#ifdef __ASSEMBLY__
- .macro MCOUNT_SAVE_FRAME
- /* taken from glibc */
- subq $0x38, %rsp
- movq %rax, (%rsp)
- movq %rcx, 8(%rsp)
- movq %rdx, 16(%rsp)
- movq %rsi, 24(%rsp)
- movq %rdi, 32(%rsp)
- movq %r8, 40(%rsp)
- movq %r9, 48(%rsp)
+ /* skip is set if the stack was already partially adjusted */
+ .macro MCOUNT_SAVE_FRAME skip=0
+ /*
+ * We add enough stack to save all regs.
+ */
+ subq $(SS+8-\skip), %rsp
+ movq %rax, RAX(%rsp)
+ movq %rcx, RCX(%rsp)
+ movq %rdx, RDX(%rsp)
+ movq %rsi, RSI(%rsp)
+ movq %rdi, RDI(%rsp)
+ movq %r8, R8(%rsp)
+ movq %r9, R9(%rsp)
+ /* Move RIP to its proper location */
+ movq SS+8(%rsp), %rdx
+ movq %rdx, RIP(%rsp)
.endm
- .macro MCOUNT_RESTORE_FRAME
- movq 48(%rsp), %r9
- movq 40(%rsp), %r8
- movq 32(%rsp), %rdi
- movq 24(%rsp), %rsi
- movq 16(%rsp), %rdx
- movq 8(%rsp), %rcx
- movq (%rsp), %rax
- addq $0x38, %rsp
+ .macro MCOUNT_RESTORE_FRAME skip=0
+ movq R9(%rsp), %r9
+ movq R8(%rsp), %r8
+ movq RDI(%rsp), %rdi
+ movq RSI(%rsp), %rsi
+ movq RDX(%rsp), %rdx
+ movq RCX(%rsp), %rcx
+ movq RAX(%rsp), %rax
+ addq $(SS+8-\skip), %rsp
.endm
#endif
#ifdef CONFIG_DYNAMIC_FTRACE
#define ARCH_SUPPORTS_FTRACE_OPS 1
+#ifdef CONFIG_X86_64
+#define ARCH_SUPPORTS_FTRACE_SAVE_REGS
+#endif
#endif
#ifndef __ASSEMBLY__
pushl %eax
pushl %ecx
pushl %edx
- movl 0xc(%esp), %eax
+ pushl $0 /* Pass NULL as regs pointer */
+ movl 4*4(%esp), %eax
movl 0x4(%ebp), %edx
leal function_trace_op, %ecx
subl $MCOUNT_INSN_SIZE, %eax
ftrace_call:
call ftrace_stub
+ addl $4,%esp /* skip NULL pointer */
popl %edx
popl %ecx
popl %eax
retq
END(mcount)
+/* skip is set if stack has been adjusted */
+.macro ftrace_caller_setup skip=0
+ MCOUNT_SAVE_FRAME \skip
+
+ /* Load the ftrace_ops into the 3rd parameter */
+ leaq function_trace_op, %rdx
+
+ /* Load ip into the first parameter */
+ movq RIP(%rsp), %rdi
+ subq $MCOUNT_INSN_SIZE, %rdi
+ /* Load the parent_ip into the second parameter */
+ movq 8(%rbp), %rsi
+.endm
+
ENTRY(ftrace_caller)
+ /* Check if tracing was disabled (quick check) */
cmpl $0, function_trace_stop
jne ftrace_stub
- MCOUNT_SAVE_FRAME
-
- leaq function_trace_op, %rdx
- movq 0x38(%rsp), %rdi
- movq 8(%rbp), %rsi
- subq $MCOUNT_INSN_SIZE, %rdi
+ ftrace_caller_setup
+ /* regs go into 4th parameter (but make it NULL) */
+ movq $0, %rcx
GLOBAL(ftrace_call)
call ftrace_stub
MCOUNT_RESTORE_FRAME
