*
* 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>
#include <linux/hardirq.h>
#include <linux/uaccess.h>
+#include <linux/module.h>
#include <linux/ftrace.h>
#include <linux/percpu.h>
#include <linux/init.h>
#include <linux/list.h>
#include <asm/cacheflush.h>
+#include <asm/code-patching.h>
#include <asm/ftrace.h>
-static unsigned int ftrace_nop = 0x60000000;
-
-#ifdef CONFIG_PPC32
-# define GET_ADDR(addr) addr
-#else
-/* PowerPC64's functions are data that points to the functions */
-# 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_call_replace(unsigned long ip, unsigned long addr, int link)
{
- return (int)(addr - ip);
-}
+ unsigned int op;
-static unsigned char *ftrace_nop_replace(void)
-{
- return (char *)&ftrace_nop;
-}
-
-static unsigned char *ftrace_call_replace(unsigned long ip, unsigned long addr)
-{
- static 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);
+ addr = ppc_function_entry((void *)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
-# define _ASM_ALIGN " .align 3 "
-# define _ASM_PTR " .llong "
-#else
-# define _ASM_ALIGN " .align 2 "
-# define _ASM_PTR " .long "
-#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
*/
/* 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);
return 0;
}
+/*
+ * Helper functions that are the same for both PPC64 and PPC32.
+ */
static int test_24bit_addr(unsigned long ip, unsigned long addr)
{
- long diff;
+
+ /* use the create_branch to verify that this offset can be branched */
+ return create_branch((unsigned int *)ip, addr, 0);
+}
+
+#ifdef CONFIG_MODULES
+
+static int is_bl_op(unsigned int op)
+{
+ return (op & 0xfc000003) == 0x48000001;
+}
+
+static unsigned long find_bl_target(unsigned long ip, unsigned int op)
+{
+ static int offset;
+
+ offset = (op & 0x03fffffc);
+ /* make it signed */
+ if (offset & 0x02000000)
+ offset |= 0xfe000000;
+
+ return ip + (long)offset;
+}
+
+#ifdef CONFIG_PPC64
+static int
+__ftrace_make_nop(struct module *mod,
+ struct dyn_ftrace *rec, unsigned long addr)
+{
+ unsigned int op;
+ unsigned int jmp[5];
+ unsigned long ptr;
+ unsigned long ip = rec->ip;
+ unsigned long tramp;
+ int offset;
+
+ /* read where this goes */
+ if (probe_kernel_read(&op, (void *)ip, sizeof(int)))
+ return -EFAULT;
+
+ /* Make sure that that this is still a 24bit jump */
+ if (!is_bl_op(op)) {
+ printk(KERN_ERR "Not expected bl: opcode is %x\n", op);
+ return -EINVAL;
+ }
+
+ /* lets find where the pointer goes */
+ tramp = find_bl_target(ip, op);
/*
- * Can we get to addr from ip in 24 bits?
- * (26 really, since we mulitply by 4 for 4 byte alignment)
+ * On PPC64 the trampoline looks like:
+ * 0x3d, 0x82, 0x00, 0x00, addis r12,r2, <high>
+ * 0x39, 0x8c, 0x00, 0x00, addi r12,r12, <low>
+ * Where the bytes 2,3,6 and 7 make up the 32bit offset
+ * to the TOC that holds the pointer.
+ * to jump to.
+ * 0xf8, 0x41, 0x00, 0x28, std r2,40(r1)
+ * 0xe9, 0x6c, 0x00, 0x20, ld r11,32(r12)
+ * The actually address is 32 bytes from the offset
+ * into the TOC.
+ * 0xe8, 0x4c, 0x00, 0x28, ld r2,40(r12)
*/
- diff = addr - ip;
+
+ pr_devel("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))) {
+ printk(KERN_ERR "Failed to read %lx\n", tramp);
+ return -EFAULT;
+ }
+
+ pr_devel(" %08x %08x", jmp[0], jmp[1]);
+
+ /* verify that this is what we expect it to be */
+ if (((jmp[0] & 0xffff0000) != 0x3d820000) ||
+ ((jmp[1] & 0xffff0000) != 0x398c0000) ||
+ (jmp[2] != 0xf8410028) ||
+ (jmp[3] != 0xe96c0020) ||
+ (jmp[4] != 0xe84c0028)) {
+ printk(KERN_ERR "Not a trampoline\n");
+ return -EINVAL;
+ }
+
+ /* The bottom half is signed extended */
+ offset = ((unsigned)((unsigned short)jmp[0]) << 16) +
+ (int)((short)jmp[1]);
+
+ pr_devel(" %x ", offset);
+
+ /* get the address this jumps too */
+ tramp = mod->arch.toc + offset + 32;
+ pr_devel("toc: %lx", tramp);
+
+ if (probe_kernel_read(jmp, (void *)tramp, 8)) {
+ printk(KERN_ERR "Failed to read %lx\n", tramp);
+ return -EFAULT;
+ }
+
+ pr_devel(" %08x %08x\n", jmp[0], jmp[1]);
+
+ ptr = ((unsigned long)jmp[0] << 32) + jmp[1];
+
+ /* This should match what was called */
+ if (ptr != ppc_function_entry((void *)addr)) {
+ printk(KERN_ERR "addr does not match %lx\n", ptr);
+ return -EINVAL;
+ }
/*
- * Return true if diff is less than 1 << 25
- * and greater than -1 << 26.
