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Commit 33cb5243 authored by Harvey Harrison's avatar Harvey Harrison Committed by Ingo Molnar
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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
Hide whitespace changes
Inline Side-by-side
Showing with 160 additions and 139 deletions
arch/x86/mm/fault_32.c
View file @ 33cb5243
/*
* linux/arch/i386/mm/fault.c
*
* Copyright (C) 1995 Linus Torvalds
*/
......@@ -30,11 +28,25 @@
#include <asm/desc.h>
#include <asm/segment.h>
extern void die(const char *,struct pt_regs *,long);
/*
* 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
......@@ -65,7 +74,7 @@ static inline int notify_page_fault(struct pt_regs *regs)
* If CS is no longer a valid code segment, or if EIP is beyond the
* limit, or if it is a kernel address when CS is not a kernel segment,
* then the returned value will be greater than *eip_limit.
*
*
* This is slow, but is very rarely executed.
*/
static inline unsigned long get_segment_eip(struct pt_regs *regs,
......@@ -84,7 +93,7 @@ static inline unsigned long get_segment_eip(struct pt_regs *regs,
/* The standard kernel/user address space limit. */
*eip_limit = user_mode(regs) ? USER_DS.seg : KERNEL_DS.seg;
/* By far the most common cases. */
if (likely(SEGMENT_IS_FLAT_CODE(seg)))
return ip;
......@@ -99,7 +108,7 @@ static inline unsigned long get_segment_eip(struct pt_regs *regs,
return 1; /* So that returned ip > *eip_limit. */
}
/* Get the GDT/LDT descriptor base.
/* Get the GDT/LDT descriptor base.
When you look for races in this code remember that
LDT and other horrors are only used in user space. */
if (seg & (1<<2)) {
......@@ -109,16 +118,16 @@ static inline unsigned long get_segment_eip(struct pt_regs *regs,
desc = (void *)desc + (seg & ~7);
} else {
/* Must disable preemption while reading the GDT. */
desc = (u32 *)get_cpu_gdt_table(get_cpu());
desc = (u32 *)get_cpu_gdt_table(get_cpu());
desc = (void *)desc + (seg & ~7);
}
/* 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.
......@@ -129,19 +138,19 @@ static inline unsigned long get_segment_eip(struct pt_regs *regs,
return ip + base;
}
/*
/*
* Sometimes AMD Athlon/Opteron CPUs report invalid exceptions on prefetch.
* Check that here and ignore it.
*/
static int __is_prefetch(struct pt_regs *regs, unsigned long addr)
{
{
unsigned long limit;
unsigned char *instr = (unsigned char *)get_segment_eip (regs, &limit);
unsigned char *instr = (unsigned char *)get_segment_eip(regs, &limit);
int scan_more = 1;
int prefetch = 0;
int prefetch = 0;
int i;
for (i = 0; scan_more && i < 15; i++) {
for (i = 0; scan_more && i < 15; i++) {
unsigned char opcode;
unsigned char instr_hi;
unsigned char instr_lo;
......@@ -149,27 +158,43 @@ static int __is_prefetch(struct pt_regs *regs, unsigned long addr)
if (instr > (unsigned char *)limit)
break;
if (probe_kernel_address(instr, opcode))
break;
break;
instr_hi = opcode & 0xf0;
instr_lo = opcode & 0x0f;
instr_hi = opcode & 0xf0;
instr_lo = opcode & 0x0f;
instr++;
switch (instr_hi) {
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;
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;
break;
case 0x00:
/* Prefetch instruction is 0x0F0D or 0x0F18 */
scan_more = 0;
......@@ -179,11 +204,11 @@ static int __is_prefetch(struct pt_regs *regs, unsigned long addr)
break;
prefetch = (instr_lo == 0xF) &&
