Merge branch 'x86/cleanups' into x86/mm

Merge recent cleanups to the x86 MM code to resolve a conflict.

Conflicts:
	arch/x86/mm/fault.c

Signed-off-by: Ingo Molnar <mingo@kernel.org>

15 files changed, 60 insertions, 111 deletions

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 7b6dd10b162a..865c1e7346fe 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -889,7 +889,7 @@ config HPET_TIMER
 
 config HPET_EMULATE_RTC
 	def_bool y
-	depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
+	depends on HPET_TIMER && (RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
 
 config APB_TIMER
 	def_bool y if X86_INTEL_MID
diff --git a/arch/x86/include/asm/irq.h b/arch/x86/include/asm/irq.h
index 528c8a71fe7f..76d389691b5b 100644
--- a/arch/x86/include/asm/irq.h
+++ b/arch/x86/include/asm/irq.h
@@ -40,8 +40,6 @@ extern void native_init_IRQ(void);
 
 extern void __handle_irq(struct irq_desc *desc, struct pt_regs *regs);
 
-extern __visible void do_IRQ(struct pt_regs *regs, unsigned long vector);
-
 extern void init_ISA_irqs(void);
 
 extern void __init init_IRQ(void);
diff --git a/arch/x86/include/asm/page_64_types.h b/arch/x86/include/asm/page_64_types.h
index 645bd1d0ee07..64297eabad63 100644
--- a/arch/x86/include/asm/page_64_types.h
+++ b/arch/x86/include/asm/page_64_types.h
@@ -66,7 +66,7 @@
  * On Intel CPUs, if a SYSCALL instruction is at the highest canonical
  * address, then that syscall will enter the kernel with a
  * non-canonical return address, and SYSRET will explode dangerously.
- * We avoid this particular problem by preventing anything executable
+ * We avoid this particular problem by preventing anything
  * from being mapped at the maximum canonical address.
  *
  * On AMD CPUs in the Ryzen family, there's a nasty bug in which the
diff --git a/arch/x86/include/asm/pgtable_types.h b/arch/x86/include/asm/pgtable_types.h
index 394757ee030a..f24d7ef8fffa 100644
--- a/arch/x86/include/asm/pgtable_types.h
+++ b/arch/x86/include/asm/pgtable_types.h
@@ -177,8 +177,6 @@ enum page_cache_mode {
 #define __pgprot(x)		((pgprot_t) { (x) } )
 #define __pg(x)			__pgprot(x)
 
-#define _PAGE_PAT_LARGE		(_AT(pteval_t, 1) << _PAGE_BIT_PAT_LARGE)
-
 #define PAGE_NONE	     __pg(   0|   0|   0|___A|   0|   0|   0|___G)
 #define PAGE_SHARED	     __pg(__PP|__RW|_USR|___A|__NX|   0|   0|   0)
 #define PAGE_SHARED_EXEC     __pg(__PP|__RW|_USR|___A|   0|   0|   0|   0)
diff --git a/arch/x86/include/asm/vm86.h b/arch/x86/include/asm/vm86.h
index 26efbec94448..9e8ac5073ecb 100644
--- a/arch/x86/include/asm/vm86.h
+++ b/arch/x86/include/asm/vm86.h
@@ -36,7 +36,6 @@ struct vm86 {
 	unsigned long saved_sp0;
 
 	unsigned long flags;
-	unsigned long screen_bitmap;
 	unsigned long cpu_type;
 	struct revectored_struct int_revectored;
 	struct revectored_struct int21_revectored;
diff --git a/arch/x86/include/uapi/asm/vm86.h b/arch/x86/include/uapi/asm/vm86.h
index d2ee4e307ef8..18909b8050bc 100644
--- a/arch/x86/include/uapi/asm/vm86.h
+++ b/arch/x86/include/uapi/asm/vm86.h
@@ -97,7 +97,7 @@ struct revectored_struct {
 struct vm86_struct {
 	struct vm86_regs regs;
 	unsigned long flags;
-	unsigned long screen_bitmap;
+	unsigned long screen_bitmap;		/* unused, preserved by vm86() */
 	unsigned long cpu_type;
 	struct revectored_struct int_revectored;
 	struct revectored_struct int21_revectored;
@@ -106,7 +106,7 @@ struct vm86_struct {
 /*
  * flags masks
  */
-#define VM86_SCREEN_BITMAP	0x0001
+#define VM86_SCREEN_BITMAP	0x0001        /* no longer supported */
 
