Merge branch 'linus' into tracing/core

Conflicts:
	kernel/trace/trace_events_filter.c

We use the tracing/core version.

Signed-off-by: Ingo Molnar <mingo@elte.hu>

2 files changed, 260 insertions, 136 deletions

diff --git a/drivers/lguest/x86/core.c b/drivers/lguest/x86/core.c
index eaf722fe309a..6ae388849a3b 100644
--- a/drivers/lguest/x86/core.c
+++ b/drivers/lguest/x86/core.c
@@ -17,13 +17,15 @@
  * along with this program; if not, write to the Free Software
  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  */
-/*P:450 This file contains the x86-specific lguest code.  It used to be all
+/*P:450
+ * This file contains the x86-specific lguest code.  It used to be all
  * mixed in with drivers/lguest/core.c but several foolhardy code slashers
  * wrestled most of the dependencies out to here in preparation for porting
  * lguest to other architectures (see what I mean by foolhardy?).
  *
  * This also contains a couple of non-obvious setup and teardown pieces which
- * were implemented after days of debugging pain. :*/
+ * were implemented after days of debugging pain.
+:*/
 #include <linux/kernel.h>
 #include <linux/start_kernel.h>
 #include <linux/string.h>
@@ -82,25 +84,33 @@ static DEFINE_PER_CPU(struct lg_cpu *, last_cpu);
  */
 static void copy_in_guest_info(struct lg_cpu *cpu, struct lguest_pages *pages)
 {
-	/* Copying all this data can be quite expensive.  We usually run the
+	/*
+	 * Copying all this data can be quite expensive.  We usually run the
 	 * same Guest we ran last time (and that Guest hasn't run anywhere else
 	 * meanwhile).  If that's not the case, we pretend everything in the
-	 * Guest has changed. */
+	 * Guest has changed.
+	 */
 	if (__get_cpu_var(last_cpu) != cpu || cpu->last_pages != pages) {
 		__get_cpu_var(last_cpu) = cpu;
 		cpu->last_pages = pages;
 		cpu->changed = CHANGED_ALL;
 	}
 
-	/* These copies are pretty cheap, so we do them unconditionally: */
-	/* Save the current Host top-level page directory. */
+	/*
+	 * These copies are pretty cheap, so we do them unconditionally: */
+	/* Save the current Host top-level page directory.
+	 */
 	pages->state.host_cr3 = __pa(current->mm->pgd);
-	/* Set up the Guest's page tables to see this CPU's pages (and no
-	 * other CPU's pages). */
+	/*
+	 * Set up the Guest's page tables to see this CPU's pages (and no
+	 * other CPU's pages).
+	 */
 	map_switcher_in_guest(cpu, pages);
-	/* Set up the two "TSS" members which tell the CPU what stack to use
+	/*
+	 * Set up the two "TSS" members which tell the CPU what stack to use
 	 * for traps which do directly into the Guest (ie. traps at privilege
-	 * level 1). */
+	 * level 1).
+	 */
 	pages->state.guest_tss.sp1 = cpu->esp1;
 	pages->state.guest_tss.ss1 = cpu->ss1;
 
@@ -125,97 +135,126 @@ static void run_guest_once(struct lg_cpu *cpu, struct lguest_pages *pages)
 	/* This is a dummy value we need for GCC's sake. */
 	unsigned int clobber;
 
-	/* Copy the guest-specific information into this CPU's "struct
-	 * lguest_pages". */
+	/*
+	 * Copy the guest-specific information into this CPU's "struct
+	 * lguest_pages".
+	 */
 	copy_in_guest_info(cpu, pages);
 
-	/* Set the trap number to 256 (impossible value).  If we fault while
+	/*
+	 * Set the trap number to 256 (impossible value).  If we fault while
 	 * switching to the Guest (bad segment registers or bug), this will
-	 * cause us to abort the Guest. */
+	 * cause us to abort the Guest.
+	 */
 	cpu->regs->trapnum = 256;
 
