perf fixes

GIT PULL Ingo Molnar 1 participant 1 message Dec 1, 2012

Subsystems (3)

x86 Kbuild perf events

lore

Share & tools

lore

Ingo Molnar

author

2012-12-01 11:11 UTC #0 lore raw

Linus,

Please pull the latest perf-urgent-for-linus git tree from:

git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git perf-urgent-for-linus

HEAD: fd6da696f38b00ffeae1185d6f0ec5d4ab3b472d Merge tag 'perf-urgent-for-mingo' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux into perf/urgent

This is mostly about unbreaking architectures that took the UAPI changes in the v3.7 cycle, plus misc fixes.

Thanks,

Ingo

------------------>
David Howells (5):
x86: Export asm/{svm.h,vmx.h,perf_regs.h}
tools: Define a Makefile function to do subdir processing
tools: Honour the O= flag when tool build called from a higher Makefile
tools: Pass the target in descend
perf: Make perf build for x86 with UAPI disintegration applied

Michael Neuling (1):
perf, powerpc: Fix hw breakpoints returning -ENOSPC

Namhyung Kim (2):
perf header: Fix numa topology printing
perf tools: Fix strbuf_addf() when the buffer needs to grow

Sukadev Bhattiprolu (1):
perf powerpc: Use uapi/unistd.h to fix build error

Xiao Guangrong (2):
perf kvm: Rename perf_kvm to perf_kvm_stat perf kvm: Fix building perf kvm on non x86 arches

 Makefile                                |   6 +-
 arch/x86/include/asm/Kbuild             |   3 +
 include/linux/hw_breakpoint.h           |  31 +-------
 include/uapi/linux/Kbuild               |   1 +
 include/uapi/linux/hw_breakpoint.h      |  30 ++++++++
 kernel/events/hw_breakpoint.c           |  12 ++--
 tools/Makefile                          |  24 +++----
 tools/perf/Makefile                     |  29 +++++++-
 tools/perf/arch/x86/include/perf_regs.h |   2 +-
 tools/perf/builtin-kvm.c                | 121 ++++++++++++++++++--------------
 tools/perf/builtin-test.c               |   2 +-
 tools/perf/perf.h                       |  16 +----
 tools/perf/util/evsel.c                 |   4 +-
 tools/perf/util/evsel.h                 |   3 +-
 tools/perf/util/header.c                |   2 +
 tools/perf/util/header.h                |   2 +-
 tools/perf/util/parse-events-test.c     |   2 +-
 tools/perf/util/parse-events.c          |   2 +-
 tools/perf/util/parse-events.h          |   2 +-
 tools/perf/util/pmu.h                   |   2 +-
 tools/perf/util/session.h               |   2 +-
 tools/perf/util/strbuf.c                |   8 +--
 tools/scripts/Makefile.include          |  23 +++++-
 23 files changed, 194 insertions(+), 135 deletions(-)
 create mode 100644 include/uapi/linux/hw_breakpoint.h

Makefile +4 -2

index 42d0e56..71dc31e 100644
@@ -1321,10 +1321,12 @@ kernelversion:
 
 # Clear a bunch of variables before executing the submake
 tools/: FORCE
-	$(Q)$(MAKE) LDFLAGS= MAKEFLAGS= -C $(src)/tools/
+	$(Q)mkdir -p $(objtree)/tools
+	$(Q)$(MAKE) LDFLAGS= MAKEFLAGS= O=$(objtree) subdir=tools -C $(src)/tools/
 
 tools/%: FORCE
-	$(Q)$(MAKE) LDFLAGS= MAKEFLAGS= -C $(src)/tools/ $*
+	$(Q)mkdir -p $(objtree)/tools
+	$(Q)$(MAKE) LDFLAGS= MAKEFLAGS= O=$(objtree) subdir=tools -C $(src)/tools/ $*
 
 # Single targets
 # ---------------------------------------------------------------------------

arch/x86/include/asm/Kbuild +3 -0

index 66e5f0e..79fd8a3 100644
@@ -12,6 +12,7 @@ header-y += mce.h
 header-y += msr-index.h
 header-y += msr.h
 header-y += mtrr.h
+header-y += perf_regs.h
 header-y += posix_types_32.h
 header-y += posix_types_64.h
 header-y += posix_types_x32.h

@@ -19,8 +20,10 @@ header-y += prctl.h
 header-y += processor-flags.h
 header-y += ptrace-abi.h
 header-y += sigcontext32.h
+header-y += svm.h
 header-y += ucontext.h
 header-y += vm86.h
+header-y += vmx.h
 header-y += vsyscall.h
 
 genhdr-y += unistd_32.h

include/linux/hw_breakpoint.h +1 ~~-30~~

index 6ae9c63..0464c85 100644
@@ -1,35 +1,8 @@
 #ifndef _LINUX_HW_BREAKPOINT_H
 #define _LINUX_HW_BREAKPOINT_H
 
-enum {
-	HW_BREAKPOINT_LEN_1 = 1,
-	HW_BREAKPOINT_LEN_2 = 2,
-	HW_BREAKPOINT_LEN_4 = 4,
-	HW_BREAKPOINT_LEN_8 = 8,
-};
-
-enum {
-	HW_BREAKPOINT_EMPTY	= 0,
-	HW_BREAKPOINT_R		= 1,
-	HW_BREAKPOINT_W		= 2,
-	HW_BREAKPOINT_RW	= HW_BREAKPOINT_R | HW_BREAKPOINT_W,
-	HW_BREAKPOINT_X		= 4,
-	HW_BREAKPOINT_INVALID   = HW_BREAKPOINT_RW | HW_BREAKPOINT_X,
-};
-
-enum bp_type_idx {
-	TYPE_INST 	= 0,
-#ifdef CONFIG_HAVE_MIXED_BREAKPOINTS_REGS
-	TYPE_DATA	= 0,
-#else
-	TYPE_DATA	= 1,
-#endif
-	TYPE_MAX
-};
-
-#ifdef __KERNEL__
-
 #include <linux/perf_event.h>
+#include <uapi/linux/hw_breakpoint.h>
 
 #ifdef CONFIG_HAVE_HW_BREAKPOINT

@@ -151,6 +124,4 @@ static inline struct arch_hw_breakpoint *counter_arch_bp(struct perf_event *bp)
 }
 
 #endif /* CONFIG_HAVE_HW_BREAKPOINT */
-#endif /* __KERNEL__ */
-
 #endif /* _LINUX_HW_BREAKPOINT_H */

include/uapi/linux/Kbuild +1 -0

index e194387..19e765f 100644
@@ -415,3 +415,4 @@ header-y += wireless.h
 header-y += x25.h
 header-y += xattr.h
 header-y += xfrm.h
+header-y += hw_breakpoint.h

include/uapi/linux/hw_breakpoint.h new file +30 -0

new file mode 100644
index 0000000..b04000a
@@ -0,0 +1,30 @@
+#ifndef _UAPI_LINUX_HW_BREAKPOINT_H
+#define _UAPI_LINUX_HW_BREAKPOINT_H
+
+enum {
+	HW_BREAKPOINT_LEN_1 = 1,
+	HW_BREAKPOINT_LEN_2 = 2,
+	HW_BREAKPOINT_LEN_4 = 4,
+	HW_BREAKPOINT_LEN_8 = 8,
+};
+
+enum {
+	HW_BREAKPOINT_EMPTY	= 0,
+	HW_BREAKPOINT_R		= 1,
+	HW_BREAKPOINT_W		= 2,
+	HW_BREAKPOINT_RW	= HW_BREAKPOINT_R | HW_BREAKPOINT_W,
+	HW_BREAKPOINT_X		= 4,
+	HW_BREAKPOINT_INVALID   = HW_BREAKPOINT_RW | HW_BREAKPOINT_X,
+};
+
+enum bp_type_idx {
+	TYPE_INST 	= 0,
+#ifdef CONFIG_HAVE_MIXED_BREAKPOINTS_REGS
+	TYPE_DATA	= 0,
+#else
+	TYPE_DATA	= 1,
+#endif
+	TYPE_MAX
+};
+
+#endif /* _UAPI_LINUX_HW_BREAKPOINT_H */

kernel/events/hw_breakpoint.c +7 -5

index 9a7b487..fe8a916 100644
@@ -111,14 +111,16 @@ static unsigned int max_task_bp_pinned(int cpu, enum bp_type_idx type)
  * Count the number of breakpoints of the same type and same task.
  * The given event must be not on the list.
  */
-static int task_bp_pinned(struct perf_event *bp, enum bp_type_idx type)
+static int task_bp_pinned(int cpu, struct perf_event *bp, enum bp_type_idx type)
 {
 	struct task_struct *tsk = bp->hw.bp_target;
 	struct perf_event *iter;
 	int count = 0;
 
 	list_for_each_entry(iter, &bp_task_head, hw.bp_list) {
-		if (iter->hw.bp_target == tsk && find_slot_idx(iter) == type)
+		if (iter->hw.bp_target == tsk &&
+		    find_slot_idx(iter) == type &&
+		    cpu == iter->cpu)
 			count += hw_breakpoint_weight(iter);
 	}

@@ -141,7 +143,7 @@ fetch_bp_busy_slots(struct bp_busy_slots *slots, struct perf_event *bp,
 		if (!tsk)
 			slots->pinned += max_task_bp_pinned(cpu, type);
 		else
-			slots->pinned += task_bp_pinned(bp, type);
+			slots->pinned += task_bp_pinned(cpu, bp, type);
 		slots->flexible = per_cpu(nr_bp_flexible[type], cpu);
 
 		return;

@@ -154,7 +156,7 @@ fetch_bp_busy_slots(struct bp_busy_slots *slots, struct perf_event *bp,
 		if (!tsk)
 			nr += max_task_bp_pinned(cpu, type);
 		else
-			nr += task_bp_pinned(bp, type);
+			nr += task_bp_pinned(cpu, bp, type);
 
 		if (nr > slots->pinned)
 			slots->pinned = nr;

@@ -188,7 +190,7 @@ static void toggle_bp_task_slot(struct perf_event *bp, int cpu, bool enable,
 	int old_idx = 0;
 	int idx = 0;
 
-	old_count = task_bp_pinned(bp, type);
+	old_count = task_bp_pinned(cpu, bp, type);
 	old_idx = old_count - 1;
 	idx = old_idx + weight;

tools/Makefile +12 ~~-12~~

index 3ae4394..1f9a529 100644
@@ -31,44 +31,44 @@ help:
 	@echo '  clean: a summary clean target to clean _all_ folders'
 
 cpupower: FORCE
-	$(QUIET_SUBDIR0)power/$@/ $(QUIET_SUBDIR1)
+	$(call descend,power/$@)
 
 firewire lguest perf usb virtio vm: FORCE
-	$(QUIET_SUBDIR0)$@/ $(QUIET_SUBDIR1)
+	$(call descend,$@)
 
 selftests: FORCE
-	$(QUIET_SUBDIR0)testing/$@/ $(QUIET_SUBDIR1)
+	$(call descend,testing/$@)
 
 turbostat x86_energy_perf_policy: FORCE
-	$(QUIET_SUBDIR0)power/x86/$@/ $(QUIET_SUBDIR1)
+	$(call descend,power/x86/$@)
 
 cpupower_install:
-	$(QUIET_SUBDIR0)power/$(@:_install=)/ $(QUIET_SUBDIR1) install
+	$(call descend,power/$(@:_install=),install)
 
