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Diffstat (limited to 'arch/powerpc/kernel/ftrace.c')
-rw-r--r--arch/powerpc/kernel/ftrace.c218
1 files changed, 160 insertions, 58 deletions
diff --git a/arch/powerpc/kernel/ftrace.c b/arch/powerpc/kernel/ftrace.c
index 60c60ccf5e3..70e2a736be1 100644
--- a/arch/powerpc/kernel/ftrace.c
+++ b/arch/powerpc/kernel/ftrace.c
@@ -5,6 +5,9 @@
*
* Thanks goes out to P.A. Semi, Inc for supplying me with a PPC64 box.
*
+ * Added function graph tracer code, taken from x86 that was written
+ * by Frederic Weisbecker, and ported to PPC by Steven Rostedt.
+ *
*/
#include <linux/spinlock.h>
@@ -20,14 +23,6 @@
#include <asm/code-patching.h>
#include <asm/ftrace.h>
-#if 0
-#define DEBUGP printk
-#else
-#define DEBUGP(fmt , ...) do { } while (0)
-#endif
-
-static unsigned int ftrace_nop = PPC_NOP_INSTR;
-
#ifdef CONFIG_PPC32
# define GET_ADDR(addr) addr
#else
@@ -35,37 +30,23 @@ static unsigned int ftrace_nop = PPC_NOP_INSTR;
# define GET_ADDR(addr) (*(unsigned long *)addr)
#endif
-
-static unsigned int ftrace_calc_offset(long ip, long addr)
+#ifdef CONFIG_DYNAMIC_FTRACE
+static unsigned int ftrace_nop_replace(void)
{
- return (int)(addr - ip);
+ return PPC_INST_NOP;
}
-static unsigned char *ftrace_nop_replace(void)
+static unsigned int
+ftrace_call_replace(unsigned long ip, unsigned long addr, int link)
{
- return (char *)&ftrace_nop;
-}
-
-static unsigned char *ftrace_call_replace(unsigned long ip, unsigned long addr)
-{
- static unsigned int op;
+ unsigned int op;
- /*
- * It would be nice to just use create_function_call, but that will
- * update the code itself. Here we need to just return the
- * instruction that is going to be modified, without modifying the
- * code.
- */
addr = GET_ADDR(addr);
- /* Set to "bl addr" */
- op = 0x48000001 | (ftrace_calc_offset(ip, addr) & 0x03fffffc);
+ /* if (link) set op to 'bl' else 'b' */
+ op = create_branch((unsigned int *)ip, addr, link ? 1 : 0);
- /*
- * No locking needed, this must be called via kstop_machine
- * which in essence is like running on a uniprocessor machine.
- */
- return (unsigned char *)&op;
+ return op;
}
#ifdef CONFIG_PPC64
@@ -77,10 +58,9 @@ static unsigned char *ftrace_call_replace(unsigned long ip, unsigned long addr)
#endif
static int
-ftrace_modify_code(unsigned long ip, unsigned char *old_code,
- unsigned char *new_code)
+ftrace_modify_code(unsigned long ip, unsigned int old, unsigned int new)
{
- unsigned char replaced[MCOUNT_INSN_SIZE];
+ unsigned int replaced;
/*
* Note: Due to modules and __init, code can
@@ -93,15 +73,15 @@ ftrace_modify_code(unsigned long ip, unsigned char *old_code,
*/
/* read the text we want to modify */
- if (probe_kernel_read(replaced, (void *)ip, MCOUNT_INSN_SIZE))
+ if (probe_kernel_read(&replaced, (void *)ip, MCOUNT_INSN_SIZE))
return -EFAULT;
/* Make sure it is what we expect it to be */
- if (memcmp(replaced, old_code, MCOUNT_INSN_SIZE) != 0)
+ if (replaced != old)
return -EINVAL;
/* replace the text with the new text */
- if (probe_kernel_write((void *)ip, new_code, MCOUNT_INSN_SIZE))