 struct vm86plus_info_struct {
 	unsigned long force_return_for_pic:1;
diff --git a/arch/x86/kernel/cpu/mtrr/cleanup.c b/arch/x86/kernel/cpu/mtrr/cleanup.c
index 5bd011737272..9231640782fa 100644
--- a/arch/x86/kernel/cpu/mtrr/cleanup.c
+++ b/arch/x86/kernel/cpu/mtrr/cleanup.c
@@ -537,9 +537,9 @@ static void __init print_out_mtrr_range_state(void)
 		if (!size_base)
 			continue;
 
-		size_base = to_size_factor(size_base, &size_factor),
+		size_base = to_size_factor(size_base, &size_factor);
 		start_base = range_state[i].base_pfn << (PAGE_SHIFT - 10);
-		start_base = to_size_factor(start_base, &start_factor),
+		start_base = to_size_factor(start_base, &start_factor);
 		type = range_state[i].type;
 
 		pr_debug("reg %d, base: %ld%cB, range: %ld%cB, type %s\n",
diff --git a/arch/x86/kernel/cpu/mtrr/generic.c b/arch/x86/kernel/cpu/mtrr/generic.c
index 23ad8e953dfb..2cf4465d5693 100644
--- a/arch/x86/kernel/cpu/mtrr/generic.c
+++ b/arch/x86/kernel/cpu/mtrr/generic.c
@@ -3,7 +3,6 @@
  * This only handles 32bit MTRR on 32bit hosts. This is strictly wrong
  * because MTRRs can span up to 40 bits (36bits on most modern x86)
  */
-#define DEBUG
 
 #include <linux/export.h>
 #include <linux/init.h>
diff --git a/arch/x86/kernel/cpu/mtrr/mtrr.c b/arch/x86/kernel/cpu/mtrr/mtrr.c
index 61eb26edc6d2..28c8a23aa42e 100644
--- a/arch/x86/kernel/cpu/mtrr/mtrr.c
+++ b/arch/x86/kernel/cpu/mtrr/mtrr.c
@@ -31,8 +31,6 @@
     System Programming Guide; Section 9.11. (1997 edition - PPro).
 */
 
-#define DEBUG
-
 #include <linux/types.h> /* FIXME: kvm_para.h needs this */
 
 #include <linux/stop_machine.h>
diff --git a/arch/x86/kernel/pci-iommu_table.c b/arch/x86/kernel/pci-iommu_table.c
index 2e9006c1e240..42e92ec62973 100644
--- a/arch/x86/kernel/pci-iommu_table.c
+++ b/arch/x86/kernel/pci-iommu_table.c
@@ -4,9 +4,6 @@
 #include <linux/string.h>
 #include <linux/kallsyms.h>
 
-
-#define DEBUG 1
-
 static struct iommu_table_entry * __init
 find_dependents_of(struct iommu_table_entry *start,
 		   struct iommu_table_entry *finish,
diff --git a/arch/x86/kernel/ptrace.c b/arch/x86/kernel/ptrace.c
index bedca011459c..87a4143aa7d7 100644
--- a/arch/x86/kernel/ptrace.c
+++ b/arch/x86/kernel/ptrace.c
@@ -704,6 +704,9 @@ void ptrace_disable(struct task_struct *child)
 #if defined CONFIG_X86_32 || defined CONFIG_IA32_EMULATION
 static const struct user_regset_view user_x86_32_view; /* Initialized below. */
 #endif
+#ifdef CONFIG_X86_64
+static const struct user_regset_view user_x86_64_view; /* Initialized below. */
+#endif
 
 long arch_ptrace(struct task_struct *child, long request,
 		 unsigned long addr, unsigned long data)
@@ -711,6 +714,14 @@ long arch_ptrace(struct task_struct *child, long request,
 	int ret;
 	unsigned long __user *datap = (unsigned long __user *)data;
 
