/*
* Kernel Debugger Architecture Independent Support Functions
*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*
* Copyright (c) 1999-2004 Silicon Graphics, Inc. All Rights Reserved.
* Copyright (c) 2009 Wind River Systems, Inc. All Rights Reserved.
* 03/02/13 added new 2.5 kallsyms <[email protected]>
*/
#include <linux/types.h>
#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/kallsyms.h>
#include <linux/stddef.h>
#include <linux/vmalloc.h>
#include <linux/ptrace.h>
#include <linux/highmem.h>
#include <linux/hardirq.h>
#include <linux/delay.h>
#include <linux/uaccess.h>
#include <linux/kdb.h>
#include <linux/slab.h>
#include <linux/ctype.h>
#include "kdb_private.h"
/*
* kdbgetsymval - Return the address of the given symbol.
*
* Parameters:
* symname Character string containing symbol name
* symtab Structure to receive results
* Returns:
* 0 Symbol not found, symtab zero filled
* 1 Symbol mapped to module/symbol/section, data in symtab
*/
int kdbgetsymval(const char *symname, kdb_symtab_t *symtab)
{
kdb_dbg_printf(AR, "symname=%s, symtab=%px\n", symname, symtab);
memset(symtab, 0, sizeof(*symtab));
symtab->sym_start = kallsyms_lookup_name(symname);
if (symtab->sym_start) {
kdb_dbg_printf(AR, "returns 1, symtab->sym_start=0x%lx\n",
symtab->sym_start);
return 1;
}
kdb_dbg_printf(AR, "returns 0\n");
return 0;
}
EXPORT_SYMBOL(kdbgetsymval);
/**
* kdbnearsym() - Return the name of the symbol with the nearest address
* less than @addr.
* @addr: Address to check for near symbol
* @symtab: Structure to receive results
*
* WARNING: This function may return a pointer to a single statically
* allocated buffer (namebuf). kdb's unusual calling context (single
* threaded, all other CPUs halted) provides us sufficient locking for
* this to be safe. The only constraint imposed by the static buffer is
* that the caller must consume any previous reply prior to another call
* to lookup a new symbol.
*
* Note that, strictly speaking, some architectures may re-enter the kdb
* trap if the system turns out to be very badly damaged and this breaks
* the single-threaded assumption above. In these circumstances successful
* continuation and exit from the inner trap is unlikely to work and any
* user attempting this receives a prominent warning before being allowed
* to progress. In these circumstances we remain memory safe because
* namebuf[KSYM_NAME_LEN-1] will never change from '\0' although we do
* tolerate the possibility of garbled symbol display from the outer kdb
* trap.
*
* Return:
* * 0 - No sections contain this address, symtab zero filled
* * 1 - Address mapped to module/symbol/section, data in symtab
*/
int kdbnearsym(unsigned long addr, kdb_symtab_t *symtab)
{
int ret = 0;
unsigned long symbolsize = 0;
unsigned long offset = 0;
static char namebuf[KSYM_NAME_LEN];
kdb_dbg_printf(AR, "addr=0x%lx, symtab=%px\n", addr, symtab);
memset(symtab, 0, sizeof(*symtab));
if (addr < 4096)
goto out;
symtab->sym_name = kallsyms_lookup(addr, &symbolsize , &offset,
(char **)(&symtab->mod_name), namebuf);
if (offset > 8*1024*1024) {
symtab->sym_name = NULL;
addr = offset = symbolsize = 0;
}
symtab->sym_start = addr - offset;
symtab->sym_end = symtab->sym_start + symbolsize;
ret = symtab->sym_name != NULL && *(symtab->sym_name) != '\0';
if (symtab->mod_name == NULL)
symtab->mod_name = "kernel";
kdb_dbg_printf(AR, "returns %d symtab->sym_start=0x%lx, symtab->mod_name=%px, symtab->sym_name=%px (%s)\n",
ret, symtab->sym_start, symtab->mod_name, symtab->sym_name, symtab->sym_name);
out:
return ret;
}
static char ks_namebuf[KSYM_NAME_LEN+1], ks_namebuf_prev[KSYM_NAME_LEN+1];
/*
* kallsyms_symbol_complete
*
* Parameters:
* prefix_name prefix of a symbol name to lookup
* max_len maximum length that can be returned
* Returns:
* Number of symbols which match the given prefix.
