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

…/kernel/git/tip/tip

Pull x86 mm updates from Ingo Molnar:
 "Various x86 low level modifications:

   - preparatory work to support virtually mapped kernel stacks (Andy
     Lutomirski)

   - support for 64-bit __get_user() on 32-bit kernels (Benjamin
     LaHaise)

   - (involved) workaround for Knights Landing CPU erratum (Dave Hansen)

   - MPX enhancements (Dave Hansen)

   - mremap() extension to allow remapping of the special VDSO vma, for
     purposes of user level context save/restore (Dmitry Safonov)

   - hweight and entry code cleanups (Borislav Petkov)

   - bitops code generation optimizations and cleanups with modern GCC
     (H. Peter Anvin)

   - syscall entry code optimizations (Paolo Bonzini)"

* 'x86-mm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (43 commits)
  x86/mm/cpa: Add missing comment in populate_pdg()
  x86/mm/cpa: Fix populate_pgd(): Stop trying to deallocate failed PUDs
  x86/syscalls: Add compat_sys_preadv64v2/compat_sys_pwritev64v2
  x86/smp: Remove unnecessary initialization of thread_info::cpu
  x86/smp: Remove stack_smp_processor_id()
  x86/uaccess: Move thread_info::addr_limit to thread_struct
  x86/dumpstack: Rename thread_struct::sig_on_uaccess_error to sig_on_uaccess_err
  x86/uaccess: Move thread_info::uaccess_err and thread_info::sig_on_uaccess_err to thread_struct
  x86/dumpstack: When OOPSing, rewind the stack before do_exit()
  x86/mm/64: In vmalloc_fault(), use CR3 instead of current->active_mm
  x86/dumpstack/64: Handle faults when printing the "Stack: " part of an OOPS
  x86/dumpstack: Try harder to get a call trace on stack overflow
  x86/mm: Remove kernel_unmap_pages_in_pgd() and efi_cleanup_page_tables()
  x86/mm/cpa: In populate_pgd(), don't set the PGD entry until it's populated
  x86/mm/hotplug: Don't remove PGD entries in remove_pagetable()
  x86/mm: Use pte_none() to test for empty PTE
  x86/mm: Disallow running with 32-bit PTEs to work around erratum
  x86/mm: Ignore A/D bits in pte/pmd/pud_none()
  x86/mm: Move swap offset/type up in PTE to work around erratum
  x86/entry: Inline enter_from_user_mode()
  ...

arch/x86/Kconfig

@@ -294,11 +294,6 @@ config X86_32_LAZY_GS
 	def_bool y
 	depends on X86_32 && !CC_STACKPROTECTOR
 
-config ARCH_HWEIGHT_CFLAGS
-	string
-	default "-fcall-saved-ecx -fcall-saved-edx" if X86_32
-	default "-fcall-saved-rdi -fcall-saved-rsi -fcall-saved-rdx -fcall-saved-rcx -fcall-saved-r8 -fcall-saved-r9 -fcall-saved-r10 -fcall-saved-r11" if X86_64
-
 config ARCH_SUPPORTS_UPROBES
 	def_bool y
 

arch/x86/boot/bitops.h

@@ -16,14 +16,16 @@
 #define BOOT_BITOPS_H
 #define _LINUX_BITOPS_H		/* Inhibit inclusion of <linux/bitops.h> */
 
-static inline int constant_test_bit(int nr, const void *addr)
+#include <linux/types.h>
+
+static inline bool constant_test_bit(int nr, const void *addr)
 {
 	const u32 *p = (const u32 *)addr;
 	return ((1UL << (nr & 31)) & (p[nr >> 5])) != 0;
 }
-static inline int variable_test_bit(int nr, const void *addr)
+static inline bool variable_test_bit(int nr, const void *addr)
 {
-	u8 v;
+	bool v;
 	const u32 *p = (const u32 *)addr;
 
 	asm("btl %2,%1; setc %0" : "=qm" (v) : "m" (*p), "Ir" (nr));

arch/x86/boot/boot.h

@@ -24,6 +24,7 @@
 #include <linux/types.h>
 #include <linux/edd.h>
 #include <asm/setup.h>
+#include <asm/asm.h>
 #include "bitops.h"
 #include "ctype.h"
 #include "cpuflags.h"
@@ -176,18 +177,18 @@ static inline void wrgs32(u32 v, addr_t addr)
 }
 