+#ifdef CONFIG_X86_64
+	/* This is native 64-bit ptrace() */
+	const struct user_regset_view *regset_view = &user_x86_64_view;
+#else
+	/* This is native 32-bit ptrace() */
+	const struct user_regset_view *regset_view = &user_x86_32_view;
+#endif
+
 	switch (request) {
 	/* read the word at location addr in the USER area. */
 	case PTRACE_PEEKUSR: {
@@ -749,28 +760,28 @@ long arch_ptrace(struct task_struct *child, long request,
 
 	case PTRACE_GETREGS:	/* Get all gp regs from the child. */
 		return copy_regset_to_user(child,
-					   task_user_regset_view(current),
+					   regset_view,
 					   REGSET_GENERAL,
 					   0, sizeof(struct user_regs_struct),
 					   datap);
 
 	case PTRACE_SETREGS:	/* Set all gp regs in the child. */
 		return copy_regset_from_user(child,
-					     task_user_regset_view(current),
+					     regset_view,
 					     REGSET_GENERAL,
 					     0, sizeof(struct user_regs_struct),
 					     datap);
 
 	case PTRACE_GETFPREGS:	/* Get the child FPU state. */
 		return copy_regset_to_user(child,
-					   task_user_regset_view(current),
+					   regset_view,
 					   REGSET_FP,
 					   0, sizeof(struct user_i387_struct),
 					   datap);
 
 	case PTRACE_SETFPREGS:	/* Set the child FPU state. */
 		return copy_regset_from_user(child,
-					     task_user_regset_view(current),
+					     regset_view,
 					     REGSET_FP,
 					     0, sizeof(struct user_i387_struct),
 					     datap);
@@ -1152,28 +1163,28 @@ static long x32_arch_ptrace(struct task_struct *child,
 
 	case PTRACE_GETREGS:	/* Get all gp regs from the child. */
 		return copy_regset_to_user(child,
-					   task_user_regset_view(current),
+					   &user_x86_64_view,
 					   REGSET_GENERAL,
 					   0, sizeof(struct user_regs_struct),
 					   datap);
 
 	case PTRACE_SETREGS:	/* Set all gp regs in the child. */
 		return copy_regset_from_user(child,
-					     task_user_regset_view(current),
+					     &user_x86_64_view,
 					     REGSET_GENERAL,
 					     0, sizeof(struct user_regs_struct),
 					     datap);
 
 	case PTRACE_GETFPREGS:	/* Get the child FPU state. */
 		return copy_regset_to_user(child,
-					   task_user_regset_view(current),
+					   &user_x86_64_view,
 					   REGSET_FP,
 					   0, sizeof(struct user_i387_struct),
 					   datap);
 
 	case PTRACE_SETFPREGS:	/* Set the child FPU state. */
 		return copy_regset_from_user(child,
-					     task_user_regset_view(current),
+					     &user_x86_64_view,
 					     REGSET_FP,
 					     0, sizeof(struct user_i387_struct),
 					     datap);
@@ -1309,6 +1320,25 @@ void __init update_regset_xstate_info(unsigned int size, u64 xstate_mask)
 	xstate_fx_sw_bytes[USER_XSTATE_XCR0_WORD] = xstate_mask;
 }
 
