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authorHelge Deller <deller@gmx.de>2016-04-13 22:27:22 +0200
committerHelge Deller <deller@gmx.de>2016-04-14 17:47:19 +0200
commit366dd4ea9d5f0eb78fdf4982d76506f99480ec0a (patch)
treea1540803a33b13685a1fe2e3fa8af13bc2e7f018 /arch
parentb562e44f507e863c6792946e4e1b1449fbbac85d (diff)
download96b-common-366dd4ea9d5f0eb78fdf4982d76506f99480ec0a.tar.gz
parisc: Fix ftrace function tracer
Fix the FTRACE function tracer for 32- and 64-bit kernel. The former code was horribly broken. Reimplement most coding in assembly and utilize optimizations, e.g. put mcount() and ftrace_stub() into one L1 cacheline. Signed-off-by: Helge Deller <deller@gmx.de>
Diffstat (limited to 'arch')
-rw-r--r--arch/parisc/Kconfig4
-rw-r--r--arch/parisc/Kconfig.debug4
-rw-r--r--arch/parisc/Makefile4
-rw-r--r--arch/parisc/include/asm/ftrace.h18
-rw-r--r--arch/parisc/kernel/Makefile4
-rw-r--r--arch/parisc/kernel/entry.S93
-rw-r--r--arch/parisc/kernel/ftrace.c146
-rw-r--r--arch/parisc/kernel/head.S9
8 files changed, 114 insertions, 168 deletions
diff --git a/arch/parisc/Kconfig b/arch/parisc/Kconfig
index 14f655cf542e..86167bf85aa1 100644
--- a/arch/parisc/Kconfig
+++ b/arch/parisc/Kconfig
@@ -4,8 +4,8 @@ config PARISC
select ARCH_MIGHT_HAVE_PC_PARPORT
select HAVE_IDE
select HAVE_OPROFILE
- select HAVE_FUNCTION_TRACER if 64BIT
- select HAVE_FUNCTION_GRAPH_TRACER if 64BIT
+ select HAVE_FUNCTION_TRACER
+ select HAVE_FUNCTION_GRAPH_TRACER
select ARCH_WANT_FRAME_POINTERS
select RTC_CLASS
select RTC_DRV_GENERIC
diff --git a/arch/parisc/Kconfig.debug b/arch/parisc/Kconfig.debug
index bc989e522a04..68b7cbd0810a 100644
--- a/arch/parisc/Kconfig.debug
+++ b/arch/parisc/Kconfig.debug
@@ -2,9 +2,13 @@ menu "Kernel hacking"
source "lib/Kconfig.debug"
+config TRACE_IRQFLAGS_SUPPORT
+ def_bool y
+
config DEBUG_RODATA
bool "Write protect kernel read-only data structures"
depends on DEBUG_KERNEL
+ default y
help
Mark the kernel read-only data as write-protected in the pagetables,
in order to catch accidental (and incorrect) writes to such const
diff --git a/arch/parisc/Makefile b/arch/parisc/Makefile
index 965a0999fc4c..75cb451b1f03 100644
--- a/arch/parisc/Makefile
+++ b/arch/parisc/Makefile
@@ -62,9 +62,7 @@ cflags-y += -mdisable-fpregs
# Without this, "ld -r" results in .text sections that are too big
# (> 0x40000) for branches to reach stubs.
-ifndef CONFIG_FUNCTION_TRACER
- cflags-y += -ffunction-sections
-endif
+cflags-y += -ffunction-sections
# Use long jumps instead of long branches (needed if your linker fails to
# link a too big vmlinux executable). Not enabled for building modules.
diff --git a/arch/parisc/include/asm/ftrace.h b/arch/parisc/include/asm/ftrace.h
index 544ed8ef87eb..24cd81d58d70 100644
--- a/arch/parisc/include/asm/ftrace.h
+++ b/arch/parisc/include/asm/ftrace.h
@@ -4,23 +4,7 @@
#ifndef __ASSEMBLY__
extern void mcount(void);
-/*
- * Stack of return addresses for functions of a thread.