+ftrace_return:
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
GLOBAL(ftrace_graph_call)
retq
END(ftrace_caller)
+ENTRY(ftrace_regs_caller)
+ /* Save the current flags before compare (in SS location)*/
+ pushfq
+
+ /* Check if tracing was disabled (quick check) */
+ cmpl $0, function_trace_stop
+ jne ftrace_restore_flags
+
+ /* skip=8 to skip flags saved in SS */
+ ftrace_caller_setup 8
+
+ /* Save the rest of pt_regs */
+ movq %r15, R15(%rsp)
+ movq %r14, R14(%rsp)
+ movq %r13, R13(%rsp)
+ movq %r12, R12(%rsp)
+ movq %r11, R11(%rsp)
+ movq %r10, R10(%rsp)
+ movq %rbp, RBP(%rsp)
+ movq %rbx, RBX(%rsp)
+ /* Copy saved flags */
+ movq SS(%rsp), %rcx
+ movq %rcx, EFLAGS(%rsp)
+ /* Kernel segments */
+ movq $__KERNEL_DS, %rcx
+ movq %rcx, SS(%rsp)
+ movq $__KERNEL_CS, %rcx
+ movq %rcx, CS(%rsp)
+ /* Stack - skipping return address */
+ leaq SS+16(%rsp), %rcx
+ movq %rcx, RSP(%rsp)
+
+ /* regs go into 4th parameter */
+ leaq (%rsp), %rcx
+
+GLOBAL(ftrace_regs_call)
+ call ftrace_stub
+
+ /* Copy flags back to SS, to restore them */
+ movq EFLAGS(%rsp), %rax
+ movq %rax, SS(%rsp)
+
+ /* restore the rest of pt_regs */
+ movq R15(%rsp), %r15
+ movq R14(%rsp), %r14
+ movq R13(%rsp), %r13
+ movq R12(%rsp), %r12
+ movq R10(%rsp), %r10
+ movq RBP(%rsp), %rbp
+ movq RBX(%rsp), %rbx
+
+ /* skip=8 to skip flags saved in SS */
+ MCOUNT_RESTORE_FRAME 8
+
+ /* Restore flags */
+ popfq
+
+ jmp ftrace_return
+ftrace_restore_flags:
+ popfq
+ jmp ftrace_stub
+
+END(ftrace_regs_caller)
+
+
#else /* ! CONFIG_DYNAMIC_FTRACE */
ENTRY(mcount)
cmpl $0, function_trace_stop
trace:
MCOUNT_SAVE_FRAME
- movq 0x38(%rsp), %rdi
+ movq RIP(%rsp), %rdi
movq 8(%rbp), %rsi
subq $MCOUNT_INSN_SIZE, %rdi
MCOUNT_SAVE_FRAME
leaq 8(%rbp), %rdi
- movq 0x38(%rsp), %rsi
+ movq RIP(%rsp), %rsi
movq (%rbp), %rdx
subq $MCOUNT_INSN_SIZE, %rsi
ftrace_modify_code(unsigned long ip, unsigned const char *old_code,
unsigned const char *new_code);
+#ifdef ARCH_SUPPORTS_FTRACE_SAVE_REGS
+/*
+ * Should never be called:
+ * As it is only called by __ftrace_replace_code() which is called by
+ * ftrace_replace_code() that x86 overrides, and by ftrace_update_code()
+ * which is called to turn mcount into nops or nops into function calls
+ * but not to convert a function from not using regs to one that uses
+ * regs, which ftrace_modify_call() is for.