+ if (probe_kernel_write((void *)ip, &new, MCOUNT_INSN_SIZE))
return -EPERM;
flush_icache_range(ip, ip + 8);
@@ -119,6 +99,8 @@ static int test_24bit_addr(unsigned long ip, unsigned long addr)
return create_branch((unsigned int *)ip, addr, 0);
}
+#ifdef CONFIG_MODULES
+
static int is_bl_op(unsigned int op)
{
return (op & 0xfc000003) == 0x48000001;
@@ -175,7 +157,7 @@ __ftrace_make_nop(struct module *mod,
* 0xe8, 0x4c, 0x00, 0x28, ld r2,40(r12)
*/
- DEBUGP("ip:%lx jumps to %lx r2: %lx", ip, tramp, mod->arch.toc);
+ pr_debug("ip:%lx jumps to %lx r2: %lx", ip, tramp, mod->arch.toc);
/* Find where the trampoline jumps to */
if (probe_kernel_read(jmp, (void *)tramp, sizeof(jmp))) {
@@ -183,7 +165,7 @@ __ftrace_make_nop(struct module *mod,
return -EFAULT;
}
- DEBUGP(" %08x %08x", jmp[0], jmp[1]);
+ pr_debug(" %08x %08x", jmp[0], jmp[1]);
/* verify that this is what we expect it to be */
if (((jmp[0] & 0xffff0000) != 0x3d820000) ||
@@ -199,18 +181,18 @@ __ftrace_make_nop(struct module *mod,
offset = ((unsigned)((unsigned short)jmp[0]) << 16) +
(int)((short)jmp[1]);
- DEBUGP(" %x ", offset);
+ pr_debug(" %x ", offset);
/* get the address this jumps too */
tramp = mod->arch.toc + offset + 32;
- DEBUGP("toc: %lx", tramp);
+ pr_debug("toc: %lx", tramp);
if (probe_kernel_read(jmp, (void *)tramp, 8)) {
printk(KERN_ERR "Failed to read %lx\n", tramp);
return -EFAULT;
}
- DEBUGP(" %08x %08x\n", jmp[0], jmp[1]);
+ pr_debug(" %08x %08x\n", jmp[0], jmp[1]);
ptr = ((unsigned long)jmp[0] << 32) + jmp[1];
@@ -287,7 +269,7 @@ __ftrace_make_nop(struct module *mod,
* 0x4e, 0x80, 0x04, 0x20 bctr
*/
- DEBUGP("ip:%lx jumps to %lx", ip, tramp);
+ pr_debug("ip:%lx jumps to %lx", ip, tramp);
/* Find where the trampoline jumps to */
if (probe_kernel_read(jmp, (void *)tramp, sizeof(jmp))) {
@@ -295,7 +277,7 @@ __ftrace_make_nop(struct module *mod,
return -EFAULT;
}
- DEBUGP(" %08x %08x ", jmp[0], jmp[1]);
+ pr_debug(" %08x %08x ", jmp[0], jmp[1]);
/* verify that this is what we expect it to be */
if (((jmp[0] & 0xffff0000) != 0x3d600000) ||
@@ -311,7 +293,7 @@ __ftrace_make_nop(struct module *mod,
if (tramp & 0x8000)
tramp -= 0x10000;
- DEBUGP(" %x ", tramp);
+ pr_debug(" %lx ", tramp);
if (tramp != addr) {
printk(KERN_ERR
@@ -320,7 +302,7 @@ __ftrace_make_nop(struct module *mod,
return -EINVAL;
}
- op = PPC_NOP_INSTR;
+ op = PPC_INST_NOP;
if (probe_kernel_write((void *)ip, &op, MCOUNT_INSN_SIZE))
return -EPERM;
@@ -330,12 +312,13 @@ __ftrace_make_nop(struct module *mod,
return 0;
}
#endif /* PPC64 */
+#endif /* CONFIG_MODULES */
int ftrace_make_nop(struct module *mod,
struct dyn_ftrace *rec, unsigned long addr)
{
- unsigned char *old, *new;
unsigned long ip = rec->ip;
+ unsigned int old, new;
/*
* If the calling address is more that 24 bits away,
@@ -344,11 +327,12 @@ int ftrace_make_nop(struct module *mod,
*/
if (test_24bit_addr(ip, addr)) {
/* within range */
- old = ftrace_call_replace(ip, addr);
+ old = ftrace_call_replace(ip, addr, 1);
new = ftrace_nop_replace();
return ftrace_modify_code(ip, old, new);
}
+#ifdef CONFIG_MODULES
/*
* Out of range jumps are called from modules.