- * Used in struct thread_info
- */
-struct ftrace_ret_stack {
- unsigned long ret;
- unsigned long func;
- unsigned long long calltime;
-};
-
-/*
- * Primary handler of a function return.
- * It relays on ftrace_return_to_handler.
- * Defined in entry.S
- */
-extern void return_to_handler(void);
-
+#define MCOUNT_INSN_SIZE 4
extern unsigned long return_address(unsigned int);
diff --git a/arch/parisc/kernel/Makefile b/arch/parisc/kernel/Makefile
index ff87b4603e3d..69a11183d48d 100644
--- a/arch/parisc/kernel/Makefile
+++ b/arch/parisc/kernel/Makefile
@@ -15,11 +15,7 @@ ifdef CONFIG_FUNCTION_TRACER
# Do not profile debug and lowlevel utilities
CFLAGS_REMOVE_ftrace.o = -pg
CFLAGS_REMOVE_cache.o = -pg
-CFLAGS_REMOVE_irq.o = -pg
-CFLAGS_REMOVE_pacache.o = -pg
CFLAGS_REMOVE_perf.o = -pg
-CFLAGS_REMOVE_traps.o = -pg
-CFLAGS_REMOVE_unaligned.o = -pg
CFLAGS_REMOVE_unwind.o = -pg
endif
diff --git a/arch/parisc/kernel/entry.S b/arch/parisc/kernel/entry.S
index 623496c11756..39127d3e70e5 100644
--- a/arch/parisc/kernel/entry.S
+++ b/arch/parisc/kernel/entry.S
@@ -1970,43 +1970,98 @@ pt_regs_ok:
b intr_restore
copy %r25,%r16
- .import schedule,code
syscall_do_resched:
- BL schedule,%r2
+ load32 syscall_check_resched,%r2 /* if resched, we start over again */
+ load32 schedule,%r19
+ bv %r0(%r19) /* jumps to schedule() */
#ifdef CONFIG_64BIT
ldo -16(%r30),%r29 /* Reference param save area */
#else
nop
#endif
- b syscall_check_resched /* if resched, we start over again */
- nop
ENDPROC(syscall_exit)
#ifdef CONFIG_FUNCTION_TRACER
+
.import ftrace_function_trampoline,code
-ENTRY(_mcount)
- copy %r3, %arg2
+ .align L1_CACHE_BYTES
+ .globl mcount
+ .type mcount, @function
+ENTRY(mcount)
+_mcount:
+ .export _mcount,data
+ .proc
+ .callinfo caller,frame=0
+ .entry
+ /*
+ * The 64bit mcount() function pointer needs 4 dwords, of which the
+ * first two are free. We optimize it here and put 2 instructions for
+ * calling mcount(), and 2 instructions for ftrace_stub(). That way we
+ * have all on one L1 cacheline.
+ */
b ftrace_function_trampoline
+ copy %r3, %arg2 /* caller original %sp */
+ftrace_stub:
+ .globl ftrace_stub
+ .type ftrace_stub, @function
+#ifdef CONFIG_64BIT
+ bve (%rp)
+#else
+ bv %r0(%rp)
+#endif
nop
-ENDPROC(_mcount)
+#ifdef CONFIG_64BIT
+ .dword mcount
+ .dword 0 /* code in head.S puts value of global gp here */
+#endif
+ .exit
+ .procend
+ENDPROC(mcount)
+ .align 8
+ .globl return_to_handler
+ .type return_to_handler, @function
ENTRY(return_to_handler)
- load32 return_trampoline, %rp
- copy %ret0, %arg0
- copy %ret1, %arg1
- b ftrace_return_to_handler
- nop
-return_trampoline:
- copy %ret0, %rp
- copy %r23, %ret0
- copy %r24, %ret1
+ .proc
+ .callinfo caller,frame=FRAME_SIZE
+ .entry
+ .export parisc_return_to_handler,data
+parisc_return_to_handler:
