Merge branch 'next' (accumulated 3.16 merge window patches) into master

Now that 3.15 is released, this merges the 'next' branch into 'master',
bringing us to the normal situation where my 'master' branch is the
merge window.

* accumulated work in next: (6809 commits)
  ufs: sb mutex merge + mutex_destroy
  powerpc: update comments for generic idle conversion
  cris: update comments for generic idle conversion
  idle: remove cpu_idle() forward declarations
  nbd: zero from and len fields in NBD_CMD_DISCONNECT.
  mm: convert some level-less printks to pr_*
  MAINTAINERS: adi-buildroot-devel is moderated
  MAINTAINERS: add linux-api for review of API/ABI changes
  mm/kmemleak-test.c: use pr_fmt for logging
  fs/dlm/debug_fs.c: replace seq_printf by seq_puts
  fs/dlm/lockspace.c: convert simple_str to kstr
  fs/dlm/config.c: convert simple_str to kstr
  mm: mark remap_file_pages() syscall as deprecated
  mm: memcontrol: remove unnecessary memcg argument from soft limit functions
  mm: memcontrol: clean up memcg zoneinfo lookup
  mm/memblock.c: call kmemleak directly from memblock_(alloc|free)
  mm/mempool.c: update the kmemleak stack trace for mempool allocations
  lib/radix-tree.c: update the kmemleak stack trace for radix tree allocations
  mm: introduce kmemleak_update_trace()
  mm/kmemleak.c: use %u to print ->checksum
  ...

1 files changed, 52 insertions, 41 deletions

diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index 205b17eed93c..e4e833d3d7d7 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -161,6 +161,7 @@
 #define Fastop      ((u64)1 << 44)  /* Use opcode::u.fastop */
 #define NoWrite     ((u64)1 << 45)  /* No writeback */
 #define SrcWrite    ((u64)1 << 46)  /* Write back src operand */
+#define NoMod	    ((u64)1 << 47)  /* Mod field is ignored */
 
 #define DstXacc     (DstAccLo | SrcAccHi | SrcWrite)
 
@@ -1077,7 +1078,7 @@ static int decode_modrm(struct x86_emulate_ctxt *ctxt,
 	ctxt->modrm_rm |= (ctxt->modrm & 0x07);
 	ctxt->modrm_seg = VCPU_SREG_DS;
 
-	if (ctxt->modrm_mod == 3) {
+	if (ctxt->modrm_mod == 3 || (ctxt->d & NoMod)) {
 		op->type = OP_REG;
 		op->bytes = (ctxt->d & ByteOp) ? 1 : ctxt->op_bytes;
 		op->addr.reg = decode_register(ctxt, ctxt->modrm_rm,
@@ -1324,7 +1325,8 @@ static int pio_in_emulated(struct x86_emulate_ctxt *ctxt,
 		rc->end = n * size;
 	}
 
-	if (ctxt->rep_prefix && !(ctxt->eflags & EFLG_DF)) {
+	if (ctxt->rep_prefix && (ctxt->d & String) &&
+	    !(ctxt->eflags & EFLG_DF)) {
 		ctxt->dst.data = rc->data + rc->pos;
 		ctxt->dst.type = OP_MEM_STR;
 		ctxt->dst.count = (rc->end - rc->pos) / size;
@@ -1409,11 +1411,11 @@ static int write_segment_descriptor(struct x86_emulate_ctxt *ctxt,
 }
 
 /* Does not support long mode */
-static int load_segment_descriptor(struct x86_emulate_ctxt *ctxt,
-				   u16 selector, int seg)
+static int __load_segment_descriptor(struct x86_emulate_ctxt *ctxt,
+				     u16 selector, int seg, u8 cpl, bool in_task_switch)
 {
 	struct desc_struct seg_desc, old_desc;
-	u8 dpl, rpl, cpl;
+	u8 dpl, rpl;
 	unsigned err_vec = GP_VECTOR;
 	u32 err_code = 0;
 	bool null_selector = !(selector & ~0x3); /* 0000-0003 are null */
@@ -1441,7 +1443,6 @@ static int load_segment_descriptor(struct x86_emulate_ctxt *ctxt,
 	}
 
 	rpl = selector & 3;
-	cpl = ctxt->ops->cpl(ctxt);
 
