s390/ftrace: remove 31 bit ftrace support

31 bit and 64 bit diverge more and more and it is rather painful
to keep both parts running.
To make things simpler just remove the 31 bit support which nobody
uses anyway.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

6 files changed, 56 insertions, 205 deletions

diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
index 608adfb65dd3..95174d2cc4fb 100644
--- a/arch/s390/Kconfig
+++ b/arch/s390/Kconfig
@@ -117,11 +117,11 @@ config S390
         select HAVE_CMPXCHG_LOCAL
         select HAVE_C_RECORDMCOUNT
         select HAVE_DEBUG_KMEMLEAK
-        select HAVE_DYNAMIC_FTRACE
+        select HAVE_DYNAMIC_FTRACE if 64BIT
         select HAVE_DYNAMIC_FTRACE_WITH_REGS if 64BIT
         select HAVE_FTRACE_MCOUNT_RECORD
-        select HAVE_FUNCTION_GRAPH_TRACER
-        select HAVE_FUNCTION_TRACER
+        select HAVE_FUNCTION_GRAPH_TRACER if 64BIT
+        select HAVE_FUNCTION_TRACER if 64BIT
         select HAVE_FUTEX_CMPXCHG if FUTEX
         select HAVE_KERNEL_BZIP2
         select HAVE_KERNEL_GZIP
diff --git a/arch/s390/include/asm/ftrace.h b/arch/s390/include/asm/ftrace.h
index d419362dc231..3aef8afec336 100644
--- a/arch/s390/include/asm/ftrace.h
+++ b/arch/s390/include/asm/ftrace.h
@@ -18,14 +18,8 @@ static inline unsigned long ftrace_call_adjust(unsigned long addr)
 
 #endif /* __ASSEMBLY__ */
 
-#ifdef CONFIG_64BIT
 #define MCOUNT_INSN_SIZE  18
-#else
-#define MCOUNT_INSN_SIZE  22
-#endif
 
-#ifdef CONFIG_64BIT
 #define ARCH_SUPPORTS_FTRACE_OPS 1
-#endif
 
 #endif /* _ASM_S390_FTRACE_H */
diff --git a/arch/s390/kernel/Makefile b/arch/s390/kernel/Makefile
index c249785669f3..204c43a4c245 100644
--- a/arch/s390/kernel/Makefile
+++ b/arch/s390/kernel/Makefile
@@ -52,8 +52,7 @@ obj-$(CONFIG_COMPAT)		+= compat_wrapper.o $(compat-obj-y)
 
 obj-$(CONFIG_STACKTRACE)        += stacktrace.o
 obj-$(CONFIG_KPROBES)           += kprobes.o
-obj-$(CONFIG_FUNCTION_TRACER)   += $(if $(CONFIG_64BIT),mcount64.o,mcount.o)
-obj-$(CONFIG_FUNCTION_TRACER)   += ftrace.o
+obj-$(CONFIG_FUNCTION_TRACER)   += mcount.o ftrace.o
 obj-$(CONFIG_CRASH_DUMP)        += crash_dump.o
 obj-$(CONFIG_UPROBES)           += uprobes.o
 
diff --git a/arch/s390/kernel/ftrace.c b/arch/s390/kernel/ftrace.c
index fcb009d3edde..f0072125926c 100644
--- a/arch/s390/kernel/ftrace.c
+++ b/arch/s390/kernel/ftrace.c
@@ -21,9 +21,8 @@ void mcount_replace_code(void);
 void ftrace_disable_code(void);
 void ftrace_enable_insn(void);
 
-#ifdef CONFIG_64BIT
 /*
- * The 64-bit mcount code looks like this:
+ * The mcount code looks like this:
  *      stg     %r14,8(%r15)            # offset 0
  *      larl    %r1,<&counter>          # offset 6
  *      brasl   %r14,_mcount            # offset 12
@@ -34,7 +33,7 @@ void ftrace_enable_insn(void);
  * Note: we do not patch the first instruction to an unconditional branch,
  * since that would break kprobes/jprobes. It is easier to leave the larl
  * instruction in and only modify the second instruction.
- * The 64-bit enabled ftrace code block looks like this:
+ * The enabled ftrace code block looks like this:
  *      larl    %r0,.+24                # offset 0
  * >    lg      %r1,__LC_FTRACE_FUNC    # offset 6
  *      br      %r1                     # offset 12
@@ -71,65 +70,15 @@ asm(
 #define MCOUNT_INSN_OFFSET      6
 #define FTRACE_INSN_SIZE        6
 
