Commit 33cb5243 authored by Harvey Harrison's avatar Harvey Harrison Committed by Ingo Molnar
Browse files

x86: cosmetic fixes fault_{32|64}.c 



First step towards unifying these files.
- Checkpatch trailing whitespace fixes
- Checkpatch indentation of switch statement fixes
- Checkpatch single statement ifs need no braces fixes
- Checkpatch consistent spacing after comma fixes
- Introduce defines for pagefault error bits from X86_64 and add useful
  comment from X86_32.  Use these defines in X86_32 where obvious.
- Unify comments between 32|64 bit
- Small ifdef movement for CONFIG_KPROBES in notify_page_fault()
- Introduce X86_64 only case statement

No Functional Changes.

Signed-off-by: default avatarHarvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
parent 1d16b53e

arch/x86/mm/fault_32.c

+83 −65
Original line number Diff line number Diff line 
/*

 *  linux/arch/i386/mm/fault.c

 *

 *  Copyright (C) 1995  Linus Torvalds

 */
@@ -30,11 +28,25 @@ 
#include <asm/desc.h>

#include <asm/segment.h>



/*

 * Page fault error code bits

 *	bit 0 == 0 means no page found, 1 means protection fault

 *	bit 1 == 0 means read, 1 means write

 *	bit 2 == 0 means kernel, 1 means user-mode

 *	bit 3 == 1 means use of reserved bit detected

 *	bit 4 == 1 means fault was an instruction fetch

 */

#define PF_PROT	(1<<0)

#define PF_WRITE	(1<<1)

#define PF_USER	(1<<2)

#define PF_RSVD	(1<<3)

#define PF_INSTR	(1<<4)



extern void die(const char *, struct pt_regs *, long);



#ifdef CONFIG_KPROBES

static inline int notify_page_fault(struct pt_regs *regs)

{

#ifdef CONFIG_KPROBES

	int ret = 0;



	/* kprobe_running() needs smp_processor_id() */
@@ -46,13 +58,10 @@ static inline int notify_page_fault(struct pt_regs *regs) 
	}



	return ret;

}

#else

static inline int notify_page_fault(struct pt_regs *regs)

{

	return 0;

}

#endif

}



/*

 * Return EIP plus the CS segment base.  The segment limit is also
@@ -116,9 +125,9 @@ static inline unsigned long get_segment_eip(struct pt_regs *regs, 
	/* Decode the code segment base from the descriptor */

	base = get_desc_base((struct desc_struct *)desc);



	if (seg & (1<<2)) { 

	if (seg & (1<<2))

		mutex_unlock(&current->mm->context.lock);

	} else

	else

		put_cpu();



	/* Adjust EIP and segment limit, and clamp at the kernel limit.
@@ -158,16 +167,32 @@ static int __is_prefetch(struct pt_regs *regs, unsigned long addr) 
		switch (instr_hi) {

		case 0x20:

		case 0x30:

			/* Values 0x26,0x2E,0x36,0x3E are valid x86 prefixes. */

			/*

			 * Values 0x26,0x2E,0x36,0x3E are valid x86 prefixes.

			 * In X86_64 long mode, the CPU will signal invalid

			 * opcode if some of these prefixes are present so

			 * X86_64 will never get here anyway

			 */

			scan_more = ((instr_lo & 7) == 0x6);

			break;

			

#ifdef CONFIG_X86_64

		case 0x40:

			/*

			 * In AMD64 long mode 0x40..0x4F are valid REX prefixes

			 * Need to figure out under what instruction mode the

			 * instruction was issued. Could check the LDT for lm,

			 * but for now it's good enough to assume that long

			 * mode only uses well known segments or kernel.

