From 52480137d82062bb8d0fb778cb9934667958e367 Mon Sep 17 00:00:00 2001 From: Andi Kleen Date: Sat, 8 Feb 2014 08:51:57 +0100 Subject: asmlinkage, kvm: Make kvm_rebooting visible kvm_rebooting is referenced from assembler code, thus needs to be visible. Cc: Gleb Natapov Cc: Paolo Bonzini Signed-off-by: Andi Kleen Link: http://lkml.kernel.org/r/1391845930-28580-1-git-send-email-ak@linux.intel.com Signed-off-by: H. Peter Anvin diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 03a0381..b5ec7fb 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -102,7 +102,7 @@ static void kvm_release_pfn_dirty(pfn_t pfn); static void mark_page_dirty_in_slot(struct kvm *kvm, struct kvm_memory_slot *memslot, gfn_t gfn); -bool kvm_rebooting; +__visible bool kvm_rebooting; EXPORT_SYMBOL_GPL(kvm_rebooting); static bool largepages_enabled = true; -- cgit v0.10.2 From d47d5c8194579bce1d62f88e26fea91d7c553e42 Mon Sep 17 00:00:00 2001 From: Andi Kleen Date: Sat, 8 Feb 2014 08:51:58 +0100 Subject: asmlinkage: Make __iowrite32_copy visible This is a assembler function on x86, so it should be visible. Signed-off-by: Andi Kleen Link: http://lkml.kernel.org/r/1391845930-28580-2-git-send-email-ak@linux.intel.com Signed-off-by: H. Peter Anvin diff --git a/include/linux/io.h b/include/linux/io.h index f4f42fa..8a18e75 100644 --- a/include/linux/io.h +++ b/include/linux/io.h @@ -24,7 +24,7 @@ struct device; -void __iowrite32_copy(void __iomem *to, const void *from, size_t count); +__visible void __iowrite32_copy(void __iomem *to, const void *from, size_t count); void __iowrite64_copy(void __iomem *to, const void *from, size_t count); #ifdef CONFIG_MMU -- cgit v0.10.2 From 40747ffa5aa8d5b99ca46c696234b9194b59e0ac Mon Sep 17 00:00:00 2001 From: Andi Kleen Date: Sat, 8 Feb 2014 08:51:59 +0100 Subject: asmlinkage: Make jiffies visible Jiffies is referenced by the linker script, so it has to be visible. Handled both the generic and the x86 version. Signed-off-by: Andi Kleen Link: http://lkml.kernel.org/r/1391845930-28580-3-git-send-email-ak@linux.intel.com Signed-off-by: H. Peter Anvin diff --git a/arch/x86/kernel/time.c b/arch/x86/kernel/time.c index 24d3c91..6ec91c0 100644 --- a/arch/x86/kernel/time.c +++ b/arch/x86/kernel/time.c @@ -23,7 +23,7 @@ #include #ifdef CONFIG_X86_64 -DEFINE_VVAR(volatile unsigned long, jiffies) = INITIAL_JIFFIES; +__visible DEFINE_VVAR(volatile unsigned long, jiffies) = INITIAL_JIFFIES; #endif unsigned long profile_pc(struct pt_regs *regs) diff --git a/kernel/timer.c b/kernel/timer.c index accfd24..d78de04 100644 --- a/kernel/timer.c +++ b/kernel/timer.c @@ -52,7 +52,7 @@ #define CREATE_TRACE_POINTS #include -u64 jiffies_64 __cacheline_aligned_in_smp = INITIAL_JIFFIES; +__visible u64 jiffies_64 __cacheline_aligned_in_smp = INITIAL_JIFFIES; EXPORT_SYMBOL(jiffies_64); -- cgit v0.10.2 From a99aa42d0253f033cbb85096d3f2bd82201321e6 Mon Sep 17 00:00:00 2001 From: Andi Kleen Date: Sat, 8 Feb 2014 08:52:00 +0100 Subject: asmlinkage, pnp: Make variables used from assembler code visible Mark variables referenced from assembler files visible. This fixes compile problems with LTO. Cc: Jaroslav Kysela Signed-off-by: Andi Kleen Link: http://lkml.kernel.org/r/1391845930-28580-4-git-send-email-ak@linux.intel.com Signed-off-by: H. Peter Anvin diff --git a/drivers/pnp/pnpbios/bioscalls.c b/drivers/pnp/pnpbios/bioscalls.c index 769d265..deb7f4b 100644 --- a/drivers/pnp/pnpbios/bioscalls.c +++ b/drivers/pnp/pnpbios/bioscalls.c @@ -21,7 +21,7 @@ #include "pnpbios.h" -static struct { +__visible struct { u16 offset; u16 segment; } pnp_bios_callpoint; @@ -41,6 +41,7 @@ asmlinkage void pnp_bios_callfunc(void); __asm__(".text \n" __ALIGN_STR "\n" + ".globl pnp_bios_callfunc\n" "pnp_bios_callfunc:\n" " pushl %edx \n" " pushl %ecx \n" @@ -66,9 +67,9 @@ static struct desc_struct bad_bios_desc = GDT_ENTRY_INIT(0x4092, * after