 	/* NULL selector is not valid for TR, CS and SS (except for long mode) */
 	if ((seg == VCPU_SREG_CS
@@ -1486,6 +1487,9 @@ static int load_segment_descriptor(struct x86_emulate_ctxt *ctxt,
 			goto exception;
 		break;
 	case VCPU_SREG_CS:
+		if (in_task_switch && rpl != dpl)
+			goto exception;
+
 		if (!(seg_desc.type & 8))
 			goto exception;
 
@@ -1543,6 +1547,13 @@ exception:
 	return X86EMUL_PROPAGATE_FAULT;
 }
 
+static int load_segment_descriptor(struct x86_emulate_ctxt *ctxt,
+				   u16 selector, int seg)
+{
+	u8 cpl = ctxt->ops->cpl(ctxt);
+	return __load_segment_descriptor(ctxt, selector, seg, cpl, false);
+}
+
 static void write_register_operand(struct operand *op)
 {
 	/* The 4-byte case *is* correct: in 64-bit mode we zero-extend. */
@@ -2404,6 +2415,7 @@ static int load_state_from_tss16(struct x86_emulate_ctxt *ctxt,
 				 struct tss_segment_16 *tss)
 {
 	int ret;
+	u8 cpl;
 
 	ctxt->_eip = tss->ip;
 	ctxt->eflags = tss->flag | 2;
@@ -2426,23 +2438,25 @@ static int load_state_from_tss16(struct x86_emulate_ctxt *ctxt,
 	set_segment_selector(ctxt, tss->ss, VCPU_SREG_SS);
 	set_segment_selector(ctxt, tss->ds, VCPU_SREG_DS);
 
+	cpl = tss->cs & 3;
+
 	/*
 	 * Now load segment descriptors. If fault happens at this stage
 	 * it is handled in a context of new task
 	 */
-	ret = load_segment_descriptor(ctxt, tss->ldt, VCPU_SREG_LDTR);
+	ret = __load_segment_descriptor(ctxt, tss->ldt, VCPU_SREG_LDTR, cpl, true);
 	if (ret != X86EMUL_CONTINUE)
 		return ret;
-	ret = load_segment_descriptor(ctxt, tss->es, VCPU_SREG_ES);
+	ret = __load_segment_descriptor(ctxt, tss->es, VCPU_SREG_ES, cpl, true);
 	if (ret != X86EMUL_CONTINUE)
 		return ret;
-	ret = load_segment_descriptor(ctxt, tss->cs, VCPU_SREG_CS);
+	ret = __load_segment_descriptor(ctxt, tss->cs, VCPU_SREG_CS, cpl, true);
 	if (ret != X86EMUL_CONTINUE)
 		return ret;
-	ret = load_segment_descriptor(ctxt, tss->ss, VCPU_SREG_SS);
+	ret = __load_segment_descriptor(ctxt, tss->ss, VCPU_SREG_SS, cpl, true);
 	if (ret != X86EMUL_CONTINUE)
 		return ret;
-	ret = load_segment_descriptor(ctxt, tss->ds, VCPU_SREG_DS);
+	ret = __load_segment_descriptor(ctxt, tss->ds, VCPU_SREG_DS, cpl, true);
 	if (ret != X86EMUL_CONTINUE)
 		return ret;
 