			 */

			scan_more = (!user_mode(regs)) || (regs->cs == __USER_CS);

			break;

#endif

		case 0x60:

			/* 0x64 thru 0x67 are valid prefixes in all modes. */

			scan_more = (instr_lo & 0xC) == 0x4;

			break;

		case 0xF0:

			/* 0xF0, 0xF2, and 0xF3 are valid prefixes */

			/* 0xF0, 0xF2, 0xF3 are valid prefixes in all modes. */

			scan_more = !instr_lo || (instr_lo>>1) == 1;

			break;

		case 0x00:
@@ -284,13 +309,6 @@ int show_unhandled_signals = 1; 
 * This routine handles page faults.  It determines the address,

 * and the problem, and then passes it off to one of the appropriate

 * routines.

 *

 * error_code:

 *	bit 0 == 0 means no page found, 1 means protection fault

 *	bit 1 == 0 means read, 1 means write

 *	bit 2 == 0 means kernel, 1 means user-mode

 *	bit 3 == 1 means use of reserved bit detected

 *	bit 4 == 1 means fault was an instruction fetch

 */

void __kprobes do_page_fault(struct pt_regs *regs, unsigned long error_code)

{
@@ -350,7 +368,7 @@ void __kprobes do_page_fault(struct pt_regs *regs, unsigned long error_code) 


	/*

	 * If we're in an interrupt, have no user context or are running in an

	 * atomic region then we must not take the fault..

	 * atomic region then we must not take the fault.

	 */

	if (in_atomic() || !mm)

		goto bad_area_nosemaphore;
@@ -371,7 +389,7 @@ void __kprobes do_page_fault(struct pt_regs *regs, unsigned long error_code) 
	 * thus avoiding the deadlock.

	 */

	if (!down_read_trylock(&mm->mmap_sem)) {

		if ((error_code & 4) == 0 &&

		if ((error_code & PF_USER) == 0 &&

		    !search_exception_tables(regs->ip))

			goto bad_area_nosemaphore;

		down_read(&mm->mmap_sem);
@@ -384,7 +402,7 @@ void __kprobes do_page_fault(struct pt_regs *regs, unsigned long error_code) 
		goto good_area;

	if (!(vma->vm_flags & VM_GROWSDOWN))

		goto bad_area;

	if (error_code & 4) {

	if (error_code & PF_USER) {

		/*

		 * Accessing the stack below %sp is always a bug.

		 * The large cushion allows instructions like enter
@@ -403,15 +421,15 @@ void __kprobes do_page_fault(struct pt_regs *regs, unsigned long error_code) 
good_area:

	si_code = SEGV_ACCERR;

	write = 0;

	switch (error_code & 3) {

	switch (error_code & (PF_PROT|PF_WRITE)) {

	default:	/* 3: write, present */

		/* fall through */

		case 2:		/* write, not present */

	case PF_WRITE:		/* write, not present */

		if (!(vma->vm_flags & VM_WRITE))

			goto bad_area;

		write++;

		break;

		case 1:		/* read, present */

	case PF_PROT:		/* read, present */

		goto bad_area;

	case 0:			/* read, not present */

		if (!(vma->vm_flags & (VM_READ | VM_EXEC | VM_WRITE)))
@@ -457,7 +475,7 @@ bad_area: 


bad_area_nosemaphore:

	/* User mode accesses just cause a SIGSEGV */

	if (error_code & 4) {

	if (error_code & PF_USER) {

		/*

		 * It's possible to have interrupts off here.

		 */
@@ -605,7 +623,7 @@ do_sigbus: 
	up_read(&mm->mmap_sem);



	/* Kernel mode? Handle exceptions or die */

	if (!(error_code & 4))

	if (!(error_code & PF_USER))

		goto no_context;



	/* User space => ok to do another page fault */

arch/x86/mm/fault_64.c

+77 −74
Original line number Diff line number Diff line 
/*

 *  linux/arch/x86-64/mm/fault.c

 *

 *  Copyright (C) 1995  Linus Torvalds

 *  Copyright (C) 2001,2002 Andi Kleen, SuSE Labs.

