From 473d1cf4ee623b043790838bcf77e77958840bf2 Mon Sep 17 00:00:00 2001 From: Paul Mundt Date: Sat, 11 Jul 2009 19:56:58 +0900 Subject: sh: Decouple mcount from ftrace. This adds a general CONFIG_MCOUNT in order to permit mcount generation without ftrace support. This is primarily for allowing platforms to enable aggressive stack overflow checking without having to enable ftrace support. Based on the sparc64 implementation. Signed-off-by: Paul Mundt --- arch/sh/Kconfig.debug | 5 +++++ arch/sh/Makefile | 4 ++++ arch/sh/boot/compressed/Makefile | 2 +- arch/sh/kernel/sh_ksyms_32.c | 2 +- arch/sh/lib/Makefile | 3 +-- 5 files changed, 12 insertions(+), 4 deletions(-) diff --git a/arch/sh/Kconfig.debug b/arch/sh/Kconfig.debug index 52a132c24aa..75b5f4e0667 100644 --- a/arch/sh/Kconfig.debug +++ b/arch/sh/Kconfig.debug @@ -134,4 +134,9 @@ config STACK_DEBUG call and will therefore incur a major performance hit. Most users should say N. +config MCOUNT + def_bool y + depends on SUPERH32 + depends on STACK_DEBUG || FUNCTION_TRACER + endmenu diff --git a/arch/sh/Makefile b/arch/sh/Makefile index 75d049b03f7..52c34bf5696 100644 --- a/arch/sh/Makefile +++ b/arch/sh/Makefile @@ -186,6 +186,10 @@ KBUILD_CFLAGS += -pipe $(cflags-y) KBUILD_CPPFLAGS += $(cflags-y) KBUILD_AFLAGS += $(cflags-y) +ifeq ($(CONFIG_MCOUNT),y) + KBUILD_CFLAGS += -pg +endif + libs-$(CONFIG_SUPERH32) := arch/sh/lib/ $(libs-y) libs-$(CONFIG_SUPERH64) := arch/sh/lib64/ $(libs-y) diff --git a/arch/sh/boot/compressed/Makefile b/arch/sh/boot/compressed/Makefile index 9531bf1b7c2..3af239cb9b0 100644 --- a/arch/sh/boot/compressed/Makefile +++ b/arch/sh/boot/compressed/Makefile @@ -23,7 +23,7 @@ IMAGE_OFFSET := $(shell /bin/bash -c 'printf "0x%08x" \ LIBGCC := $(shell $(CC) $(KBUILD_CFLAGS) -print-libgcc-file-name) -ifeq ($(CONFIG_FUNCTION_TRACER),y) +ifeq ($(CONFIG_MCOUNT),y) ORIG_CFLAGS := $(KBUILD_CFLAGS) KBUILD_CFLAGS = $(subst -pg, , $(ORIG_CFLAGS)) endif diff --git a/arch/sh/kernel/sh_ksyms_32.c b/arch/sh/kernel/sh_ksyms_32.c index fcc5de31f83..5b81116046c 100644 --- a/arch/sh/kernel/sh_ksyms_32.c +++ b/arch/sh/kernel/sh_ksyms_32.c @@ -106,7 +106,7 @@ EXPORT_SYMBOL(flush_dcache_page); EXPORT_SYMBOL(clear_user_page); #endif -#ifdef CONFIG_FUNCTION_TRACER +#ifdef CONFIG_MCOUNT EXPORT_SYMBOL(mcount); #endif EXPORT_SYMBOL(csum_partial); diff --git a/arch/sh/lib/Makefile b/arch/sh/lib/Makefile index 19328d90a2d..c2b28d8b2dd 100644 --- a/arch/sh/lib/Makefile +++ b/arch/sh/lib/Makefile @@ -24,8 +24,7 @@ memcpy-y := memcpy.o memcpy-$(CONFIG_CPU_SH4) := memcpy-sh4.o lib-$(CONFIG_MMU) += copy_page.o clear_page.o -lib-$(CONFIG_FUNCTION_TRACER) += mcount.o -lib-$(CONFIG_FUNCTION_GRAPH_TRACER) += mcount.o +lib-$(CONFIG_MCOUNT) += mcount.o lib-y += $(memcpy-y) $(udivsi3-y) EXTRA_CFLAGS += -Werror -- cgit v1.2.3-18-g5258 From 9f14b84afda297d301b81a5bcbd65e83d7b02034 Mon Sep 17 00:00:00 2001 From: Paul Mundt Date: Sat, 11 Jul 2009 20:05:34 +0900 Subject: sh: Replace DEBUG_STACKOVERFLOW with STACK_DEBUG. STACK_DEBUG ties in to mcount in order to do function-granular stack overflow checks as opposed to lazily checking from IRQ context. As the default is nohz, the frequency of overflow checking is too irregular to catch much useful information, and so the mcount approach employed by sparc64 is adopted instead. This kills off the old check entirely from the do_IRQ() path and now adopts CONFIG_MCOUNT instead. Signed-off-by: Paul Mundt --- arch/sh/Kconfig.debug | 17 ++++------------- arch/sh/kernel/irq.c | 17 ----------------- 2 files changed, 4 insertions(+), 30 deletions(-) diff --git a/arch/sh/Kconfig.debug b/arch/sh/Kconfig.debug index 75b5f4e0667..b440fd93671 100644 --- a/arch/sh/Kconfig.debug +++ b/arch/sh/Kconfig.debug @@ -61,12 +61,14 @@ config EARLY_PRINTK select both the EARLY_SCIF_CONSOLE and SH_STANDARD_BIOS, using the kernel command line option to toggle back and forth. -config DEBUG_STACKOVERFLOW +config STACK_DEBUG bool "Check for stack overflows" depends on DEBUG_KERNEL && SUPERH32 help This option will cause messages to be printed if free stack space - drops below a certain limit. + drops below a certain limit. Saying Y here will add overhead to + every function call and will therefore incur a major + performance hit. Most users should say N. config DEBUG_STACK_USAGE bool "Stack utilization instrumentation" @@ -123,17 +125,6 @@ config SH64_SR_WATCH bool "Debug: set SR.WATCH to enable hardware watchpoints and trace" depends on SUPERH64 -config STACK_DEBUG - bool "Enable diagnostic checks of the kernel stack" - depends on FUNCTION_TRACER - select DEBUG_STACKOVERFLOW - default n - help - This option allows checks to be performed on the kernel stack - at runtime. Saying Y here will add overhead to every function - call and will therefore incur a major performance hit. Most - users should say N. - config MCOUNT def_bool y depends on SUPERH32 diff --git a/arch/sh/kernel/irq.c b/arch/sh/kernel/irq.c index 3d09062f468..278c68c6048 100644 --- a/arch/sh/kernel/irq.c +++ b/arch/sh/kernel/irq.c @@ -114,23 +114,6 @@ asmlinkage int do_IRQ(unsigned int irq, struct pt_regs *regs) #endif irq_enter(); - -#ifdef CONFIG_DEBUG_STACKOVERFLOW - /* Debugging check for stack overflow: is there less than 1KB free? */ - { - long sp; - - __asm__ __volatile__ ("and r15, %0" : - "=r" (sp) : "0" (THREAD_SIZE - 1)); - - if (unlikely(sp < (sizeof(struct thread_info) + STACK_WARN))) { - printk("do_IRQ: stack overflow: %ld\n", - sp - sizeof(struct thread_info)); - dump_stack(); - } - } -#endif - irq = irq_demux(intc_evt2irq(irq)); #ifdef CONFIG_IRQSTACKS -- cgit v1.2.3-18-g5258 From fe27932052aebf77ac5f3e73962825d2aeb457a0 Mon Sep 17 00:00:00 2001 From: Paul Mundt Date: Sat, 11 Jul 2009 20:32:14 +0900 Subject: sh: Use DECLARE_EXPORT() for mcount symbol export. The function prototype for mcount is not defined if we are not building with ftrace support enabled, so use DECLARE_EXPORT() to stub one in. Signed-off-by: Paul Mundt --- arch/sh/kernel/sh_ksyms_32.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/sh/kernel/sh_ksyms_32.c b/arch/sh/kernel/sh_ksyms_32.c index 5b81116046c..cec610888e2 100644 --- a/arch/sh/kernel/sh_ksyms_32.c +++ b/arch/sh/kernel/sh_ksyms_32.c @@ -107,7 +107,7 @@ EXPORT_SYMBOL(clear_user_page); #endif #ifdef CONFIG_MCOUNT -EXPORT_SYMBOL(mcount); +DECLARE_EXPORT(mcount); #endif EXPORT_SYMBOL(csum_partial); EXPORT_SYMBOL(csum_partial_copy_generic); -- cgit v1.2.3-18-g5258 From a470b95e99ea77ef1e307ff181e59a4a16caa4f4 Mon Sep 17 00:00:00 2001 From: Paul Mundt Date: Sat, 11 Jul 2009 20:33:34 +0900 Subject: sh: Fix up ftrace build error when STACK_DEBUG=n. Presently the closest reference to function_trace_stop is within a CONFIG_STACK_DEBUG block. When this is turned off, the build bails out with a pcrel too far error. Reorder things a bit to handle the various combinations. Signed-off-by: Paul Mundt --- arch/sh/lib/mcount.S | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/arch/sh/lib/mcount.S