 firewire_install lguest_install perf_install usb_install virtio_install vm_install:
-	$(QUIET_SUBDIR0)$(@:_install=)/ $(QUIET_SUBDIR1) install
+	$(call descend,$(@:_install=),install)
 
 selftests_install:
-	$(QUIET_SUBDIR0)testing/$(@:_clean=)/ $(QUIET_SUBDIR1) install
+	$(call descend,testing/$(@:_clean=),install)
 
 turbostat_install x86_energy_perf_policy_install:
-	$(QUIET_SUBDIR0)power/x86/$(@:_install=)/ $(QUIET_SUBDIR1) install
+	$(call descend,power/x86/$(@:_install=),install)
 
 install: cpupower_install firewire_install lguest_install perf_install \
 		selftests_install turbostat_install usb_install virtio_install \
 		vm_install x86_energy_perf_policy_install
 
 cpupower_clean:
-	$(QUIET_SUBDIR0)power/cpupower/ $(QUIET_SUBDIR1) clean
+	$(call descend,power/cpupower,clean)
 
 firewire_clean lguest_clean perf_clean usb_clean virtio_clean vm_clean:
-	$(QUIET_SUBDIR0)$(@:_clean=)/ $(QUIET_SUBDIR1) clean
+	$(call descend,$(@:_clean=),clean)
 
 selftests_clean:
-	$(QUIET_SUBDIR0)testing/$(@:_clean=)/ $(QUIET_SUBDIR1) clean
+	$(call descend,testing/$(@:_clean=),clean)
 
 turbostat_clean x86_energy_perf_policy_clean:
-	$(QUIET_SUBDIR0)power/x86/$(@:_clean=)/ $(QUIET_SUBDIR1) clean
+	$(call descend,power/x86/$(@:_clean=),clean)
 
 clean: cpupower_clean firewire_clean lguest_clean perf_clean selftests_clean \
 		turbostat_clean usb_clean virtio_clean vm_clean \

tools/perf/Makefile +28 -1

index 00deed4d..0a619af 100644
@@ -169,7 +169,34 @@ endif
 
 ### --- END CONFIGURATION SECTION ---
 
-BASIC_CFLAGS = -Iutil/include -Iarch/$(ARCH)/include -I$(OUTPUT)util -I$(TRACE_EVENT_DIR) -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -D_GNU_SOURCE
+ifeq ($(srctree),)
+srctree := $(patsubst %/,%,$(dir $(shell pwd)))
+srctree := $(patsubst %/,%,$(dir $(srctree)))
+#$(info Determined 'srctree' to be $(srctree))
+endif
+
+ifneq ($(objtree),)
+#$(info Determined 'objtree' to be $(objtree))
+endif
+
+ifneq ($(OUTPUT),)
+#$(info Determined 'OUTPUT' to be $(OUTPUT))
+endif
+
+BASIC_CFLAGS = \
+	-Iutil/include \
+	-Iarch/$(ARCH)/include \
+	$(if $(objtree),-I$(objtree)/arch/$(ARCH)/include/generated/uapi) \
+	-I$(srctree)/arch/$(ARCH)/include/uapi \
+	-I$(srctree)/arch/$(ARCH)/include \
+	$(if $(objtree),-I$(objtree)/include/generated/uapi) \
+	-I$(srctree)/include/uapi \
+	-I$(srctree)/include \
+	-I$(OUTPUT)util \
+	-Iutil \
+	-I. \
+	-I$(TRACE_EVENT_DIR) \
+	-D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -D_GNU_SOURCE
 BASIC_LDFLAGS =
 
 # Guard against environment variables

tools/perf/arch/x86/include/perf_regs.h +1 -1

index 46fc9f1..7fcdcdb 100644
@@ -3,7 +3,7 @@
 
 #include <stdlib.h>
 #include "../../util/types.h"
-#include "../../../../../arch/x86/include/asm/perf_regs.h"
+#include <asm/perf_regs.h>
 
 #ifndef ARCH_X86_64
 #define PERF_REGS_MASK ((1ULL << PERF_REG_X86_32_MAX) - 1)

tools/perf/builtin-kvm.c +67 ~~-54~~

341 lines not on this page · raw message

tools/perf/builtin-test.c +1 -1

index 484f26c..5acd6e8 100644
@@ -15,7 +15,7 @@
 #include "util/thread_map.h"
 #include "util/pmu.h"
 #include "event-parse.h"
-#include "../../include/linux/hw_breakpoint.h"
+#include <linux/hw_breakpoint.h>
 
 #include <sys/mman.h>

tools/perf/perf.h +3 ~~-13~~

index c50985e..238f923 100644
@@ -5,8 +5,9 @@ struct winsize;
 
 void get_term_dimensions(struct winsize *ws);
 
+#include <asm/unistd.h>
+
 #if defined(__i386__)
-#include "../../arch/x86/include/asm/unistd.h"
 #define rmb()		asm volatile("lock; addl $0,0(%%esp)" ::: "memory")
 #define cpu_relax()	asm volatile("rep; nop" ::: "memory");
 #define CPUINFO_PROC	"model name"

@@ -16,7 +17,6 @@ void get_term_dimensions(struct winsize *ws);
 #endif
 
 #if defined(__x86_64__)
-#include "../../arch/x86/include/asm/unistd.h"
 #define rmb()		asm volatile("lfence" ::: "memory")
 #define cpu_relax()	asm volatile("rep; nop" ::: "memory");
 #define CPUINFO_PROC	"model name"

@@ -26,20 +26,17 @@ void get_term_dimensions(struct winsize *ws);
 #endif
 
 #ifdef __powerpc__
-#include "../../arch/powerpc/include/asm/unistd.h"
 #define rmb()		asm volatile ("sync" ::: "memory")
 #define cpu_relax()	asm volatile ("" ::: "memory");
 #define CPUINFO_PROC	"cpu"
 #endif
 
 #ifdef __s390__
-#include "../../arch/s390/include/asm/unistd.h"
 #define rmb()		asm volatile("bcr 15,0" ::: "memory")
 #define cpu_relax()	asm volatile("" ::: "memory");
 #endif
 
 #ifdef __sh__
-#include "../../arch/sh/include/asm/unistd.h"
 #if defined(__SH4A__) || defined(__SH5__)
 # define rmb()		asm volatile("synco" ::: "memory")
 #else

@@ -50,35 +47,30 @@ void get_term_dimensions(struct winsize *ws);
 #endif
 
 #ifdef __hppa__
-#include "../../arch/parisc/include/asm/unistd.h"
 #define rmb()		asm volatile("" ::: "memory")
 #define cpu_relax()	asm volatile("" ::: "memory");
 #define CPUINFO_PROC	"cpu"
 #endif
 
 #ifdef __sparc__
-#include "../../arch/sparc/include/uapi/asm/unistd.h"
 #define rmb()		asm volatile("":::"memory")
 #define cpu_relax()	asm volatile("":::"memory")
 #define CPUINFO_PROC	"cpu"
 #endif
 
 #ifdef __alpha__
-#include "../../arch/alpha/include/asm/unistd.h"
 #define rmb()		asm volatile("mb" ::: "memory")
 #define cpu_relax()	asm volatile("" ::: "memory")
 #define CPUINFO_PROC	"cpu model"
 #endif
 
 #ifdef __ia64__
-#include "../../arch/ia64/include/asm/unistd.h"
 #define rmb()		asm volatile ("mf" ::: "memory")
 #define cpu_relax()	asm volatile ("hint @pause" ::: "memory")
 #define CPUINFO_PROC	"model name"
 #endif
 
 #ifdef __arm__
-#include "../../arch/arm/include/asm/unistd.h"
 /*
  * Use the __kuser_memory_barrier helper in the CPU helper page. See
  * arch/arm/kernel/entry-armv.S in the kernel source for details.

