1 files changed, 85 insertions, 97 deletions

diff --git a/arch/powerpc/kernel/ftrace.c b/arch/powerpc/kernel/ftrace.c
index 3271cd698e4c..5355244c99ff 100644
--- a/arch/powerpc/kernel/ftrace.c
+++ b/arch/powerpc/kernel/ftrace.c
@@ -114,19 +114,9 @@ ftrace_modify_code(unsigned long ip, unsigned char *old_code,
  */
 static int test_24bit_addr(unsigned long ip, unsigned long addr)
 {
-        long diff;
 
-        /*
-         * Can we get to addr from ip in 24 bits?
-         *  (26 really, since we mulitply by 4 for 4 byte alignment)
-         */
-        diff = addr - ip;
-
-        /*
-         * Return true if diff is less than 1 << 25
-         *  and greater than -1 << 26.
-         */
-        return (diff < (1 << 25)) && (diff > (-1 << 26));
+        /* use the create_branch to verify that this offset can be branched */
+        return create_branch((unsigned int *)ip, addr, 0);
 }
 
 static int is_bl_op(unsigned int op)
@@ -134,11 +124,6 @@ static int is_bl_op(unsigned int op)
         return (op & 0xfc000003) == 0x48000001;
 }
 
-static int test_offset(unsigned long offset)
-{
-        return (offset + 0x2000000 > 0x3ffffff) || ((offset & 3) != 0);
-}
-
 static unsigned long find_bl_target(unsigned long ip, unsigned int op)
 {
         static int offset;
@@ -151,37 +136,30 @@ static unsigned long find_bl_target(unsigned long ip, unsigned int op)
         return ip + (long)offset;
 }
 
-static unsigned int branch_offset(unsigned long offset)
-{
-        /* return "bl ip+offset" */
-        return 0x48000001 | (offset & 0x03fffffc);
-}
-
 #ifdef CONFIG_PPC64
 static int
 __ftrace_make_nop(struct module *mod,
                   struct dyn_ftrace *rec, unsigned long addr)
 {
-        unsigned char replaced[MCOUNT_INSN_SIZE * 2];
-        unsigned int *op = (unsigned *)&replaced;
-        unsigned char jmp[8];
-        unsigned long *ptr = (unsigned long *)&jmp;
+        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(replaced, (void *)ip, MCOUNT_INSN_SIZE))
+        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);
+        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);
+        tramp = find_bl_target(ip, op);
 
         /*
          * On PPC64 the trampoline looks like:
@@ -200,19 +178,25 @@ __ftrace_make_nop(struct module *mod,
         DEBUGP("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, 8)) {
+        if (probe_kernel_read(jmp, (void *)tramp, sizeof(jmp))) {
                 printk(KERN_ERR "Failed to read %lx\n", tramp);
                 return -EFAULT;
         }
 
-        DEBUGP(" %08x %08x",
-               (unsigned)(*ptr >> 32),
-               (unsigned)*ptr);
+        DEBUGP(" %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;
+        }
 
-        offset = (unsigned)jmp[2] << 24 |
-                (unsigned)jmp[3] << 16 |
-                (unsigned)jmp[6] << 8 |
-                (unsigned)jmp[7];
+        offset = (unsigned)((unsigned short)jmp[0]) << 16 |
+                (unsigned)((unsigned short)jmp[1]);
 
         DEBUGP(" %x ", offset);
 
@@ -225,13 +209,13 @@ __ftrace_make_nop(struct module *mod,
                 return -EFAULT;
         }
 
-        DEBUGP(" %08x %08x\n",
-               (unsigned)(*ptr >> 32),
-               (unsigned)*ptr);
+        DEBUGP(" %08x %08x\n", jmp[0], jmp[1]);
+
+        ptr = ((unsigned long)jmp[0] << 32) + jmp[1];
 
         /* This should match what was called */
-        if (*ptr != GET_ADDR(addr)) {
-                printk(KERN_ERR "addr does not match %lx\n", *ptr);
+        if (ptr != GET_ADDR(addr)) {
+                printk(KERN_ERR "addr does not match %lx\n", ptr);
                 return -EINVAL;
         }
 
@@ -240,11 +224,11 @@ __ftrace_make_nop(struct module *mod,
          *  0xe8, 0x41, 0x00, 0x28   ld r2,40(r1)
          * This needs to be turned to a nop too.
          */
-        if (probe_kernel_read(replaced, (void *)(ip+4), MCOUNT_INSN_SIZE))
+        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);
+        if (op != 0xe8410028) {
+                printk(KERN_ERR "Next line is not ld! (%08x)\n", op);
                 return -EINVAL;
         }
 
@@ -261,11 +245,14 @@ __ftrace_make_nop(struct module *mod,
          *   ld r2,40(r1)
          *  1:
          */
-        op[0] = 0x48000008;     /* b +8 */
+        op = 0x48000008;        /* b +8 */
 
-        if (probe_kernel_write((void *)ip, replaced, MCOUNT_INSN_SIZE))
+        if (probe_kernel_write((void *)ip, &op, MCOUNT_INSN_SIZE))
                 return -EPERM;
 
