3 files changed, 192 insertions, 163 deletions

diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c
index 2e060c58b860..b69795efa226 100644
--- a/arch/x86/kernel/ftrace.c
+++ b/arch/x86/kernel/ftrace.c
@@ -23,25 +23,6 @@
 /* Long is fine, even if it is only 4 bytes ;-) */
 static long *ftrace_nop;
 
-struct ftrace_record {
-        struct dyn_ftrace       rec;
-        int                     failed;
-} __attribute__((packed));
-
-struct ftrace_page {
-        struct ftrace_page      *next;
-        int                     index;
-        struct ftrace_record    records[];
-} __attribute__((packed));
-
-#define ENTRIES_PER_PAGE \
-  ((PAGE_SIZE - sizeof(struct ftrace_page)) / sizeof(struct ftrace_record))
-
-/* estimate from running different kernels */
-#define NR_TO_INIT              10000
-
-#define MCOUNT_ADDR ((long)(&mcount))
-
 union ftrace_code_union {
         char code[5];
         struct {
@@ -50,33 +31,41 @@ union ftrace_code_union {
         } __attribute__((packed));
 };
 
-static struct ftrace_page       *ftrace_pages_start;
-static struct ftrace_page       *ftrace_pages;
-
-notrace struct dyn_ftrace *ftrace_alloc_shutdown_node(unsigned long ip)
+notrace int ftrace_ip_converted(unsigned long ip)
 {
-        struct ftrace_record *rec;
         unsigned long save;
 
         ip -= CALL_BACK;
         save = *(long *)ip;
 
-        /* If this was already converted, skip it */
-        if (save == *ftrace_nop)
-                return NULL;
+        return save == *ftrace_nop;
+}
 
-        if (ftrace_pages->index == ENTRIES_PER_PAGE) {
-                if (!ftrace_pages->next)
-                        return NULL;
-                ftrace_pages = ftrace_pages->next;
-        }
+static int notrace ftrace_calc_offset(long ip, long addr)
+{
+        return (int)(addr - ip);
+}
 
-        rec = &ftrace_pages->records[ftrace_pages->index++];
+notrace unsigned char *ftrace_nop_replace(void)
+{
+        return (char *)ftrace_nop;
+}
+
+notrace unsigned char *ftrace_call_replace(unsigned long ip, unsigned long addr)
+{
+        static union ftrace_code_union calc;
 
-        return &rec->rec;
+        calc.e8         = 0xe8;
+        calc.offset     = ftrace_calc_offset(ip, addr);
+
+        /*
+         * No locking needed, this must be called via kstop_machine
+         * which in essence is like running on a uniprocessor machine.
+         */
+        return calc.code;
 }
 
-static int notrace
+notrace int
 ftrace_modify_code(unsigned long ip, unsigned char *old_code,
                    unsigned char *new_code)
 {
@@ -86,6 +75,9 @@ ftrace_modify_code(unsigned long ip, unsigned char *old_code,
         unsigned char newch = new_code[4];
         int faulted = 0;
 
+        /* move the IP back to the start of the call */
+        ip -= CALL_BACK;
+
         /*
          * Note: Due to modules and __init, code can
          *  disappear and change, we need to protect against faulting
@@ -117,129 +109,12 @@ ftrace_modify_code(unsigned long ip, unsigned char *old_code,
         return faulted;
 }
 
-static int notrace ftrace_calc_offset(long ip)
-{
-        return (int)(MCOUNT_ADDR - ip);
-}
-
-notrace void ftrace_code_disable(struct dyn_ftrace *rec)
-{
-        unsigned long ip;
-        union ftrace_code_union save;
-        struct ftrace_record *r =
-                container_of(rec, struct ftrace_record, rec);
-
-        ip = rec->ip;
-
-        save.e8         = 0xe8;
-        save.offset     = ftrace_calc_offset(ip);
-
-        /* move the IP back to the start of the call */
-        ip -= CALL_BACK;
-
-        r->failed = ftrace_modify_code(ip, save.code, (char *)ftrace_nop);
-}
-
-static void notrace ftrace_replace_code(int saved)
-{
-        unsigned char *new = NULL, *old = NULL;
-        struct ftrace_record *rec;
-        struct ftrace_page *pg;
-        unsigned long ip;
-        int i;
-
-        if (saved)
-                old = (char *)ftrace_nop;
-        else
-                new = (char *)ftrace_nop;
-
-        for (pg = ftrace_pages_start; pg; pg = pg->next) {
-                for (i = 0; i < pg->index; i++) {
-                        union ftrace_code_union calc;
-                        rec = &pg->records[i];
-
-                        /* don't modify code that has already faulted */
-                        if (rec->failed)
-                                continue;
-
-                        ip = rec->rec.ip;
-
-                        calc.e8         = 0xe8;
-                        calc.offset     = ftrace_calc_offset(ip);
-
-                        if (saved)
-                                new = calc.code;
-                        else
-                                old = calc.code;
-
-                        ip -= CALL_BACK;
-
-                        rec->failed = ftrace_modify_code(ip, old, new);
-                }
-        }
-
-}
-
-notrace void ftrace_startup_code(void)
-{
-        ftrace_replace_code(1);
-}
-
-notrace void ftrace_shutdown_code(void)
-{
-        ftrace_replace_code(0);
-}
-
-notrace void ftrace_shutdown_replenish(void)
-{
-        if (ftrace_pages->next)
-                return;
-
-        /* allocate another page */
-        ftrace_pages->next = (void *)get_zeroed_page(GFP_KERNEL);
-}
-
-notrace int __init ftrace_shutdown_arch_init(void)
+int __init ftrace_dyn_arch_init(void)
 {
         const unsigned char *const *noptable = find_nop_table();
-        struct ftrace_page *pg;
-        int cnt;
-        int i;
 
