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

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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: Harvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
This commit is contained in:
Harvey Harrison
2008-01-30 13:32:19 +01:00
committed by Ingo Molnar
parent 1d16b53e38
commit 33cb524383
2 changed files with 160 additions and 139 deletions
Download Patch File Download Diff File Expand all files Collapse all files

72
arch/x86/mm/fault_32.c
View File

@@ -1,6 +1,4 @@
/* /*
* linux/arch/i386/mm/fault.c
*
* Copyright (C) 1995 Linus Torvalds * Copyright (C) 1995 Linus Torvalds
*/ */
@@ -30,11 +28,25 @@
#include <asm/desc.h> #include <asm/desc.h>
#include <asm/segment.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); extern void die(const char *, struct pt_regs *, long);
#ifdef CONFIG_KPROBES
static inline int notify_page_fault(struct pt_regs *regs) static inline int notify_page_fault(struct pt_regs *regs)
{ {
#ifdef CONFIG_KPROBES
int ret = 0; int ret = 0;
/* kprobe_running() needs smp_processor_id() */ /* kprobe_running() needs smp_processor_id() */
@@ -46,13 +58,10 @@ static inline int notify_page_fault(struct pt_regs *regs)
} }
return ret; return ret;
}
#else #else
static inline int notify_page_fault(struct pt_regs *regs)
{
return 0; return 0;
}
#endif #endif
}
/* /*
* Return EIP plus the CS segment base. The segment limit is also * 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 */ /* Decode the code segment base from the descriptor */
base = get_desc_base((struct desc_struct *)desc); base = get_desc_base((struct desc_struct *)desc);
if (seg & (1<<2)) { if (seg & (1<<2))
mutex_unlock(&current->mm->context.lock); mutex_unlock(&current->mm->context.lock);
} else else
put_cpu(); put_cpu();
/* Adjust EIP and segment limit, and clamp at the kernel limit. /* 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) { switch (instr_hi) {
case 0x20: case 0x20:
case 0x30: 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); scan_more = ((instr_lo & 7) == 0x6);
break; 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: case 0x60:
/* 0x64 thru 0x67 are valid prefixes in all modes. */ /* 0x64 thru 0x67 are valid prefixes in all modes. */
scan_more = (instr_lo & 0xC) == 0x4; scan_more = (instr_lo & 0xC) == 0x4;
break; break;
case 0xF0: 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; scan_more = !instr_lo || (instr_lo>>1) == 1;
break; break;
case 0x00: case 0x00:
@@ -284,13 +309,6 @@ int show_unhandled_signals = 1;
* This routine handles page faults. It determines the address, * This routine handles page faults. It determines the address,
* and the problem, and then passes it off to one of the appropriate * and the problem, and then passes it off to one of the appropriate
* routines. * 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) 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 * 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) if (in_atomic() || !mm)
goto bad_area_nosemaphore; 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. * thus avoiding the deadlock.
*/ */
if (!down_read_trylock(&mm->mmap_sem)) { if (!down_read_trylock(&mm->mmap_sem)) {
if ((error_code & 4) == 0 && if ((error_code & PF_USER) == 0 &&
!search_exception_tables(regs->ip)) !search_exception_tables(regs->ip))
goto bad_area_nosemaphore; goto bad_area_nosemaphore;
down_read(&mm->mmap_sem); 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; goto good_area;
if (!(vma->vm_flags & VM_GROWSDOWN)) if (!(vma->vm_flags & VM_GROWSDOWN))
goto bad_area; goto bad_area;
if (error_code & 4) { if (error_code & PF_USER) {
/* /*
* Accessing the stack below %sp is always a bug. * Accessing the stack below %sp is always a bug.
* The large cushion allows instructions like enter * 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: good_area:
si_code = SEGV_ACCERR; si_code = SEGV_ACCERR;
write = 0; write = 0;
switch (error_code & 3) { switch (error_code & (PF_PROT|PF_WRITE)) {
default: /* 3: write, present */ default: /* 3: write, present */
/* fall through */ /* fall through */
case 2: /* write, not present */ case PF_WRITE: /* write, not present */
if (!(vma->vm_flags & VM_WRITE)) if (!(vma->vm_flags & VM_WRITE))
goto bad_area; goto bad_area;
write++; write++;
break; break;
case 1: /* read, present */ case PF_PROT: /* read, present */
goto bad_area; goto bad_area;
case 0: /* read, not present */ case 0: /* read, not present */
if (!(vma->vm_flags & (VM_READ | VM_EXEC | VM_WRITE))) if (!(vma->vm_flags & (VM_READ | VM_EXEC | VM_WRITE)))
@@ -457,7 +475,7 @@ bad_area:
bad_area_nosemaphore: bad_area_nosemaphore:
/* User mode accesses just cause a SIGSEGV */ /* User mode accesses just cause a SIGSEGV */
if (error_code & 4) { if (error_code & PF_USER) {
/* /*
* It's possible to have interrupts off here. * It's possible to have interrupts off here.
*/ */
@@ -605,7 +623,7 @@ do_sigbus:
up_read(&mm->mmap_sem); up_read(&mm->mmap_sem);
/* Kernel mode? Handle exceptions or die */ /* Kernel mode? Handle exceptions or die */
if (!(error_code & 4)) if (!(error_code & PF_USER))
goto no_context; goto no_context;
/* User space => ok to do another page fault */ /* User space => ok to do another page fault */