* We should either already have a pointer to the module
@@ -373,9 +357,13 @@ int ftrace_make_nop(struct module *mod,
mod = rec->arch.mod;
return __ftrace_make_nop(mod, rec, addr);
-
+#else
+ /* We should not get here without modules */
+ return -EINVAL;
+#endif /* CONFIG_MODULES */
}
+#ifdef CONFIG_MODULES
#ifdef CONFIG_PPC64
static int
__ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
@@ -392,7 +380,7 @@ __ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
* b +8; ld r2,40(r1)
*/
if (((op[0] != 0x48000008) || (op[1] != 0xe8410028)) &&
- ((op[0] != PPC_NOP_INSTR) || (op[1] != PPC_NOP_INSTR))) {
+ ((op[0] != PPC_INST_NOP) || (op[1] != PPC_INST_NOP))) {
printk(KERN_ERR "Expected NOPs but have %x %x\n", op[0], op[1]);
return -EINVAL;
}
@@ -414,7 +402,7 @@ __ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
/* ld r2,40(r1) */
op[1] = 0xe8410028;
- DEBUGP("write to %lx\n", rec->ip);
+ pr_debug("write to %lx\n", rec->ip);
if (probe_kernel_write((void *)ip, op, MCOUNT_INSN_SIZE * 2))
return -EPERM;
@@ -435,7 +423,7 @@ __ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
return -EFAULT;
/* It should be pointing to a nop */
- if (op != PPC_NOP_INSTR) {
+ if (op != PPC_INST_NOP) {
printk(KERN_ERR "Expected NOP but have %x\n", op);
return -EINVAL;
}
@@ -454,7 +442,7 @@ __ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
return -EINVAL;
}
- DEBUGP("write to %lx\n", rec->ip);
+ pr_debug("write to %lx\n", rec->ip);
if (probe_kernel_write((void *)ip, &op, MCOUNT_INSN_SIZE))
return -EPERM;
@@ -464,11 +452,12 @@ __ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
return 0;
}
#endif /* CONFIG_PPC64 */
+#endif /* CONFIG_MODULES */
int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
{
- unsigned char *old, *new;
unsigned long ip = rec->ip;
+ unsigned int old, new;
/*
* If the calling address is more that 24 bits away,
@@ -478,10 +467,11 @@ int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
if (test_24bit_addr(ip, addr)) {
/* within range */
old = ftrace_nop_replace();
- new = ftrace_call_replace(ip, addr);
+ new = ftrace_call_replace(ip, addr, 1);
return ftrace_modify_code(ip, old, new);
}
+#ifdef CONFIG_MODULES
/*
* Out of range jumps are called from modules.