+ */
+int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr,
+ unsigned long addr)
+{
+ WARN_ON(1);
+ return -EINVAL;
+}
+#endif
+
int ftrace_update_ftrace_func(ftrace_func_t func)
{
unsigned long ip = (unsigned long)(&ftrace_call);
ret = ftrace_modify_code(ip, old, new);
+#ifdef ARCH_SUPPORTS_FTRACE_SAVE_REGS
+ /* Also update the regs callback function */
+ if (!ret) {
+ ip = (unsigned long)(&ftrace_regs_call);
+ memcpy(old, &ftrace_regs_call, MCOUNT_INSN_SIZE);
+ new = ftrace_call_replace(ip, (unsigned long)func);
+ ret = ftrace_modify_code(ip, old, new);
+ }
+#endif
+
atomic_dec(&modifying_ftrace_code);
return ret;
return add_break(rec->ip, old);
}
+/*
+ * If the record has the FTRACE_FL_REGS set, that means that it
+ * wants to convert to a callback that saves all regs. If FTRACE_FL_REGS
+ * is not not set, then it wants to convert to the normal callback.
+ */
+static unsigned long get_ftrace_addr(struct dyn_ftrace *rec)
+{
+ if (rec->flags & FTRACE_FL_REGS)
+ return (unsigned long)FTRACE_REGS_ADDR;
+ else
+ return (unsigned long)FTRACE_ADDR;
+}
+
+/*
+ * The FTRACE_FL_REGS_EN is set when the record already points to
+ * a function that saves all the regs. Basically the '_EN' version
+ * represents the current state of the function.
+ */
+static unsigned long get_ftrace_old_addr(struct dyn_ftrace *rec)
+{
+ if (rec->flags & FTRACE_FL_REGS_EN)
+ return (unsigned long)FTRACE_REGS_ADDR;
+ else
+ return (unsigned long)FTRACE_ADDR;
+}
+
static int add_breakpoints(struct dyn_ftrace *rec, int enable)
{
unsigned long ftrace_addr;
ret = ftrace_test_record(rec, enable);
- ftrace_addr = (unsigned long)FTRACE_ADDR;
+ ftrace_addr = get_ftrace_addr(rec);
switch (ret) {
case FTRACE_UPDATE_IGNORE:
/* converting nop to call */
return add_brk_on_nop(rec);
+ case FTRACE_UPDATE_MODIFY_CALL_REGS:
+ case FTRACE_UPDATE_MODIFY_CALL:
+ ftrace_addr = get_ftrace_old_addr(rec);
+ /* fall through */
case FTRACE_UPDATE_MAKE_NOP:
/* converting a call to a nop */
return add_brk_on_call(rec, ftrace_addr);
* If not, don't touch the breakpoint, we make just create
* a disaster.
*/
- ftrace_addr = (unsigned long)FTRACE_ADDR;
+ ftrace_addr = get_ftrace_addr(rec);
+ nop = ftrace_call_replace(ip, ftrace_addr);
+
+ if (memcmp(&ins[1], &nop[1], MCOUNT_INSN_SIZE - 1) == 0)
+ goto update;
+
+ /* Check both ftrace_addr and ftrace_old_addr */
+ ftrace_addr = get_ftrace_old_addr(rec);
nop = ftrace_call_replace(ip, ftrace_addr);
if (memcmp(&ins[1], &nop[1], MCOUNT_INSN_SIZE - 1) != 0)
return -EINVAL;
}
+ update:
return probe_kernel_write((void *)ip, &nop[0], 1);
}
ret = ftrace_test_record(rec, enable);
- ftrace_addr = (unsigned long)FTRACE_ADDR;
+ ftrace_addr = get_ftrace_addr(rec);
switch (ret) {
case FTRACE_UPDATE_IGNORE:
return 0;
+ case FTRACE_UPDATE_MODIFY_CALL_REGS:
+ case FTRACE_UPDATE_MODIFY_CALL:
case FTRACE_UPDATE_MAKE_CALL:
/* converting nop to call */
return add_update_call(rec, ftrace_addr);
ret = ftrace_update_record(rec, enable);
- ftrace_addr = (unsigned long)FTRACE_ADDR;
+ ftrace_addr = get_ftrace_addr(rec);
switch (ret) {
case FTRACE_UPDATE_IGNORE:
return 0;
+ case FTRACE_UPDATE_MODIFY_CALL_REGS:
+ case FTRACE_UPDATE_MODIFY_CALL:
case FTRACE_UPDATE_MAKE_CALL:
/* converting nop to call */
return finish_update_call(rec, ftrace_addr);
* could be controled by following calls:
* ftrace_function_local_enable
* ftrace_function_local_disable
+ * SAVE_REGS - The ftrace_ops wants regs saved at each function called
+ * and passed to the callback. If this flag is set, but the
+ * architecture does not support passing regs
+ * (ARCH_SUPPORTS_FTRACE_SAVE_REGS is not defined), then the
+ * ftrace_ops will fail to register, unless the next flag
+ * is set.