(opcode == 0x0D || opcode == 0x18);
break;
break;
default:
scan_more = 0;
break;
}
}
}
return prefetch;
}
......@@ -199,7 +224,7 @@ static inline int is_prefetch(struct pt_regs *regs, unsigned long addr,
return __is_prefetch(regs, addr);
}
return 0;
}
}
static noinline void force_sig_info_fault(int si_signo, int si_code,
unsigned long address, struct task_struct *tsk)
......@@ -284,19 +309,12 @@ 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)
{
struct task_struct *tsk;
struct mm_struct *mm;
struct vm_area_struct * vma;
struct vm_area_struct *vma;
unsigned long address;
int write, si_code;
int fault;
......@@ -307,7 +325,7 @@ void __kprobes do_page_fault(struct pt_regs *regs, unsigned long error_code)
trace_hardirqs_fixup();
/* get the address */
address = read_cr2();
address = read_cr2();
tsk = current;
......@@ -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
......@@ -403,19 +421,19 @@ 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) {
default: /* 3: write, present */
/* fall through */
case 2: /* write, not present */
if (!(vma->vm_flags & VM_WRITE))
goto bad_area;
write++;
break;
case 1: /* read, present */
switch (error_code & (PF_PROT|PF_WRITE)) {
default: /* 3: write, present */
/* fall through */
case PF_WRITE: /* write, not present */
if (!(vma->vm_flags & VM_WRITE))
goto bad_area;
write++;
break;
case PF_PROT: /* read, present */
goto bad_area;
case 0: /* read, not present */
if (!(vma->vm_flags & (VM_READ | VM_EXEC | VM_WRITE)))
goto bad_area;
case 0: /* read, not present */
if (!(vma->vm_flags & (VM_READ | VM_EXEC | VM_WRITE)))
goto bad_area;
}
survive:
......@@ -457,14 +475,14 @@ void __kprobes do_page_fault(struct pt_regs *regs, unsigned long error_code)
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.
*/
local_irq_enable();
/*
* Valid to do another page fault here because this one came
/*
* Valid to do another page fault here because this one came
* from user space.
*/
if (is_prefetch(regs, address, error_code))
......@@ -492,7 +510,7 @@ void __kprobes do_page_fault(struct pt_regs *regs, unsigned long error_code)
*/
if (boot_cpu_data.f00f_bug) {
unsigned long nr;
nr = (address - idt_descr.address) >> 3;
if (nr == 6) {
......@@ -507,13 +525,13 @@ void __kprobes do_page_fault(struct pt_regs *regs, unsigned long error_code)
if (fixup_exception(regs))
return;
/*
/*
* Valid to do another page fault here, because if this fault
* had been triggered by is_prefetch fixup_exception would have
* had been triggered by is_prefetch fixup_exception would have
* handled it.
*/
if (is_prefetch(regs, address, error_code))
return;
if (is_prefetch(regs, address, error_code))
return;
/*
* Oops. The kernel tried to access some bad page. We'll have to
......@@ -541,7 +559,7 @@ void __kprobes do_page_fault(struct pt_regs *regs, unsigned long error_code)
else
printk(KERN_ALERT "BUG: unable to handle kernel paging"
" request");
printk(" at virtual address %08lx\n",address);
printk(" at virtual address %08lx\n", address);
printk(KERN_ALERT "printing ip: %08lx ", regs->ip);
page = read_cr3();
......@@ -605,7 +623,7 @@ void __kprobes do_page_fault(struct pt_regs *regs, unsigned long error_code)
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
View file @ 33cb5243
/*
* 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() */
......@@ -54,75 +59,75 @@ 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.