-	/* Now: we push the "eflags" register on the stack, then do an "lcall".
+	/*
+	 * Now: we push the "eflags" register on the stack, then do an "lcall".
 	 * This is how we change from using the kernel code segment to using
 	 * the dedicated lguest code segment, as well as jumping into the
 	 * Switcher.
 	 *
 	 * The lcall also pushes the old code segment (KERNEL_CS) onto the
 	 * stack, then the address of this call.  This stack layout happens to
-	 * exactly match the stack layout created by an interrupt... */
+	 * exactly match the stack layout created by an interrupt...
+	 */
 	asm volatile("pushf; lcall *lguest_entry"
-		     /* This is how we tell GCC that %eax ("a") and %ebx ("b")
-		      * are changed by this routine.  The "=" means output. */
+		     /*
+		      * This is how we tell GCC that %eax ("a") and %ebx ("b")
+		      * are changed by this routine.  The "=" means output.
+		      */
 		     : "=a"(clobber), "=b"(clobber)
-		     /* %eax contains the pages pointer.  ("0" refers to the
+		     /*
+		      * %eax contains the pages pointer.  ("0" refers to the
 		      * 0-th argument above, ie "a").  %ebx contains the
 		      * physical address of the Guest's top-level page
-		      * directory. */
+		      * directory.
+		      */
 		     : "0"(pages), "1"(__pa(cpu->lg->pgdirs[cpu->cpu_pgd].pgdir))
-		     /* We tell gcc that all these registers could change,
+		     /*
+		      * We tell gcc that all these registers could change,
 		      * which means we don't have to save and restore them in
-		      * the Switcher. */
+		      * the Switcher.
+		      */
 		     : "memory", "%edx", "%ecx", "%edi", "%esi");
 }
 /*:*/
 
-/*M:002 There are hooks in the scheduler which we can register to tell when we
+/*M:002
+ * There are hooks in the scheduler which we can register to tell when we
  * get kicked off the CPU (preempt_notifier_register()).  This would allow us
  * to lazily disable SYSENTER which would regain some performance, and should
  * also simplify copy_in_guest_info().  Note that we'd still need to restore
  * things when we exit to Launcher userspace, but that's fairly easy.
  *
- * We could also try using this hooks for PGE, but that might be too expensive.
+ * We could also try using these hooks for PGE, but that might be too expensive.
  *
- * The hooks were designed for KVM, but we can also put them to good use. :*/
+ * The hooks were designed for KVM, but we can also put them to good use.
+:*/
 
-/*H:040 This is the i386-specific code to setup and run the Guest.  Interrupts
- * are disabled: we own the CPU. */
+/*H:040
+ * This is the i386-specific code to setup and run the Guest.  Interrupts
+ * are disabled: we own the CPU.
+ */
 void lguest_arch_run_guest(struct lg_cpu *cpu)
 {
-	/* Remember the awfully-named TS bit?  If the Guest has asked to set it
+	/*
+	 * Remember the awfully-named TS bit?  If the Guest has asked to set it
 	 * we set it now, so we can trap and pass that trap to the Guest if it
-	 * uses the FPU. */
+	 * uses the FPU.
+	 */
 	if (cpu->ts)
 		unlazy_fpu(current);
 
-	/* SYSENTER is an optimized way of doing system calls.  We can't allow
+	/*
+	 * SYSENTER is an optimized way of doing system calls.  We can't allow
 	 * it because it always jumps to privilege level 0.  A normal Guest
 	 * won't try it because we don't advertise it in CPUID, but a malicious
 	 * Guest (or malicious Guest userspace program) could, so we tell the
-	 * CPU to disable it before running the Guest. */
+	 * CPU to disable it before running the Guest.
+	 */
 	if (boot_cpu_has(X86_FEATURE_SEP))
 		wrmsr(MSR_IA32_SYSENTER_CS, 0, 0);
 
-	/* Now we actually run the Guest.  It will return when something
+	/*
+	 * Now we actually run the Guest.  It will return when something
 	 * interesting happens, and we can examine its registers to see what it
-	 * was doing. */
+	 * was doing.
+	 */
 	run_guest_once(cpu, lguest_pages(raw_smp_processor_id()));
 
-	/* Note that the "regs" structure contains two extra entries which are
+	/*
+	 * Note that the "regs" structure contains two extra entries which are
 	 * not really registers: a trap number which says what interrupt or
 	 * trap made the switcher code come back, and an error code which some
-	 * traps set.  */
+	 * traps set.
+	 */
 
