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131484c8da
linux/arch/x86/kernel
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Ingo Molnar 131484c8da x86/debug: Remove perpetually broken, unmaintainable dwarf annotations 
So the dwarf2 annotations in low level assembly code have
become an increasing hindrance: unreadable, messy macros
mixed into some of the most security sensitive code paths
of the Linux kernel.

These debug info annotations don't even buy the upstream
kernel anything: dwarf driven stack unwinding has caused
problems in the past so it's out of tree, and the upstream
kernel only uses the much more robust framepointers based
stack unwinding method.

In addition to that there's a steady, slow bitrot going
on with these annotations, requiring frequent fixups.
There's no tooling and no functionality upstream that
keeps it correct.

So burn down the sick forest, allowing new, healthier growth:

   27 files changed, 350 insertions(+), 1101 deletions(-)

Someone who has the willingness and time to do this
properly can attempt to reintroduce dwarf debuginfo in x86
assembly code plus dwarf unwinding from first principles,
with the following conditions:

 - it should be maximally readable, and maximally low-key to
   'ordinary' code reading and maintenance.

 - find a build time method to insert dwarf annotations
   automatically in the most common cases, for pop/push
   instructions that manipulate the stack pointer. This could
   be done for example via a preprocessing step that just
   looks for common patterns - plus special annotations for
   the few cases where we want to depart from the default.
   We have hundreds of CFI annotations, so automating most of
   that makes sense.

 - it should come with build tooling checks that ensure that
   CFI annotations are sensible. We've seen such efforts from
   the framepointer side, and there's no reason it couldn't be
   done on the dwarf side.

Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Frédéric Weisbecker <fweisbec@gmail.com
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jan Beulich <JBeulich@suse.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-06-02 07:57:48 +02:00
..
acpi Merge branch 'linus' into x86/asm, before applying dependent patch 2015-05-08 13:33:33 +02:00
apic x86/asm/entry/irq: Clean up IRQn_VECTOR macros 2015-05-10 12:34:28 +02:00
cpu Merge branch 'linus' into x86/asm, to resolve conflicts 2015-05-17 07:57:31 +02:00
kprobes Merge branch 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2015-04-14 14:37:47 -07:00
.gitignore
alternative.c x86/alternatives: Switch AMD F15h and later to the P6 NOPs 2015-05-11 10:26:05 +02:00
amd_gart_64.c x86: enable DMA CMA with swiotlb 2014-06-04 16:53:57 -07:00
amd_nb.c x86, amd_nb: Add device IDs to NB tables for F15h M60h 2014-10-20 14:18:45 +02:00
apb_timer.c x86/platform: Remove unused function from apb_timer.c 2014-12-23 10:43:35 +01:00
aperture_64.c x86/gart: Tidy messages and add bridge device info 2014-05-23 10:47:19 -06:00
apm_32.c cpuidle: Invert CPUIDLE_FLAG_TIME_VALID logic 2014-11-12 21:17:27 +01:00
asm-offsets_32.c x86/asm: Remove unused TI_cpu 2015-04-15 11:28:50 +02:00
asm-offsets_64.c x86/asm: Merge common 32-bit values in asm-offsets.c 2015-04-15 11:28:49 +02:00
asm-offsets.c x86, paravirt, xen: Remove the 64-bit ->irq_enable_sysexit() pvop 2015-04-22 08:07:45 +02:00
audit_64.c x86: hook up execveat system call 2014-12-13 12:42:51 -08:00
bootflag.c
check.c x86/mm: memblock: switch to use NUMA_NO_NODE 2014-01-21 16:19:47 -08:00
cpuid.c x86, cpuid: Use PTR_ERR_OR_ZERO 2014-10-17 13:40:51 -07:00
crash_dump_32.c
crash_dump_64.c
crash.c x86/asm/entry: Change all 'user_mode_vm()' calls to 'user_mode()' 2015-03-23 11:14:17 +01:00
devicetree.c x86/mm: Use early_memunmap() instead of early_iounmap() 2015-02-24 15:58:06 +01:00
doublefault.c x86: Delete non-required instances of include <linux/init.h> 2014-01-06 21:25:18 -08:00
dumpstack_32.c Merge branch 'x86-debug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2015-04-13 13:23:34 -07:00
dumpstack_64.c x86/kernel: Use kstack_end() in dumpstack_64.c 2015-02-23 18:37:13 +01:00
dumpstack.c Merge branch 'x86-debug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2015-04-13 13:23:34 -07:00
e820.c Merge branch 'x86-pmem-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2015-04-18 11:42:49 -04:00
early_printk.c TTY/Serial patches for 4.1-rc1 2015-04-21 09:33:10 -07:00
early-quirks.c drm/i915/skl: Add the additional graphics stolen sizes 2014-09-24 14:47:39 +02:00
entry_32.S x86/debug: Remove perpetually broken, unmaintainable dwarf annotations 2015-06-02 07:57:48 +02:00
entry_64.S x86/debug: Remove perpetually broken, unmaintainable dwarf annotations 2015-06-02 07:57:48 +02:00
espfix_64.c x86, espfix: Remove stale ptemask 2014-11-11 17:57:46 +01:00
ftrace.c module: remove mod arg from module_free, rename module_memfree(). 2015-01-20 11:38:33 +10:30
head32.c x86: Store a per-cpu shadow copy of CR4 2015-02-04 12:10:42 +01:00
head64.c x86/asm/irq: Stop relying on magic JMP behavior for early_idt_handlers 2015-05-24 08:35:03 +02:00
head_32.S x86/asm/irq: Stop relying on magic JMP behavior for early_idt_handlers 2015-05-24 08:35:03 +02:00
head_64.S x86/asm/irq: Stop relying on magic JMP behavior for early_idt_handlers 2015-05-24 08:35:03 +02:00
head.c x86: Make sure we can boot in the case the BDA contains pure garbage 2013-02-27 13:38:57 -08:00
hpet.c kernel.h: remove ancient __FUNCTION__ hack 2015-02-12 18:54:13 -08:00
hw_breakpoint.c perf/x86: Remove get_hbp_len and replace with bp_len 2014-12-03 15:14:30 +01:00
