b/shell/ash_ptr_hack.c
@@ -0,0 +1,16 @@
+/* vi: set sw=4 ts=4: */
+/*
+ * Copyright (C) 2008 by Denys Vlasenko <vda.linux@googlemail.com>
+ *
+ * Licensed under GPLv2, see file LICENSE in this tarball for details.
+ */
+
+/* We cheat here. They are declared as const ptr in ash.c,
+ * but here we make them live in R/W memory */
+struct globals_misc;
+struct globals_memstack;
+struct globals_var;
+
+struct globals_misc *ash_ptr_to_globals_misc;
+struct globals_memstack *ash_ptr_to_globals_memstack;
+struct globals_var *ash_ptr_to_globals_var;
diff --git a/shell/hush.c b/shell/hush.c
index d9ef2390e..b44f35bdd 100644
--- a/shell/hush.c
+++ b/shell/hush.c
@@ -460,6 +460,9 @@ enum { run_list_level = 0 };
#endif
#define charmap (G.charmap )
#define user_input_buf (G.user_input_buf )
+#define INIT_G() do { \
+ SET_PTR_TO_GLOBALS(xzalloc(sizeof(G))); \
+} while (0)
#define B_CHUNK 100
@@ -3778,7 +3781,7 @@ int hush_main(int argc, char **argv)
char **e;
struct variable *cur_var;
- PTR_TO_GLOBALS = xzalloc(sizeof(G));
+ INIT_G();
/* Deal with HUSH_VERSION */
shell_ver = const_shell_ver; /* copying struct here */
diff --git a/shell/msh.c b/shell/msh.c
index 917b08a1e..569011bbd 100644
--- a/shell/msh.c
+++ b/shell/msh.c
@@ -705,7 +705,7 @@ struct globals {
#define child_cmd (G.child_cmd )
#define iostack (G.iostack )
#define INIT_G() do { \
- PTR_TO_GLOBALS = xzalloc(sizeof(G)); \
+ SET_PTR_TO_GLOBALS(xzalloc(sizeof(G))); \
global_env.linep = line; \
global_env.iobase = iostack; \
global_env.iop = iostack - 1; \