PnP BIOS oopses. */ -u32 pnp_bios_fault_esp; -u32 pnp_bios_fault_eip; -u32 pnp_bios_is_utter_crap = 0; +__visible u32 pnp_bios_fault_esp; +__visible u32 pnp_bios_fault_eip; +__visible u32 pnp_bios_is_utter_crap = 0; static spinlock_t pnp_bios_lock; -- cgit v0.10.2 From 63f9a7fde715352e0769302527670542a664b981 Mon Sep 17 00:00:00 2001 From: Andi Kleen Date: Sat, 8 Feb 2014 08:52:01 +0100 Subject: asmlinkage: Make lockdep_sys_exit asmlinkage lockdep_sys_exit can be called from assembler code, so make it asmlinkage. Cc: Peter Zijlstra Cc: Ingo Molnar Signed-off-by: Andi Kleen Link: http://lkml.kernel.org/r/1391845930-28580-5-git-send-email-ak@linux.intel.com Signed-off-by: H. Peter Anvin diff --git a/include/linux/lockdep.h b/include/linux/lockdep.h index 92b1bfc..7df9aa6 100644 --- a/include/linux/lockdep.h +++ b/include/linux/lockdep.h @@ -265,7 +265,7 @@ extern void lockdep_info(void); extern void lockdep_reset(void); extern void lockdep_reset_lock(struct lockdep_map *lock); extern void lockdep_free_key_range(void *start, unsigned long size); -extern void lockdep_sys_exit(void); +extern asmlinkage void lockdep_sys_exit(void); extern void lockdep_off(void); extern void lockdep_on(void); diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c index eb8a547..c8b6753c 100644 --- a/kernel/locking/lockdep.c +++ b/kernel/locking/lockdep.c @@ -4191,7 +4191,7 @@ void debug_show_held_locks(struct task_struct *task) } EXPORT_SYMBOL_GPL(debug_show_held_locks); -void lockdep_sys_exit(void) +asmlinkage void lockdep_sys_exit(void) { struct task_struct *curr = current; -- cgit v0.10.2 From b35f8305339f1ba3070fe606c6ef0d86ef093dee Mon Sep 17 00:00:00 2001 From: Andi Kleen Date: Sat, 8 Feb 2014 08:52:02 +0100 Subject: asmlinkage: Make trace_hardirq visible Can be called from assembler code. Cc: Peter Zijlstra Cc: Ingo Molnar Signed-off-by: Andi Kleen Link: http://lkml.kernel.org/r/1391845930-28580-6-git-send-email-ak@linux.intel.com Signed-off-by: H. Peter Anvin diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c index c8b6753c..aa3bf15 100644 --- a/kernel/locking/lockdep.c +++ b/kernel/locking/lockdep.c @@ -2557,7 +2557,7 @@ static void __trace_hardirqs_on_caller(unsigned long ip) debug_atomic_inc(hardirqs_on_events); } -void trace_hardirqs_on_caller(unsigned long ip) +__visible void trace_hardirqs_on_caller(unsigned long ip) { time_hardirqs_on(CALLER_ADDR0, ip); @@ -2610,7 +2610,7 @@ EXPORT_SYMBOL(trace_hardirqs_on); /* * Hardirqs were disabled: */ -void trace_hardirqs_off_caller(unsigned long ip) +__visible void trace_hardirqs_off_caller(unsigned long ip) { struct task_struct *curr = current; -- cgit v0.10.2 From 22d9fd3411c693ccae5f5c2280fb1f9bb106ad4f Mon Sep 17 00:00:00 2001 From: Andi Kleen Date: Sat, 8 Feb 2014 08:52:03 +0100 Subject: asmlinkage, mutex: Mark __visible Various kernel/mutex.c functions can be called from inline assembler, so they should be all global and __visible. Cc: Ingo Molnar Signed-off-by: Andi Kleen Link: http://lkml.kernel.org/r/1391845930-28580-7-git-send-email-ak@linux.intel.com Signed-off-by: H. Peter Anvin diff --git a/kernel/locking/mutex.c b/kernel/locking/mutex.c index 4dd6e4c..adbc0d0 100644 --- a/kernel/locking/mutex.c +++ b/kernel/locking/mutex.c @@ -67,8 +67,7 @@ EXPORT_SYMBOL(__mutex_init); * We also put the fastpath first in the kernel image, to make sure the * branch is predicted by the CPU as default-untaken. */ -static __used noinline void __sched -__mutex_lock_slowpath(atomic_t *lock_count); +__visible void __sched __mutex_lock_slowpath(atomic_t *lock_count); /** * mutex_lock - acquire the mutex @@ -225,7 +224,8 @@ static inline int mutex_can_spin_on_owner(struct mutex *lock) } #endif -static __used noinline void __sched __mutex_unlock_slowpath(atomic_t *lock_count); +__visible __used noinline +void __sched __mutex_unlock_slowpath(atomic_t *lock_count); /** * mutex_unlock - release the mutex @@ -746,7 +746,7 @@ __mutex_unlock_common_slowpath(atomic_t *lock_count, int nested) /* * Release the lock, slowpath: */ -static __used noinline void +__visible void __mutex_unlock_slowpath(atomic_t *lock_count) { __mutex_unlock_common_slowpath(lock_count, 1); @@ -803,7 +803,7 @@ int __sched mutex_lock_killable(struct mutex *lock) } EXPORT_SYMBOL(mutex_lock_killable); -static __used noinline void __sched +__visible void __sched __mutex_lock_slowpath(atomic_t *lock_count) { struct mutex *lock = container_of(lock_count, struct mutex, count); -- cgit v0.10.2 From 00b7103078596a243c16239004e0dc9416910f13 Mon Sep 17 00:00:00 2001 From: Andi Kleen Date: Sat, 8 Feb 2014 08:52:04 +0100 Subject: asmlinkage: Make main_extable_sort_needed visible main_extable_sort_needed is used by the build system and needs to be a normal ELF symbol. Make it visible so that LTO does not remove or mangle it. Signed-off-by: Andi Kleen Link: http://lkml.kernel.org/r/1391845930-28580-8-git-send-email-ak@linux.intel.com Signed-off-by: H. Peter Anvin diff --git a/kernel/extable.c b/kernel/extable.c index 763faf0..d8a6446 100644 --- a/kernel/extable.c +++ b/kernel/extable.c @@ -36,7 +36,7 @@ extern struct exception_table_entry __start___ex_table[]; extern struct exception_table_entry __stop___ex_table[]; /* Cleared by build time tools if the table is already sorted. */ -u32 __initdata main_extable_sort_needed = 1; +u32 __initdata __visible main_extable_sort_needed = 1; /* Sort the kernel's built-in exception table */ void __init sort_main_extable(void) -- cgit v0.10.2 From 3ebae4f3a2e746ae17f25c741e249294e7d6d7c2 Mon Sep 17 00:00:00 2001 From: Andi Kleen Date: Sat, 8 Feb 2014 08:52:05 +0100 Subject: asmlinkage: Mark rwsem functions that can be called from assembler asmlinkage Mark the rwsem functions that can be called from assembler asmlinkage. Signed-off-by: Andi Kleen Link: http://lkml.kernel.org/r/1391845930-28580-9-git-send-email-ak@linux.intel.com Signed-off-by: H. Peter Anvin diff --git a/kernel/locking/rwsem-xadd.c b/kernel/locking/rwsem-xadd.c index 19c5fa9..1d66e08 100644 --- a/kernel/locking/rwsem-xadd.c +++ b/kernel/locking/rwsem-xadd.c @@ -143,6 +143,7 @@ __rwsem_do_wake(struct rw_semaphore *sem, enum rwsem_wake_type wake_type) /* * wait for the read lock to be granted */ +__visible struct rw_semaphore __sched *rwsem_down_read_failed(struct rw_semaphore *sem) { long count, adjustment = -RWSEM_ACTIVE_READ_BIAS; @@ -190,6 +191,7 @@ struct rw_semaphore __sched *rwsem_down_read_failed(struct rw_semaphore *sem) /* * wait until we successfully acquire the write lock */ +__visible struct rw_semaphore __sched *rwsem_down_write_failed(struct rw_semaphore *sem) { long count, adjustment = -RWSEM_ACTIVE_WRITE_BIAS; @@ -252,6 +254,7 @@ struct rw_semaphore __sched *rwsem_down_write_failed(struct rw_semaphore *sem) * handle waking up a waiter on the semaphore * - up_read/up_write has decremented the active part of count if we come here */ +__visible struct rw_semaphore *rwsem_wake(struct rw_semaphore *sem) { unsigned long flags; @@ -272,6 +275,7 @@ struct rw_semaphore *rwsem_wake(struct rw_semaphore *sem) * - caller incremented waiting part of count and discovered it still negative * - just wake up any readers at the front of the queue */ +__visible struct rw_semaphore *rwsem_downgrade_wake(struct rw_semaphore *sem) { unsigned long flags; -- cgit v0.10.2 From a7330c997d0f74d909a7d3553b1d550d8be2b61a Mon Sep 17 00:00:00 2001 From: Andi Kleen Date: Sat, 8 Feb 2014 08:52:06 +0100 Subject: asmlinkage Make __stack_chk_failed and memcmp visible In LTO symbols implicitely referenced by the compiler need to be visible. Earlier these symbols were visible implicitely from being exported, but we disabled implicit visibility fo EXPORTs when modules are disabled to improve code size. So now