-#else /* CONFIG_64BIT */
-/*
- * The 31-bit mcount code looks like this:
- *      st      %r14,4(%r15)            # offset 0
- * >    bras    %r1,0f                  # offset 4
- * >    .long   _mcount                 # offset 8
- * >    .long   <&counter>              # offset 12
- * > 0: l       %r14,0(%r1)             # offset 16
- * >    l       %r1,4(%r1)              # offset 20
- *      basr    %r14,%r14               # offset 24
- *      l       %r14,4(%r15)            # offset 26
- * Total length is 30 bytes. The twenty bytes starting from offset 4
- * to offset 24 get overwritten by ftrace_make_nop / ftrace_make_call.
- * The 31-bit enabled ftrace code block looks like this:
- *      st      %r14,4(%r15)            # offset 0
- * >    l       %r14,__LC_FTRACE_FUNC   # offset 4
- * >    j       0f                      # offset 8
- * >    .fill   12,1,0x07               # offset 12
- *   0: basr    %r14,%r14               # offset 24
- *      l       %r14,4(%r14)            # offset 26
- * The return points of the mcount/ftrace function have the same offset 26.
- * The 31-bit disabled ftrace code block looks like this:
- *      st      %r14,4(%r15)            # offset 0
- * >    j       .+26                    # offset 4
- * >    j       0f                      # offset 8
- * >    .fill   12,1,0x07               # offset 12
- *   0: basr    %r14,%r14               # offset 24
- *      l       %r14,4(%r14)            # offset 26
- * The j instruction branches to offset 30 to skip as many instructions
- * as possible.
- */
-asm(
-        "       .align  4\n"
-        "ftrace_disable_code:\n"
-        "       j       1f\n"
-        "       j       0f\n"
-        "       .fill   12,1,0x07\n"
-        "0:     basr    %r14,%r14\n"
-        "1:\n"
-        "       .align  4\n"
-        "ftrace_enable_insn:\n"
-        "       l       %r14,"__stringify(__LC_FTRACE_FUNC)"\n");
-
-#define FTRACE_INSN_SIZE        4
-
-#endif /* CONFIG_64BIT */
-
-#ifdef CONFIG_64BIT
 int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr,
                        unsigned long addr)
 {
         return 0;
 }
-#endif
 
 int ftrace_make_nop(struct module *mod, struct dyn_ftrace *rec,
                     unsigned long addr)
 {
-#ifdef CONFIG_64BIT
         /* Initial replacement of the whole mcount block */
         if (addr == MCOUNT_ADDR) {
                 if (probe_kernel_write((void *) rec->ip - MCOUNT_INSN_OFFSET,
@@ -138,7 +87,6 @@ int ftrace_make_nop(struct module *mod, struct dyn_ftrace *rec,
                         return -EPERM;
                 return 0;
         }
-#endif
         if (probe_kernel_write((void *) rec->ip, ftrace_disable_code,
                                MCOUNT_INSN_SIZE))
                 return -EPERM;
@@ -196,8 +144,6 @@ out:
  * the original offset to prepare_ftrace_return and put it back.
  */
 
-#ifdef CONFIG_64BIT
-
 int ftrace_enable_ftrace_graph_caller(void)
 {
         static unsigned short offset = 0x0002;
@@ -216,25 +162,4 @@ int ftrace_disable_ftrace_graph_caller(void)
                                   &offset, sizeof(offset));
 }
 
-#else /* CONFIG_64BIT */
-
-int ftrace_enable_ftrace_graph_caller(void)
-{
-        unsigned short offset;
-
-        offset = ((void *) prepare_ftrace_return -
-                  (void *) ftrace_graph_caller) / 2;
-        return probe_kernel_write((void *) ftrace_graph_caller + 2,
-                                  &offset, sizeof(offset));
-}
-
-int ftrace_disable_ftrace_graph_caller(void)
-{
-        static unsigned short offset = 0x0002;
-
-        return probe_kernel_write((void *) ftrace_graph_caller + 2,
-                                  &offset, sizeof(offset));
-}
-
-#endif /* CONFIG_64BIT */
 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
diff --git a/arch/s390/kernel/mcount.S b/arch/s390/kernel/mcount.S
index be6dbd9a81a7..07abe8d464d4 100644
--- a/arch/s390/kernel/mcount.S
+++ b/arch/s390/kernel/mcount.S
@@ -8,60 +8,73 @@
 #include <linux/linkage.h>
 #include <asm/asm-offsets.h>
 #include <asm/ftrace.h>
+#include <asm/ptrace.h>
 
