1 files changed, 177 insertions, 56 deletions

diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index 1962008fe743..52a5c03c353c 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -39,6 +39,7 @@
 #include <linux/io.h>
 #include <linux/ftrace.h>
 #include <linux/syscalls.h>
+#include <linux/iommu.h>
 
 #include <asm/processor.h>
 #include <asm/pkru.h>
@@ -55,6 +56,8 @@
 #include <asm/resctrl.h>
 #include <asm/unistd.h>
 #include <asm/fsgsbase.h>
+#include <asm/fred.h>
+#include <asm/msr.h>
 #ifdef CONFIG_IA32_EMULATION
 /* Not included via unistd.h */
 #include <asm/unistd_32_ia32.h>
@@ -93,8 +96,8 @@ void __show_regs(struct pt_regs *regs, enum show_regs_mode mode,
 		return;
 
 	if (mode == SHOW_REGS_USER) {
-		rdmsrl(MSR_FS_BASE, fs);
-		rdmsrl(MSR_KERNEL_GS_BASE, shadowgs);
+		rdmsrq(MSR_FS_BASE, fs);
+		rdmsrq(MSR_KERNEL_GS_BASE, shadowgs);
 		printk("%sFS:  %016lx GS:  %016lx\n",
 		       log_lvl, fs, shadowgs);
 		return;
@@ -105,9 +108,9 @@ void __show_regs(struct pt_regs *regs, enum show_regs_mode mode,
 	asm("movl %%fs,%0" : "=r" (fsindex));
 	asm("movl %%gs,%0" : "=r" (gsindex));
 
-	rdmsrl(MSR_FS_BASE, fs);
-	rdmsrl(MSR_GS_BASE, gs);
-	rdmsrl(MSR_KERNEL_GS_BASE, shadowgs);
+	rdmsrq(MSR_FS_BASE, fs);
+	rdmsrq(MSR_GS_BASE, gs);
+	rdmsrq(MSR_KERNEL_GS_BASE, shadowgs);
 
 	cr0 = read_cr0();
 	cr2 = read_cr2();
@@ -116,7 +119,7 @@ void __show_regs(struct pt_regs *regs, enum show_regs_mode mode,
 
 	printk("%sFS:  %016lx(%04x) GS:%016lx(%04x) knlGS:%016lx\n",
 	       log_lvl, fs, fsindex, gs, gsindex, shadowgs);
-	printk("%sCS:  %04lx DS: %04x ES: %04x CR0: %016lx\n",
+	printk("%sCS:  %04x DS: %04x ES: %04x CR0: %016lx\n",
 		log_lvl, regs->cs, ds, es, cr0);
 	printk("%sCR2: %016lx CR3: %016lx CR4: %016lx\n",
 		log_lvl, cr2, cr3, cr4);
@@ -130,14 +133,14 @@ void __show_regs(struct pt_regs *regs, enum show_regs_mode mode,
 
 	/* Only print out debug registers if they are in their non-default state. */
 	if (!((d0 == 0) && (d1 == 0) && (d2 == 0) && (d3 == 0) &&
-	    (d6 == DR6_RESERVED) && (d7 == 0x400))) {
+	    (d6 == DR6_RESERVED) && (d7 == DR7_FIXED_1))) {
 		printk("%sDR0: %016lx DR1: %016lx DR2: %016lx\n",
 		       log_lvl, d0, d1, d2);
 		printk("%sDR3: %016lx DR6: %016lx DR7: %016lx\n",
 		       log_lvl, d3, d6, d7);
 	}
 
-	if (cpu_feature_enabled(X86_FEATURE_OSPKE))
+	if (cr4 & X86_CR4_PKE)
 		printk("%sPKRU: %08x\n", log_lvl, read_pkru());
 }
 
@@ -165,13 +168,35 @@ static noinstr unsigned long __rdgsbase_inactive(void)
 
 	lockdep_assert_irqs_disabled();
 