* Notes:
* prefix_name is changed to contain the longest unique prefix that
* starts with this prefix (tab completion).
*/
int kallsyms_symbol_complete(char *prefix_name, int max_len)
{
loff_t pos = 0;
int prefix_len = strlen(prefix_name), prev_len = 0;
int i, number = 0;
const char *name;
while ((name = kdb_walk_kallsyms(&pos))) {
if (strncmp(name, prefix_name, prefix_len) == 0) {
strscpy(ks_namebuf, name, sizeof(ks_namebuf));
/* Work out the longest name that matches the prefix */
if (++number == 1) {
prev_len = min_t(int, max_len-1,
strlen(ks_namebuf));
memcpy(ks_namebuf_prev, ks_namebuf, prev_len);
ks_namebuf_prev[prev_len] = '\0';
continue;
}
for (i = 0; i < prev_len; i++) {
if (ks_namebuf[i] != ks_namebuf_prev[i]) {
prev_len = i;
ks_namebuf_prev[i] = '\0';
break;
}
}
}
}
if (prev_len > prefix_len)
memcpy(prefix_name, ks_namebuf_prev, prev_len+1);
return number;
}
/*
* kallsyms_symbol_next
*
* Parameters:
* prefix_name prefix of a symbol name to lookup
* flag 0 means search from the head, 1 means continue search.
* buf_size maximum length that can be written to prefix_name
* buffer
* Returns:
* 1 if a symbol matches the given prefix.
* 0 if no string found
*/
int kallsyms_symbol_next(char *prefix_name, int flag, int buf_size)
{
int prefix_len = strlen(prefix_name);
static loff_t pos;
const char *name;
if (!flag)
pos = 0;
while ((name = kdb_walk_kallsyms(&pos))) {
if (!strncmp(name, prefix_name, prefix_len))
return strscpy(prefix_name, name, buf_size);
}
return 0;
}
/*
* kdb_symbol_print - Standard method for printing a symbol name and offset.
* Inputs:
* addr Address to be printed.
* symtab Address of symbol data, if NULL this routine does its
* own lookup.
* punc Punctuation for string, bit field.
* Remarks:
* The string and its punctuation is only printed if the address
* is inside the kernel, except that the value is always printed
* when requested.
*/
void kdb_symbol_print(unsigned long addr, const kdb_symtab_t *symtab_p,
unsigned int punc)
{
kdb_symtab_t symtab, *symtab_p2;
if (symtab_p) {
symtab_p2 = (kdb_symtab_t *)symtab_p;
} else {
symtab_p2 = &symtab;
kdbnearsym(addr, symtab_p2);
}
if (!(symtab_p2->sym_name || (punc & KDB_SP_VALUE)))
return;
if (punc & KDB_SP_SPACEB)
kdb_printf(" ");
if (punc & KDB_SP_VALUE)
kdb_printf(kdb_machreg_fmt0, addr);
if (symtab_p2->sym_name) {
if (punc & KDB_SP_VALUE)
kdb_printf(" ");
if (punc & KDB_SP_PAREN)
kdb_printf("(");
if (strcmp(symtab_p2->mod_name, "kernel"))
kdb_printf("[%s]", symtab_p2->mod_name);
kdb_printf("%s", symtab_p2->sym_name);
if (addr != symtab_p2->sym_start)
kdb_printf("+0x%lx", addr - symtab_p2->sym_start);
if (punc & KDB_SP_SYMSIZE)
kdb_printf("/0x%lx",
symtab_p2->sym_end - symtab_p2->sym_start);
if (punc & KDB_SP_PAREN)
kdb_printf(")");
}
if (punc & KDB_SP_SPACEA)
kdb_printf(" ");
if (punc & KDB_SP_NEWLINE)
kdb_printf("\n");
}
/*
* kdb_strdup - kdb equivalent of strdup, for disasm code.
* Inputs:
* str The string to duplicate.