@@ -2496,7 +2510,7 @@ static int task_switch_16(struct x86_emulate_ctxt *ctxt,
 static void save_state_to_tss32(struct x86_emulate_ctxt *ctxt,
 				struct tss_segment_32 *tss)
 {
-	tss->cr3 = ctxt->ops->get_cr(ctxt, 3);
+	/* CR3 and ldt selector are not saved intentionally */
 	tss->eip = ctxt->_eip;
 	tss->eflags = ctxt->eflags;
 	tss->eax = reg_read(ctxt, VCPU_REGS_RAX);
@@ -2514,13 +2528,13 @@ static void save_state_to_tss32(struct x86_emulate_ctxt *ctxt,
 	tss->ds = get_segment_selector(ctxt, VCPU_SREG_DS);
 	tss->fs = get_segment_selector(ctxt, VCPU_SREG_FS);
 	tss->gs = get_segment_selector(ctxt, VCPU_SREG_GS);
-	tss->ldt_selector = get_segment_selector(ctxt, VCPU_SREG_LDTR);
 }
 
 static int load_state_from_tss32(struct x86_emulate_ctxt *ctxt,
 				 struct tss_segment_32 *tss)
 {
 	int ret;
+	u8 cpl;
 
 	if (ctxt->ops->set_cr(ctxt, 3, tss->cr3))
 		return emulate_gp(ctxt, 0);
@@ -2539,7 +2553,8 @@ static int load_state_from_tss32(struct x86_emulate_ctxt *ctxt,
 
 	/*
 	 * SDM says that segment selectors are loaded before segment
-	 * descriptors
+	 * descriptors.  This is important because CPL checks will
+	 * use CS.RPL.
 	 */
 	set_segment_selector(ctxt, tss->ldt_selector, VCPU_SREG_LDTR);
 	set_segment_selector(ctxt, tss->es, VCPU_SREG_ES);
@@ -2553,43 +2568,38 @@ static int load_state_from_tss32(struct x86_emulate_ctxt *ctxt,
 	 * If we're switching between Protected Mode and VM86, we need to make
 	 * sure to update the mode before loading the segment descriptors so
 	 * that the selectors are interpreted correctly.
-	 *
-	 * Need to get rflags to the vcpu struct immediately because it
-	 * influences the CPL which is checked at least when loading the segment
-	 * descriptors and when pushing an error code to the new kernel stack.
-	 *
-	 * TODO Introduce a separate ctxt->ops->set_cpl callback
 	 */
-	if (ctxt->eflags & X86_EFLAGS_VM)
+	if (ctxt->eflags & X86_EFLAGS_VM) {
 		ctxt->mode = X86EMUL_MODE_VM86;
-	else
+		cpl = 3;
+	} else {
 		ctxt->mode = X86EMUL_MODE_PROT32;
-
-	ctxt->ops->set_rflags(ctxt, ctxt->eflags);
+		cpl = tss->cs & 3;
+	}
 
 	/*
 	 * Now load segment descriptors. If fault happenes at this stage
 	 * it is handled in a context of new task
 	 */
-	ret = load_segment_descriptor(ctxt, tss->ldt_selector, VCPU_SREG_LDTR);
+	ret = __load_segment_descriptor(ctxt, tss->ldt_selector, VCPU_SREG_LDTR, cpl, true);
 	if (ret != X86EMUL_CONTINUE)
 		return ret;
-	ret = load_segment_descriptor(ctxt, tss->es, VCPU_SREG_ES);
+	ret = __load_segment_descriptor(ctxt, tss->es, VCPU_SREG_ES, cpl, true);
 	if (ret != X86EMUL_CONTINUE)
 		return ret;
-	ret = load_segment_descriptor(ctxt, tss->cs, VCPU_SREG_CS);
+	ret = __load_segment_descriptor(ctxt, tss->cs, VCPU_SREG_CS, cpl, true);
 	if (ret != X86EMUL_CONTINUE)
 		return ret;
-	ret = load_segment_descriptor(ctxt, tss->ss, VCPU_SREG_SS);
+	ret = __load_segment_descriptor(ctxt, tss->ss, VCPU_SREG_SS, cpl, true);
 	if (ret != X86EMUL_CONTINUE)
 		return ret;
-	ret = load_segment_descriptor(ctxt, tss->ds, VCPU_SREG_DS);
+	ret = __load_segment_descriptor(ctxt, tss->ds, VCPU_SREG_DS, cpl, true);
 	if (ret != X86EMUL_CONTINUE)
 		return ret;
-	ret = load_segment_descriptor(ctxt, tss->fs, VCPU_SREG_FS);
+	ret = __load_segment_descriptor(ctxt, tss->fs, VCPU_SREG_FS, cpl, true);
 	if (ret != X86EMUL_CONTINUE)
 		return ret;
-	ret = load_segment_descriptor(ctxt, tss->gs, VCPU_SREG_GS);
+	ret = __load_segment_descriptor(ctxt, tss->gs, VCPU_SREG_GS, cpl, true);
 	if (ret != X86EMUL_CONTINUE)
 		return ret;
 