         .section .kprobes.text, "ax"
 
 ENTRY(ftrace_stub)
         br      %r14
 
+#define STACK_FRAME_SIZE  (STACK_FRAME_OVERHEAD + __PT_SIZE)
+#define STACK_PTREGS      (STACK_FRAME_OVERHEAD)
+#define STACK_PTREGS_GPRS (STACK_PTREGS + __PT_GPRS)
+#define STACK_PTREGS_PSW  (STACK_PTREGS + __PT_PSW)
+
 ENTRY(_mcount)
         br      %r14
 
 ENTRY(ftrace_caller)
-        stm     %r2,%r5,16(%r15)
-        bras    %r1,1f
-0:      .long   ftrace_trace_function
-1:      st      %r14,56(%r15)
-        lr      %r0,%r15
-        ahi     %r15,-96
-        l       %r3,100(%r15)
-        la      %r2,0(%r14)
-        st      %r0,__SF_BACKCHAIN(%r15)
-        la      %r3,0(%r3)
-        ahi     %r2,-MCOUNT_INSN_SIZE
-        l       %r14,0b-0b(%r1)
-        l       %r14,0(%r14)
-        basr    %r14,%r14
+        .globl  ftrace_regs_caller
+        .set    ftrace_regs_caller,ftrace_caller
+        lgr     %r1,%r15
+        aghi    %r15,-STACK_FRAME_SIZE
+        stg     %r1,__SF_BACKCHAIN(%r15)
+        stg     %r1,(STACK_PTREGS_GPRS+15*8)(%r15)
+        stg     %r0,(STACK_PTREGS_PSW+8)(%r15)
+        stmg    %r2,%r14,(STACK_PTREGS_GPRS+2*8)(%r15)
+#ifdef CONFIG_HAVE_MARCH_Z196_FEATURES
+        aghik   %r2,%r0,-MCOUNT_INSN_SIZE
+        lgrl    %r4,function_trace_op
+        lgrl    %r1,ftrace_trace_function
+#else
+        lgr     %r2,%r0
+        aghi    %r2,-MCOUNT_INSN_SIZE
+        larl    %r4,function_trace_op
+        lg      %r4,0(%r4)
+        larl    %r1,ftrace_trace_function
+        lg      %r1,0(%r1)
+#endif
+        lgr     %r3,%r14
+        la      %r5,STACK_PTREGS(%r15)
+        basr    %r14,%r1
 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
-        l       %r2,100(%r15)
-        l       %r3,152(%r15)
-ENTRY(ftrace_graph_caller)
-# The bras instruction gets runtime patched to call prepare_ftrace_return.
+# The j instruction gets runtime patched to a nop instruction.
 # See ftrace_enable_ftrace_graph_caller. The patched instruction is:
-#       bras    %r14,prepare_ftrace_return
-        bras    %r14,0f
-0:      st      %r2,100(%r15)
+#       j       .+4
+ENTRY(ftrace_graph_caller)
+        j       ftrace_graph_caller_end
+        lg      %r2,(STACK_PTREGS_GPRS+14*8)(%r15)
+        lg      %r3,(STACK_PTREGS_PSW+8)(%r15)
+        brasl   %r14,prepare_ftrace_return
+        stg     %r2,(STACK_PTREGS_GPRS+14*8)(%r15)
+ftrace_graph_caller_end:
+        .globl  ftrace_graph_caller_end
 #endif
-        ahi     %r15,96
-        l       %r14,56(%r15)
-        lm      %r2,%r5,16(%r15)
-        br      %r14
+        lg      %r1,(STACK_PTREGS_PSW+8)(%r15)
+        lmg     %r2,%r15,(STACK_PTREGS_GPRS+2*8)(%r15)
+        br      %r1
 
 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 
 ENTRY(return_to_handler)
-        stm     %r2,%r5,16(%r15)
-        st      %r14,56(%r15)
-        lr      %r0,%r15
-        ahi     %r15,-96
-        st      %r0,__SF_BACKCHAIN(%r15)
-        bras    %r1,0f
-        .long   ftrace_return_to_handler
-0:      l       %r2,0b-0b(%r1)
-        basr    %r14,%r2
-        lr      %r14,%r2
-        ahi     %r15,96
-        lm      %r2,%r5,16(%r15)
+        stmg    %r2,%r5,32(%r15)
+        lgr     %r1,%r15
+        aghi    %r15,-STACK_FRAME_OVERHEAD
+        stg     %r1,__SF_BACKCHAIN(%r15)
+        brasl   %r14,ftrace_return_to_handler
+        aghi    %r15,STACK_FRAME_OVERHEAD
+        lgr     %r14,%r2
+        lmg     %r2,%r5,32(%r15)
         br      %r14
 