 */
@@ -33,16 +31,23 @@ 
#include <asm/proto.h>

#include <asm-generic/sections.h>



/* Page fault error code bits */

#define PF_PROT	(1<<0)		/* or no page found */

/*

 * Page fault error code bits

 *	bit 0 == 0 means no page found, 1 means protection fault

 *	bit 1 == 0 means read, 1 means write

 *	bit 2 == 0 means kernel, 1 means user-mode

 *	bit 3 == 1 means use of reserved bit detected

 *	bit 4 == 1 means fault was an instruction fetch

 */

#define PF_PROT	(1<<0)

#define PF_WRITE	(1<<1)

#define PF_USER	(1<<2)

#define PF_RSVD	(1<<3)

#define PF_INSTR	(1<<4)



#ifdef CONFIG_KPROBES

static inline int notify_page_fault(struct pt_regs *regs)

{

#ifdef CONFIG_KPROBES

	int ret = 0;



	/* kprobe_running() needs smp_processor_id() */
@@ -54,13 +59,10 @@ static inline int notify_page_fault(struct pt_regs *regs) 
	}



	return ret;

}

#else

static inline int notify_page_fault(struct pt_regs *regs)

{

	return 0;

}

#endif

}



/* Sometimes the CPU reports invalid exceptions on prefetch.

   Check that here and ignore.
@@ -98,23 +100,26 @@ static noinline int is_prefetch(struct pt_regs *regs, unsigned long addr, 
		switch (instr_hi) {

		case 0x20:

		case 0x30:

			/* Values 0x26,0x2E,0x36,0x3E are valid x86

			   prefixes.  In long mode, the CPU will signal

			   invalid opcode if some of these prefixes are

			   present so we will never get here anyway */

			/*

			 * Values 0x26,0x2E,0x36,0x3E are valid x86 prefixes.

			 * In X86_64 long mode, the CPU will signal invalid

			 * opcode if some of these prefixes are present so

			 * X86_64 will never get here anyway

			 */

			scan_more = ((instr_lo & 7) == 0x6);

			break;

			

#ifdef CONFIG_X86_64

		case 0x40:

			/* In AMD64 long mode, 0x40 to 0x4F are valid REX prefixes

			   Need to figure out under what instruction mode the

			   instruction was issued ... */

			/* Could check the LDT for lm, but for now it's good

			   enough to assume that long mode only uses well known

			   segments or kernel. */

			/*

			 * In AMD64 long mode 0x40..0x4F are valid REX prefixes

			 * Need to figure out under what instruction mode the

			 * instruction was issued. Could check the LDT for lm,

			 * but for now it's good enough to assume that long

			 * mode only uses well known segments or kernel.

			 */

			scan_more = (!user_mode(regs)) || (regs->cs == __USER_CS);

			break;

			

#endif

		case 0x60:

			/* 0x64 thru 0x67 are valid prefixes in all modes. */

			scan_more = (instr_lo & 0xC) == 0x4;
@@ -360,8 +365,8 @@ asmlinkage void __kprobes do_page_fault(struct pt_regs *regs, 
		pgtable_bad(address, regs, error_code);



	/*

	 * If we're in an interrupt or have no user

	 * context, we must not take the fault..

	 * If we're in an interrupt, have no user context or are running in an

	 * atomic region then we must not take the fault.

	 */

	if (unlikely(in_atomic() || !mm))

		goto bad_area_nosemaphore;
@@ -403,7 +408,7 @@ asmlinkage void __kprobes do_page_fault(struct pt_regs *regs, 
		goto good_area;

	if (!(vma->vm_flags & VM_GROWSDOWN))

		goto bad_area;

	if (error_code & 4) {

	if (error_code & PF_USER) {

		/* Allow userspace just enough access below the stack pointer

		 * to let the 'enter' instruction work.

		 */
@@ -505,11 +510,9 @@ bad_area_nosemaphore: 
	}



no_context:

	

	/* Are we prepared to handle this kernel fault?  */

	if (fixup_exception(regs)) {

	if (fixup_exception(regs))

		return;

	}



	/*

	 * Hall of shame of CPU/BIOS bugs.

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