Merge branch 'x86-asm-for-linus' of git://git.kernel.org/pub/scm/linu…

…x/kernel/git/tip/tip

Pull x86 asm updates from Ingo Molnar:
 "The main changes in this development cycle were:

   - a large number of call stack dumping/printing improvements: higher
     robustness, better cross-context dumping, improved output, etc.
     (Josh Poimboeuf)

   - vDSO getcpu() performance improvement for future Intel CPUs with
     the RDPID instruction (Andy Lutomirski)

   - add two new Intel AVX512 features and the CPUID support
     infrastructure for it: AVX512IFMA and AVX512VBMI. (Gayatri Kammela,
     He Chen)

   - more copy-user unification (Borislav Petkov)

   - entry code assembly macro simplifications (Alexander Kuleshov)

   - vDSO C/R support improvements (Dmitry Safonov)

   - misc fixes and cleanups (Borislav Petkov, Paul Bolle)"

* 'x86-asm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (40 commits)
  scripts/decode_stacktrace.sh: Fix address line detection on x86
  x86/boot/64: Use defines for page size
  x86/dumpstack: Make stack name tags more comprehensible
  selftests/x86: Add test_vdso to test getcpu()
  x86/vdso: Use RDPID in preference to LSL when available
  x86/dumpstack: Handle NULL stack pointer in show_trace_log_lvl()
  x86/cpufeatures: Enable new AVX512 cpu features
  x86/cpuid: Provide get_scattered_cpuid_leaf()
  x86/cpuid: Cleanup cpuid_regs definitions
  x86/copy_user: Unify the code by removing the 64-bit asm _copy_*_user() variants
  x86/unwind: Ensure stack grows down
  x86/vdso: Set vDSO pointer only after success
  x86/prctl/uapi: Remove #ifdef for CHECKPOINT_RESTORE
  x86/unwind: Detect bad stack return address
  x86/dumpstack: Warn on stack recursion
  x86/unwind: Warn on bad frame pointer
  x86/decoder: Use stderr if insn sanity test fails
  x86/decoder: Use stdout if insn decoder test is successful
  mm/page_alloc: Remove kernel address exposure in free_reserved_area()
  x86/dumpstack: Remove raw stack dump
  ...

Documentation/kernel-parameters.txt

@@ -1963,9 +1963,6 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
 			kmemcheck=2 (one-shot mode)
 			Default: 2 (one-shot mode)
 
-	kstack=N	[X86] Print N words from the kernel stack
-			in oops dumps.
-
 	kvm.ignore_msrs=[KVM] Ignore guest accesses to unhandled MSRs.
 			Default is 0 (don't ignore, but inject #GP)
 

Documentation/sysctl/kernel.txt

@@ -40,7 +40,6 @@ show up in /proc/sys/kernel:
 - hung_task_warnings
 - kexec_load_disabled
 - kptr_restrict
-- kstack_depth_to_print       [ X86 only ]
 - l2cr                        [ PPC only ]
 - modprobe                    ==> Documentation/debugging-modules.txt
 - modules_disabled
@@ -395,13 +394,6 @@ When kptr_restrict is set to (2), kernel pointers printed using
 
 ==============================================================
 
-kstack_depth_to_print: (X86 only)
-
-Controls the number of words to print when dumping the raw
-kernel stack.
-
-==============================================================
-
 l2cr: (PPC only)
 
 This flag controls the L2 cache of G3 processor boards. If

Documentation/x86/x86_64/boot-options.txt

@@ -277,10 +277,6 @@ IOMMU (input/output memory management unit)
     space might stop working. Use this option if you have devices that
     are accessed from userspace directly on some PCI host bridge.
 
-Debugging
-
-  kstack=N	Print N words from the kernel stack in oops dumps.
-
 Miscellaneous
 
 	nogbpages

arch/x86/entry/calling.h

@@ -90,8 +90,8 @@ For 32-bit we have the following conventions - kernel is built with
 
 #define SIZEOF_PTREGS	21*8
 
-	.macro ALLOC_PT_GPREGS_ON_STACK addskip=0
-	addq	$-(15*8+\addskip), %rsp
+	.macro ALLOC_PT_GPREGS_ON_STACK
+	addq	$-(15*8), %rsp
 	.endm
 
 	.macro SAVE_C_REGS_HELPER offset=0 rax=1 rcx=1 r8910=1 r11=1
@@ -147,15 +147,6 @@ For 32-bit we have the following conventions - kernel is built with
 	movq 5*8+\offset(%rsp), %rbx
 	.endm
 
-	.macro ZERO_EXTRA_REGS
-	xorl	%r15d, %r15d
-	xorl	%r14d, %r14d
-	xorl	%r13d, %r13d
-	xorl	%r12d, %r12d
-	xorl	%ebp, %ebp
-	xorl	%ebx, %ebx
-	.endm
-
 	.macro RESTORE_C_REGS_HELPER rstor_rax=1, rstor_rcx=1, rstor_r11=1, rstor_r8910=1, rstor_rdx=1
 	.if \rstor_r11
 	movq 6*8(%rsp), %r11
@@ -201,6 +192,26 @@ For 32-bit we have the following conventions - kernel is built with
 	.byte 0xf1
 	.endm
 
+/*
+ * This is a sneaky trick to help the unwinder find pt_regs on the stack.  The
+ * frame pointer is replaced with an encoded pointer to pt_regs.  The encoding
+ * is just setting the LSB, which makes it an invalid stack address and is also
+ * a signal to the unwinder that it's a pt_regs pointer in disguise.
+ *
+ * NOTE: This macro must be used *after* SAVE_EXTRA_REGS because it corrupts
+ * the original rbp.
+ */
+.macro ENCODE_FRAME_POINTER ptregs_offset=0
+#ifdef CONFIG_FRAME_POINTER
+	.if \ptregs_offset
+		leaq \ptregs_offset(%rsp), %rbp
+	.else
+		mov %rsp, %rbp
+	.endif
+	orq	$0x1, %rbp
+#endif
+.endm
+
 #endif /* CONFIG_X86_64 */
 
 /*