+
+        flush_icache_range(ip, ip + 8);
+
         return 0;
 }
 
@@ -274,46 +261,52 @@ static int
 __ftrace_make_nop(struct module *mod,
                   struct dyn_ftrace *rec, unsigned long addr)
 {
-        unsigned char replaced[MCOUNT_INSN_SIZE];
-        unsigned int *op = (unsigned *)&replaced;
-        unsigned char jmp[8];
-        unsigned int *ptr = (unsigned int *)&jmp;
+        unsigned int op;
+        unsigned int jmp[4];
         unsigned long ip = rec->ip;
         unsigned long tramp;
-        int offset;
 
-        if (probe_kernel_read(replaced, (void *)ip, MCOUNT_INSN_SIZE))
+        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);
+        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);
+        tramp = find_bl_target(ip, op);
 
         /*
          * On PPC32 the trampoline looks like:
-         * lis r11,sym@ha
-         * addi r11,r11,sym@l
-         * mtctr r11
-         * bctr
+         *  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
          */
 
         DEBUGP("ip:%lx jumps to %lx", ip, tramp);
 
         /* Find where the trampoline jumps to */
-        if (probe_kernel_read(jmp, (void *)tramp, 8)) {
+        if (probe_kernel_read(jmp, (void *)tramp, sizeof(jmp))) {
                 printk(KERN_ERR "Failed to read %lx\n", tramp);
                 return -EFAULT;
         }
 
-        DEBUGP(" %08x %08x ", ptr[0], ptr[1]);
+        DEBUGP(" %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 = (ptr[1] & 0xffff) |
-                ((ptr[0] & 0xffff) << 16);
+        tramp = (jmp[1] & 0xffff) |
+                ((jmp[0] & 0xffff) << 16);
         if (tramp & 0x8000)
                 tramp -= 0x10000;
 
@@ -326,11 +319,13 @@ __ftrace_make_nop(struct module *mod,
                 return -EINVAL;
         }
 
-        op[0] = PPC_NOP_INSTR;
+        op = PPC_NOP_INSTR;
 
-        if (probe_kernel_write((void *)ip, replaced, MCOUNT_INSN_SIZE))
+        if (probe_kernel_write((void *)ip, &op, MCOUNT_INSN_SIZE))
                 return -EPERM;
 
+        flush_icache_range(ip, ip + 8);
+
         return 0;
 }
 #endif /* PPC64 */
@@ -384,13 +379,11 @@ int ftrace_make_nop(struct module *mod,
 static int
 __ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
 {
-        unsigned char replaced[MCOUNT_INSN_SIZE * 2];
-        unsigned int *op = (unsigned *)&replaced;
+        unsigned int op[2];
         unsigned long ip = rec->ip;
-        unsigned long offset;
 
         /* read where this goes */
-        if (probe_kernel_read(replaced, (void *)ip, MCOUNT_INSN_SIZE * 2))
+        if (probe_kernel_read(op, (void *)ip, MCOUNT_INSN_SIZE * 2))
                 return -EFAULT;
 
         /*
@@ -409,43 +402,40 @@ __ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
                 return -EINVAL;
         }
 
-        /* now calculate a jump to the ftrace caller trampoline */
-        offset = rec->arch.mod->arch.tramp - ip;
-
-        if (test_offset(offset)) {
-                printk(KERN_ERR "REL24 %li out of range!\n",
-                       (long int)offset);
+        /* 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;
         }
 
-        /* Set to "bl addr" */
-        op[0] = branch_offset(offset);
         /* ld r2,40(r1) */
         op[1] = 0xe8410028;
 
         DEBUGP("write to %lx\n", rec->ip);
 
-        if (probe_kernel_write((void *)ip, replaced, MCOUNT_INSN_SIZE * 2))
+        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 char replaced[MCOUNT_INSN_SIZE];
-        unsigned int *op = (unsigned *)&replaced;
+        unsigned int op;
         unsigned long ip = rec->ip;
-        unsigned long offset;
 
         /* read where this goes */
-        if (probe_kernel_read(replaced, (void *)ip, MCOUNT_INSN_SIZE))
+        if (probe_kernel_read(&op, (void *)ip, MCOUNT_INSN_SIZE))
                 return -EFAULT;
 
         /* It should be pointing to a nop */
-        if (op[0] != PPC_NOP_INSTR) {
-                printk(KERN_ERR "Expected NOP but have %x\n", op[0]);
+        if (op != PPC_NOP_INSTR) {
+                printk(KERN_ERR "Expected NOP but have %x\n", op);
                 return -EINVAL;
         }
 
@@ -455,23 +445,21 @@ __ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
                 return -EINVAL;
         }
 
-        /* now calculate a jump to the ftrace caller trampoline */
-        offset = rec->arch.mod->arch.tramp - ip;
-
-        if (test_offset(offset)) {
-                printk(KERN_ERR "REL24 %li out of range!\n",
-                       (long int)offset);
+        /* 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;
         }
 
-        /* Set to "bl addr" */
-        op[0] = branch_offset(offset);
-
         DEBUGP("write to %lx\n", rec->ip);
 
-        if (probe_kernel_write((void *)ip, replaced, MCOUNT_INSN_SIZE))
+        if (probe_kernel_write((void *)ip, &op, MCOUNT_INSN_SIZE))
                 return -EPERM;
 
+        flush_icache_range(ip, ip + 8);
+
         return 0;
 }
 #endif /* CONFIG_PPC64 */