+ * SAVE_REGS_IF_SUPPORTED - This is the same as SAVE_REGS, but if the
+ * handler can handle an arch that does not save regs
+ * (the handler tests if regs == NULL), then it can set
+ * this flag instead. It will not fail registering the ftrace_ops
+ * but, the regs field will be NULL if the arch does not support
+ * passing regs to the handler.
+ * Note, if this flag is set, the SAVE_REGS flag will automatically
+ * get set upon registering the ftrace_ops, if the arch supports it.
*/
enum {
- FTRACE_OPS_FL_ENABLED = 1 << 0,
- FTRACE_OPS_FL_GLOBAL = 1 << 1,
- FTRACE_OPS_FL_DYNAMIC = 1 << 2,
- FTRACE_OPS_FL_CONTROL = 1 << 3,
+ FTRACE_OPS_FL_ENABLED = 1 << 0,
+ FTRACE_OPS_FL_GLOBAL = 1 << 1,
+ FTRACE_OPS_FL_DYNAMIC = 1 << 2,
+ FTRACE_OPS_FL_CONTROL = 1 << 3,
+ FTRACE_OPS_FL_SAVE_REGS = 1 << 4,
+ FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED = 1 << 5,
};
struct ftrace_ops {
extern int ftrace_text_reserved(void *start, void *end);
+/*
+ * The dyn_ftrace record's flags field is split into two parts.
+ * the first part which is '0-FTRACE_REF_MAX' is a counter of
+ * the number of callbacks that have registered the function that
+ * the dyn_ftrace descriptor represents.
+ *
+ * The second part is a mask:
+ * ENABLED - the function is being traced
+ * REGS - the record wants the function to save regs
+ * REGS_EN - the function is set up to save regs.
+ *
+ * When a new ftrace_ops is registered and wants a function to save
+ * pt_regs, the rec->flag REGS is set. When the function has been
+ * set up to save regs, the REG_EN flag is set. Once a function
+ * starts saving regs it will do so until all ftrace_ops are removed
+ * from tracing that function.
+ */
enum {
- FTRACE_FL_ENABLED = (1 << 30),
+ FTRACE_FL_ENABLED = (1UL << 29),
+ FTRACE_FL_REGS = (1UL << 30),
+ FTRACE_FL_REGS_EN = (1UL << 31)
};
-#define FTRACE_FL_MASK (0x3UL << 30)
-#define FTRACE_REF_MAX ((1 << 30) - 1)
+#define FTRACE_FL_MASK (0x7UL << 29)
+#define FTRACE_REF_MAX ((1UL << 29) - 1)
struct dyn_ftrace {
union {
FTRACE_STOP_FUNC_RET = (1 << 4),
};
+/*
+ * The FTRACE_UPDATE_* enum is used to pass information back
+ * from the ftrace_update_record() and ftrace_test_record()
+ * functions. These are called by the code update routines
+ * to find out what is to be done for a given function.