 	 /* Restore SYSENTER if it's supposed to be on. */
 	 if (boot_cpu_has(X86_FEATURE_SEP))
 		wrmsr(MSR_IA32_SYSENTER_CS, __KERNEL_CS, 0);
 
-	/* If the Guest page faulted, then the cr2 register will tell us the
+	/*
+	 * If the Guest page faulted, then the cr2 register will tell us the
 	 * bad virtual address.  We have to grab this now, because once we
 	 * re-enable interrupts an interrupt could fault and thus overwrite
-	 * cr2, or we could even move off to a different CPU. */
+	 * cr2, or we could even move off to a different CPU.
+	 */
 	if (cpu->regs->trapnum == 14)
 		cpu->arch.last_pagefault = read_cr2();
-	/* Similarly, if we took a trap because the Guest used the FPU,
+	/*
+	 * Similarly, if we took a trap because the Guest used the FPU,
 	 * we have to restore the FPU it expects to see.
 	 * math_state_restore() may sleep and we may even move off to
 	 * a different CPU. So all the critical stuff should be done
-	 * before this.  */
+	 * before this.
+	 */
 	else if (cpu->regs->trapnum == 7)
 		math_state_restore();
 }
 
-/*H:130 Now we've examined the hypercall code; our Guest can make requests.
+/*H:130
+ * Now we've examined the hypercall code; our Guest can make requests.
  * Our Guest is usually so well behaved; it never tries to do things it isn't
  * allowed to, and uses hypercalls instead.  Unfortunately, Linux's paravirtual
  * infrastructure isn't quite complete, because it doesn't contain replacements
@@ -225,26 +264,33 @@ void lguest_arch_run_guest(struct lg_cpu *cpu)
  *
  * When the Guest uses one of these instructions, we get a trap (General
  * Protection Fault) and come here.  We see if it's one of those troublesome
- * instructions and skip over it.  We return true if we did. */
+ * instructions and skip over it.  We return true if we did.
+ */
 static int emulate_insn(struct lg_cpu *cpu)
 {
 	u8 insn;
 	unsigned int insnlen = 0, in = 0, shift = 0;
-	/* The eip contains the *virtual* address of the Guest's instruction:
-	 * guest_pa just subtracts the Guest's page_offset. */
+	/*
+	 * The eip contains the *virtual* address of the Guest's instruction:
+	 * guest_pa just subtracts the Guest's page_offset.
+	 */
 	unsigned long physaddr = guest_pa(cpu, cpu->regs->eip);
 
-	/* This must be the Guest kernel trying to do something, not userspace!
+	/*
+	 * This must be the Guest kernel trying to do something, not userspace!
 	 * The bottom two bits of the CS segment register are the privilege
-	 * level. */
+	 * level.
+	 */
 	if ((cpu->regs->cs & 3) != GUEST_PL)
 		return 0;
 
 	/* Decoding x86 instructions is icky. */
 	insn = lgread(cpu, physaddr, u8);
 
-	/* 0x66 is an "operand prefix".  It means it's using the upper 16 bits
-	   of the eax register. */
+	/*
+	 * 0x66 is an "operand prefix".  It means it's using the upper 16 bits
+	 * of the eax register.
+	 */
 	if (insn == 0x66) {
 		shift = 16;
 		/* The instruction is 1 byte so far, read the next byte. */
@@ -252,8 +298,10 @@ static int emulate_insn(struct lg_cpu *cpu)
 		insn = lgread(cpu, physaddr + insnlen, u8);
 	}
 
-	/* We can ignore the lower bit for the moment and decode the 4 opcodes
-	 * we need to emulate. */
+	/*
+	 * We can ignore the lower bit for the moment and decode the 4 opcodes
+	 * we need to emulate.
+	 */
 	switch (insn & 0xFE) {
 	case 0xE4: /* in     <next byte>,%al */
 		insnlen += 2;
@@ -274,9 +322,11 @@ static int emulate_insn(struct lg_cpu *cpu)
 		return 0;
 	}
 