* type Flags to kmalloc for the new string.
* Returns:
* Address of the new string, NULL if storage could not be allocated.
* Remarks:
* This is not in lib/string.c because it uses kmalloc which is not
* available when string.o is used in boot loaders.
*/
char *kdb_strdup(const char *str, gfp_t type)
{
int n = strlen(str)+1;
char *s = kmalloc(n, type);
if (!s)
return NULL;
return strcpy(s, str);
}
/*
* kdb_getarea_size - Read an area of data. The kdb equivalent of
* copy_from_user, with kdb messages for invalid addresses.
* Inputs:
* res Pointer to the area to receive the result.
* addr Address of the area to copy.
* size Size of the area.
* Returns:
* 0 for success, < 0 for error.
*/
int kdb_getarea_size(void *res, unsigned long addr, size_t size)
{
int ret = copy_from_kernel_nofault((char *)res, (char *)addr, size);
if (ret) {
if (!KDB_STATE(SUPPRESS)) {
kdb_func_printf("Bad address 0x%lx\n", addr);
KDB_STATE_SET(SUPPRESS);
}
ret = KDB_BADADDR;
} else {
KDB_STATE_CLEAR(SUPPRESS);
}
return ret;
}
/*
* kdb_putarea_size - Write an area of data. The kdb equivalent of
* copy_to_user, with kdb messages for invalid addresses.
* Inputs:
* addr Address of the area to write to.
* res Pointer to the area holding the data.
* size Size of the area.
* Returns:
* 0 for success, < 0 for error.
*/
int kdb_putarea_size(unsigned long addr, void *res, size_t size)
{
int ret = copy_to_kernel_nofault((char *)addr, (char *)res, size);
if (ret) {
if (!KDB_STATE(SUPPRESS)) {
kdb_func_printf("Bad address 0x%lx\n", addr);
KDB_STATE_SET(SUPPRESS);
}
ret = KDB_BADADDR;
} else {
KDB_STATE_CLEAR(SUPPRESS);
}
return ret;
}
/*
* kdb_getphys - Read data from a physical address. Validate the
* address is in range, use kmap_atomic() to get data
* similar to kdb_getarea() - but for phys addresses
* Inputs:
* res Pointer to the word to receive the result
* addr Physical address of the area to copy
* size Size of the area
* Returns:
* 0 for success, < 0 for error.
*/
static int kdb_getphys(void *res, unsigned long addr, size_t size)
{
unsigned long pfn;
void *vaddr;
struct page *page;
pfn = (addr >> PAGE_SHIFT);
if (!pfn_valid(pfn))
return 1;
page = pfn_to_page(pfn);
vaddr = kmap_atomic(page);
memcpy(res, vaddr + (addr & (PAGE_SIZE - 1)), size);
kunmap_atomic(vaddr);
return 0;
}
/*
* kdb_getphysword
* Inputs:
* word Pointer to the word to receive the result.
* addr Address of the area to copy.
* size Size of the area.
* Returns:
* 0 for success, < 0 for error.
*/
int kdb_getphysword(unsigned long *word, unsigned long addr, size_t size)
{
int diag;
__u8 w1;
__u16 w2;
__u32 w4;
__u64 w8;
*word = 0; /* Default value if addr or size is invalid */
switch (size) {
case 1:
diag = kdb_getphys(&w1, addr, sizeof(w1));
if (!diag)
*word = w1;
break;
case 2:
diag = kdb_getphys(&w2, addr, sizeof(w2));
if (!diag)
*word = w2;
break;
case 4:
diag = kdb_getphys(&w4, addr, sizeof(w4));
if (!diag)
*word = w4;
break;
case 8:
if (size <= sizeof(*word)) {
diag = kdb_getphys(&w8, addr, sizeof(w8));
if (!diag)
*word = w8;
break;
}
fallthrough;
default:
diag = KDB_BADWIDTH;
kdb_func_printf("bad width %zu\n", size);
}
return diag;
}
/*
* kdb_getword - Read a binary value. Unlike kdb_getarea, this treats
* data as numbers.
* Inputs:
* word Pointer to the word to receive the result.
* addr Address of the area to copy.