 #endif
diff --git a/arch/s390/kernel/mcount64.S b/arch/s390/kernel/mcount64.S
deleted file mode 100644
index 07abe8d464d4..000000000000
--- a/arch/s390/kernel/mcount64.S
+++ /dev/null
@@ -1,80 +0,0 @@
-/*
- * Copyright IBM Corp. 2008, 2009
- *
- *   Author(s): Heiko Carstens <heiko.carstens@de.ibm.com>,
- *
- */
-
-#include <linux/linkage.h>
-#include <asm/asm-offsets.h>
-#include <asm/ftrace.h>
-#include <asm/ptrace.h>
-
-        .section .kprobes.text, "ax"
-
-ENTRY(ftrace_stub)
-        br      %r14
-
-#define STACK_FRAME_SIZE  (STACK_FRAME_OVERHEAD + __PT_SIZE)
-#define STACK_PTREGS      (STACK_FRAME_OVERHEAD)
-#define STACK_PTREGS_GPRS (STACK_PTREGS + __PT_GPRS)
-#define STACK_PTREGS_PSW  (STACK_PTREGS + __PT_PSW)
-
-ENTRY(_mcount)
-        br      %r14
-
-ENTRY(ftrace_caller)
-        .globl  ftrace_regs_caller
-        .set    ftrace_regs_caller,ftrace_caller
-        lgr     %r1,%r15
-        aghi    %r15,-STACK_FRAME_SIZE
-        stg     %r1,__SF_BACKCHAIN(%r15)
-        stg     %r1,(STACK_PTREGS_GPRS+15*8)(%r15)
-        stg     %r0,(STACK_PTREGS_PSW+8)(%r15)
-        stmg    %r2,%r14,(STACK_PTREGS_GPRS+2*8)(%r15)
-#ifdef CONFIG_HAVE_MARCH_Z196_FEATURES
-        aghik   %r2,%r0,-MCOUNT_INSN_SIZE
-        lgrl    %r4,function_trace_op
-        lgrl    %r1,ftrace_trace_function
-#else
-        lgr     %r2,%r0
-        aghi    %r2,-MCOUNT_INSN_SIZE
-        larl    %r4,function_trace_op
-        lg      %r4,0(%r4)
-        larl    %r1,ftrace_trace_function
-        lg      %r1,0(%r1)
-#endif
-        lgr     %r3,%r14
-        la      %r5,STACK_PTREGS(%r15)
-        basr    %r14,%r1
-#ifdef CONFIG_FUNCTION_GRAPH_TRACER
-# The j instruction gets runtime patched to a nop instruction.
-# See ftrace_enable_ftrace_graph_caller. The patched instruction is:
-#       j       .+4
-ENTRY(ftrace_graph_caller)
-        j       ftrace_graph_caller_end
-        lg      %r2,(STACK_PTREGS_GPRS+14*8)(%r15)
-        lg      %r3,(STACK_PTREGS_PSW+8)(%r15)
-        brasl   %r14,prepare_ftrace_return
-        stg     %r2,(STACK_PTREGS_GPRS+14*8)(%r15)
-ftrace_graph_caller_end:
-        .globl  ftrace_graph_caller_end
-#endif
-        lg      %r1,(STACK_PTREGS_PSW+8)(%r15)
-        lmg     %r2,%r15,(STACK_PTREGS_GPRS+2*8)(%r15)
-        br      %r1
-
-#ifdef CONFIG_FUNCTION_GRAPH_TRACER
-
-ENTRY(return_to_handler)
-        stmg    %r2,%r5,32(%r15)
-        lgr     %r1,%r15
-        aghi    %r15,-STACK_FRAME_OVERHEAD
-        stg     %r1,__SF_BACKCHAIN(%r15)
-        brasl   %r14,ftrace_return_to_handler
-        aghi    %r15,STACK_FRAME_OVERHEAD
-        lgr     %r14,%r2
-        lmg     %r2,%r5,32(%r15)
-        br      %r14
-
-#endif