-	/* If it was an "IN" instruction, they expect the result to be read
+	/*
+	 * If it was an "IN" instruction, they expect the result to be read
 	 * into %eax, so we change %eax.  We always return all-ones, which
-	 * traditionally means "there's nothing there". */
+	 * traditionally means "there's nothing there".
+	 */
 	if (in) {
 		/* Lower bit tells is whether it's a 16 or 32 bit access */
 		if (insn & 0x1)
@@ -290,7 +340,8 @@ static int emulate_insn(struct lg_cpu *cpu)
 	return 1;
 }
 
-/* Our hypercalls mechanism used to be based on direct software interrupts.
+/*
+ * Our hypercalls mechanism used to be based on direct software interrupts.
  * After Anthony's "Refactor hypercall infrastructure" kvm patch, we decided to
  * change over to using kvm hypercalls.
  *
@@ -318,16 +369,20 @@ static int emulate_insn(struct lg_cpu *cpu)
  */
 static void rewrite_hypercall(struct lg_cpu *cpu)
 {
-	/* This are the opcodes we use to patch the Guest.  The opcode for "int
+	/*
+	 * This are the opcodes we use to patch the Guest.  The opcode for "int
 	 * $0x1f" is "0xcd 0x1f" but vmcall instruction is 3 bytes long, so we
-	 * complete the sequence with a NOP (0x90). */
+	 * complete the sequence with a NOP (0x90).
+	 */
 	u8 insn[3] = {0xcd, 0x1f, 0x90};
 
 	__lgwrite(cpu, guest_pa(cpu, cpu->regs->eip), insn, sizeof(insn));
-	/* The above write might have caused a copy of that page to be made
+	/*
+	 * The above write might have caused a copy of that page to be made
 	 * (if it was read-only).  We need to make sure the Guest has
 	 * up-to-date pagetables.  As this doesn't happen often, we can just
-	 * drop them all. */
+	 * drop them all.
+	 */
 	guest_pagetable_clear_all(cpu);
 }
 
@@ -335,9 +390,11 @@ static bool is_hypercall(struct lg_cpu *cpu)
 {
 	u8 insn[3];
 
-	/* This must be the Guest kernel trying to do something.
+	/*
+	 * This must be the Guest kernel trying to do something.
 	 * The bottom two bits of the CS segment register are the privilege
-	 * level. */
+	 * level.
+	 */
 	if ((cpu->regs->cs & 3) != GUEST_PL)
 		return false;
 
@@ -351,86 +408,105 @@ void lguest_arch_handle_trap(struct lg_cpu *cpu)
 {
 	switch (cpu->regs->trapnum) {
 	case 13: /* We've intercepted a General Protection Fault. */
-		/* Check if this was one of those annoying IN or OUT
+		/*
+		 * Check if this was one of those annoying IN or OUT
 		 * instructions which we need to emulate.  If so, we just go
-		 * back into the Guest after we've done it. */
+		 * back into the Guest after we've done it.
+		 */
 		if (cpu->regs->errcode == 0) {
 			if (emulate_insn(cpu))
 				return;
 		}
-		/* If KVM is active, the vmcall instruction triggers a
-		 * General Protection Fault.  Normally it triggers an
-		 * invalid opcode fault (6): */
+		/*
+		 * If KVM is active, the vmcall instruction triggers a General
+		 * Protection Fault.  Normally it triggers an invalid opcode
+		 * fault (6):
+		 */
 	case 6:
-		/* We need to check if ring == GUEST_PL and
-		 * faulting instruction == vmcall. */
+		/*
+		 * We need to check if ring == GUEST_PL and faulting
+		 * instruction == vmcall.
+		 */
 		if (is_hypercall(cpu)) {
 			rewrite_hypercall(cpu);
 			return;
 		}
 		break;
 	case 14: /* We've intercepted a Page Fault. */
-		/* The Guest accessed a virtual address that wasn't mapped.
+		/*
+		 * The Guest accessed a virtual address that wasn't mapped.
 		 * This happens a lot: we don't actually set up most of the page
 		 * tables for the Guest at all when we start: as it runs it asks
 		 * for more and more, and we set them up as required. In this
 		 * case, we don't even tell the Guest that the fault happened.
 		 *
 		 * The errcode tells whether this was a read or a write, and
-		 * whether kernel or userspace code. */
+		 * whether kernel or userspace code.
+		 */
 		if (demand_page(cpu, cpu->arch.last_pagefault,
 				cpu->regs->errcode))
 			return;
 