Opcode checker based on code by Richard Brunner */
static noinline int is_prefetch(struct pt_regs *regs, unsigned long addr,
unsigned long error_code)
{
{
unsigned char *instr;
int scan_more = 1;
int prefetch = 0;
int prefetch = 0;
unsigned char *max_instr;
/* If it was a exec fault ignore */
if (error_code & PF_INSTR)
return 0;
instr = (unsigned char __user *)convert_rip_to_linear(current, regs);
max_instr = instr + 15;
if (user_mode(regs) && instr >= (unsigned char *)TASK_SIZE)
return 0;
while (scan_more && instr < max_instr) {
while (scan_more && instr < max_instr) {
unsigned char opcode;
unsigned char instr_hi;
unsigned char instr_lo;
if (probe_kernel_address(instr, opcode))
break;
break;
instr_hi = opcode & 0xf0;
instr_lo = opcode & 0x0f;
instr_hi = opcode & 0xf0;
instr_lo = opcode & 0x0f;
instr++;
switch (instr_hi) {
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;
break;
break;
case 0xF0:
/* 0xF0, 0xF2, and 0xF3 are valid prefixes in all modes. */
scan_more = !instr_lo || (instr_lo>>1) == 1;
break;
break;
case 0x00:
/* Prefetch instruction is 0x0F0D or 0x0F18 */
scan_more = 0;
......@@ -130,20 +135,20 @@ static noinline int is_prefetch(struct pt_regs *regs, unsigned long addr,
break;
prefetch = (instr_lo == 0xF) &&
(opcode == 0x0D || opcode == 0x18);
break;
break;
default:
scan_more = 0;
break;
}
}
}
return prefetch;
}
static int bad_address(void *p)
{
static int bad_address(void *p)
{
unsigned long dummy;
return probe_kernel_address((unsigned long *)p, dummy);
}
}
void dump_pagetable(unsigned long address)
{
......@@ -154,11 +159,11 @@ void dump_pagetable(unsigned long address)
pgd = (pgd_t *)read_cr3();
pgd = __va((unsigned long)pgd & PHYSICAL_PAGE_MASK);
pgd = __va((unsigned long)pgd & PHYSICAL_PAGE_MASK);
pgd += pgd_index(address);
if (bad_address(pgd)) goto bad;
printk("PGD %lx ", pgd_val(*pgd));
if (!pgd_present(*pgd)) goto ret;
if (!pgd_present(*pgd)) goto ret;
pud = pud_offset(pgd, address);
if (bad_address(pud)) goto bad;
......@@ -172,7 +177,7 @@ void dump_pagetable(unsigned long address)
pte = pte_offset_kernel(pmd, address);
if (bad_address(pte)) goto bad;
printk("PTE %lx", pte_val(*pte));
printk("PTE %lx", pte_val(*pte));
ret:
printk("\n");
return;
......@@ -180,7 +185,7 @@ void dump_pagetable(unsigned long address)
printk("BAD\n");
}
static const char errata93_warning[] =
static const char errata93_warning[] =
KERN_ERR "******* Your BIOS seems to not contain a fix for K8 errata #93\n"
KERN_ERR "******* Working around it, but it may cause SEGVs or burn power.\n"
KERN_ERR "******* Please consider a BIOS update.\n"
......@@ -188,31 +193,31 @@ KERN_ERR "******* Disabling USB legacy in the BIOS may also help.\n";
/* Workaround for K8 erratum #93 & buggy BIOS.
BIOS SMM functions are required to use a specific workaround
to avoid corruption of the 64bit RIP register on C stepping K8.
A lot of BIOS that didn't get tested properly miss this.
to avoid corruption of the 64bit RIP register on C stepping K8.
A lot of BIOS that didn't get tested properly miss this.
The OS sees this as a page fault with the upper 32bits of RIP cleared.
Try to work around it here.