+/*
+ * This is used by the core dump code to decide which regset to dump.  The
+ * core dump code writes out the resulting .e_machine and the corresponding
+ * regsets.  This is suboptimal if the task is messing around with its CS.L
+ * field, but at worst the core dump will end up missing some information.
+ *
+ * Unfortunately, it is also used by the broken PTRACE_GETREGSET and
+ * PTRACE_SETREGSET APIs.  These APIs look at the .regsets field but have
+ * no way to make sure that the e_machine they use matches the caller's
+ * expectations.  The result is that the data format returned by
+ * PTRACE_GETREGSET depends on the returned CS field (and even the offset
+ * of the returned CS field depends on its value!) and the data format
+ * accepted by PTRACE_SETREGSET is determined by the old CS value.  The
+ * upshot is that it is basically impossible to use these APIs correctly.
+ *
+ * The best way to fix it in the long run would probably be to add new
+ * improved ptrace() APIs to read and write registers reliably, possibly by
+ * allowing userspace to select the ELF e_machine variant that they expect.
+ */
 const struct user_regset_view *task_user_regset_view(struct task_struct *task)
 {
 #ifdef CONFIG_IA32_EMULATION
diff --git a/arch/x86/kernel/sys_x86_64.c b/arch/x86/kernel/sys_x86_64.c
index 504fa5425bce..660b78827638 100644
--- a/arch/x86/kernel/sys_x86_64.c
+++ b/arch/x86/kernel/sys_x86_64.c
@@ -90,14 +90,10 @@ SYSCALL_DEFINE6(mmap, unsigned long, addr, unsigned long, len,
 		unsigned long, prot, unsigned long, flags,
 		unsigned long, fd, unsigned long, off)
 {
-	long error;
-	error = -EINVAL;
 	if (off & ~PAGE_MASK)
-		goto out;
+		return -EINVAL;
 
-	error = ksys_mmap_pgoff(addr, len, prot, flags, fd, off >> PAGE_SHIFT);
-out:
-	return error;
+	return ksys_mmap_pgoff(addr, len, prot, flags, fd, off >> PAGE_SHIFT);
 }
 
 static void find_start_end(unsigned long addr, unsigned long flags,
diff --git a/arch/x86/kernel/vm86_32.c b/arch/x86/kernel/vm86_32.c
index 764573de3996..e5a7a10a0164 100644
--- a/arch/x86/kernel/vm86_32.c
+++ b/arch/x86/kernel/vm86_32.c
@@ -134,7 +134,11 @@ void save_v86_state(struct kernel_vm86_regs *regs, int retval)
 	unsafe_put_user(regs->ds, &user->regs.ds, Efault_end);
 	unsafe_put_user(regs->fs, &user->regs.fs, Efault_end);
 	unsafe_put_user(regs->gs, &user->regs.gs, Efault_end);
-	unsafe_put_user(vm86->screen_bitmap, &user->screen_bitmap, Efault_end);
+
+	/*
+	 * Don't write screen_bitmap in case some user had a value there
+	 * and expected it to remain unchanged.
+	 */
 
 	user_access_end();
 
@@ -160,49 +164,6 @@ Efault:
 	do_exit(SIGSEGV);
 }
 
-static void mark_screen_rdonly(struct mm_struct *mm)
-{
-	struct vm_area_struct *vma;
-	spinlock_t *ptl;
-	pgd_t *pgd;
-	p4d_t *p4d;
-	pud_t *pud;
-	pmd_t *pmd;
-	pte_t *pte;
-	int i;
-
-	mmap_write_lock(mm);
-	pgd = pgd_offset(mm, 0xA0000);
-	if (pgd_none_or_clear_bad(pgd))
-		goto out;
-	p4d = p4d_offset(pgd, 0xA0000);
-	if (p4d_none_or_clear_bad(p4d))
-		goto out;
-	pud = pud_offset(p4d, 0xA0000);
-	if (pud_none_or_clear_bad(pud))
-		goto out;
-	pmd = pmd_offset(pud, 0xA0000);
-
-	if (pmd_trans_huge(*pmd)) {
-		vma = find_vma(mm, 0xA0000);
-		split_huge_pmd(vma, pmd, 0xA0000);
-	}
-	if (pmd_none_or_clear_bad(pmd))
-		goto out;
-	pte = pte_offset_map_lock(mm, pmd, 0xA0000, &ptl);
-	for (i = 0; i < 32; i++) {
-		if (pte_present(*pte))
-			set_pte(pte, pte_wrprotect(*pte));
-		pte++;
-	}
-	pte_unmap_unlock(pte, ptl);
-out:
-	mmap_write_unlock(mm);
-	flush_tlb_mm_range(mm, 0xA0000, 0xA0000 + 32*PAGE_SIZE, PAGE_SHIFT, false);
-}
-
-
-
 static int do_vm86_irq_handling(int subfunction, int irqnumber);
 static long do_sys_vm86(struct vm86plus_struct __user *user_vm86, bool plus);
 