-	if (!static_cpu_has(X86_FEATURE_XENPV)) {
+	/*
+	 * SWAPGS is no longer needed thus NOT allowed with FRED because
+	 * FRED transitions ensure that an operating system can _always_
+	 * operate with its own GS base address:
+	 * - For events that occur in ring 3, FRED event delivery swaps
+	 *   the GS base address with the IA32_KERNEL_GS_BASE MSR.
+	 * - ERETU (the FRED transition that returns to ring 3) also swaps
+	 *   the GS base address with the IA32_KERNEL_GS_BASE MSR.
+	 *
+	 * And the operating system can still setup the GS segment for a
+	 * user thread without the need of loading a user thread GS with:
+	 * - Using LKGS, available with FRED, to modify other attributes
+	 *   of the GS segment without compromising its ability always to
+	 *   operate with its own GS base address.
+	 * - Accessing the GS segment base address for a user thread as
+	 *   before using RDMSR or WRMSR on the IA32_KERNEL_GS_BASE MSR.
+	 *
+	 * Note, LKGS loads the GS base address into the IA32_KERNEL_GS_BASE
+	 * MSR instead of the GS segment’s descriptor cache. As such, the
+	 * operating system never changes its runtime GS base address.
+	 */
+	if (!cpu_feature_enabled(X86_FEATURE_FRED) &&
+	    !cpu_feature_enabled(X86_FEATURE_XENPV)) {
 		native_swapgs();
 		gsbase = rdgsbase();
 		native_swapgs();
 	} else {
 		instrumentation_begin();
-		rdmsrl(MSR_KERNEL_GS_BASE, gsbase);
+		rdmsrq(MSR_KERNEL_GS_BASE, gsbase);
 		instrumentation_end();
 	}
 
@@ -190,13 +215,14 @@ static noinstr void __wrgsbase_inactive(unsigned long gsbase)
 {
 	lockdep_assert_irqs_disabled();
 
-	if (!static_cpu_has(X86_FEATURE_XENPV)) {
+	if (!cpu_feature_enabled(X86_FEATURE_FRED) &&
+	    !cpu_feature_enabled(X86_FEATURE_XENPV)) {
 		native_swapgs();
 		wrgsbase(gsbase);
 		native_swapgs();
 	} else {
 		instrumentation_begin();
-		wrmsrl(MSR_KERNEL_GS_BASE, gsbase);
+		wrmsrq(MSR_KERNEL_GS_BASE, gsbase);
 		instrumentation_end();
 	}
 }
@@ -328,7 +354,7 @@ static __always_inline void load_seg_legacy(unsigned short prev_index,
 		} else {
 			if (prev_index != next_index)
 				loadseg(which, next_index);
-			wrmsrl(which == FS ? MSR_FS_BASE : MSR_KERNEL_GS_BASE,
+			wrmsrq(which == FS ? MSR_FS_BASE : MSR_KERNEL_GS_BASE,
 			       next_base);
 		}
 	} else {
@@ -438,7 +464,7 @@ unsigned long x86_gsbase_read_cpu_inactive(void)
 		gsbase = __rdgsbase_inactive();
 		local_irq_restore(flags);
 	} else {
-		rdmsrl(MSR_KERNEL_GS_BASE, gsbase);
+		rdmsrq(MSR_KERNEL_GS_BASE, gsbase);
 	}
 
 	return gsbase;
@@ -453,7 +479,7 @@ void x86_gsbase_write_cpu_inactive(unsigned long gsbase)
 		__wrgsbase_inactive(gsbase);
 		local_irq_restore(flags);
 	} else {
-		wrmsrl(MSR_KERNEL_GS_BASE, gsbase);
+		wrmsrq(MSR_KERNEL_GS_BASE, gsbase);
 	}
 }
 
@@ -504,7 +530,7 @@ void x86_gsbase_write_task(struct task_struct *task, unsigned long gsbase)
 static void
 start_thread_common(struct pt_regs *regs, unsigned long new_ip,
 		    unsigned long new_sp,
-		    unsigned int _cs, unsigned int _ss, unsigned int _ds)
+		    u16 _cs, u16 _ss, u16 _ds)
 {
 	WARN_ON_ONCE(regs != current_pt_regs());
 
@@ -514,16 +540,43 @@ start_thread_common(struct pt_regs *regs, unsigned long new_ip,
 		load_gs_index(__USER_DS);
 	}
 
+	reset_thread_features();
+
 	loadsegment(fs, 0);
 	loadsegment(es, _ds);
 	loadsegment(ds, _ds);
 	load_gs_index(0);
 
-	regs->ip		= new_ip;
-	regs->sp		= new_sp;
-	regs->cs		= _cs;
-	regs->ss		= _ss;
-	regs->flags		= X86_EFLAGS_IF;
+	regs->ip	= new_ip;
+	regs->sp	= new_sp;
+	regs->csx	= _cs;
+	regs->ssx	= _ss;
+	/*
+	 * Allow single-step trap and NMI when starting a new task, thus
+	 * once the new task enters user space, single-step trap and NMI
+	 * are both enabled immediately.
+	 *
+	 * Entering a new task is logically speaking a return from a
+	 * system call (exec, fork, clone, etc.). As such, if ptrace
+	 * enables single stepping a single step exception should be
+	 * allowed to trigger immediately upon entering user space.
+	 * This is not optional.
+	 *
+	 * NMI should *never* be disabled in user space. As such, this
+	 * is an optional, opportunistic way to catch errors.
+	 *
+	 * Paranoia: High-order 48 bits above the lowest 16 bit SS are
+	 * discarded by the legacy IRET instruction on all Intel, AMD,
+	 * and Cyrix/Centaur/VIA CPUs, thus can be set unconditionally,
+	 * even when FRED is not enabled. But we choose the safer side
+	 * to use these bits only when FRED is enabled.
+	 */
+	if (cpu_feature_enabled(X86_FEATURE_FRED)) {
+		regs->fred_ss.swevent	= true;
+		regs->fred_ss.nmi	= true;
+	}
+
+	regs->flags	= X86_EFLAGS_IF | X86_EFLAGS_FIXED;
 }
 