-		/* OK, it's really not there (or not OK): the Guest needs to
+		/*
+		 * OK, it's really not there (or not OK): the Guest needs to
 		 * know.  We write out the cr2 value so it knows where the
 		 * fault occurred.
 		 *
 		 * Note that if the Guest were really messed up, this could
 		 * happen before it's done the LHCALL_LGUEST_INIT hypercall, so
-		 * lg->lguest_data could be NULL */
+		 * lg->lguest_data could be NULL
+		 */
 		if (cpu->lg->lguest_data &&
 		    put_user(cpu->arch.last_pagefault,
 			     &cpu->lg->lguest_data->cr2))
 			kill_guest(cpu, "Writing cr2");
 		break;
 	case 7: /* We've intercepted a Device Not Available fault. */
-		/* If the Guest doesn't want to know, we already restored the
-		 * Floating Point Unit, so we just continue without telling
-		 * it. */
+		/*
+		 * If the Guest doesn't want to know, we already restored the
+		 * Floating Point Unit, so we just continue without telling it.
+		 */
 		if (!cpu->ts)
 			return;
 		break;
 	case 32 ... 255:
-		/* These values mean a real interrupt occurred, in which case
+		/*
+		 * These values mean a real interrupt occurred, in which case
 		 * the Host handler has already been run. We just do a
 		 * friendly check if another process should now be run, then
-		 * return to run the Guest again */
+		 * return to run the Guest again
+		 */
 		cond_resched();
 		return;
 	case LGUEST_TRAP_ENTRY:
-		/* Our 'struct hcall_args' maps directly over our regs: we set
-		 * up the pointer now to indicate a hypercall is pending. */
+		/*
+		 * Our 'struct hcall_args' maps directly over our regs: we set
+		 * up the pointer now to indicate a hypercall is pending.
+		 */
 		cpu->hcall = (struct hcall_args *)cpu->regs;
 		return;
 	}
 
 	/* We didn't handle the trap, so it needs to go to the Guest. */
 	if (!deliver_trap(cpu, cpu->regs->trapnum))
-		/* If the Guest doesn't have a handler (either it hasn't
+		/*
+		 * If the Guest doesn't have a handler (either it hasn't
 		 * registered any yet, or it's one of the faults we don't let
-		 * it handle), it dies with this cryptic error message. */
+		 * it handle), it dies with this cryptic error message.
+		 */
 		kill_guest(cpu, "unhandled trap %li at %#lx (%#lx)",
 			   cpu->regs->trapnum, cpu->regs->eip,
 			   cpu->regs->trapnum == 14 ? cpu->arch.last_pagefault
 			   : cpu->regs->errcode);
 }
 
-/* Now we can look at each of the routines this calls, in increasing order of
+/*
+ * Now we can look at each of the routines this calls, in increasing order of
  * complexity: do_hypercalls(), emulate_insn(), maybe_do_interrupt(),
  * deliver_trap() and demand_page().  After all those, we'll be ready to
  * examine the Switcher, and our philosophical understanding of the Host/Guest
- * duality will be complete. :*/
+ * duality will be complete.
+:*/
 static void adjust_pge(void *on)
 {
 	if (on)
@@ -439,13 +515,16 @@ static void adjust_pge(void *on)
 		write_cr4(read_cr4() & ~X86_CR4_PGE);
 }
 
-/*H:020 Now the Switcher is mapped and every thing else is ready, we need to do
- * some more i386-specific initialization. */
+/*H:020
+ * Now the Switcher is mapped and every thing else is ready, we need to do
+ * some more i386-specific initialization.
+ */
 void __init lguest_arch_host_init(void)
 {
 	int i;
 
-	/* Most of the i386/switcher.S doesn't care that it's been moved; on
+	/*
+	 * Most of the i386/switcher.S doesn't care that it's been moved; on
 	 * Intel, jumps are relative, and it doesn't access any references to
 	 * external code or data.
 	 *
@@ -453,7 +532,8 @@ void __init lguest_arch_host_init(void)
 	 * addresses are placed in a table (default_idt_entries), so we need to
 	 * update the table with the new addresses.  switcher_offset() is a
 	 * convenience function which returns the distance between the
-	 * compiled-in switcher code and the high-mapped copy we just made. */
+	 * compiled-in switcher code and the high-mapped copy we just made.
+	 */
 	for (i = 0; i < IDT_ENTRIES; i++)
 		default_idt_entries[i] += switcher_offset();
 