         ftrace_nop = (unsigned long *)noptable[CALL_BACK];
 
-        /* allocate a few pages */
-        ftrace_pages_start = (void *)get_zeroed_page(GFP_KERNEL);
-        if (!ftrace_pages_start)
-                return -1;
-
-        /*
-         * Allocate a few more pages.
-         *
-         * TODO: have some parser search vmlinux before
-         *   final linking to find all calls to ftrace.
-         *   Then we can:
-         *    a) know how many pages to allocate.
-         *     and/or
-         *    b) set up the table then.
-         *
-         *  The dynamic code is still necessary for
-         *  modules.
-         */
-
-        pg = ftrace_pages = ftrace_pages_start;
-
-        cnt = NR_TO_INIT / ENTRIES_PER_PAGE;
-
-        for (i = 0; i < cnt; i++) {
-                pg->next = (void *)get_zeroed_page(GFP_KERNEL);
-
-                /* If we fail, we'll try later anyway */
-                if (!pg->next)
-                        break;
-
-                pg = pg->next;
-        }
-
         return 0;
 }
+
diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
index ccd8537dbdb7..d509ad6c9cb8 100644
--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h
@@ -42,19 +42,23 @@ extern void mcount(void);
 # define FTRACE_HASHBITS        10
 # define FTRACE_HASHSIZE        (1<<FTRACE_HASHBITS)
 
+enum {
+        FTRACE_FL_FAILED        = (1<<0),
+};
+
 struct dyn_ftrace {
         struct hlist_node node;
         unsigned long     ip;
+        unsigned long     flags;
 };
 
 /* defined in arch */
-extern struct dyn_ftrace *
-ftrace_alloc_shutdown_node(unsigned long ip);
-extern int ftrace_shutdown_arch_init(void);
-extern void ftrace_code_disable(struct dyn_ftrace *rec);
-extern void ftrace_startup_code(void);
-extern void ftrace_shutdown_code(void);
-extern void ftrace_shutdown_replenish(void);
+extern int ftrace_ip_converted(unsigned long ip);
+extern unsigned char *ftrace_nop_replace(void);
+extern unsigned char *ftrace_call_replace(unsigned long ip, unsigned long addr);
+extern int ftrace_dyn_arch_init(void);
+extern int ftrace_modify_code(unsigned long ip, unsigned char *old_code,
+                              unsigned char *new_code);
 #endif
 
 #ifdef CONFIG_FRAME_POINTER
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index d3de37299ba4..f6d9af3bf66b 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -156,6 +156,21 @@ static DEFINE_PER_CPU(int, ftrace_shutdown_disable_cpu);
 static DEFINE_SPINLOCK(ftrace_shutdown_lock);
 static DEFINE_MUTEX(ftraced_lock);
 
+struct ftrace_page {
+        struct ftrace_page      *next;
+        int                     index;
+        struct dyn_ftrace       records[];
+} __attribute__((packed));
+
+#define ENTRIES_PER_PAGE \
+  ((PAGE_SIZE - sizeof(struct ftrace_page)) / sizeof(struct dyn_ftrace))
+
+/* estimate from running different kernels */
+#define NR_TO_INIT              10000
+
+static struct ftrace_page       *ftrace_pages_start;
+static struct ftrace_page       *ftrace_pages;
+
 static int ftraced_trigger;
 static int ftraced_suspend;
 
@@ -184,6 +199,21 @@ ftrace_add_hash(struct dyn_ftrace *node, unsigned long key)
         hlist_add_head(&node->node, &ftrace_hash[key]);
 }
 