these symbols have to be marked visible explicitely. Do this for __stack_chk_fail (with stack protector) and memcmp. Signed-off-by: Andi Kleen Link: http://lkml.kernel.org/r/1391845930-28580-10-git-send-email-ak@linux.intel.com Signed-off-by: H. Peter Anvin diff --git a/kernel/panic.c b/kernel/panic.c index 6d63003..3eb0ffb 100644 --- a/kernel/panic.c +++ b/kernel/panic.c @@ -459,7 +459,7 @@ EXPORT_SYMBOL(warn_slowpath_null); * Called when gcc's -fstack-protector feature is used, and * gcc detects corruption of the on-stack canary value */ -void __stack_chk_fail(void) +__visible void __stack_chk_fail(void) { panic("stack-protector: Kernel stack is corrupted in: %p\n", __builtin_return_address(0)); diff --git a/lib/string.c b/lib/string.c index e5878de..9b1f906 100644 --- a/lib/string.c +++ b/lib/string.c @@ -648,7 +648,7 @@ EXPORT_SYMBOL(memmove); * @count: The size of the area. */ #undef memcmp -int memcmp(const void *cs, const void *ct, size_t count) +__visible int memcmp(const void *cs, const void *ct, size_t count) { const unsigned char *su1, *su2; int res = 0; -- cgit v0.10.2 From a9143296dd612dceb0765229ccfb13fd642e2840 Mon Sep 17 00:00:00 2001 From: Andi Kleen Date: Sat, 8 Feb 2014 08:52:07 +0100 Subject: asmlinkage, x86: Fix 32bit memcpy for LTO These functions can be called implicitely from gcc, and thus need to be visible. Signed-off-by: Andi Kleen Link: http://lkml.kernel.org/r/1391845930-28580-11-git-send-email-ak@linux.intel.com Signed-off-by: H. Peter Anvin diff --git a/arch/x86/lib/memcpy_32.c b/arch/x86/lib/memcpy_32.c index e78761d..a404b4b 100644 --- a/arch/x86/lib/memcpy_32.c +++ b/arch/x86/lib/memcpy_32.c @@ -4,7 +4,7 @@ #undef memcpy #undef memset -void *memcpy(void *to, const void *from, size_t n) +__visible void *memcpy(void *to, const void *from, size_t n) { #ifdef CONFIG_X86_USE_3DNOW return __memcpy3d(to, from, n); @@ -14,13 +14,13 @@ void *memcpy(void *to, const void *from, size_t n) } EXPORT_SYMBOL(memcpy); -void *memset(void *s, int c, size_t count) +__visible void *memset(void *s, int c, size_t count) { return __memset(s, c, count); } EXPORT_SYMBOL(memset); -void *memmove(void *dest, const void *src, size_t n) +__visible void *memmove(void *dest, const void *src, size_t n) { int d0,d1,d2,d3,d4,d5; char *ret = dest; -- cgit v0.10.2 From 285c00adf651c9b1d6c73d5eee482d2a617a64c1 Mon Sep 17 00:00:00 2001 From: Andi Kleen Date: Sat, 8 Feb 2014 08:52:08 +0100 Subject: asmlinkage: Make trace_hardirqs_on/off_caller visible These functions are called from assembler, and thus need to be __visible. Cc: Steven Rostedt Signed-off-by: Andi Kleen Link: http://lkml.kernel.org/r/1391845930-28580-12-git-send-email-ak@linux.intel.com Signed-off-by: H. Peter Anvin diff --git a/kernel/trace/trace_irqsoff.c b/kernel/trace/trace_irqsoff.c index 2aefbee..887ef88 100644 --- a/kernel/trace/trace_irqsoff.c +++ b/kernel/trace/trace_irqsoff.c @@ -498,14 +498,14 @@ void trace_hardirqs_off(void) } EXPORT_SYMBOL(trace_hardirqs_off); -void trace_hardirqs_on_caller(unsigned long caller_addr) +__visible void trace_hardirqs_on_caller(unsigned long caller_addr) { if (!preempt_trace() && irq_trace()) stop_critical_timing(CALLER_ADDR0, caller_addr); } EXPORT_SYMBOL(trace_hardirqs_on_caller); -void trace_hardirqs_off_caller(unsigned long caller_addr) +__visible void trace_hardirqs_off_caller(unsigned long caller_addr) { if (!preempt_trace() && irq_trace()) start_critical_timing(CALLER_ADDR0, caller_addr); -- cgit v0.10.2 From 3be5588ad5c2628c8aa4a578bcbb114fa2b49260 Mon Sep 17 00:00:00 2001 From: Andi Kleen Date: Sat, 8 Feb 2014 08:52:09 +0100 Subject: initconst: Fix initconst mistake in dcdbas const must be __initconst. Cc: Douglas_Warzecha@dell.com Signed-off-by: Andi Kleen Link: http://lkml.kernel.org/r/1391845930-28580-13-git-send-email-ak@linux.intel.com Signed-off-by: H. Peter Anvin diff --git