+ * We want to nop the line, but the next line is
+ * 0xe8, 0x41, 0x00, 0x28 ld r2,40(r1)
+ * This needs to be turned to a nop too.
*/
- return (diff < (1 << 25)) && (diff > (-1 << 26));
+ if (probe_kernel_read(&op, (void *)(ip+4), MCOUNT_INSN_SIZE))
+ return -EFAULT;
+
+ if (op != 0xe8410028) {
+ printk(KERN_ERR "Next line is not ld! (%08x)\n", op);
+ return -EINVAL;
+ }
+
+ /*
+ * Milton Miller pointed out that we can not blindly do nops.
+ * If a task was preempted when calling a trace function,
+ * the nops will remove the way to restore the TOC in r2
+ * and the r2 TOC will get corrupted.
+ */
+
+ /*
+ * Replace:
+ * bl <tramp> <==== will be replaced with "b 1f"
+ * ld r2,40(r1)
+ * 1:
+ */
+ op = 0x48000008; /* b +8 */
+
+ if (probe_kernel_write((void *)ip, &op, MCOUNT_INSN_SIZE))
+ return -EPERM;
+
+
+ flush_icache_range(ip, ip + 8);
+
+ return 0;
}
+#else /* !PPC64 */
+static int
+__ftrace_make_nop(struct module *mod,
+ struct dyn_ftrace *rec, unsigned long addr)
+{
+ unsigned int op;
+ unsigned int jmp[4];
+ unsigned long ip = rec->ip;
+ unsigned long tramp;
+
+ if (probe_kernel_read(&op, (void *)ip, MCOUNT_INSN_SIZE))
+ return -EFAULT;
+
+ /* Make sure that that this is still a 24bit jump */
+ if (!is_bl_op(op)) {
+ printk(KERN_ERR "Not expected bl: opcode is %x\n", op);
+ return -EINVAL;
+ }
+
+ /* lets find where the pointer goes */
+ tramp = find_bl_target(ip, op);
+
+ /*
+ * On PPC32 the trampoline looks like:
+ * 0x3d, 0x60, 0x00, 0x00 lis r11,sym@ha
+ * 0x39, 0x6b, 0x00, 0x00 addi r11,r11,sym@l
+ * 0x7d, 0x69, 0x03, 0xa6 mtctr r11
+ * 0x4e, 0x80, 0x04, 0x20 bctr
+ */
+
+ pr_devel("ip:%lx jumps to %lx", ip, tramp);
+
+ /* Find where the trampoline jumps to */
+ if (probe_kernel_read(jmp, (void *)tramp, sizeof(jmp))) {
+ printk(KERN_ERR "Failed to read %lx\n", tramp);
+ return -EFAULT;
+ }
+
+ pr_devel(" %08x %08x ", jmp[0], jmp[1]);
+
+ /* verify that this is what we expect it to be */
+ if (((jmp[0] & 0xffff0000) != 0x3d600000) ||
+ ((jmp[1] & 0xffff0000) != 0x396b0000) ||
+ (jmp[2] != 0x7d6903a6) ||
+ (jmp[3] != 0x4e800420)) {
+ printk(KERN_ERR "Not a trampoline\n");
+ return -EINVAL;
+ }
+
+ tramp = (jmp[1] & 0xffff) |
+ ((jmp[0] & 0xffff) << 16);
+ if (tramp & 0x8000)
+ tramp -= 0x10000;
+
+ pr_devel(" %lx ", tramp);
+
+ if (tramp != addr) {
+ printk(KERN_ERR
+ "Trampoline location %08lx does not match addr\n",
+ tramp);
+ return -EINVAL;
+ }
+
+ op = PPC_INST_NOP;
+
+ if (probe_kernel_write((void *)ip, &op, MCOUNT_INSN_SIZE))
+ return -EPERM;
+
+ flush_icache_range(ip, ip + 8);
+
+ 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,
* then we had to use a trampoline to make the call.
