[PATCH v10 4/6] init: allow initcall tables to be emitted using relative references
Ard Biesheuvel
ard.biesheuvel at linaro.org
Wed Jul 4 18:36:49 AEST 2018
Allow the initcall tables to be emitted using relative references that
are only half the size on 64-bit architectures and don't require fixups
at runtime on relocatable kernels.
Acked-by: James Morris <james.morris at microsoft.com>
Acked-by: Sergey Senozhatsky <sergey.senozhatsky at gmail.com>
Acked-by: Petr Mladek <pmladek at suse.com>
Acked-by: Michael Ellerman <mpe at ellerman.id.au>
Acked-by: Ingo Molnar <mingo at kernel.org>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel at linaro.org>
---
include/linux/init.h | 44 +++++++++++++++-----
init/main.c | 32 +++++++-------
kernel/printk/printk.c | 16 +++----
security/security.c | 17 ++++----
4 files changed, 68 insertions(+), 41 deletions(-)
diff --git a/include/linux/init.h b/include/linux/init.h
index bc27cf03c41e..2538d176dd1f 100644
--- a/include/linux/init.h
+++ b/include/linux/init.h
@@ -116,8 +116,24 @@
typedef int (*initcall_t)(void);
typedef void (*exitcall_t)(void);
-extern initcall_t __con_initcall_start[], __con_initcall_end[];
-extern initcall_t __security_initcall_start[], __security_initcall_end[];
+#ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS
+typedef int initcall_entry_t;
+
+static inline initcall_t initcall_from_entry(initcall_entry_t *entry)
+{
+ return offset_to_ptr(entry);
+}
+#else
+typedef initcall_t initcall_entry_t;
+
+static inline initcall_t initcall_from_entry(initcall_entry_t *entry)
+{
+ return *entry;
+}
+#endif
+
+extern initcall_entry_t __con_initcall_start[], __con_initcall_end[];
+extern initcall_entry_t __security_initcall_start[], __security_initcall_end[];
/* Used for contructor calls. */
typedef void (*ctor_fn_t)(void);
@@ -167,9 +183,20 @@ extern bool initcall_debug;
* as KEEP() in the linker script.
*/
-#define __define_initcall(fn, id) \
+#ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS
+#define ___define_initcall(fn, id, __sec) \
+ __ADDRESSABLE(fn) \
+ asm(".section \"" #__sec ".init\", \"a\" \n" \
+ "__initcall_" #fn #id ": \n" \
+ ".long " #fn " - . \n" \
+ ".previous \n");
+#else
+#define ___define_initcall(fn, id, __sec) \
static initcall_t __initcall_##fn##id __used \
- __attribute__((__section__(".initcall" #id ".init"))) = fn;
+ __attribute__((__section__(#__sec ".init"))) = fn;
+#endif
+
+#define __define_initcall(fn, id) ___define_initcall(fn, id, .initcall##id)
/*
* Early initcalls run before initializing SMP.