i386_ksyms_32.c sched, x86: Optimize the preempt_schedule() call 2013-09-25 14:23:07 +02:00
i387.c x86/fpu: Load xsave pointer *after* initialization 2015-04-17 10:15:47 +02:00
i8237.c
i8253.c
i8259.c x86/asm/entry/irq: Clean up IRQn_VECTOR macros 2015-05-10 12:34:28 +02:00
io_delay.c
ioport.c x86/asm/entry: Rename 'init_tss' to 'cpu_tss' 2015-03-06 08:32:58 +01:00
iosf_mbi.c x86/platform/intel/iosf: Add debugfs config option for IOSF 2014-09-19 13:08:43 +02:00
irq_32.c x86/irq: Merge irq_regs & irq_stat 2015-05-10 12:34:27 +02:00
irq_64.c x86/irq: Merge irq_regs & irq_stat 2015-05-10 12:34:27 +02:00
irq_work.c x86: Tell irq work about self IPI support 2014-09-13 18:38:29 +02:00
irq.c x86/irq: Merge irq_regs & irq_stat 2015-05-10 12:34:27 +02:00
irqinit.c x86/asm/entry/irq: Clean up IRQn_VECTOR macros 2015-05-10 12:34:28 +02:00
jump_label.c x86/jump_label: expect default_nop if static_key gets enabled on boot-up 2013-10-19 19:45:35 -04:00
kdebugfs.c
kexec-bzimage64.c kexec-bzimage64: fix sparse warnings 2014-10-14 02:18:21 +02:00
kgdb.c Linux 4.0-rc7 2015-04-08 09:01:54 +02:00
ksysfs.c x86: ksysfs.c build fix 2014-01-03 14:37:13 +00:00
kvm.c watchdog: introduce the hardlockup_detector_disable() function 2015-04-14 16:48:59 -07:00
kvmclock.c x86, kvm: Clear paravirt_enabled on KVM guests for espfix32's benefit 2014-12-10 12:49:39 +01:00
ldt.c Revert "x86-64, modify_ldt: Make support for 16-bit segments a runtime option" 2014-05-21 10:22:59 -07:00
livepatch.c livepatch: kernel: add support for live patching 2014-12-22 15:40:49 +01:00
machine_kexec_32.c x86, irq: Move IOAPIC related declarations from hw_irq.h into io_apic.h 2014-12-16 14:08:17 +01:00
machine_kexec_64.c x86, irq: Move IOAPIC related declarations from hw_irq.h into io_apic.h 2014-12-16 14:08:17 +01:00
Makefile Merge branch 'x86-pmem-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2015-04-18 11:42:49 -04:00
mcount_64.S ftrace/fgraph/x86: Have prepare_ftrace_return() take ip as first parameter 2014-12-01 14:08:58 -05:00
mmconf-fam10h_64.c x86: delete __cpuinit usage from all x86 files 2013-07-14 19:36:56 -04:00
module.c x86/mm/KASLR: Propagate KASLR status to kernel proper 2015-04-03 15:26:15 +02:00
mpparse.c x86, apic: Remove mps_oem_check callback 2014-07-31 08:05:42 -07:00
msr.c x86, msr: Use seek definitions instead of hard-coded values 2014-10-17 13:40:55 -07:00
nmi_selftest.c
nmi.c kprobes, x86: Use NOKPROBE_SYMBOL() instead of __kprobes annotation 2014-04-24 10:26:38 +02:00
paravirt_patch_32.c
paravirt_patch_64.c x86, paravirt, xen: Remove the 64-bit ->irq_enable_sysexit() pvop 2015-04-22 08:07:45 +02:00
paravirt-spinlocks.c x86, ticketlock: Add slowpath logic 2013-08-09 07:54:00 -07:00
paravirt.c Merge branch 'linus' into x86/asm, before applying dependent patch 2015-05-08 13:33:33 +02:00
pci-calgary_64.c x86, calgary: Use 8M TCE table size by default 2014-04-10 19:51:32 -07:00
pci-dma.c arch/x86/kernel/pci-dma.c: fix dma_generic_alloc_coherent() when CONFIG_DMA_CMA is enabled 2014-06-04 16:53:57 -07:00
pci-iommu_table.c
pci-nommu.c x86: Delete non-required instances of include <linux/init.h> 2014-01-06 21:25:18 -08:00
pci-swiotlb.c x86: enable DMA CMA with swiotlb 2014-06-04 16:53:57 -07:00
pcspeaker.c
perf_regs.c perf/x86/64: Report regs_user->ax too in get_regs_user() 2015-04-11 13:08:53 +02:00
pmc_atom.c x86: pmc_atom: Expose contents of PSS 2015-01-20 12:50:14 +01:00
pmem.c x86/mm: Add support for the non-standard protected e820 type 2015-04-01 17:02:43 +02:00
probe_roms.c
process_32.c x86/entry: Remove unused 'kernel_stack' per-cpu variable 2015-05-08 13:49:43 +02:00
process_64.c x86/entry: Remove unused 'kernel_stack' per-cpu variable 2015-05-08 13:49:43 +02:00