* Otherwise just update the call site.
*/
- if (test_24bit_addr(rec->ip, addr)) {
+ if (test_24bit_addr(ip, addr)) {
/* within range */
- old = ftrace_call_replace(rec->ip, addr);
- new = ftrace_nop_replace();
- return ftrace_modify_code(rec->ip, old, new);
+ old = ftrace_call_replace(ip, addr, 1);
+ new = PPC_INST_NOP;
+ 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
+ * or it has been passed in.
+ */
+ if (!rec->arch.mod) {
+ if (!mod) {
+ printk(KERN_ERR "No module loaded addr=%lx\n",
+ addr);
+ return -EFAULT;
+ }
+ rec->arch.mod = mod;
+ } else if (mod) {
+ if (mod != rec->arch.mod) {
+ printk(KERN_ERR
+ "Record mod %p not equal to passed in mod %p\n",
+ rec->arch.mod, mod);
+ return -EINVAL;
+ }
+ /* nothing to do if mod == rec->arch.mod */
+ } else
+ 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)
+{
+ unsigned int op[2];
+ unsigned long ip = rec->ip;
+
+ /* read where this goes */
+ if (probe_kernel_read(op, (void *)ip, MCOUNT_INSN_SIZE * 2))
+ return -EFAULT;
+
+ /*
+ * It should be pointing to two nops or
+ * b +8; ld r2,40(r1)
+ */
+ if (((op[0] != 0x48000008) || (op[1] != 0xe8410028)) &&
+ ((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;
+ }
+
+ /* If we never set up a trampoline to ftrace_caller, then bail */
+ if (!rec->arch.mod->arch.tramp) {
+ printk(KERN_ERR "No ftrace trampoline\n");
+ return -EINVAL;
+ }
+
+ /* create the branch to the trampoline */
+ op[0] = create_branch((unsigned int *)ip,
+ rec->arch.mod->arch.tramp, BRANCH_SET_LINK);
+ if (!op[0]) {
+ printk(KERN_ERR "REL24 out of range!\n");
+ return -EINVAL;
+ }
+
+ /* ld r2,40(r1) */
+ op[1] = 0xe8410028;
+
+ pr_devel("write to %lx\n", rec->ip);
+
+ if (probe_kernel_write((void *)ip, op, MCOUNT_INSN_SIZE * 2))
+ return -EPERM;
+
+ flush_icache_range(ip, ip + 8);
+
+ return 0;
+}
+#else
+static int
+__ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
+{
+ unsigned int op;
+ unsigned long ip = rec->ip;
+
+ /* read where this goes */
+ if (probe_kernel_read(&op, (void *)ip, MCOUNT_INSN_SIZE))
+ return -EFAULT;
+
+ /* It should be pointing to a nop */
+ if (op != PPC_INST_NOP) {
+ printk(KERN_ERR "Expected NOP but have %x\n", op);
+ return -EINVAL;
+ }
+
+ /* If we never set up a trampoline to ftrace_caller, then bail */
+ if (!rec->arch.mod->arch.tramp) {
+ printk(KERN_ERR "No ftrace trampoline\n");
+ return -EINVAL;
}
+ /* create the branch to the trampoline */
+ op = create_branch((unsigned int *)ip,
+ rec->arch.mod->arch.tramp, BRANCH_SET_LINK);
+ if (!op) {
+ printk(KERN_ERR "REL24 out of range!\n");
+ return -EINVAL;
+ }
+
+ pr_devel("write to %lx\n", rec->ip);
+
+ if (probe_kernel_write((void *)ip, &op, MCOUNT_INSN_SIZE))
+ return -EPERM;
+
+ flush_icache_range(ip, ip + 8);
+
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,
* then we had to use a trampoline to make the call.
* Otherwise just update the call site.
*/
- if (test_24bit_addr(rec->ip, addr)) {
+ if (test_24bit_addr(ip, addr)) {
/* within range */
- old = ftrace_nop_replace();
- new = ftrace_call_replace(rec->ip, addr);
- return ftrace_modify_code(rec->ip, old, new);
+ old = PPC_INST_NOP;
+ new = ftrace_call_replace(ip, addr, 1);
+ return ftrace_modify_code(ip, old, new);
}
- return 0;
+#ifdef CONFIG_MODULES
+ /*
+ * Out of range jumps are called from modules.
+ * Being that we are converting from nop, it had better
+ * already have a module defined.
+ */
+ if (!rec->arch.mod) {
+ printk(KERN_ERR "No module loaded\n");
+ return -EINVAL;
+ }
+
+ 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;
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(¤t->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 = ppc_function_entry((void *)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, 0) == -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 */
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff