From: Andi Kleen <a...@linux.intel.com>
As suggested by Ingo.
Make HW_BREAKPOINTS a config option. HW_BREAKPOINTS depends
on perf. This allows disabling PERF_EVENTS for systems that
don't need it (e.g. anything not used for development)
Disabling PERF_EVENTS saves over 700k of kernel text (~5% of my config)
and significant data/bss:
text data bss dec hex filename
13692640 1922416 1478656 17093712 104d450 obj/vmlinux
12980092 1787544 1470464 16238100 f7c614 obj-noperf/vmlinux
I didn't make it depend on CONFIG_EXPERT for now, as the system
should be very usable even without it. To actually disable perf
a couple of options depending on it need to be disabled, including
KVM and HW_BREAKPOINTS.
Longer term it would be probably nice to have modular perf.
Cc: fweis...@gmail.com
Cc: pet...@infradead.org
Signed-off-by: Andi Kleen <a...@linux.intel.com>
---
arch/x86/Kconfig | 11 ++++++++---
arch/x86/kernel/Makefile | 3 ++-
arch/x86/kvm/Kconfig | 1 +
3 files changed, 11 insertions(+), 4 deletions(-)
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index c9d2b81..a8418ed 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -67,9 +67,6 @@ config X86
select HAVE_KERNEL_XZ
select HAVE_KERNEL_LZO
select HAVE_KERNEL_LZ4
- select HAVE_HW_BREAKPOINT
- select HAVE_MIXED_BREAKPOINTS_REGS
- select PERF_EVENTS
select HAVE_PERF_EVENTS_NMI
select HAVE_PERF_REGS
select HAVE_PERF_USER_STACK_DUMP
@@ -602,6 +599,14 @@ config SCHED_OMIT_FRAME_POINTER
If in doubt, say "Y".
+config HW_BREAKPOINTS
+ bool "Enable hardware breakpoints support"
+ select HAVE_HW_BREAKPOINT
+ select HAVE_MIXED_BREAKPOINTS_REGS
+ ---help---
+ Enable support for x86 hardware breakpoints for debuggers
+ and perf. This will implicitly enable perf-events.
+
menuconfig HYPERVISOR_GUEST
bool "Linux guest support"
---help---
diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile
index a5408b9..1b09567 100644
--- a/arch/x86/kernel/Makefile
+++ b/arch/x86/kernel/Makefile
@@ -31,7 +31,7 @@ obj-$(CONFIG_X86_64) += vsyscall_64.o
obj-$(CONFIG_X86_64) += vsyscall_emu_64.o
obj-y += bootflag.o e820.o
obj-y += pci-dma.o quirks.o topology.o kdebugfs.o
-obj-y += alternative.o i8253.o pci-nommu.o hw_breakpoint.o
+obj-y += alternative.o i8253.o pci-nommu.o
obj-y += tsc.o io_delay.o rtc.o
obj-y += pci-iommu_table.o
obj-y += resource.o
@@ -73,6 +73,7 @@ obj-$(CONFIG_DOUBLEFAULT) += doublefault.o
obj-$(CONFIG_KGDB) += kgdb.o
obj-$(CONFIG_VM86) += vm86_32.o
obj-$(CONFIG_EARLY_PRINTK) += early_printk.o
+obj-$(CONFIG_HW_BREAKPOINTS) += hw_breakpoint.o
obj-$(CONFIG_HPET_TIMER) += hpet.o
obj-$(CONFIG_APB_TIMER) += apb_timer.o
diff --git a/arch/x86/kvm/Kconfig b/arch/x86/kvm/Kconfig
index a47a3e5..de4190a 100644
--- a/arch/x86/kvm/Kconfig
+++ b/arch/x86/kvm/Kconfig
@@ -36,6 +36,7 @@ config KVM
select TASKSTATS
select TASK_DELAY_ACCT
select PERF_EVENTS
+ select HW_BREAKPOINTS
select HAVE_KVM_MSI
select HAVE_KVM_CPU_RELAX_INTERCEPT
---help---
--
1.8.3.1
--
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