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Diffstat (limited to 'arch/x86/kernel/ftrace.c')
-rw-r--r--arch/x86/kernel/ftrace.c101
1 files changed, 24 insertions, 77 deletions
diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c
index 9dbb527e165..30968924543 100644
--- a/arch/x86/kernel/ftrace.c
+++ b/arch/x86/kernel/ftrace.c
@@ -9,6 +9,8 @@
* the dangers of modifying code on the run.
*/
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
#include <linux/spinlock.h>
#include <linux/hardirq.h>
#include <linux/uaccess.h>
@@ -187,9 +189,26 @@ static void wait_for_nmi(void)
nmi_wait_count++;
}
+static inline int
+within(unsigned long addr, unsigned long start, unsigned long end)
+{
+ return addr >= start && addr < end;
+}
+
static int
do_ftrace_mod_code(unsigned long ip, void *new_code)
{
+ /*
+ * On x86_64, kernel text mappings are mapped read-only with
+ * CONFIG_DEBUG_RODATA. So we use the kernel identity mapping instead
+ * of the kernel text mapping to modify the kernel text.
+ *
+ * For 32bit kernels, these mappings are same and we can use
+ * kernel identity mapping to modify code.
+ */
+ if (within(ip, (unsigned long)_text, (unsigned long)_etext))
+ ip = (unsigned long)__va(__pa(ip));
+
mod_code_ip = (void *)ip;
mod_code_newcode = new_code;
@@ -336,15 +355,15 @@ int __init ftrace_dyn_arch_init(void *data)
switch (faulted) {
case 0:
- pr_info("ftrace: converting mcount calls to 0f 1f 44 00 00\n");
+ pr_info("converting mcount calls to 0f 1f 44 00 00\n");
memcpy(ftrace_nop, ftrace_test_p6nop, MCOUNT_INSN_SIZE);
break;
case 1:
- pr_info("ftrace: converting mcount calls to 66 66 66 66 90\n");
+ pr_info("converting mcount calls to 66 66 66 66 90\n");
memcpy(ftrace_nop, ftrace_test_nop5, MCOUNT_INSN_SIZE);
break;
case 2:
- pr_info("ftrace: converting mcount calls to jmp . + 5\n");
+ pr_info("converting mcount calls to jmp . + 5\n");
memcpy(ftrace_nop, ftrace_test_jmp, MCOUNT_INSN_SIZE);
break;
}
@@ -468,82 +487,10 @@ void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr,
#ifdef CONFIG_FTRACE_SYSCALLS
-extern unsigned long __start_syscalls_metadata[];
-extern unsigned long __stop_syscalls_metadata[];
extern unsigned long *sys_call_table;
-static struct syscall_metadata **syscalls_metadata;
-
-static struct syscall_metadata *find_syscall_meta(unsigned long *syscall)
-{
- struct syscall_metadata *start;
- struct syscall_metadata *stop;
- char str[KSYM_SYMBOL_LEN];
-
-
- start = (struct syscall_metadata *)__start_syscalls_metadata;
- stop = (struct syscall_metadata *)__stop_syscalls_metadata;
- kallsyms_lookup((unsigned long) syscall, NULL, NULL, NULL, str);
-
- for ( ; start < stop; start++) {
- if (start->name && !strcmp(start->name, str))
- return start;
- }
- return NULL;
-}
-
-struct syscall_metadata *syscall_nr_to_meta(int nr)
-{
- if (!syscalls_metadata || nr >= NR_syscalls || nr < 0)
- return NULL;
-
- return syscalls_metadata[nr];
-}
-
-int syscall_name_to_nr(char *name)
-{
- int i;
-
- if (!syscalls_metadata)
- return -1;
-
- for (i = 0; i < NR_syscalls; i++) {
- if (syscalls_metadata[i]) {
- if (!strcmp(syscalls_metadata[i]->name, name))
- return i;
- }
- }
- return -1;
-}
-
-void set_syscall_enter_id(int num, int id)
-{
- syscalls_metadata[num]->enter_id = id;
-}
-
-void set_syscall_exit_id(int num, int id)
+unsigned long __init arch_syscall_addr(int nr)
{
- syscalls_metadata[num]->exit_id = id;
-}
-
-static int __init arch_init_ftrace_syscalls(void)
-{
- int i;
- struct syscall_metadata *meta;
- unsigned long **psys_syscall_table = &sys_call_table;
-
- syscalls_metadata = kzalloc(sizeof(*syscalls_metadata) *
- NR_syscalls, GFP_KERNEL);
- if (!syscalls_metadata) {
- WARN_ON(1);
- return -ENOMEM;
- }
-
- for (i = 0; i < NR_syscalls; i++) {
- meta = find_syscall_meta(psys_syscall_table[i]);
- syscalls_metadata[i] = meta;
- }
- return 0;
+ return (unsigned long)(&sys_call_table)[nr];
}
-arch_initcall(arch_init_ftrace_syscalls);
#endif