+ *
+ * IGNORE - The function is already what we want it to be
+ * MAKE_CALL - Start tracing the function
+ * MODIFY_CALL - Stop saving regs for the function
+ * MODIFY_CALL_REGS - Start saving regs for the function
+ * MAKE_NOP - Stop tracing the function
+ */
enum {
FTRACE_UPDATE_IGNORE,
FTRACE_UPDATE_MAKE_CALL,
+ FTRACE_UPDATE_MODIFY_CALL,
+ FTRACE_UPDATE_MODIFY_CALL_REGS,
FTRACE_UPDATE_MAKE_NOP,
};
extern void ftrace_replace_code(int enable);
extern int ftrace_update_ftrace_func(ftrace_func_t func);
extern void ftrace_caller(void);
+extern void ftrace_regs_caller(void);
extern void ftrace_call(void);
+extern void ftrace_regs_call(void);
extern void mcount_call(void);
void ftrace_modify_all_code(int command);
#ifndef FTRACE_ADDR
#define FTRACE_ADDR ((unsigned long)ftrace_caller)
#endif
+
+#ifndef FTRACE_REGS_ADDR
+#ifdef ARCH_SUPPORTS_FTRACE_SAVE_REGS
+# define FTRACE_REGS_ADDR ((unsigned long)ftrace_regs_caller)
+#else
+# define FTRACE_REGS_ADDR FTRACE_ADDR
+#endif
+#endif
+
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
extern void ftrace_graph_caller(void);
extern int ftrace_enable_ftrace_graph_caller(void);
*/
extern int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr);
+#ifdef ARCH_SUPPORTS_FTRACE_SAVE_REGS
+/**
+ * ftrace_modify_call - convert from one addr to another (no nop)
+ * @rec: the mcount call site record
+ * @old_addr: the address expected to be currently called to
+ * @addr: the address to change to
+ *
+ * This is a very sensitive operation and great care needs
+ * to be taken by the arch. The operation should carefully
+ * read the location, check to see if what is read is indeed
+ * what we expect it to be, and then on success of the compare,
+ * it should write to the location.
+ *
+ * The code segment at @rec->ip should be a caller to @old_addr
+ *
+ * Return must be:
+ * 0 on success
+ * -EFAULT on error reading the location
+ * -EINVAL on a failed compare of the contents
+ * -EPERM on error writing to the location
+ * Any other value will be considered a failure.
+ */
+extern int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr,
+ unsigned long addr);
+#else
+/* Should never be called */
+static inline int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr,
+ unsigned long addr)
+{
+ return -EINVAL;
+}
+#endif
+
/* May be defined in arch */
extern int ftrace_arch_read_dyn_info(char *buf, int size);
if ((ops->flags & FL_GLOBAL_CONTROL_MASK) == FL_GLOBAL_CONTROL_MASK)
return -EINVAL;
+#ifndef ARCH_SUPPORTS_FTRACE_SAVE_REGS
+ /*
+ * If the ftrace_ops specifies SAVE_REGS, then it only can be used
+ * if the arch supports it, or SAVE_REGS_IF_SUPPORTED is also set.
+ * Setting SAVE_REGS_IF_SUPPORTED makes SAVE_REGS irrelevant.
+ */
+ if (ops->flags & FTRACE_OPS_FL_SAVE_REGS &&
+ !(ops->flags & FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED))
+ return -EINVAL;
+
+ if (ops->flags & FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED)
+ ops->flags |= FTRACE_OPS_FL_SAVE_REGS;
+#endif
+
if (!core_kernel_data((unsigned long)ops))
ops->flags |= FTRACE_OPS_FL_DYNAMIC;
rec->flags++;
if (FTRACE_WARN_ON((rec->flags & ~FTRACE_FL_MASK) == FTRACE_REF_MAX))
return;
+ /*
+ * If any ops wants regs saved for this function
+ * then all ops will get saved regs.
+ */
+ if (ops->flags & FTRACE_OPS_FL_SAVE_REGS)
+ rec->flags |= FTRACE_FL_REGS;
} else {
if (FTRACE_WARN_ON((rec->flags & ~FTRACE_FL_MASK) == 0))
return;
if (enable && (rec->flags & ~FTRACE_FL_MASK))
flag = FTRACE_FL_ENABLED;
+ /*
+ * If enabling and the REGS flag does not match the REGS_EN, then
+ * do not ignore this record. Set flags to fail the compare against
+ * ENABLED.