@@ -208,13 +235,8 @@ extern bool initcall_debug;
#define __exitcall(fn) \
static exitcall_t __exitcall_##fn __exit_call = fn
-#define console_initcall(fn) \
- static initcall_t __initcall_##fn \
- __used __section(.con_initcall.init) = fn
-
-#define security_initcall(fn) \
- static initcall_t __initcall_##fn \
- __used __section(.security_initcall.init) = fn
+#define console_initcall(fn) ___define_initcall(fn,, .con_initcall)
+#define security_initcall(fn) ___define_initcall(fn,, .security_initcall)
struct obs_kernel_param {
const char *str;
diff --git a/init/main.c b/init/main.c
index 3b4ada11ed52..e59a01f163d6 100644
--- a/init/main.c
+++ b/init/main.c
@@ -901,18 +901,18 @@ int __init_or_module do_one_initcall(initcall_t fn)
}
-extern initcall_t __initcall_start[];
-extern initcall_t __initcall0_start[];
-extern initcall_t __initcall1_start[];
-extern initcall_t __initcall2_start[];
-extern initcall_t __initcall3_start[];
-extern initcall_t __initcall4_start[];
-extern initcall_t __initcall5_start[];
-extern initcall_t __initcall6_start[];
-extern initcall_t __initcall7_start[];
-extern initcall_t __initcall_end[];
-
-static initcall_t *initcall_levels[] __initdata = {
+extern initcall_entry_t __initcall_start[];
+extern initcall_entry_t __initcall0_start[];
+extern initcall_entry_t __initcall1_start[];
+extern initcall_entry_t __initcall2_start[];
+extern initcall_entry_t __initcall3_start[];
+extern initcall_entry_t __initcall4_start[];
+extern initcall_entry_t __initcall5_start[];
+extern initcall_entry_t __initcall6_start[];
+extern initcall_entry_t __initcall7_start[];
+extern initcall_entry_t __initcall_end[];
+
+static initcall_entry_t *initcall_levels[] __initdata = {
__initcall0_start,
__initcall1_start,
__initcall2_start,
@@ -938,7 +938,7 @@ static char *initcall_level_names[] __initdata = {
static void __init do_initcall_level(int level)
{
- initcall_t *fn;
+ initcall_entry_t *fn;
strcpy(initcall_command_line, saved_command_line);
parse_args(initcall_level_names[level],
@@ -949,7 +949,7 @@ static void __init do_initcall_level(int level)
trace_initcall_level(initcall_level_names[level]);
for (fn = initcall_levels[level]; fn < initcall_levels[level+1]; fn++)
- do_one_initcall(*fn);
+ do_one_initcall(initcall_from_entry(fn));
}
static void __init do_initcalls(void)
@@ -980,11 +980,11 @@ static void __init do_basic_setup(void)
static void __init do_pre_smp_initcalls(void)
{
- initcall_t *fn;
+ initcall_entry_t *fn;
trace_initcall_level("early");
for (fn = __initcall_start; fn < __initcall0_start; fn++)
- do_one_initcall(*fn);
+ do_one_initcall(initcall_from_entry(fn));
}
/*
diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index 247808333ba4..688a27b0888c 100644
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -2772,7 +2772,8 @@ EXPORT_SYMBOL(unregister_console);
void __init console_init(void)
{
int ret;
- initcall_t *call;
+ initcall_t call;
+ initcall_entry_t *ce;
/* Setup the default TTY line discipline. */
n_tty_init();
@@ -2781,13 +2782,14 @@ void __init console_init(void)
* set up the console device so that later boot sequences can
* inform about problems etc..
*/
- call = __con_initcall_start;
+ ce = __con_initcall_start;
trace_initcall_level("console");
- while (call < __con_initcall_end) {
- trace_initcall_start((*call));
- ret = (*call)();
- trace_initcall_finish((*call), ret);
- call++;
+ while (ce < __con_initcall_end) {
+ call = initcall_from_entry(ce);
+ trace_initcall_start(call);
+ ret = call();
+ trace_initcall_finish(call, ret);
+ ce++;
}
}
diff --git a/security/security.c b/security/security.c
index 68f46d849abe..1e7b1486d82a 100644
--- a/security/security.c
+++ b/security/security.c
@@ -48,14 +48,17 @@ static __initdata char chosen_lsm[SECURITY_NAME_MAX + 1] =
static void __init do_security_initcalls(void)
{
int ret;
- initcall_t *call;
- call = __security_initcall_start;
+ initcall_t call;
+ initcall_entry_t *ce;
+
+ ce = __security_initcall_start;
trace_initcall_level("security");
- while (call < __security_initcall_end) {
- trace_initcall_start((*call));
- ret = (*call) ();
- trace_initcall_finish((*call), ret);
- call++;
+ while (ce < __security_initcall_end) {
+ call = initcall_from_entry(ce);
+ trace_initcall_start(call);
+ ret = call();
+ trace_initcall_finish(call, ret);
+ ce++;
}
}
--
2.17.1
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