@@ -2604,6 +2614,8 @@ static int task_switch_32(struct x86_emulate_ctxt *ctxt,
 	struct tss_segment_32 tss_seg;
 	int ret;
 	u32 new_tss_base = get_desc_base(new_desc);
+	u32 eip_offset = offsetof(struct tss_segment_32, eip);
+	u32 ldt_sel_offset = offsetof(struct tss_segment_32, ldt_selector);
 
 	ret = ops->read_std(ctxt, old_tss_base, &tss_seg, sizeof tss_seg,
 			    &ctxt->exception);
@@ -2613,8 +2625,9 @@ static int task_switch_32(struct x86_emulate_ctxt *ctxt,
 
 	save_state_to_tss32(ctxt, &tss_seg);
 
-	ret = ops->write_std(ctxt, old_tss_base, &tss_seg, sizeof tss_seg,
-			     &ctxt->exception);
+	/* Only GP registers and segment selectors are saved */
+	ret = ops->write_std(ctxt, old_tss_base + eip_offset, &tss_seg.eip,
+			     ldt_sel_offset - eip_offset, &ctxt->exception);
 	if (ret != X86EMUL_CONTINUE)
 		/* FIXME: need to provide precise fault address */
 		return ret;
@@ -3386,10 +3399,6 @@ static int check_cr_write(struct x86_emulate_ctxt *ctxt)
 		ctxt->ops->get_msr(ctxt, MSR_EFER, &efer);
 		if (efer & EFER_LMA)
 			rsvd = CR3_L_MODE_RESERVED_BITS;
-		else if (ctxt->ops->get_cr(ctxt, 4) & X86_CR4_PAE)
-			rsvd = CR3_PAE_RESERVED_BITS;
-		else if (ctxt->ops->get_cr(ctxt, 0) & X86_CR0_PG)
-			rsvd = CR3_NONPAE_RESERVED_BITS;
 
 		if (new_val & rsvd)
 			return emulate_gp(ctxt, 0);
@@ -3869,10 +3878,12 @@ static const struct opcode twobyte_table[256] = {
 	N, N, N, N, N, N, N, N,
 	D(ImplicitOps | ModRM), N, N, N, N, N, N, D(ImplicitOps | ModRM),
 	/* 0x20 - 0x2F */
-	DIP(ModRM | DstMem | Priv | Op3264, cr_read, check_cr_read),
-	DIP(ModRM | DstMem | Priv | Op3264, dr_read, check_dr_read),
-	IIP(ModRM | SrcMem | Priv | Op3264, em_cr_write, cr_write, check_cr_write),
-	IIP(ModRM | SrcMem | Priv | Op3264, em_dr_write, dr_write, check_dr_write),
+	DIP(ModRM | DstMem | Priv | Op3264 | NoMod, cr_read, check_cr_read),
+	DIP(ModRM | DstMem | Priv | Op3264 | NoMod, dr_read, check_dr_read),
+	IIP(ModRM | SrcMem | Priv | Op3264 | NoMod, em_cr_write, cr_write,
+						check_cr_write),
+	IIP(ModRM | SrcMem | Priv | Op3264 | NoMod, em_dr_write, dr_write,
+						check_dr_write),
 	N, N, N, N,
 	GP(ModRM | DstReg | SrcMem | Mov | Sse, &pfx_0f_28_0f_29),
 	GP(ModRM | DstMem | SrcReg | Mov | Sse, &pfx_0f_28_0f_29),