+ */
+ if (flag &&
+ (!(rec->flags & FTRACE_FL_REGS) != !(rec->flags & FTRACE_FL_REGS_EN)))
+ flag |= FTRACE_FL_REGS;
+
/* If the state of this record hasn't changed, then do nothing */
if ((rec->flags & FTRACE_FL_ENABLED) == flag)
return FTRACE_UPDATE_IGNORE;
if (flag) {
- if (update)
+ /* Save off if rec is being enabled (for return value) */
+ flag ^= rec->flags & FTRACE_FL_ENABLED;
+
+ if (update) {
rec->flags |= FTRACE_FL_ENABLED;
- return FTRACE_UPDATE_MAKE_CALL;
+ if (flag & FTRACE_FL_REGS) {
+ if (rec->flags & FTRACE_FL_REGS)
+ rec->flags |= FTRACE_FL_REGS_EN;
+ else
+ rec->flags &= ~FTRACE_FL_REGS_EN;
+ }
+ }
+
+ /*
+ * If this record is being updated from a nop, then
+ * return UPDATE_MAKE_CALL.
+ * Otherwise, if the EN flag is set, then return
+ * UPDATE_MODIFY_CALL_REGS to tell the caller to convert
+ * from the non-save regs, to a save regs function.
+ * Otherwise,
+ * return UPDATE_MODIFY_CALL to tell the caller to convert
+ * from the save regs, to a non-save regs function.
+ */
+ if (flag & FTRACE_FL_ENABLED)
+ return FTRACE_UPDATE_MAKE_CALL;
+ else if (rec->flags & FTRACE_FL_REGS_EN)
+ return FTRACE_UPDATE_MODIFY_CALL_REGS;
+ else
+ return FTRACE_UPDATE_MODIFY_CALL;
}
- if (update)
- rec->flags &= ~FTRACE_FL_ENABLED;
+ if (update) {
+ /* If there's no more users, clear all flags */
+ if (!(rec->flags & ~FTRACE_FL_MASK))
+ rec->flags = 0;
+ else
+ /* Just disable the record (keep REGS state) */
+ rec->flags &= ~FTRACE_FL_ENABLED;
+ }
return FTRACE_UPDATE_MAKE_NOP;
}
static int
__ftrace_replace_code(struct dyn_ftrace *rec, int enable)
{
+ unsigned long ftrace_old_addr;
unsigned long ftrace_addr;
int ret;
- ftrace_addr = (unsigned long)FTRACE_ADDR;
-
ret = ftrace_update_record(rec, enable);
+ if (rec->flags & FTRACE_FL_REGS)
+ ftrace_addr = (unsigned long)FTRACE_REGS_ADDR;
+ else
+ ftrace_addr = (unsigned long)FTRACE_ADDR;
+
switch (ret) {
case FTRACE_UPDATE_IGNORE:
return 0;
case FTRACE_UPDATE_MAKE_NOP:
return ftrace_make_nop(NULL, rec, ftrace_addr);
+
+ case FTRACE_UPDATE_MODIFY_CALL_REGS:
+ case FTRACE_UPDATE_MODIFY_CALL:
+ if (rec->flags & FTRACE_FL_REGS)
+ ftrace_old_addr = (unsigned long)FTRACE_ADDR;
+ else
+ ftrace_old_addr = (unsigned long)FTRACE_REGS_ADDR;
+
+ return ftrace_modify_call(rec, ftrace_old_addr, ftrace_addr);
}
return -1; /* unknow ftrace bug */
seq_printf(m, "%ps", (void *)rec->ip);
if (iter->flags & FTRACE_ITER_ENABLED)
- seq_printf(m, " (%ld)",
- rec->flags & ~FTRACE_FL_MASK);
+ seq_printf(m, " (%ld)%s",
+ rec->flags & ~FTRACE_FL_MASK,
+ rec->flags & FTRACE_FL_REGS ? " R" : "");
seq_printf(m, "\n");
return 0;
projects / openwrt / staging / blogic.git / commitdiff