* Being that we are converting from nop, it had better
@@ -493,16 +483,20 @@ int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
}
return __ftrace_make_call(rec, addr);
+#else
+ /* We should not get here without modules */
+ return -EINVAL;
+#endif /* CONFIG_MODULES */
}
int ftrace_update_ftrace_func(ftrace_func_t func)
{
unsigned long ip = (unsigned long)(&ftrace_call);
- unsigned char old[MCOUNT_INSN_SIZE], *new;
+ unsigned int old, new;
int ret;
- memcpy(old, &ftrace_call, MCOUNT_INSN_SIZE);
- new = ftrace_call_replace(ip, (unsigned long)func);
+ old = *(unsigned int *)&ftrace_call;
+ new = ftrace_call_replace(ip, (unsigned long)func, 1);
ret = ftrace_modify_code(ip, old, new);
return ret;
@@ -517,3 +511,111 @@ int __init ftrace_dyn_arch_init(void *data)
return 0;
}
+#endif /* CONFIG_DYNAMIC_FTRACE */
+
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+
+#ifdef CONFIG_DYNAMIC_FTRACE
+extern void ftrace_graph_call(void);
+extern void ftrace_graph_stub(void);
+
+int ftrace_enable_ftrace_graph_caller(void)
+{
+ unsigned long ip = (unsigned long)(&ftrace_graph_call);
+ unsigned long addr = (unsigned long)(&ftrace_graph_caller);
+ unsigned long stub = (unsigned long)(&ftrace_graph_stub);
+ unsigned int old, new;
+
+ old = ftrace_call_replace(ip, stub, 0);
+ new = ftrace_call_replace(ip, addr, 0);
+
+ return ftrace_modify_code(ip, old, new);
+}
+
+int ftrace_disable_ftrace_graph_caller(void)
+{
+ unsigned long ip = (unsigned long)(&ftrace_graph_call);
+ unsigned long addr = (unsigned long)(&ftrace_graph_caller);
+ unsigned long stub = (unsigned long)(&ftrace_graph_stub);
+ unsigned int old, new;
+
+ old = ftrace_call_replace(ip, addr, 0);
+ new = ftrace_call_replace(ip, stub, 0);
+
+ return ftrace_modify_code(ip, old, new);
+}
+#endif /* CONFIG_DYNAMIC_FTRACE */
+
+#ifdef CONFIG_PPC64
+extern void mod_return_to_handler(void);
+#endif
+
+/*
+ * Hook the return address and push it in the stack of return addrs
+ * in current thread info.
+ */
+void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr)
+{
+ unsigned long old;
+ int faulted;
+ struct ftrace_graph_ent trace;
+ unsigned long return_hooker = (unsigned long)&return_to_handler;
+
+ if (unlikely(atomic_read(&current->tracing_graph_pause)))
+ return;
+
+#ifdef CONFIG_PPC64
+ /* non core kernel code needs to save and restore the TOC */
+ if (REGION_ID(self_addr) != KERNEL_REGION_ID)
+ return_hooker = (unsigned long)&mod_return_to_handler;
+#endif
+
+ return_hooker = GET_ADDR(return_hooker);
+
+ /*
+ * Protect against fault, even if it shouldn't
+ * happen. This tool is too much intrusive to
+ * ignore such a protection.
+ */
+ asm volatile(
+ "1: " PPC_LL "%[old], 0(%[parent])\n"
+ "2: " PPC_STL "%[return_hooker], 0(%[parent])\n"
+ " li %[faulted], 0\n"
+ "3:\n"
+
+ ".section .fixup, \"ax\"\n"
+ "4: li %[faulted], 1\n"
+ " b 3b\n"
+ ".previous\n"
+
+ ".section __ex_table,\"a\"\n"
+ PPC_LONG_ALIGN "\n"
+ PPC_LONG "1b,4b\n"
+ PPC_LONG "2b,4b\n"
+ ".previous"
+
+ : [old] "=r" (old), [faulted] "=r" (faulted)
+ : [parent] "r" (parent), [return_hooker] "r" (return_hooker)
+ : "memory"
+ );
+
+ if (unlikely(faulted)) {
+ ftrace_graph_stop();
+ WARN_ON(1);
+ return;
+ }
+
+ if (ftrace_push_return_trace(old, self_addr, &trace.depth) == -EBUSY) {
+ *parent = old;
+ return;
+ }
+
+ trace.func = self_addr;
+
+ /* Only trace if the calling function expects to */
+ if (!ftrace_graph_entry(&trace)) {
+ current->curr_ret_stack--;
+ *parent = old;
+ }
+}
+#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-07 21:50:44 +0000