+ copy %r3,%r1
+ STREG %r0,-RP_OFFSET(%sp) /* store 0 as %rp */
+ copy %sp,%r3
+ STREGM %r1,FRAME_SIZE(%sp)
+ STREG %ret0,8(%r3)
+ STREG %ret1,16(%r3)
-.globl ftrace_stub
-ftrace_stub:
+#ifdef CONFIG_64BIT
+ loadgp
+#endif
+
+ /* call ftrace_return_to_handler(0) */
+#ifdef CONFIG_64BIT
+ ldo -16(%sp),%ret1 /* Reference param save area */
+#endif
+ BL ftrace_return_to_handler,%r2
+ ldi 0,%r26
+ copy %ret0,%rp
+
+ /* restore original return values */
+ LDREG 8(%r3),%ret0
+ LDREG 16(%r3),%ret1
+
+ /* return from function */
+#ifdef CONFIG_64BIT
+ bve (%rp)
+#else
bv %r0(%rp)
- nop
+#endif
+ LDREGM -FRAME_SIZE(%sp),%r3
+ .exit
+ .procend
ENDPROC(return_to_handler)
+
#endif /* CONFIG_FUNCTION_TRACER */
#ifdef CONFIG_IRQSTACKS
diff --git a/arch/parisc/kernel/ftrace.c b/arch/parisc/kernel/ftrace.c
index 559d400f9385..b13f9ec6f294 100644
--- a/arch/parisc/kernel/ftrace.c
+++ b/arch/parisc/kernel/ftrace.c
@@ -1,6 +1,6 @@
/*
* Code for tracing calls in Linux kernel.
- * Copyright (C) 2009 Helge Deller <deller@gmx.de>
+ * Copyright (C) 2009-2016 Helge Deller <deller@gmx.de>
*
* based on code for x86 which is:
* Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com>
@@ -13,104 +13,21 @@
#include <linux/init.h>
#include <linux/ftrace.h>
+#include <asm/assembly.h>
#include <asm/sections.h>
#include <asm/ftrace.h>
-
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
-
-/* Add a function return address to the trace stack on thread info.*/
-static int push_return_trace(unsigned long ret, unsigned long long time,
- unsigned long func, int *depth)
-{
- int index;
-
- if (!current->ret_stack)
- return -EBUSY;
-
- /* The return trace stack is full */
- if (current->curr_ret_stack == FTRACE_RETFUNC_DEPTH - 1) {
- atomic_inc(&current->trace_overrun);
- return -EBUSY;
- }
-
- index = ++current->curr_ret_stack;
- barrier();
- current->ret_stack[index].ret = ret;
- current->ret_stack[index].func = func;
- current->ret_stack[index].calltime = time;
- *depth = index;
-
- return 0;
-}
-
-/* Retrieve a function return address to the trace stack on thread info.*/
-static void pop_return_trace(struct ftrace_graph_ret *trace, unsigned long *ret)
-{
- int index;
-
- index = current->curr_ret_stack;
-
- if (unlikely(index < 0)) {
- ftrace_graph_stop();
- WARN_ON(1);
- /* Might as well panic, otherwise we have no where to go */
- *ret = (unsigned long)
- dereference_function_descriptor(&panic);
- return;
- }
-
- *ret = current->ret_stack[index].ret;
- trace->func = current->ret_stack[index].func;
- trace->calltime = current->ret_stack[index].calltime;
- trace->overrun = atomic_read(&current->trace_overrun);
- trace->depth = index;
- barrier();
- current->curr_ret_stack--;
-
-}
-
-/*
- * Send the trace to the ring-buffer.
- * @return the original return address.