@@ -468,63 +548,81 @@ void __init lguest_arch_host_init(void)
 	for_each_possible_cpu(i) {
 		/* lguest_pages() returns this CPU's two pages. */
 		struct lguest_pages *pages = lguest_pages(i);
-		/* This is a convenience pointer to make the code fit one
-		 * statement to a line. */
+		/* This is a convenience pointer to make the code neater. */
 		struct lguest_ro_state *state = &pages->state;
 
-		/* The Global Descriptor Table: the Host has a different one
+		/*
+		 * The Global Descriptor Table: the Host has a different one
 		 * for each CPU.  We keep a descriptor for the GDT which says
 		 * where it is and how big it is (the size is actually the last
-		 * byte, not the size, hence the "-1"). */
+		 * byte, not the size, hence the "-1").
+		 */
 		state->host_gdt_desc.size = GDT_SIZE-1;
 		state->host_gdt_desc.address = (long)get_cpu_gdt_table(i);
 
-		/* All CPUs on the Host use the same Interrupt Descriptor
+		/*
+		 * All CPUs on the Host use the same Interrupt Descriptor
 		 * Table, so we just use store_idt(), which gets this CPU's IDT
-		 * descriptor. */
+		 * descriptor.
+		 */
 		store_idt(&state->host_idt_desc);
 
-		/* The descriptors for the Guest's GDT and IDT can be filled
+		/*
+		 * The descriptors for the Guest's GDT and IDT can be filled
 		 * out now, too.  We copy the GDT & IDT into ->guest_gdt and
-		 * ->guest_idt before actually running the Guest. */
+		 * ->guest_idt before actually running the Guest.
+		 */
 		state->guest_idt_desc.size = sizeof(state->guest_idt)-1;
 		state->guest_idt_desc.address = (long)&state->guest_idt;
 		state->guest_gdt_desc.size = sizeof(state->guest_gdt)-1;
 		state->guest_gdt_desc.address = (long)&state->guest_gdt;
 
-		/* We know where we want the stack to be when the Guest enters
+		/*
+		 * We know where we want the stack to be when the Guest enters
 		 * the Switcher: in pages->regs.  The stack grows upwards, so
-		 * we start it at the end of that structure. */
+		 * we start it at the end of that structure.
+		 */
 		state->guest_tss.sp0 = (long)(&pages->regs + 1);
-		/* And this is the GDT entry to use for the stack: we keep a
-		 * couple of special LGUEST entries. */
+		/*
+		 * And this is the GDT entry to use for the stack: we keep a
+		 * couple of special LGUEST entries.
+		 */
 		state->guest_tss.ss0 = LGUEST_DS;
 
-		/* x86 can have a finegrained bitmap which indicates what I/O
+		/*
+		 * x86 can have a finegrained bitmap which indicates what I/O
 		 * ports the process can use.  We set it to the end of our
-		 * structure, meaning "none". */
+		 * structure, meaning "none".
+		 */
 		state->guest_tss.io_bitmap_base = sizeof(state->guest_tss);
 
-		/* Some GDT entries are the same across all Guests, so we can
-		 * set them up now. */
+		/*
+		 * Some GDT entries are the same across all Guests, so we can
+		 * set them up now.
+		 */
 		setup_default_gdt_entries(state);
 		/* Most IDT entries are the same for all Guests, too.*/
 		setup_default_idt_entries(state, default_idt_entries);
 
-		/* The Host needs to be able to use the LGUEST segments on this
-		 * CPU, too, so put them in the Host GDT. */
+		/*
+		 * The Host needs to be able to use the LGUEST segments on this
+		 * CPU, too, so put them in the Host GDT.
+		 */
 		get_cpu_gdt_table(i)[GDT_ENTRY_LGUEST_CS] = FULL_EXEC_SEGMENT;
 		get_cpu_gdt_table(i)[GDT_ENTRY_LGUEST_DS] = FULL_SEGMENT;
 	}
 