b/arch/sh/lib/mcount.S index bd3ec648bec..9e397aafc16 100644 --- a/arch/sh/lib/mcount.S +++ b/arch/sh/lib/mcount.S @@ -192,6 +192,10 @@ ftrace_call: #endif /* CONFIG_FUNCTION_GRAPH_TRACER */ #endif /* CONFIG_DYNAMIC_FTRACE */ + .align 2 +.Lfunction_trace_stop: + .long function_trace_stop + /* * NOTE: From here on the locations of the .Lftrace_stub label and * ftrace_stub itself are fixed. Adding additional data here will skew @@ -199,7 +203,6 @@ ftrace_call: * Place new labels either after the ftrace_stub body, or before * ftrace_caller. You have been warned. */ - .align 2 .Lftrace_stub: .long ftrace_stub @@ -223,8 +226,6 @@ stack_panic: nop .align 2 -.Lfunction_trace_stop: - .long function_trace_stop .L_ebss: .long _ebss .L_init_thread_union: -- cgit v1.2.3-18-g5258 From e460ab27b6c3ea313762169713086529d5bfb8bc Mon Sep 17 00:00:00 2001 From: Paul Mundt Date: Sat, 11 Jul 2009 21:06:53 +0900 Subject: sh: Fix up stack overflow check with ftrace disabled. Presently the STACK_CHECK() code is called in to multiple times, although it's only necessary from the mcount entry. The code still attempts to treat the nop case as an ftrace path resulting in superfluous code flow for the case where ftrace is disabled. And finally, this also fixes up references to a few undefined symbols when FUNCTION_TRACER=n. Signed-off-by: Paul Mundt --- arch/sh/lib/mcount.S | 76 +++++++++++++++++++++++++++------------------------- 1 file changed, 40 insertions(+), 36 deletions(-) diff --git a/arch/sh/lib/mcount.S b/arch/sh/lib/mcount.S index 9e397aafc16..84a57761f17 100644 --- a/arch/sh/lib/mcount.S +++ b/arch/sh/lib/mcount.S @@ -1,7 +1,7 @@ /* * arch/sh/lib/mcount.S * - * Copyright (C) 2008 Paul Mundt + * Copyright (C) 2008, 2009 Paul Mundt * Copyright (C) 2008, 2009 Matt Fleming * * This file is subject to the terms and conditions of the GNU General Public @@ -86,13 +86,18 @@ .type mcount,@function _mcount: mcount: + STACK_CHECK() + +#ifndef CONFIG_FUNCTION_TRACER + rts + nop +#else #ifndef CONFIG_DYNAMIC_FTRACE mov.l .Lfunction_trace_stop, r0 mov.l @r0, r0 tst r0, r0 bf ftrace_stub #endif - STACK_CHECK() MCOUNT_ENTER() @@ -174,8 +179,6 @@ ftrace_caller: tst r0, r0 bf ftrace_stub - STACK_CHECK() - MCOUNT_ENTER() .globl ftrace_call @@ -211,38 +214,6 @@ ftrace_stub: rts nop -#ifdef CONFIG_STACK_DEBUG - .globl stack_panic -stack_panic: - mov.l .Ldump_stack, r0 - jsr @r0 - nop - - mov.l .Lpanic, r0 - jsr @r0 - mov.l .Lpanic_s, r4 - - rts - nop - - .align 2 -.L_ebss: - .long _ebss -.L_init_thread_union: - .long init_thread_union -.Lpanic: - .long panic -.Lpanic_s: - .long .Lpanic_str -.Ldump_stack: - .long dump_stack - - .section .rodata - .align 2 -.Lpanic_str: - .string "Stack error" -#endif /* CONFIG_STACK_DEBUG */ - #ifdef CONFIG_FUNCTION_GRAPH_TRACER .globl ftrace_graph_caller ftrace_graph_caller: @@ -304,3 +275,36 @@ return_to_handler: .Lftrace_return_to_handler: .long ftrace_return_to_handler #endif /* CONFIG_FUNCTION_GRAPH_TRACER */ +#endif /* CONFIG_FUNCTION_TRACER */ + +#ifdef CONFIG_STACK_DEBUG + .globl stack_panic +stack_panic: + mov.l .Ldump_stack, r0 + jsr @r0 + nop + + mov.l .Lpanic, r0 + jsr @r0 + mov.l .Lpanic_s, r4 + + rts + nop + + .align 2 +.L_ebss: + .long _ebss +.L_init_thread_union: + .long init_thread_union +.Lpanic: + .long panic +.Lpanic_s: + .long .Lpanic_str +.Ldump_stack: + .long dump_stack + + .section .rodata + .align 2 +.Lpanic_str: + .string "Stack error" +#endif /* CONFIG_STACK_DEBUG */ -- cgit v1.2.3-18-g5258