* size Size of the area.
* Returns:
* 0 for success, < 0 for error.
*/
int kdb_getword(unsigned long *word, unsigned long addr, size_t size)
{
int diag;
__u8 w1;
__u16 w2;
__u32 w4;
__u64 w8;
*word = 0; /* Default value if addr or size is invalid */
switch (size) {
case 1:
diag = kdb_getarea(w1, addr);
if (!diag)
*word = w1;
break;
case 2:
diag = kdb_getarea(w2, addr);
if (!diag)
*word = w2;
break;
case 4:
diag = kdb_getarea(w4, addr);
if (!diag)
*word = w4;
break;
case 8:
if (size <= sizeof(*word)) {
diag = kdb_getarea(w8, addr);
if (!diag)
*word = w8;
break;
}
fallthrough;
default:
diag = KDB_BADWIDTH;
kdb_func_printf("bad width %zu\n", size);
}
return diag;
}
/*
* kdb_putword - Write a binary value. Unlike kdb_putarea, this
* treats data as numbers.
* Inputs:
* addr Address of the area to write to..
* word The value to set.
* size Size of the area.
* Returns:
* 0 for success, < 0 for error.
*/
int kdb_putword(unsigned long addr, unsigned long word, size_t size)
{
int diag;
__u8 w1;
__u16 w2;
__u32 w4;
__u64 w8;
switch (size) {
case 1:
w1 = word;
diag = kdb_putarea(addr, w1);
break;
case 2:
w2 = word;
diag = kdb_putarea(addr, w2);
break;
case 4:
w4 = word;
diag = kdb_putarea(addr, w4);
break;
case 8:
if (size <= sizeof(word)) {
w8 = word;
diag = kdb_putarea(addr, w8);
break;
}
fallthrough;
default:
diag = KDB_BADWIDTH;
kdb_func_printf("bad width %zu\n", size);
}
return diag;
}
/*
* kdb_task_state_char - Return the character that represents the task state.
* Inputs:
* p struct task for the process
* Returns:
* One character to represent the task state.
*/
char kdb_task_state_char (const struct task_struct *p)
{
unsigned long tmp;
char state;
int cpu;
if (!p ||
copy_from_kernel_nofault(&tmp, (char *)p, sizeof(unsigned long)))
return 'E';
state = task_state_to_char((struct task_struct *) p);
if (is_idle_task(p)) {
/* Idle task. Is it really idle, apart from the kdb
* interrupt? */
cpu = kdb_process_cpu(p);
if (!kdb_task_has_cpu(p) || kgdb_info[cpu].irq_depth == 1) {
if (cpu != kdb_initial_cpu)
state = '-'; /* idle task */
}
} else if (!p->mm && strchr("IMS", state)) {
state = tolower(state); /* sleeping system daemon */
}
return state;
}
/*
* kdb_task_state - Return true if a process has the desired state
* given by the mask.
* Inputs:
* p struct task for the process
* mask set of characters used to select processes; both NULL
* and the empty string mean adopt a default filter, which
* is to suppress sleeping system daemons and the idle tasks
* Returns:
* True if the process matches at least one criteria defined by the mask.
*/
bool kdb_task_state(const struct task_struct *p, const char *mask)
{
char state = kdb_task_state_char(p);
/* If there is no mask, then we will filter code that runs when the
* scheduler is idling and any system daemons that are currently
* sleeping.
*/
if (!mask || mask[0] == '\0')
return !strchr("-ims", state);
/* A is a special case that matches all states */
if (strchr(mask, 'A'))
return true;
return strchr(mask, state);
}
/* Maintain a small stack of kdb_flags to allow recursion without disturbing
* the global kdb state.
*/
static int kdb_flags_stack[4], kdb_flags_index;
void kdb_save_flags(void)
{
BUG_ON(kdb_flags_index >= ARRAY_SIZE(kdb_flags_stack));
kdb_flags_stack[kdb_flags_index++] = kdb_flags;
}
void kdb_restore_flags(void)
{
BUG_ON(kdb_flags_index <= 0);
kdb_flags = kdb_flags_stack[--kdb_flags_index];
}
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