 /* Note: these only return true/false, not a signed return value! */
-static inline int memcmp_fs(const void *s1, addr_t s2, size_t len)
+static inline bool memcmp_fs(const void *s1, addr_t s2, size_t len)
 {
-	u8 diff;
-	asm volatile("fs; repe; cmpsb; setnz %0"
-		     : "=qm" (diff), "+D" (s1), "+S" (s2), "+c" (len));
+	bool diff;
+	asm volatile("fs; repe; cmpsb" CC_SET(nz)
+		     : CC_OUT(nz) (diff), "+D" (s1), "+S" (s2), "+c" (len));
 	return diff;
 }
-static inline int memcmp_gs(const void *s1, addr_t s2, size_t len)
+static inline bool memcmp_gs(const void *s1, addr_t s2, size_t len)
 {
-	u8 diff;
-	asm volatile("gs; repe; cmpsb; setnz %0"
-		     : "=qm" (diff), "+D" (s1), "+S" (s2), "+c" (len));
+	bool diff;
+	asm volatile("gs; repe; cmpsb" CC_SET(nz)
+		     : CC_OUT(nz) (diff), "+D" (s1), "+S" (s2), "+c" (len));
 	return diff;
 }
 
@@ -294,6 +295,7 @@ static inline int cmdline_find_option_bool(const char *option)
 
 /* cpu.c, cpucheck.c */
 int check_cpu(int *cpu_level_ptr, int *req_level_ptr, u32 **err_flags_ptr);
+int check_knl_erratum(void);
 int validate_cpu(void);
 
 /* early_serial_console.c */

arch/x86/boot/cpu.c

@@ -93,6 +93,8 @@ int validate_cpu(void)
 		show_cap_strs(err_flags);
 		putchar('\n');
 		return -1;
+	} else if (check_knl_erratum()) {
+		return -1;
 	} else {
 		return 0;
 	}

arch/x86/boot/cpucheck.c

@@ -24,6 +24,7 @@
 # include "boot.h"
 #endif
 #include <linux/types.h>
+#include <asm/intel-family.h>
 #include <asm/processor-flags.h>
 #include <asm/required-features.h>
 #include <asm/msr-index.h>
@@ -175,6 +176,8 @@ int check_cpu(int *cpu_level_ptr, int *req_level_ptr, u32 **err_flags_ptr)
 			puts("WARNING: PAE disabled. Use parameter 'forcepae' to enable at your own risk!\n");
 		}
 	}
+	if (!err)
+		err = check_knl_erratum();
 
 	if (err_flags_ptr)
 		*err_flags_ptr = err ? err_flags : NULL;
@@ -185,3 +188,33 @@ int check_cpu(int *cpu_level_ptr, int *req_level_ptr, u32 **err_flags_ptr)
 
 	return (cpu.level < req_level || err) ? -1 : 0;
 }
+
+int check_knl_erratum(void)
+{
+	/*
+	 * First check for the affected model/family:
+	 */
+	if (!is_intel() ||
+	    cpu.family != 6 ||
+	    cpu.model != INTEL_FAM6_XEON_PHI_KNL)
+		return 0;
+
+	/*
+	 * This erratum affects the Accessed/Dirty bits, and can
+	 * cause stray bits to be set in !Present PTEs.  We have
+	 * enough bits in our 64-bit PTEs (which we have on real
+	 * 64-bit mode or PAE) to avoid using these troublesome
+	 * bits.  But, we do not have enough space in our 32-bit
+	 * PTEs.  So, refuse to run on 32-bit non-PAE kernels.
+	 */
+	if (IS_ENABLED(CONFIG_X86_64) || IS_ENABLED(CONFIG_X86_PAE))
+		return 0;
+
+	puts("This 32-bit kernel can not run on this Xeon Phi x200\n"
+	     "processor due to a processor erratum.  Use a 64-bit\n"
+	     "kernel, or enable PAE in this 32-bit kernel.\n\n");
+
+	return -1;
+}
+
+

arch/x86/boot/cpuflags.c

@@ -102,6 +102,7 @@ void get_cpuflags(void)
 			cpuid(0x1, &tfms, &ignored, &cpu.flags[4],
 			      &cpu.flags[0]);
 			cpu.level = (tfms >> 8) & 15;
+			cpu.family = cpu.level;
 			cpu.model = (tfms >> 4) & 15;
 			if (cpu.level >= 6)
 				cpu.model += ((tfms >> 16) & 0xf) << 4;

arch/x86/boot/cpuflags.h

@@ -6,6 +6,7 @@
 
 struct cpu_features {
 	int level;		/* Family, or 64 for x86-64 */
+	int family;		/* Family, always */
 	int model;
 	u32 flags[NCAPINTS];
 };

arch/x86/boot/string.c

@@ -17,7 +17,7 @@
 
 int memcmp(const void *s1, const void *s2, size_t len)
 {
-	u8 diff;
+	bool diff;
 	asm("repe; cmpsb; setnz %0"
 	    : "=qm" (diff), "+D" (s1), "+S" (s2), "+c" (len));
 	return diff;

arch/x86/entry/common.c

@@ -40,10 +40,10 @@ static struct thread_info *pt_regs_to_thread_info(struct pt_regs *regs)
 