57
arch/x86/mm/fault_64.c
View File

@@ -1,6 +1,4 @@
/* /*
* linux/arch/x86-64/mm/fault.c
*
* Copyright (C) 1995 Linus Torvalds * Copyright (C) 1995 Linus Torvalds
* Copyright (C) 2001,2002 Andi Kleen, SuSE Labs. * Copyright (C) 2001,2002 Andi Kleen, SuSE Labs.
*/ */
@@ -33,16 +31,23 @@
#include <asm/proto.h> #include <asm/proto.h>
#include <asm-generic/sections.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_WRITE (1<<1)
#define PF_USER (1<<2) #define PF_USER (1<<2)
#define PF_RSVD (1<<3) #define PF_RSVD (1<<3)
#define PF_INSTR (1<<4) #define PF_INSTR (1<<4)
#ifdef CONFIG_KPROBES
static inline int notify_page_fault(struct pt_regs *regs) static inline int notify_page_fault(struct pt_regs *regs)
{ {
#ifdef CONFIG_KPROBES
int ret = 0; int ret = 0;
/* kprobe_running() needs smp_processor_id() */ /* kprobe_running() needs smp_processor_id() */
@@ -54,13 +59,10 @@ static inline int notify_page_fault(struct pt_regs *regs)
} }
return ret; return ret;
}
#else #else
static inline int notify_page_fault(struct pt_regs *regs)
{
return 0; return 0;
}
#endif #endif
}
/* Sometimes the CPU reports invalid exceptions on prefetch. /* Sometimes the CPU reports invalid exceptions on prefetch.
Check that here and ignore. Check that here and ignore.
@@ -98,23 +100,26 @@ static noinline int is_prefetch(struct pt_regs *regs, unsigned long addr,
switch (instr_hi) { switch (instr_hi) {
case 0x20: case 0x20:
case 0x30: case 0x30:
/* Values 0x26,0x2E,0x36,0x3E are valid x86 /*
prefixes. In long mode, the CPU will signal * Values 0x26,0x2E,0x36,0x3E are valid x86 prefixes.
invalid opcode if some of these prefixes are * In X86_64 long mode, the CPU will signal invalid
present so we will never get here anyway */ * opcode if some of these prefixes are present so
* X86_64 will never get here anyway
*/
scan_more = ((instr_lo & 7) == 0x6); scan_more = ((instr_lo & 7) == 0x6);
break; break;
#ifdef CONFIG_X86_64
case 0x40: case 0x40:
/* In AMD64 long mode, 0x40 to 0x4F are valid REX prefixes /*
Need to figure out under what instruction mode the * In AMD64 long mode 0x40..0x4F are valid REX prefixes
instruction was issued ... */ * Need to figure out under what instruction mode the
/* Could check the LDT for lm, but for now it's good * instruction was issued. Could check the LDT for lm,
enough to assume that long mode only uses well known * but for now it's good enough to assume that long
segments or kernel. */ * mode only uses well known segments or kernel.
*/
scan_more = (!user_mode(regs)) || (regs->cs == __USER_CS); scan_more = (!user_mode(regs)) || (regs->cs == __USER_CS);
break; break;
#endif
case 0x60: case 0x60:
/* 0x64 thru 0x67 are valid prefixes in all modes. */ /* 0x64 thru 0x67 are valid prefixes in all modes. */
scan_more = (instr_lo & 0xC) == 0x4; 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); pgtable_bad(address, regs, error_code);
/* /*
* If we're in an interrupt or have no user * If we're in an interrupt, have no user context or are running in an
* context, we must not take the fault.. * atomic region then we must not take the fault.
*/ */
if (unlikely(in_atomic() || !mm)) if (unlikely(in_atomic() || !mm))
goto bad_area_nosemaphore; goto bad_area_nosemaphore;
@@ -403,7 +408,7 @@ asmlinkage void __kprobes do_page_fault(struct pt_regs *regs,
goto good_area; goto good_area;
if (!(vma->vm_flags & VM_GROWSDOWN)) if (!(vma->vm_flags & VM_GROWSDOWN))
goto bad_area; goto bad_area;
if (error_code & 4) { if (error_code & PF_USER) {
/* Allow userspace just enough access below the stack pointer /* Allow userspace just enough access below the stack pointer
* to let the 'enter' instruction work. * to let the 'enter' instruction work.
*/ */
@@ -505,11 +510,9 @@ bad_area_nosemaphore:
} }
no_context: no_context:
/* Are we prepared to handle this kernel fault? */ /* Are we prepared to handle this kernel fault? */
if (fixup_exception(regs)) { if (fixup_exception(regs))
return; return;
}
/* /*
* Hall of shame of CPU/BIOS bugs. * Hall of shame of CPU/BIOS bugs.