@@ -89,13 +81,11 @@ void get_term_dimensions(struct winsize *ws);
 #endif
 
 #ifdef __aarch64__
-#include "../../arch/arm64/include/asm/unistd.h"
 #define rmb()		asm volatile("dmb ld" ::: "memory")
 #define cpu_relax()	asm volatile("yield" ::: "memory")
 #endif
 
 #ifdef __mips__
-#include "../../arch/mips/include/asm/unistd.h"
 #define rmb()		asm volatile(					\
 				".set	mips2\n\t"			\
 				"sync\n\t"				\

@@ -112,7 +102,7 @@ void get_term_dimensions(struct winsize *ws);
 #include <sys/types.h>
 #include <sys/syscall.h>
 
-#include "../../include/uapi/linux/perf_event.h"
+#include <linux/perf_event.h>
 #include "util/types.h"
 #include <stdbool.h>

tools/perf/util/evsel.c +2 -2

index 618d411..d144d46 100644
@@ -18,8 +18,8 @@
 #include "cpumap.h"
 #include "thread_map.h"
 #include "target.h"
-#include "../../../include/linux/hw_breakpoint.h"
-#include "../../../include/uapi/linux/perf_event.h"
+#include <linux/hw_breakpoint.h>
+#include <linux/perf_event.h>
 #include "perf_regs.h"
 
 #define FD(e, x, y) (*(int *)xyarray__entry(e->fd, x, y))

tools/perf/util/evsel.h +2 -1

index 6f94d6d..d99b476 100644
@@ -3,7 +3,8 @@
 
 #include <linux/list.h>
 #include <stdbool.h>
-#include "../../../include/uapi/linux/perf_event.h"
+#include <stddef.h>
+#include <linux/perf_event.h>
 #include "types.h"
 #include "xyarray.h"
 #include "cgroup.h"

tools/perf/util/header.c +2 -0

index 7daad23..566b84c 100644
@@ -1378,6 +1378,8 @@ static void print_numa_topology(struct perf_header *ph, int fd __maybe_unused,
 
 		str = tmp + 1;
 		fprintf(fp, "# node%u cpu list : %s\n", c, str);
+
+		str += strlen(str) + 1;
 	}
 	return;
 error:

tools/perf/util/header.h +1 -1

index 879d215..9bc0078 100644
@@ -1,7 +1,7 @@
 #ifndef __PERF_HEADER_H
 #define __PERF_HEADER_H
 
-#include "../../../include/uapi/linux/perf_event.h"
+#include <linux/perf_event.h>
 #include <sys/types.h>
 #include <stdbool.h>
 #include "types.h"

tools/perf/util/parse-events-test.c +1 -1

index 516ecd9..6ef213b 100644
@@ -3,7 +3,7 @@
 #include "evsel.h"
 #include "evlist.h"
 #include "sysfs.h"
-#include "../../../include/linux/hw_breakpoint.h"
+#include <linux/hw_breakpoint.h>
 
 #define TEST_ASSERT_VAL(text, cond) \
 do { \

tools/perf/util/parse-events.c +1 -1

index 75c7b0f..6b6d03e 100644
@@ -1,4 +1,4 @@
-#include "../../../include/linux/hw_breakpoint.h"
+#include <linux/hw_breakpoint.h>
 #include "util.h"
 #include "../perf.h"
 #include "evlist.h"

tools/perf/util/parse-events.h +1 -1

index 839230c..2820c40 100644
@@ -7,7 +7,7 @@
 #include <linux/list.h>
 #include <stdbool.h>
 #include "types.h"
-#include "../../../include/uapi/linux/perf_event.h"
+#include <linux/perf_event.h>
 #include "types.h"
 
 struct list_head;

tools/perf/util/pmu.h +1 -1

index 39f3aba..fdeb8ac 100644
@@ -2,7 +2,7 @@
 #define __PMU_H
 
 #include <linux/bitops.h>
-#include "../../../include/uapi/linux/perf_event.h"
+#include <linux/perf_event.h>
 