a/drivers/firmware/dcdbas.c b/drivers/firmware/dcdbas.c index 1b5e8e4..7160c43 100644 --- a/drivers/firmware/dcdbas.c +++ b/drivers/firmware/dcdbas.c @@ -584,7 +584,7 @@ static struct platform_driver dcdbas_driver = { .remove = dcdbas_remove, }; -static const struct platform_device_info dcdbas_dev_info __initdata = { +static const struct platform_device_info dcdbas_dev_info __initconst = { .name = DRIVER_NAME, .id = -1, .dma_mask = DMA_BIT_MASK(32), -- cgit v0.10.2 From 634676c203f130c8efa138296c2efba219821346 Mon Sep 17 00:00:00 2001 From: Andi Kleen Date: Sat, 8 Feb 2014 08:52:10 +0100 Subject: initconst, x86: Fix initconst mistake in ts5500 code const data must be initconst. Signed-off-by: Andi Kleen Link: http://lkml.kernel.org/r/1391845930-28580-14-git-send-email-ak@linux.intel.com Signed-off-by: H. Peter Anvin diff --git a/arch/x86/platform/ts5500/ts5500.c b/arch/x86/platform/ts5500/ts5500.c index 39febb2..9471b94 100644 --- a/arch/x86/platform/ts5500/ts5500.c +++ b/arch/x86/platform/ts5500/ts5500.c @@ -88,7 +88,7 @@ struct ts5500_sbc { static const struct { const char * const string; const ssize_t offset; -} ts5500_signatures[] __initdata = { +} ts5500_signatures[] __initconst = { { "TS-5x00 AMD Elan", 0xb14 }, }; -- cgit v0.10.2 From 67424d5a22124fa2d115faa8f32d12506989628f Mon Sep 17 00:00:00 2001 From: Andi Kleen Date: Sat, 8 Feb 2014 09:01:05 +0100 Subject: x86, lto: Disable LTO for the x86 VDSO The VDSO does not play well with LTO, so just disable LTO for it. Also pass a 32bit linker flag for the 32bit version. [ hpa: change braces to parens to match kernel Makefile style ] Signed-off-by: Andi Kleen Link: http://lkml.kernel.org/r/1391846481-31491-1-git-send-email-ak@linux.intel.com Signed-off-by: H. Peter Anvin diff --git a/arch/x86/vdso/Makefile b/arch/x86/vdso/Makefile index fd14be1..9206ac7 100644 --- a/arch/x86/vdso/Makefile +++ b/arch/x86/vdso/Makefile @@ -2,6 +2,8 @@ # Building vDSO images for x86. # +KBUILD_CFLAGS += $(DISABLE_LTO) + VDSO64-$(CONFIG_X86_64) := y VDSOX32-$(CONFIG_X86_X32_ABI) := y VDSO32-$(CONFIG_X86_32) := y @@ -35,7 +37,8 @@ export CPPFLAGS_vdso.lds += -P -C VDSO_LDFLAGS_vdso.lds = -m64 -Wl,-soname=linux-vdso.so.1 \ -Wl,--no-undefined \ - -Wl,-z,max-page-size=4096 -Wl,-z,common-page-size=4096 + -Wl,-z,max-page-size=4096 -Wl,-z,common-page-size=4096 \ + $(DISABLE_LTO) $(obj)/vdso.o: $(src)/vdso.S $(obj)/vdso.so @@ -127,7 +130,7 @@ vdso32.so-$(VDSO32-y) += sysenter vdso32-images = $(vdso32.so-y:%=vdso32-%.so) CPPFLAGS_vdso32.lds = $(CPPFLAGS_vdso.lds) -VDSO_LDFLAGS_vdso32.lds = -m32 -Wl,-soname=linux-gate.so.1 +VDSO_LDFLAGS_vdso32.lds = -m32 -Wl,-m,elf_i386 -Wl,-soname=linux-gate.so.1 # This makes sure the $(obj) subdirectory exists even though vdso32/ # is not a kbuild sub-make subdirectory. @@ -181,7 +184,8 @@ quiet_cmd_vdso = VDSO $@ -Wl,-T,$(filter %.lds,$^) $(filter %.o,$^) && \ sh $(srctree)/$(src)/checkundef.sh '$(NM)' '$@' -VDSO_LDFLAGS = -fPIC -shared $(call cc-ldoption, -Wl$(comma)--hash-style=sysv) +VDSO_LDFLAGS = -fPIC -shared $(call cc-ldoption, -Wl$(comma)--hash-style=sysv) \ + $(LTO_CFLAGS) GCOV_PROFILE := n # -- cgit v0.10.2 From 128ea04a9885af9629059e631ddf0cab4815b589 Mon Sep 17 00:00:00 2001 From: Andi Kleen Date: Sat, 8 Feb 2014 09:01:07 +0100 Subject: lto: Make asmlinkage __visible Signed-off-by: Andi Kleen Link: http://lkml.kernel.org/r/1391846481-31491-3-git-send-email-ak@linux.intel.com Signed-off-by: H. Peter Anvin diff --git a/include/linux/linkage.h b/include/linux/linkage.h index a6a42dd..34a513a 100644 --- a/include/linux/linkage.h +++ b/include/linux/linkage.h @@ -12,9 +12,9 @@ #endif #ifdef __cplusplus -#define CPP_ASMLINKAGE extern "C" +#define CPP_ASMLINKAGE extern "C" __visible #else -#define CPP_ASMLINKAGE +#define CPP_ASMLINKAGE __visible #endif #ifndef asmlinkage -- cgit v0.10.2 From ef1b893c29d0dba778f67ad97b554b37f9108dcc