 void
@@ -553,19 +606,18 @@ void compat_start_thread(struct pt_regs *regs, u32 new_ip, u32 new_sp, bool x32)
  * Kprobes not supported here. Set the probe on schedule instead.
  * Function graph tracer not supported too.
  */
+__no_kmsan_checks
 __visible __notrace_funcgraph struct task_struct *
 __switch_to(struct task_struct *prev_p, struct task_struct *next_p)
 {
 	struct thread_struct *prev = &prev_p->thread;
 	struct thread_struct *next = &next_p->thread;
-	struct fpu *prev_fpu = &prev->fpu;
 	int cpu = smp_processor_id();
 
 	WARN_ON_ONCE(IS_ENABLED(CONFIG_DEBUG_ENTRY) &&
 		     this_cpu_read(hardirq_stack_inuse));
 
-	if (!test_thread_flag(TIF_NEED_FPU_LOAD))
-		switch_fpu_prepare(prev_fpu, cpu);
+	switch_fpu(prev_p, cpu);
 
 	/* We must save %fs and %gs before load_TLS() because
 	 * %fs and %gs may be cleared by load_TLS().
@@ -616,10 +668,8 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p)
 	/*
 	 * Switch the PDA and FPU contexts.
 	 */
-	this_cpu_write(current_task, next_p);
-	this_cpu_write(cpu_current_top_of_stack, task_top_of_stack(next_p));
-
-	switch_fpu_finish();
+	raw_cpu_write(current_task, next_p);
+	raw_cpu_write(cpu_current_top_of_stack, task_top_of_stack(next_p));
 
 	/* Reload sp0. */
 	update_task_stack(next_p);
@@ -655,7 +705,11 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p)
 	}
 
 	/* Load the Intel cache allocation PQR MSR. */
-	resctrl_sched_in();
+	resctrl_arch_sched_in(next_p);
+
+	/* Reset hw history on AMD CPUs */
+	if (cpu_feature_enabled(X86_FEATURE_AMD_WORKLOAD_CLASS))
+		wrmsrl(MSR_AMD_WORKLOAD_HRST, 0x1);
 
 	return prev_p;
 }
@@ -670,7 +724,7 @@ void set_personality_64bit(void)
 	task_pt_regs(current)->orig_ax = __NR_execve;
 	current_thread_info()->status &= ~TS_COMPAT;
 	if (current->mm)
-		current->mm->context.flags = MM_CONTEXT_HAS_VSYSCALL;
+		__set_bit(MM_CONTEXT_HAS_VSYSCALL, &current->mm->context.flags);
 
 	/* TBD: overwrites user setup. Should have two bits.
 	   But 64bit processes have always behaved this way,
@@ -707,7 +761,7 @@ static void __set_personality_ia32(void)
 		 * uprobes applied to this MM need to know this and
 		 * cannot use user_64bit_mode() at that time.
 		 */
-		current->mm->context.flags = MM_CONTEXT_UPROBE_IA32;
+		__set_bit(MM_CONTEXT_UPROBE_IA32, &current->mm->context.flags);
 	}
 
 	current->personality |= force_personality32;
@@ -742,6 +796,74 @@ static long prctl_map_vdso(const struct vdso_image *image, unsigned long addr)
 }
 #endif
 