- */
-unsigned long ftrace_return_to_handler(unsigned long retval0,
- unsigned long retval1)
-{
- struct ftrace_graph_ret trace;
- unsigned long ret;
-
- pop_return_trace(&trace, &ret);
- trace.rettime = local_clock();
- ftrace_graph_return(&trace);
-
- if (unlikely(!ret)) {
- ftrace_graph_stop();
- WARN_ON(1);
- /* Might as well panic. What else to do? */
- ret = (unsigned long)
- dereference_function_descriptor(&panic);
- }
-
- /* HACK: we hand over the old functions' return values
- in %r23 and %r24. Assembly in entry.S will take care
- and move those to their final registers %ret0 and %ret1 */
- asm( "copy %0, %%r23 \n\t"
- "copy %1, %%r24 \n" : : "r" (retval0), "r" (retval1) );
-
- return ret;
-}
-
/*
* 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)
+static void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr)
{
unsigned long old;
- unsigned long long calltime;
struct ftrace_graph_ent trace;
+ extern int parisc_return_to_handler;
if (unlikely(ftrace_graph_is_dead()))
return;
@@ -119,64 +36,47 @@ void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr)
return;
old = *parent;
- *parent = (unsigned long)
- dereference_function_descriptor(&return_to_handler);
- if (unlikely(!__kernel_text_address(old))) {
- ftrace_graph_stop();
- *parent = old;
- WARN_ON(1);
- return;
- }
-
- calltime = local_clock();
+ trace.func = self_addr;
+ trace.depth = current->curr_ret_stack + 1;
- if (push_return_trace(old, calltime,
- self_addr, &trace.depth) == -EBUSY) {
- *parent = old;
+ /* Only trace if the calling function expects to */
+ if (!ftrace_graph_entry(&trace))
return;
- }
- trace.func = self_addr;
+ if (ftrace_push_return_trace(old, self_addr, &trace.depth,
+ 0 ) == -EBUSY)
+ return;
- /* Only trace if the calling function expects to */
- if (!ftrace_graph_entry(&trace)) {
- current->curr_ret_stack--;
- *parent = old;
- }
+ /* activate parisc_return_to_handler() as return point */
+ *parent = (unsigned long) &parisc_return_to_handler;
}
-
#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
-
-void ftrace_function_trampoline(unsigned long parent,
+void notrace ftrace_function_trampoline(unsigned long parent,
unsigned long self_addr,
unsigned long org_sp_gr3)
{
- extern ftrace_func_t ftrace_trace_function;
+ extern ftrace_func_t ftrace_trace_function; /* depends on CONFIG_DYNAMIC_FTRACE */
+ extern int ftrace_graph_entry_stub(struct ftrace_graph_ent *trace);
if (ftrace_trace_function != ftrace_stub) {
- ftrace_trace_function(parent, self_addr);
+ /* struct ftrace_ops *op, struct pt_regs *regs); */
+ ftrace_trace_function(parent, self_addr, NULL, NULL);
return;
}
+
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
- if (ftrace_graph_entry && ftrace_graph_return) {
- unsigned long sp;
+ if (ftrace_graph_return != (trace_func_graph_ret_t) ftrace_stub ||
+ ftrace_graph_entry != ftrace_graph_entry_stub) {
unsigned long *parent_rp;
- asm volatile ("copy %%r30, %0" : "=r"(sp));
- /* sanity check: is stack pointer which we got from
- assembler function in entry.S in a reasonable
- range compared to current stack pointer? */
- if ((sp - org_sp_gr3) > 0x400)
- return;
-
/* calculate pointer to %rp in stack */
- parent_rp = (unsigned long *) org_sp_gr3 - 0x10;
+ parent_rp = (unsigned long *) (org_sp_gr3 - RP_OFFSET);
/* sanity check: parent_rp should hold parent */
if (*parent_rp != parent)
return;
-
+
prepare_ftrace_return(parent_rp, self_addr);
return;
}
diff --git a/arch/parisc/kernel/head.S b/arch/parisc/kernel/head.S
index 75aa0db9f69e..bbbe360b458f 100644
--- a/arch/parisc/kernel/head.S
+++ b/arch/parisc/kernel/head.S
@@ -129,6 +129,15 @@ $pgt_fill_loop:
/* And the stack pointer too */
ldo THREAD_SZ_ALGN(%r6),%sp
+#if defined(CONFIG_64BIT) && defined(CONFIG_FUNCTION_TRACER)
+ .import _mcount,data
+ /* initialize mcount FPTR */
+ /* Get the global data pointer */
+ loadgp
+ load32 PA(_mcount), %r10
+ std %dp,0x18(%r10)
+#endif
+
#ifdef CONFIG_SMP
/* Set the smp rendezvous address into page zero.
** It would be safer to do this in init_smp_config() but