process.c x86/fpu: Always restore_xinit_state() when use_eager_cpu() 2015-05-06 11:22:03 +02:00
ptrace.c x86/asm/entry: Change all 'user_mode_vm()' calls to 'user_mode()' 2015-03-23 11:14:17 +01:00
pvclock.c x86: pvclock: Really remove the sched notifier for cross-cpu migrations 2015-04-27 15:49:30 +02:00
quirks.c x86: HPET force enable for e6xx based systems 2014-09-15 17:53:35 -07:00
reboot_fixups_32.c
reboot.c x86/reboot: Add ASRock Q1900DC-ITX mainboard reboot quirk 2015-04-01 14:08:09 +02:00
relocate_kernel_32.S x86/asm: Optimize unnecessarily wide TEST instructions 2015-03-07 11:12:43 +01:00
relocate_kernel_64.S x86/asm: Replace "MOVQ $imm, %reg" with MOVL 2015-04-01 13:17:39 +02:00
resource.c x86: don't exclude low BIOS area when allocating address space for non-PCI cards 2014-07-16 12:29:36 -06:00
rtc.c kernel.h: remove ancient __FUNCTION__ hack 2015-02-12 18:54:13 -08:00
setup_percpu.c x86: Convert a few more per-CPU items to read-mostly ones 2014-11-04 20:13:28 +01:00
setup.c Merge branch 'x86-mm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2015-04-13 13:31:32 -07:00
signal.c Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2015-04-18 11:31:11 -04:00
smp.c asmlinkage, x86: Add explicit __visible to arch/x86/* 2014-05-05 16:07:44 -07:00
smpboot.c x86/entry: Remove unused 'kernel_stack' per-cpu variable 2015-05-08 13:49:43 +02:00
stacktrace.c
step.c
sys_x86_64.c x86/mm: Improve AMD Bulldozer ASLR workaround 2015-03-31 10:01:17 +02:00
syscall_32.c x86/compat: Merge native and compat 32-bit syscall tables 2015-03-04 06:16:21 +01:00
syscall_64.c x86, asmlinkage: Make syscall tables visible 2013-08-06 14:20:18 -07:00
sysfb_efi.c x86: sysfb: move EFI quirks from efifb to sysfb 2013-08-02 16:17:47 -07:00
sysfb_simplefb.c x86/simplefb: Use PTR_ERR_OR_ZERO 2014-10-17 13:40:52 -07:00
sysfb.c x86/sysfb: Use PTR_ERR_OR_ZERO 2014-10-17 13:40:52 -07:00
tboot.c x86 / tboot / ACPI: Fail extended mode reduced hardware sleep 2013-07-31 14:25:51 +02:00
tce_64.c
test_nx.c
test_rodata.c treewide: Fix typo in printk messages 2015-03-06 23:05:39 +01:00
time.c x86/asm/entry: Change all 'user_mode_vm()' calls to 'user_mode()' 2015-03-23 11:14:17 +01:00
tls.c x86, tls: Interpret an all-zero struct user_desc as "no segment" 2015-01-22 21:45:07 +01:00
tls.h
topology.c hotplug, powerpc, x86: Remove cpu_hotplug_driver_lock() 2013-09-30 19:55:51 +02:00
trace_clock.c
tracepoint.c x86: Make sure IDT is page aligned 2013-07-16 15:14:48 -07:00
traps.c x86/asm/entry: Remove SYSCALL_VECTOR 2015-05-10 12:34:28 +02:00
tsc_msr.c x86: tsc: Add missing Baytrail frequency to the table 2014-02-19 17:12:24 +01:00
tsc_sync.c x86: Delete non-required instances of include <linux/init.h> 2014-01-06 21:25:18 -08:00
tsc.c x86/tsc: Change Fast TSC calibration failed from error to info 2015-01-23 10:53:52 +01:00
uprobes.c x86/asm/entry: Change all 'user_mode_vm()' calls to 'user_mode()' 2015-03-23 11:14:17 +01:00
verify_cpu.S
vm86_32.c x86/asm/entry: Rename 'init_tss' to 'cpu_tss' 2015-03-06 08:32:58 +01:00
vmlinux.lds.S x86-64: Use RIP-relative addressing for most per-CPU accesses 2014-11-04 20:43:14 +01:00
vsmp_64.c x86/apic/vsmp: Make is_vsmp_box() static 2014-08-01 15:09:45 -07:00
vsyscall_64.c x86_64/vsyscall: Restore orig_ax after vsyscall seccomp 2014-11-10 10:46:35 +01:00
vsyscall_emu_64.S
vsyscall_gtod.c time: Rename timekeeper::tkr to timekeeper::tkr_mono 2015-03-27 09:45:06 +01:00
vsyscall_trace.h
x86_init.c Revert "PCI: Add x86_msi.msi_mask_irq() and msix_mask_irq()" 2014-11-11 15:14:30 -07:00
x8664_ksyms_64.c x86_64: kasan: add interceptors for memset/memmove/memcpy functions 2015-02-13 21:21:41 -08:00
xsave.c x86/fpu: Kill eager_fpu_init_bp() 2015-03-23 10:14:00 +01:00