+#ifdef CONFIG_ADDRESS_MASKING
+
+#define LAM_U57_BITS 6
+
+static void enable_lam_func(void *__mm)
+{
+	struct mm_struct *mm = __mm;
+	unsigned long lam;
+
+	if (this_cpu_read(cpu_tlbstate.loaded_mm) == mm) {
+		lam = mm_lam_cr3_mask(mm);
+		write_cr3(__read_cr3() | lam);
+		cpu_tlbstate_update_lam(lam, mm_untag_mask(mm));
+	}
+}
+
+static void mm_enable_lam(struct mm_struct *mm)
+{
+	mm->context.lam_cr3_mask = X86_CR3_LAM_U57;
+	mm->context.untag_mask =  ~GENMASK(62, 57);
+
+	/*
+	 * Even though the process must still be single-threaded at this
+	 * point, kernel threads may be using the mm.  IPI those kernel
+	 * threads if they exist.
+	 */
+	on_each_cpu_mask(mm_cpumask(mm), enable_lam_func, mm, true);
+	set_bit(MM_CONTEXT_LOCK_LAM, &mm->context.flags);
+}
+
+static int prctl_enable_tagged_addr(struct mm_struct *mm, unsigned long nr_bits)
+{
+	if (!cpu_feature_enabled(X86_FEATURE_LAM))
+		return -ENODEV;
+
+	/* PTRACE_ARCH_PRCTL */
+	if (current->mm != mm)
+		return -EINVAL;
+
+	if (mm_valid_pasid(mm) &&
+	    !test_bit(MM_CONTEXT_FORCE_TAGGED_SVA, &mm->context.flags))
+		return -EINVAL;
+
+	if (mmap_write_lock_killable(mm))
+		return -EINTR;
+
+	/*
+	 * MM_CONTEXT_LOCK_LAM is set on clone.  Prevent LAM from
+	 * being enabled unless the process is single threaded:
+	 */
+	if (test_bit(MM_CONTEXT_LOCK_LAM, &mm->context.flags)) {
+		mmap_write_unlock(mm);
+		return -EBUSY;
+	}
+
+	if (!nr_bits || nr_bits > LAM_U57_BITS) {
+		mmap_write_unlock(mm);
+		return -EINVAL;
+	}
+
+	mm_enable_lam(mm);
+
+	mmap_write_unlock(mm);
+
+	return 0;
+}
+#endif
+
 long do_arch_prctl_64(struct task_struct *task, int option, unsigned long arg2)
 {
 	int ret = 0;
@@ -822,14 +944,36 @@ long do_arch_prctl_64(struct task_struct *task, int option, unsigned long arg2)
 	case ARCH_MAP_VDSO_X32:
 		return prctl_map_vdso(&vdso_image_x32, arg2);
 # endif
-# if defined CONFIG_X86_32 || defined CONFIG_IA32_EMULATION
+# ifdef CONFIG_IA32_EMULATION
 	case ARCH_MAP_VDSO_32:
 		return prctl_map_vdso(&vdso_image_32, arg2);
 # endif
 	case ARCH_MAP_VDSO_64:
 		return prctl_map_vdso(&vdso_image_64, arg2);
 #endif
-
+#ifdef CONFIG_ADDRESS_MASKING
+	case ARCH_GET_UNTAG_MASK:
+		return put_user(task->mm->context.untag_mask,
+				(unsigned long __user *)arg2);
+	case ARCH_ENABLE_TAGGED_ADDR:
+		return prctl_enable_tagged_addr(task->mm, arg2);
+	case ARCH_FORCE_TAGGED_SVA:
+		if (current != task)
+			return -EINVAL;
+		set_bit(MM_CONTEXT_FORCE_TAGGED_SVA, &task->mm->context.flags);
+		return 0;
+	case ARCH_GET_MAX_TAG_BITS:
+		if (!cpu_feature_enabled(X86_FEATURE_LAM))
+			return put_user(0, (unsigned long __user *)arg2);
+		else
+			return put_user(LAM_U57_BITS, (unsigned long __user *)arg2);
+#endif
+	case ARCH_SHSTK_ENABLE:
+	case ARCH_SHSTK_DISABLE:
+	case ARCH_SHSTK_LOCK:
+	case ARCH_SHSTK_UNLOCK:
+	case ARCH_SHSTK_STATUS:
+		return shstk_prctl(task, option, arg2);
 	default:
 		ret = -EINVAL;
 		break;
@@ -837,26 +981,3 @@ long do_arch_prctl_64(struct task_struct *task, int option, unsigned long arg2)
 
 	return ret;
 }
-
-SYSCALL_DEFINE2(arch_prctl, int, option, unsigned long, arg2)
-{
-	long ret;
-
-	ret = do_arch_prctl_64(current, option, arg2);
-	if (ret == -EINVAL)
-		ret = do_arch_prctl_common(option, arg2);
-
-	return ret;
-}
-
-#ifdef CONFIG_IA32_EMULATION
-COMPAT_SYSCALL_DEFINE2(arch_prctl, int, option, unsigned long, arg2)
-{
-	return do_arch_prctl_common(option, arg2);
-}
-#endif
-
-unsigned long KSTK_ESP(struct task_struct *task)
-{
-	return task_pt_regs(task)->sp;
-}