 #ifdef CONFIG_CONTEXT_TRACKING
 /* Called on entry from user mode with IRQs off. */
-__visible void enter_from_user_mode(void)
+__visible inline void enter_from_user_mode(void)
 {
 	CT_WARN_ON(ct_state() != CONTEXT_USER);
-	user_exit();
+	user_exit_irqoff();
 }
 #else
 static inline void enter_from_user_mode(void) {}
@@ -274,7 +274,7 @@ __visible inline void prepare_exit_to_usermode(struct pt_regs *regs)
 	ti->status &= ~TS_COMPAT;
 #endif
 
-	user_enter();
+	user_enter_irqoff();
 }
 
 #define SYSCALL_EXIT_WORK_FLAGS				\

arch/x86/entry/entry_32.S

@@ -1153,3 +1153,14 @@ ENTRY(async_page_fault)
 	jmp	error_code
 END(async_page_fault)
 #endif
+
+ENTRY(rewind_stack_do_exit)
+	/* Prevent any naive code from trying to unwind to our caller. */
+	xorl	%ebp, %ebp
+
+	movl	PER_CPU_VAR(cpu_current_top_of_stack), %esi
+	leal	-TOP_OF_KERNEL_STACK_PADDING-PTREGS_SIZE(%esi), %esp
+
+	call	do_exit
+1:	jmp 1b
+END(rewind_stack_do_exit)

arch/x86/entry/entry_64.S

@@ -1423,3 +1423,14 @@ ENTRY(ignore_sysret)
 	mov	$-ENOSYS, %eax
 	sysret
 END(ignore_sysret)
+
+ENTRY(rewind_stack_do_exit)
+	/* Prevent any naive code from trying to unwind to our caller. */
+	xorl	%ebp, %ebp
+
+	movq	PER_CPU_VAR(cpu_current_top_of_stack), %rax
+	leaq	-TOP_OF_KERNEL_STACK_PADDING-PTREGS_SIZE(%rax), %rsp
+
+	call	do_exit
+1:	jmp 1b
+END(rewind_stack_do_exit)

arch/x86/entry/syscalls/syscall_64.tbl

@@ -374,5 +374,5 @@
 543	x32	io_setup		compat_sys_io_setup
 544	x32	io_submit		compat_sys_io_submit
 545	x32	execveat		compat_sys_execveat/ptregs
-534	x32	preadv2			compat_sys_preadv2
-535	x32	pwritev2		compat_sys_pwritev2
+546	x32	preadv2			compat_sys_preadv64v2
+547	x32	pwritev2		compat_sys_pwritev64v2

arch/x86/entry/thunk_64.S

@@ -33,7 +33,7 @@
 	.endif
 
 	call \func
-	jmp  restore
+	jmp  .L_restore
 	_ASM_NOKPROBE(\name)
 	.endm
 
@@ -54,7 +54,7 @@
 #if defined(CONFIG_TRACE_IRQFLAGS) \
  || defined(CONFIG_DEBUG_LOCK_ALLOC) \
  || defined(CONFIG_PREEMPT)
-restore:
+.L_restore:
 	popq %r11
 	popq %r10
 	popq %r9
@@ -66,5 +66,5 @@ restore:
 	popq %rdi
 	popq %rbp
 	ret
-	_ASM_NOKPROBE(restore)
+	_ASM_NOKPROBE(.L_restore)
 #endif

arch/x86/entry/vdso/Makefile

@@ -134,7 +134,7 @@ VDSO_LDFLAGS_vdso32.lds = -m32 -Wl,-m,elf_i386 -Wl,-soname=linux-gate.so.1
 override obj-dirs = $(dir $(obj)) $(obj)/vdso32/
 
 targets += vdso32/vdso32.lds
-targets += vdso32/note.o vdso32/vclock_gettime.o vdso32/system_call.o
+targets += vdso32/note.o vdso32/system_call.o vdso32/sigreturn.o
 targets += vdso32/vclock_gettime.o
 