@@ -282,6 +243,15 @@ static long do_sys_vm86(struct vm86plus_struct __user *user_vm86, bool plus)
 			offsetof(struct vm86_struct, int_revectored)))
 		return -EFAULT;
 
+
+	/* VM86_SCREEN_BITMAP had numerous bugs and appears to have no users. */
+	if (v.flags & VM86_SCREEN_BITMAP) {
+		char comm[TASK_COMM_LEN];
+
+		pr_info_once("vm86: '%s' uses VM86_SCREEN_BITMAP, which is no longer supported\n", get_task_comm(comm, current));
+		return -EINVAL;
+	}
+
 	memset(&vm86regs, 0, sizeof(vm86regs));
 
 	vm86regs.pt.bx = v.regs.ebx;
@@ -302,7 +272,6 @@ static long do_sys_vm86(struct vm86plus_struct __user *user_vm86, bool plus)
 	vm86regs.gs = v.regs.gs;
 
 	vm86->flags = v.flags;
-	vm86->screen_bitmap = v.screen_bitmap;
 	vm86->cpu_type = v.cpu_type;
 
 	if (copy_from_user(&vm86->int_revectored,
@@ -370,9 +339,6 @@ static long do_sys_vm86(struct vm86plus_struct __user *user_vm86, bool plus)
 	update_task_stack(tsk);
 	preempt_enable();
 
-	if (vm86->flags & VM86_SCREEN_BITMAP)
-		mark_screen_rdonly(tsk->mm);
-
 	memcpy((struct kernel_vm86_regs *)regs, &vm86regs, sizeof(vm86regs));
 	return regs->ax;
 }
diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
index 7b3a125e1e98..525197381baa 100644
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -282,25 +282,6 @@ void arch_sync_kernel_mappings(unsigned long start, unsigned long end)
 	}
 }
 
-/*
- * Did it hit the DOS screen memory VA from vm86 mode?
- */
-static inline void
-check_v8086_mode(struct pt_regs *regs, unsigned long address,
-		 struct task_struct *tsk)
-{
-#ifdef CONFIG_VM86
-	unsigned long bit;
-
-	if (!v8086_mode(regs) || !tsk->thread.vm86)
-		return;
-
-	bit = (address - 0xA0000) >> PAGE_SHIFT;
-	if (bit < 32)
-		tsk->thread.vm86->screen_bitmap |= 1 << bit;
-#endif
-}
-
 static bool low_pfn(unsigned long pfn)
 {
 	return pfn < max_low_pfn;
@@ -355,15 +336,6 @@ KERN_ERR
 "******* Disabling USB legacy in the BIOS may also help.\n";
 #endif
 
-/*
- * No vm86 mode in 64-bit mode:
- */
-static inline void
-check_v8086_mode(struct pt_regs *regs, unsigned long address,
-		 struct task_struct *tsk)
-{
-}
-
 static int bad_address(void *p)
 {
 	unsigned long dummy;
@@ -1465,8 +1437,6 @@ good_area:
 		else
 			BUG();
 	}
-
-	check_v8086_mode(regs, address, tsk);
 }
 NOKPROBE_SYMBOL(do_user_addr_fault);
 
diff --git a/arch/x86/mm/mmio-mod.c b/arch/x86/mm/mmio-mod.c
index bd7aff5c51f7..cd768dafca9e 100644
--- a/arch/x86/mm/mmio-mod.c
+++ b/arch/x86/mm/mmio-mod.c
@@ -10,8 +10,6 @@
 
 #define pr_fmt(fmt) "mmiotrace: " fmt
 
-#define DEBUG 1
-
 #include <linux/moduleparam.h>
 #include <linux/debugfs.h>
 #include <linux/slab.h>