Note we only handle faults in kernel here. */
static int is_errata93(struct pt_regs *regs, unsigned long address)
static int is_errata93(struct pt_regs *regs, unsigned long address)
{
static int warned;
if (address != regs->ip)
return 0;
if ((address >> 32) != 0)
if ((address >> 32) != 0)
return 0;
address |= 0xffffffffUL << 32;
if ((address >= (u64)_stext && address <= (u64)_etext) ||
(address >= MODULES_VADDR && address <= MODULES_END)) {
if ((address >= (u64)_stext && address <= (u64)_etext) ||
(address >= MODULES_VADDR && address <= MODULES_END)) {
if (!warned) {
printk(errata93_warning);
printk(errata93_warning);
warned = 1;
}
regs->ip = address;
return 1;
}
return 0;
}
}
static noinline void pgtable_bad(unsigned long address, struct pt_regs *regs,
unsigned long error_code)
......@@ -296,7 +301,7 @@ asmlinkage void __kprobes do_page_fault(struct pt_regs *regs,
{
struct task_struct *tsk;
struct mm_struct *mm;
struct vm_area_struct * vma;
struct vm_area_struct *vma;
unsigned long address;
int write, fault;
unsigned long flags;
......@@ -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.
*/
......@@ -420,18 +425,18 @@ asmlinkage void __kprobes do_page_fault(struct pt_regs *regs,
info.si_code = SEGV_ACCERR;
write = 0;
switch (error_code & (PF_PROT|PF_WRITE)) {
default: /* 3: write, present */
/* fall through */
case PF_WRITE: /* write, not present */
if (!(vma->vm_flags & VM_WRITE))
goto bad_area;
write++;
break;
case PF_PROT: /* read, present */
default: /* 3: write, present */
/* fall through */
case PF_WRITE: /* write, not present */
if (!(vma->vm_flags & VM_WRITE))
goto bad_area;
write++;
break;
case PF_PROT: /* read, present */
goto bad_area;
case 0: /* read, not present */
if (!(vma->vm_flags & (VM_READ | VM_EXEC | VM_WRITE)))
goto bad_area;
case 0: /* read, not present */
if (!(vma->vm_flags & (VM_READ | VM_EXEC | VM_WRITE)))
goto bad_area;
}
/*
......@@ -491,7 +496,7 @@ asmlinkage void __kprobes do_page_fault(struct pt_regs *regs,
tsk->comm, tsk->pid, address, regs->ip,
regs->sp, error_code);
}
tsk->thread.cr2 = address;
/* Kernel addresses are always protection faults */
tsk->thread.error_code = error_code | (address >= TASK_SIZE);
......@@ -505,21 +510,19 @@ asmlinkage void __kprobes do_page_fault(struct pt_regs *regs,
}
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.
*/
if (is_prefetch(regs, address, error_code))
return;
if (is_prefetch(regs, address, error_code))
return;
if (is_errata93(regs, address))
return;
return;
/*
* Oops. The kernel tried to access some bad page. We'll have to
......@@ -532,7 +535,7 @@ asmlinkage void __kprobes do_page_fault(struct pt_regs *regs,
printk(KERN_ALERT "Unable to handle kernel NULL pointer dereference");
else
printk(KERN_ALERT "Unable to handle kernel paging request");
printk(" at %016lx RIP: \n" KERN_ALERT,address);
printk(" at %016lx RIP: \n" KERN_ALERT, address);
printk_address(regs->ip);
dump_pagetable(address);
tsk->thread.cr2 = address;
......@@ -582,7 +585,7 @@ LIST_HEAD(pgd_list);
void vmalloc_sync_all(void)
{
/* Note that races in the updates of insync and start aren't
/* Note that races in the updates of insync and start aren't
problematic:
insync can only get set bits added, and updates to start are only
improving performance (without affecting correctness if undone). */
......@@ -614,6 +617,6 @@ void vmalloc_sync_all(void)
}
/* Check that there is no need to do the same for the modules area. */
BUILD_BUG_ON(!(MODULES_VADDR > __START_KERNEL));
BUILD_BUG_ON(!(((MODULES_END - 1) & PGDIR_MASK) ==
BUILD_BUG_ON(!(((MODULES_END - 1) & PGDIR_MASK) ==
(__START_KERNEL & PGDIR_MASK)));
}
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