 KBUILD_AFLAGS_32 := $(filter-out -m64,$(KBUILD_AFLAGS)) -DBUILD_VDSO
@@ -156,7 +156,8 @@ $(obj)/vdso32.so.dbg: FORCE \
 		      $(obj)/vdso32/vdso32.lds \
 		      $(obj)/vdso32/vclock_gettime.o \
 		      $(obj)/vdso32/note.o \
-		      $(obj)/vdso32/system_call.o
+		      $(obj)/vdso32/system_call.o \
+		      $(obj)/vdso32/sigreturn.o
 	$(call if_changed,vdso)
 
 #

arch/x86/entry/vdso/vdso32/sigreturn.S

@@ -1,11 +1,3 @@
-/*
- * Common code for the sigreturn entry points in vDSO images.
- * So far this code is the same for both int80 and sysenter versions.
- * This file is #include'd by int80.S et al to define them first thing.
- * The kernel assumes that the addresses of these routines are constant
- * for all vDSO implementations.
- */
-
 #include <linux/linkage.h>
 #include <asm/unistd_32.h>
 #include <asm/asm-offsets.h>

arch/x86/entry/vdso/vdso32/system_call.S

@@ -2,16 +2,11 @@
  * AT_SYSINFO entry point
 */
 
+#include <linux/linkage.h>
 #include <asm/dwarf2.h>
 #include <asm/cpufeatures.h>
 #include <asm/alternative-asm.h>
 
-/*
- * First get the common code for the sigreturn entry points.
- * This must come first.
- */
-#include "sigreturn.S"
-
 	.text
 	.globl __kernel_vsyscall
 	.type __kernel_vsyscall,@function

arch/x86/entry/vdso/vma.c

@@ -12,6 +12,7 @@
 #include <linux/random.h>
 #include <linux/elf.h>
 #include <linux/cpu.h>
+#include <linux/ptrace.h>
 #include <asm/pvclock.h>
 #include <asm/vgtod.h>
 #include <asm/proto.h>
@@ -97,10 +98,40 @@ static int vdso_fault(const struct vm_special_mapping *sm,
 	return 0;
 }
 
-static const struct vm_special_mapping text_mapping = {
-	.name = "[vdso]",
-	.fault = vdso_fault,
-};
+static void vdso_fix_landing(const struct vdso_image *image,
+		struct vm_area_struct *new_vma)
+{
+#if defined CONFIG_X86_32 || defined CONFIG_IA32_EMULATION
+	if (in_ia32_syscall() && image == &vdso_image_32) {
+		struct pt_regs *regs = current_pt_regs();
+		unsigned long vdso_land = image->sym_int80_landing_pad;
+		unsigned long old_land_addr = vdso_land +
+			(unsigned long)current->mm->context.vdso;
+
+		/* Fixing userspace landing - look at do_fast_syscall_32 */
+		if (regs->ip == old_land_addr)
+			regs->ip = new_vma->vm_start + vdso_land;
+	}
+#endif
+}
+
+static int vdso_mremap(const struct vm_special_mapping *sm,
+		struct vm_area_struct *new_vma)
+{
+	unsigned long new_size = new_vma->vm_end - new_vma->vm_start;
+	const struct vdso_image *image = current->mm->context.vdso_image;
+
+	if (image->size != new_size)
+		return -EINVAL;
+
+	if (WARN_ON_ONCE(current->mm != new_vma->vm_mm))
+		return -EFAULT;
+
+	vdso_fix_landing(image, new_vma);
+	current->mm->context.vdso = (void __user *)new_vma->vm_start;
+
+	return 0;
+}
 
 static int vvar_fault(const struct vm_special_mapping *sm,
 		      struct vm_area_struct *vma, struct vm_fault *vmf)
@@ -151,6 +182,12 @@ static int map_vdso(const struct vdso_image *image, bool calculate_addr)
 	struct vm_area_struct *vma;
 	unsigned long addr, text_start;
 	int ret = 0;
+
+	static const struct vm_special_mapping vdso_mapping = {
+		.name = "[vdso]",
+		.fault = vdso_fault,
+		.mremap = vdso_mremap,
+	};
 	static const struct vm_special_mapping vvar_mapping = {
 		.name = "[vvar]",
 		.fault = vvar_fault,
@@ -185,7 +222,7 @@ static int map_vdso(const struct vdso_image *image, bool calculate_addr)
 				       image->size,
 				       VM_READ|VM_EXEC|
 				       VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC,
-				       &text_mapping);
+				       &vdso_mapping);
 
 	if (IS_ERR(vma)) {
 		ret = PTR_ERR(vma);