Mon Sep 17 00:00:00 2001 From: Andi Kleen Date: Sat, 8 Feb 2014 09:01:08 +0100 Subject: lto, workaround: Add workaround for initcall reordering MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Work around a LTO gcc problem: when there is no reference to a variable in a module it will be moved to the end of the program. This causes reordering of initcalls which the kernel does not like. Add a dummy reference function to avoid this. The function is deleted by the linker. This replaces a previous much slower workaround. Thanks to Jan "Honza" Hubička for suggesting this technique. Suggested-by: Jan Hubička Signed-off-by: Andi Kleen Link: http://lkml.kernel.org/r/1391846481-31491-4-git-send-email-ak@linux.intel.com Signed-off-by: H. Peter Anvin diff --git a/include/linux/init.h b/include/linux/init.h index e168880..a3ba270 100644 --- a/include/linux/init.h +++ b/include/linux/init.h @@ -163,6 +163,23 @@ extern bool initcall_debug; #ifndef __ASSEMBLY__ +#ifdef CONFIG_LTO +/* Work around a LTO gcc problem: when there is no reference to a variable + * in a module it will be moved to the end of the program. This causes + * reordering of initcalls which the kernel does not like. + * Add a dummy reference function to avoid this. The function is + * deleted by the linker. + */ +#define LTO_REFERENCE_INITCALL(x) \ + ; /* yes this is needed */ \ + static __used __exit void *reference_##x(void) \ + { \ + return &x; \ + } +#else +#define LTO_REFERENCE_INITCALL(x) +#endif + /* initcalls are now grouped by functionality into separate * subsections. Ordering inside the subsections is determined * by link order. @@ -175,7 +192,8 @@ extern bool initcall_debug; #define __define_initcall(fn, id) \ static initcall_t __initcall_##fn##id __used \ - __attribute__((__section__(".initcall" #id ".init"))) = fn + __attribute__((__section__(".initcall" #id ".init"))) = fn; \ + LTO_REFERENCE_INITCALL(__initcall_##fn##id) /* * Early initcalls run before initializing SMP. -- cgit v0.10.2 From 80375980f1608f43b47abc2671456b23ec68c434 Mon Sep 17 00:00:00 2001 From: Joe Mario Date: Sat, 8 Feb 2014 09:01:09 +0100 Subject: lto: Handle LTO common symbols in module loader Here is the workaround I made for having the kernel not reject modules built with -flto. The clean solution would be to get the compiler to not emit the symbol. Or if it has to emit the symbol, then emit it as initialized data but put it into a comdat/linkonce section. Minor tweaks by AK over Joe's patch. Cc: Rusty Russell Signed-off-by: Andi Kleen Link: http://lkml.kernel.org/r/1391846481-31491-5-git-send-email-ak@linux.intel.com Signed-off-by: H. Peter Anvin diff --git a/kernel/module.c b/kernel/module.c index d24fcf2..b99e801 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -1948,6 +1948,10 @@ static int simplify_symbols(struct module *mod, const struct load_info *info) switch (sym[i].st_shndx) { case SHN_COMMON: + /* Ignore common symbols */ + if (!strncmp(name, "__gnu_lto", 9)) + break; + /* We compiled with -fno-common. These are not supposed to happen. */ pr_debug("Common symbol: %s\n", name); -- cgit v0.10.2 From 58edae3aac9f2ccd1afb12ea08127e840a0a706c Mon Sep 17 00:00:00 2001 From: Andi Kleen Date: Sat, 8 Feb 2014 09:01:10 +0100 Subject: lto: Disable LTO for sys_ni The assembler alias code in cond_syscall does not work when compiled for LTO. Just disable LTO for that file. Signed-off-by: Andi Kleen Link: http://lkml.kernel.org/r/1391846481-31491-6-git-send-email-ak@linux.intel.com Signed-off-by: H. Peter Anvin diff --git a/kernel/Makefile b/kernel/Makefile index bc010ee..31c26c6 100644 --- a/kernel/Makefile +++ b/kernel/Makefile @@ -18,6 +18,9 @@ CFLAGS_REMOVE_cgroup-debug.o = -pg CFLAGS_REMOVE_irq_work.o = -pg endif +# cond_syscall is currently not LTO compatible +CFLAGS_sys_ni.o = $(DISABLE_LTO) + obj-y += sched/ obj-y += locking/ obj-y += power/ -- cgit v0.10.2 From 77ab21adae509c5540956729e2d03bc1a59bc82a Mon Sep 17 00:00:00 2001 From: Andi Kleen Date: Sat, 8 Feb 2014 09:01:11 +0100 Subject: Kbuild, lto, workaround: Don't warn for initcall_reference in modpost This reference is discarded, but can cause warnings when it refers to exit. Ignore for now. This is a workaround and can be removed once we get rid of -fno-toplevel-reorder Signed-off-by: Andi Kleen Link: http://lkml.kernel.org/r/1391846481-31491-7-git-send-email-ak@linux.intel.com Signed-off-by: H. Peter Anvin diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index 4061098..1f1b154 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -1455,6 +1455,10 @@ static void check_section_mismatch(const char *modname, struct elf_info *elf, to = find_elf_symbol(elf, r->r_addend, sym); tosym = sym_name(elf, to); + if (!strncmp(fromsym, "reference___initcall", + sizeof("reference___initcall")-1)) + return; + /* check whitelist - we may ignore it */ if (secref_whitelist(mismatch, fromsec, fromsym, tosec, tosym)) { -- cgit v0.10.2 From 7d02b490e93c199a15b3c4bce1c393588c1300ca Mon Sep 17 00:00:00 2001 From: Andi Kleen Date: Sat, 8 Feb 2014 09:01:12 +0100 Subject: Kbuild, lto: Drop .number postfixes in modpost LTO turns all global symbols effectively into statics. This has the side effect that they all have a .NUMBER postfix to make them unique. In modpost drop this postfix because it confuses it. Signed-off-by: Andi Kleen Link: http://lkml.kernel.org/r/1391846481-31491-8-git-send-email-ak@linux.intel.com Signed-off-by: H. Peter Anvin diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index 1f1b154..f91dd45 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -1684,6 +1684,19 @@ static void check_sec_ref(struct module *mod, const char *modname, } } +static char *remove_dot(char *s) +{ + char *end; + int n = strcspn(s, "."); + + if (n > 0 && s[n] != 0) { + strtoul(s + n + 1, &end, 10); + if (end > s + n + 1 && (*end == '.' || *end == 0)) + s[n] = 0; + } + return s; +} + static void read_symbols(char *modname) { const char *symname; @@ -1722,7 +1735,7 @@ static void read_symbols(char *modname) } for (sym = info.symtab_start; sym < info.symtab_stop; sym++) { - symname = info.strtab + sym->st_name; + symname = remove_dot(info.strtab + sym->st_name); handle_modversions(mod, &info, sym, symname); handle_moddevtable(mod, &info, sym, symname); diff --git a/scripts/mod/modpost.h b/scripts/mod/modpost.h index 51207e4..168b43d 100644 --- a/scripts/mod/modpost.h +++ b/scripts/mod/modpost.h @@ -127,7 +127,7 @@ struct elf_info { Elf_Section export_gpl_sec; Elf_Section export_unused_gpl_sec; Elf_Section export_gpl_future_sec; - const char *strtab; + char *strtab; char *modinfo; unsigned int modinfo_len; -- cgit v0.10.2 From ccbef1674a1579842c7dbdf554efca85d2cd245a Mon Sep 17 00:00:00 2001 From: Andi Kleen Date: Sat, 8 Feb 2014 09:01:13 +0100 Subject: Kbuild, lto: add ld-version and ld-ifversion macros To check the linker version. Used by the LTO makefile. Signed-off-by: Andi Kleen Link: http://lkml.kernel.org/r/1391846481-31491-9-git-send-email-ak@linux.intel.com Signed-off-by: H. Peter Anvin diff --git a/scripts/Kbuild.include b/scripts/Kbuild.include index 547e15d..93a0da2 100644 --- a/scripts/Kbuild.include +++ b/scripts/Kbuild.include @@ -155,6 +155,15 @@ ld-option = $(call try-run,\ # Important: no spaces around options ar-option = $(call try-run, $(AR) rc$(1) "$$TMP",$(1),$(2)) +# ld-version +# Usage: $(call ld-version) +# Note this is mainly for HJ Lu's 3 number binutil versions +ld-version = $(shell $(LD) --version | $(srctree)/scripts/ld-version.sh) + +# ld-ifversion +# Usage: $(call ld-ifversion, -ge, 22252, y) +ld-ifversion = $(shell [ $(call ld-version) $(1) $(2) ] && echo $(3)) + ###### ### diff --git a/scripts/ld-version.sh b/scripts/ld-version.sh new file mode 100755 index 0000000..198580d --- /dev/null +++ b/scripts/ld-version.sh @@ -0,0 +1,8 @@ +#!