+static notrace struct dyn_ftrace *ftrace_alloc_shutdown_node(unsigned long ip)
+{
+        /* If this was already converted, skip it */
+        if (ftrace_ip_converted(ip))
+                return NULL;
+
+        if (ftrace_pages->index == ENTRIES_PER_PAGE) {
+                if (!ftrace_pages->next)
+                        return NULL;
+                ftrace_pages = ftrace_pages->next;
+        }
+
+        return &ftrace_pages->records[ftrace_pages->index++];
+}
+
 static void notrace
 ftrace_record_ip(unsigned long ip, unsigned long parent_ip)
 {
@@ -252,6 +282,62 @@ static struct ftrace_ops ftrace_shutdown_ops __read_mostly =
         .func = ftrace_record_ip,
 };
 
+#define MCOUNT_ADDR ((long)(&mcount))
+
+static void notrace ftrace_replace_code(int saved)
+{
+        unsigned char *new = NULL, *old = NULL;
+        struct dyn_ftrace *rec;
+        struct ftrace_page *pg;
+        unsigned long ip;
+        int failed;
+        int i;
+
+        if (saved)
+                old = ftrace_nop_replace();
+        else
+                new = ftrace_nop_replace();
+
+        for (pg = ftrace_pages_start; pg; pg = pg->next) {
+                for (i = 0; i < pg->index; i++) {
+                        rec = &pg->records[i];
+
+                        /* don't modify code that has already faulted */
+                        if (rec->flags & FTRACE_FL_FAILED)
+                                continue;
+
+                        ip = rec->ip;
+
+                        if (saved)
+                                new = ftrace_call_replace(ip, MCOUNT_ADDR);
+                        else
+                                old = ftrace_call_replace(ip, MCOUNT_ADDR);
+
+                        failed = ftrace_modify_code(ip, old, new);
+                        if (failed)
+                                rec->flags |= FTRACE_FL_FAILED;
+                }
+        }
+}
+
+static notrace void ftrace_startup_code(void)
+{
+        ftrace_replace_code(1);
+}
+
+static notrace void ftrace_shutdown_code(void)
+{
+        ftrace_replace_code(0);
+}
+
+static notrace void ftrace_shutdown_replenish(void)
+{
+        if (ftrace_pages->next)
+                return;
+
+        /* allocate another page */
+        ftrace_pages->next = (void *)get_zeroed_page(GFP_KERNEL);
+}
 
 static int notrace __ftrace_modify_code(void *data)
 {
@@ -261,6 +347,23 @@ static int notrace __ftrace_modify_code(void *data)
         return 0;
 }
 
+static notrace void
+ftrace_code_disable(struct dyn_ftrace *rec, unsigned long addr)
+{
+        unsigned long ip;
+        unsigned char *nop, *call;
+        int failed;
+
+        ip = rec->ip;
+
+        nop = ftrace_nop_replace();
+        call = ftrace_call_replace(ip, addr);
+
+        failed = ftrace_modify_code(ip, call, nop);
+        if (failed)
+                rec->flags |= FTRACE_FL_FAILED;
+}
+
 static void notrace ftrace_run_startup_code(void)
 {
         stop_machine_run(__ftrace_modify_code, ftrace_startup_code, NR_CPUS);
@@ -346,7 +449,7 @@ static int notrace __ftrace_update_code(void *ignore)
 
                 /* all CPUS are stopped, we are safe to modify code */
                 hlist_for_each_entry(p, t, &head, node) {
-                        ftrace_code_disable(p);
+                        ftrace_code_disable(p, MCOUNT_ADDR);
                         ftrace_update_cnt++;
                 }
 
@@ -407,12 +510,59 @@ static int notrace ftraced(void *ignore)
         return 0;
 }
 
+static int __init ftrace_dyn_table_alloc(void)
+{
+        struct ftrace_page *pg;
+        int cnt;
+        int i;
+        int ret;
+
+        ret = ftrace_dyn_arch_init();
+        if (ret)
+                return ret;
+
+        /* allocate a few pages */
+        ftrace_pages_start = (void *)get_zeroed_page(GFP_KERNEL);
+        if (!ftrace_pages_start)
+                return -1;
+
+        /*
+         * Allocate a few more pages.
+         *
+         * TODO: have some parser search vmlinux before
+         *   final linking to find all calls to ftrace.
+         *   Then we can:
+         *    a) know how many pages to allocate.
+         *     and/or
+         *    b) set up the table then.
+         *
+         *  The dynamic code is still necessary for
+         *  modules.
+         */
+
+        pg = ftrace_pages = ftrace_pages_start;
+
+        cnt = NR_TO_INIT / ENTRIES_PER_PAGE;
+
+        for (i = 0; i < cnt; i++) {
+                pg->next = (void *)get_zeroed_page(GFP_KERNEL);
+
+                /* If we fail, we'll try later anyway */
+                if (!pg->next)
+                        break;
+
+                pg = pg->next;
+        }
+
+        return 0;
+}
+
 static int __init notrace ftrace_shutdown_init(void)
 {
         struct task_struct *p;
         int ret;
 
-        ret = ftrace_shutdown_arch_init();
+        ret = ftrace_dyn_table_alloc();
         if (ret)
                 return ret;