 enum {
 	PERF_PMU_FORMAT_VALUE_CONFIG,

tools/perf/util/session.h +1 -1

index dd64261..0eae00a 100644
@@ -7,7 +7,7 @@
 #include "symbol.h"
 #include "thread.h"
 #include <linux/rbtree.h>
-#include "../../../include/uapi/linux/perf_event.h"
+#include <linux/perf_event.h>
 
 struct sample_queue;
 struct ip_callchain;

tools/perf/util/strbuf.c +4 -4

index 2eeb51b..cfa9068 100644
@@ -90,17 +90,17 @@ void strbuf_addf(struct strbuf *sb, const char *fmt, ...)
 	if (!strbuf_avail(sb))
 		strbuf_grow(sb, 64);
 	va_start(ap, fmt);
-	len = vscnprintf(sb->buf + sb->len, sb->alloc - sb->len, fmt, ap);
+	len = vsnprintf(sb->buf + sb->len, sb->alloc - sb->len, fmt, ap);
 	va_end(ap);
 	if (len < 0)
-		die("your vscnprintf is broken");
+		die("your vsnprintf is broken");
 	if (len > strbuf_avail(sb)) {
 		strbuf_grow(sb, len);
 		va_start(ap, fmt);
-		len = vscnprintf(sb->buf + sb->len, sb->alloc - sb->len, fmt, ap);
+		len = vsnprintf(sb->buf + sb->len, sb->alloc - sb->len, fmt, ap);
 		va_end(ap);
 		if (len > strbuf_avail(sb)) {
-			die("this should not happen, your snprintf is broken");
+			die("this should not happen, your vsnprintf is broken");
 		}
 	}
 	strbuf_setlen(sb, sb->len + len);

tools/scripts/Makefile.include +20 -3

index 96ce80a..2964b96 100644
@@ -1,8 +1,11 @@
-ifeq ("$(origin O)", "command line")
+ifeq ($(origin O), command line)
 	dummy := $(if $(shell test -d $(O) || echo $(O)),$(error O=$(O) does not exist),)
 	ABSOLUTE_O := $(shell cd $(O) ; pwd)
-	OUTPUT := $(ABSOLUTE_O)/
+	OUTPUT := $(ABSOLUTE_O)/$(if $(subdir),$(subdir)/)
 	COMMAND_O := O=$(ABSOLUTE_O)
+ifeq ($(objtree),)
+	objtree := $(O)
+endif
 endif
 
 ifneq ($(OUTPUT),)

@@ -41,7 +44,16 @@ else
 NO_SUBDIR = :
 endif
 
-QUIET_SUBDIR0  = +$(MAKE) -C # space to separate -C and subdir
+#
+# Define a callable command for descending to a new directory
+#
+# Call by doing: $(call descend,directory[,target])
+#
+descend = \
+	+mkdir -p $(OUTPUT)$(1) && \
+	$(MAKE) $(COMMAND_O) subdir=$(if $(subdir),$(subdir)/$(1),$(1)) $(PRINT_DIR) -C $(1) $(2)
+
+QUIET_SUBDIR0  = +$(MAKE) $(COMMAND_O) -C # space to separate -C and subdir
 QUIET_SUBDIR1  =
 
 ifneq ($(findstring $(MAKEFLAGS),s),s)

@@ -56,5 +68,10 @@ ifndef V
 			 $(MAKE) $(PRINT_DIR) -C $$subdir
 	QUIET_FLEX     = @echo '   ' FLEX $@;
 	QUIET_BISON    = @echo '   ' BISON $@;
+
+	descend = \
+		@echo '   ' DESCEND $(1); \
+		mkdir -p $(OUTPUT)$(1) && \
+		$(MAKE) $(COMMAND_O) subdir=$(if $(subdir),$(subdir)/$(1),$(1)) $(PRINT_DIR) -C $(1) $(2)
 endif
 endif