/usr/bin/awk -f +# extract linker version number from stdin and turn into single number + { + gsub(".*)", ""); + split($1,a, "."); + print a[1]*10000000 + a[2]*100000 + a[3]*10000 + a[4]*100 + a[5]; + exit + } -- cgit v0.10.2 From 8564ed2b3888176ac323eefea1722003daeba3d3 Mon Sep 17 00:00:00 2001 From: Andi Kleen Date: Sat, 8 Feb 2014 09:01:14 +0100 Subject: Kbuild, lto: Add a gcc-ld script to let run gcc as ld For LTO we need to run the link step with gcc, not ld. Since there are a lot of linker options passed to it, add a gcc-ld wrapper that wraps them as -Wl, Signed-off-by: Andi Kleen Link: http://lkml.kernel.org/r/1391846481-31491-10-git-send-email-ak@linux.intel.com Signed-off-by: H. Peter Anvin diff --git a/scripts/gcc-ld b/scripts/gcc-ld new file mode 100644 index 0000000..cadab9a --- /dev/null +++ b/scripts/gcc-ld @@ -0,0 +1,29 @@ +#!/bin/sh +# run gcc with ld options +# used as a wrapper to execute link time optimizations +# yes virginia, this is not pretty + +ARGS="-nostdlib" + +while [ "$1" != "" ] ; do + case "$1" in + -save-temps|-m32|-m64) N="$1" ;; + -r) N="$1" ;; + -[Wg]*) N="$1" ;; + -[olv]|-[Ofd]*|-nostdlib) N="$1" ;; + --end-group|--start-group) + N="-Wl,$1" ;; + -[RTFGhIezcbyYu]*|\ +--script|--defsym|-init|-Map|--oformat|-rpath|\ +-rpath-link|--sort-section|--section-start|-Tbss|-Tdata|-Ttext|\ +--version-script|--dynamic-list|--version-exports-symbol|--wrap|-m) + A="$1" ; shift ; N="-Wl,$A,$1" ;; + -[m]*) N="$1" ;; + -*) N="-Wl,$1" ;; + *) N="$1" ;; + esac + ARGS="$ARGS $N" + shift +done + +exec $CC $ARGS -- cgit v0.10.2 From 1e64ff42ea3d8d2fc8aa71f9717b3c1cb6c2f893 Mon Sep 17 00:00:00 2001 From: Andi Kleen Date: Sat, 8 Feb 2014 09:01:15 +0100 Subject: Kbuild, lto: Disable LTO for asm-offsets.c The asm-offset.c technique to fish data out of the assembler file does not work with LTO. Just disable for the asm-offset.c build. Signed-off-by: Andi Kleen Link: http://lkml.kernel.org/r/1391846481-31491-11-git-send-email-ak@linux.intel.com Signed-off-by: H. Peter Anvin diff --git a/scripts/Makefile.build b/scripts/Makefile.build index d5d859c..9f0ee22 100644 --- a/scripts/Makefile.build +++ b/scripts/Makefile.build @@ -198,7 +198,7 @@ $(multi-objs-y:.o=.s) : modname = $(modname-multi) $(multi-objs-y:.o=.lst) : modname = $(modname-multi) quiet_cmd_cc_s_c = CC $(quiet_modtag) $@ -cmd_cc_s_c = $(CC) $(c_flags) -fverbose-asm -S -o $@ $< +cmd_cc_s_c = $(CC) $(c_flags) $(DISABLE_LTO) -fverbose-asm -S -o $@ $< $(obj)/%.s: $(src)/%.c FORCE $(call if_changed_dep,cc_s_c) -- cgit v0.10.2 From ef178f9238b142cc1020265e176b20d27fd02ba9 Mon Sep 17 00:00:00 2001 From: Andi Kleen Date: Sat, 8 Feb 2014 09:01:17 +0100 Subject: Kbuild, lto: Handle basic LTO in modpost - Don't warn about LTO marker symbols. modpost runs before the linker, so the module is not necessarily LTOed yet. - Don't complain about .gnu.lto* sections Signed-off-by: Andi Kleen Link: http://lkml.kernel.org/r/1391846481-31491-13-git-send-email-ak@linux.intel.com Signed-off-by: H. Peter Anvin diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index f91dd45..63804a1 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -623,7 +623,10 @@ static void handle_modversions(struct module *mod, struct elf_info *info, switch (sym->st_shndx) { case SHN_COMMON: - warn("\"%s\" [%s] is COMMON symbol\n", symname, mod->name); + if (!strncmp(symname, "__gnu_lto_", sizeof("__gnu_lto_")-1)) { + /* Should warn here, but modpost runs before the linker */ + } else + warn("\"%s\" [%s] is COMMON symbol\n", symname, mod->name); break; case SHN_UNDEF: /* undefined symbol */ @@ -849,6 +852,7 @@ static const char *section_white_list[] = ".xt.lit", /* xtensa */ ".arcextmap*", /* arc */ ".gnu.linkonce.arcext*", /* arc : modules */ + ".gnu.lto*", NULL }; -- cgit v0.10.2