-	/* In the Switcher, we want the %cs segment register to use the
+	/*
+	 * In the Switcher, we want the %cs segment register to use the
 	 * LGUEST_CS GDT entry: we've put that in the Host and Guest GDTs, so
 	 * it will be undisturbed when we switch.  To change %cs and jump we
-	 * need this structure to feed to Intel's "lcall" instruction. */
+	 * need this structure to feed to Intel's "lcall" instruction.
+	 */
 	lguest_entry.offset = (long)switch_to_guest + switcher_offset();
 	lguest_entry.segment = LGUEST_CS;
 
-	/* Finally, we need to turn off "Page Global Enable".  PGE is an
+	/*
+	 * Finally, we need to turn off "Page Global Enable".  PGE is an
 	 * optimization where page table entries are specially marked to show
 	 * they never change.  The Host kernel marks all the kernel pages this
 	 * way because it's always present, even when userspace is running.
@@ -534,16 +632,21 @@ void __init lguest_arch_host_init(void)
 	 * you'll get really weird bugs that you'll chase for two days.
 	 *
 	 * I used to turn PGE off every time we switched to the Guest and back
-	 * on when we return, but that slowed the Switcher down noticibly. */
+	 * on when we return, but that slowed the Switcher down noticibly.
+	 */
 
-	/* We don't need the complexity of CPUs coming and going while we're
-	 * doing this. */
+	/*
+	 * We don't need the complexity of CPUs coming and going while we're
+	 * doing this.
+	 */
 	get_online_cpus();
 	if (cpu_has_pge) { /* We have a broader idea of "global". */
 		/* Remember that this was originally set (for cleanup). */
 		cpu_had_pge = 1;
-		/* adjust_pge is a helper function which sets or unsets the PGE
-		 * bit on its CPU, depending on the argument (0 == unset). */
+		/*
+		 * adjust_pge is a helper function which sets or unsets the PGE
+		 * bit on its CPU, depending on the argument (0 == unset).
+		 */
 		on_each_cpu(adjust_pge, (void *)0, 1);
 		/* Turn off the feature in the global feature set. */
 		clear_cpu_cap(&boot_cpu_data, X86_FEATURE_PGE);
@@ -590,26 +693,32 @@ int lguest_arch_init_hypercalls(struct lg_cpu *cpu)
 {
 	u32 tsc_speed;
 
-	/* The pointer to the Guest's "struct lguest_data" is the only argument.
-	 * We check that address now. */
+	/*
+	 * The pointer to the Guest's "struct lguest_data" is the only argument.
+	 * We check that address now.
+	 */
 	if (!lguest_address_ok(cpu->lg, cpu->hcall->arg1,
 			       sizeof(*cpu->lg->lguest_data)))
 		return -EFAULT;
 
-	/* Having checked it, we simply set lg->lguest_data to point straight
+	/*
+	 * Having checked it, we simply set lg->lguest_data to point straight
 	 * into the Launcher's memory at the right place and then use
 	 * copy_to_user/from_user from now on, instead of lgread/write.  I put
 	 * this in to show that I'm not immune to writing stupid
-	 * optimizations. */
+	 * optimizations.
+	 */
 	cpu->lg->lguest_data = cpu->lg->mem_base + cpu->hcall->arg1;
 
-	/* We insist that the Time Stamp Counter exist and doesn't change with
+	/*
+	 * We insist that the Time Stamp Counter exist and doesn't change with
 	 * cpu frequency.  Some devious chip manufacturers decided that TSC
 	 * changes could be handled in software.  I decided that time going
 	 * backwards might be good for benchmarks, but it's bad for users.
 	 *
 	 * We also insist that the TSC be stable: the kernel detects unreliable
-	 * TSCs for its own purposes, and we use that here. */
+	 * TSCs for its own purposes, and we use that here.
+	 */
 	if (boot_cpu_has(X86_FEATURE_CONSTANT_TSC) && !check_tsc_unstable())
 		tsc_speed = tsc_khz;
 	else
@@ -625,38 +734,47 @@ int lguest_arch_init_hypercalls(struct lg_cpu *cpu)
 }
 /*:*/
 
-/*L:030 lguest_arch_setup_regs()
+/*L:030
+ * lguest_arch_setup_regs()
  *
  * Most of the Guest's registers are left alone: we used get_zeroed_page() to
- * allocate the structure, so they will be 0. */
+ * allocate the structure, so they will be 0.
+ */
 void lguest_arch_setup_regs(struct lg_cpu *cpu, unsigned long start)
 {
 	struct lguest_regs *regs = cpu->regs;
 
-	/* There are four "segment" registers which the Guest needs to boot:
+	/*
+	 * There are four "segment" registers which the Guest needs to boot:
 	 * The "code segment" register (cs) refers to the kernel code segment
 	 * __KERNEL_CS, and the "data", "extra" and "stack" segment registers
 	 * refer to the kernel data segment __KERNEL_DS.
 	 *
 	 * The privilege level is packed into the lower bits.  The Guest runs
-	 * at privilege level 1 (GUEST_PL).*/
+	 * at privilege level 1 (GUEST_PL).
+	 */
 	regs->ds = regs->es = regs->ss = __KERNEL_DS|GUEST_PL;
 	regs->cs = __KERNEL_CS|GUEST_PL;
 
-	/* The "eflags" register contains miscellaneous flags.  Bit 1 (0x002)
+	/*
+	 * The "eflags" register contains miscellaneous flags.  Bit 1 (0x002)
 	 * is supposed to always be "1".  Bit 9 (0x200) controls whether
 	 * interrupts are enabled.  We always leave interrupts enabled while
-	 * running the Guest. */
+	 * running the Guest.
+	 */
 	regs->eflags = X86_EFLAGS_IF | 0x2;
 
-	/* The "Extended Instruction Pointer" register says where the Guest is
-	 * running. */
+	/*
+	 * The "Extended Instruction Pointer" register says where the Guest is
+	 * running.
+	 */
 	regs->eip = start;
 
-	/* %esi points to our boot information, at physical address 0, so don't
-	 * touch it. */
+	/*
+	 * %esi points to our boot information, at physical address 0, so don't
+	 * touch it.
+	 */
 
-	/* There are a couple of GDT entries the Guest expects when first
-	 * booting. */
+	/* There are a couple of GDT entries the Guest expects at boot. */
 	setup_guest_gdt(cpu);
 }
diff --git a/drivers/lguest/x86/switcher_32.S b/drivers/lguest/x86/switcher_32.S
index 3fc15318a80f..40634b0db9f7 100644
--- a/drivers/lguest/x86/switcher_32.S
+++ b/drivers/lguest/x86/switcher_32.S
@@ -1,12 +1,15 @@
-/*P:900 This is the Switcher: code which sits at 0xFFC00000 astride both the
- * Host and Guest to do the low-level Guest<->Host switch.  It is as simple as
- * it can be made, but it's naturally very specific to x86.
+/*P:900
+ * This is the Switcher: code which sits at 0xFFC00000 (or 0xFFE00000) astride
+ * both the Host and Guest to do the low-level Guest<->Host switch.  It is as
+ * simple as it can be made, but it's naturally very specific to x86.
  *
  * You have now completed Preparation.  If this has whet your appetite; if you
  * are feeling invigorated and refreshed then the next, more challenging stage
- * can be found in "make Guest". :*/
+ * can be found in "make Guest".
+ :*/
 
-/*M:012 Lguest is meant to be simple: my rule of thumb is that 1% more LOC must
+/*M:012
+ * Lguest is meant to be simple: my rule of thumb is that 1% more LOC must
  * gain at least 1% more performance.  Since neither LOC nor performance can be
  * measured beforehand, it generally means implementing a feature then deciding
  * if it's worth it.  And once it's implemented, who can say no?
@@ -31,11 +34,14 @@
  * Host (which is actually really easy).
  *
  * Two questions remain.  Would the performance gain outweigh the complexity?
- * And who would write the verse documenting it? :*/
+ * And who would write the verse documenting it?
+:*/
 
-/*M:011 Lguest64 handles NMI.  This gave me NMI envy (until I looked at their
+/*M:011
+ * Lguest64 handles NMI.  This gave me NMI envy (until I looked at their
  * code).  It's worth doing though, since it would let us use oprofile in the
- * Host when a Guest is running. :*/
+ * Host when a Guest is running.
+:*/
 
 /*S:100
  * Welcome to the Switcher itself!