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Diffstat (limited to 'kernel/debug/kdb/kdb_support.c')
-rw-r--r--kernel/debug/kdb/kdb_support.c513
1 files changed, 71 insertions, 442 deletions
diff --git a/kernel/debug/kdb/kdb_support.c b/kernel/debug/kdb/kdb_support.c
index b8e6306e7e13..0a39497140bf 100644
--- a/kernel/debug/kdb/kdb_support.c
+++ b/kernel/debug/kdb/kdb_support.c
@@ -10,7 +10,6 @@
* 03/02/13 added new 2.5 kallsyms <xavier.bru@bull.net>
*/
-#include <stdarg.h>
#include <linux/types.h>
#include <linux/sched.h>
#include <linux/mm.h>
@@ -18,13 +17,13 @@
#include <linux/stddef.h>
#include <linux/vmalloc.h>
#include <linux/ptrace.h>
-#include <linux/module.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"
/*
@@ -39,68 +38,61 @@
*/
int kdbgetsymval(const char *symname, kdb_symtab_t *symtab)
{
- if (KDB_DEBUG(AR))
- kdb_printf("kdbgetsymval: symname=%s, symtab=%px\n", symname,
- 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) {
- if (KDB_DEBUG(AR))
- kdb_printf("kdbgetsymval: returns 1, "
- "symtab->sym_start=0x%lx\n",
- symtab->sym_start);
+ kdb_dbg_printf(AR, "returns 1, symtab->sym_start=0x%lx\n",
+ symtab->sym_start);
return 1;
}
- if (KDB_DEBUG(AR))
- kdb_printf("kdbgetsymval: returns 0\n");
+ kdb_dbg_printf(AR, "returns 0\n");
return 0;
}
EXPORT_SYMBOL(kdbgetsymval);
-static char *kdb_name_table[100]; /* arbitrary size */
-
-/*
- * kdbnearsym - Return the name of the symbol with the nearest address
- * less than 'addr'.
+/**
+ * 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
*
- * Parameters:
- * addr Address to check for symbol near
- * symtab Structure to receive results
- * Returns:
- * 0 No sections contain this address, symtab zero filled
- * 1 Address mapped to module/symbol/section, data in symtab
- * Remarks:
- * 2.6 kallsyms has a "feature" where it unpacks the name into a
- * string. If that string is reused before the caller expects it
- * then the caller sees its string change without warning. To
- * avoid cluttering up the main kdb code with lots of kdb_strdup,
- * tests and kfree calls, kdbnearsym maintains an LRU list of the
- * last few unique strings. The list is sized large enough to
- * hold active strings, no kdb caller of kdbnearsym makes more
- * than ~20 later calls before using a saved value.
+ * 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;
-#define knt1_size 128 /* must be >= kallsyms table size */
- char *knt1 = NULL;
+ static char namebuf[KSYM_NAME_LEN];
- if (KDB_DEBUG(AR))
- kdb_printf("kdbnearsym: addr=0x%lx, symtab=%px\n", addr, symtab);
+ kdb_dbg_printf(AR, "addr=0x%lx, symtab=%px\n", addr, symtab);
memset(symtab, 0, sizeof(*symtab));
if (addr < 4096)
goto out;
- knt1 = debug_kmalloc(knt1_size, GFP_ATOMIC);
- if (!knt1) {
- kdb_printf("kdbnearsym: addr=0x%lx cannot kmalloc knt1\n",
- addr);
- goto out;
- }
+
symtab->sym_name = kallsyms_lookup(addr, &symbolsize , &offset,
- (char **)(&symtab->mod_name), knt1);
+ (char **)(&symtab->mod_name), namebuf);
if (offset > 8*1024*1024) {
symtab->sym_name = NULL;
addr = offset = symbolsize = 0;
@@ -109,66 +101,14 @@ int kdbnearsym(unsigned long addr, kdb_symtab_t *symtab)
symtab->sym_end = symtab->sym_start + symbolsize;
ret = symtab->sym_name != NULL && *(symtab->sym_name) != '\0';
- if (ret) {
- int i;
- /* Another 2.6 kallsyms "feature". Sometimes the sym_name is
- * set but the buffer passed into kallsyms_lookup is not used,
- * so it contains garbage. The caller has to work out which
- * buffer needs to be saved.
- *
- * What was Rusty smoking when he wrote that code?
- */
- if (symtab->sym_name != knt1) {
- strncpy(knt1, symtab->sym_name, knt1_size);
- knt1[knt1_size-1] = '\0';
- }
- for (i = 0; i < ARRAY_SIZE(kdb_name_table); ++i) {
- if (kdb_name_table[i] &&
- strcmp(kdb_name_table[i], knt1) == 0)
- break;
- }
- if (i >= ARRAY_SIZE(kdb_name_table)) {
- debug_kfree(kdb_name_table[0]);
- memmove(kdb_name_table, kdb_name_table+1,
- sizeof(kdb_name_table[0]) *
- (ARRAY_SIZE(kdb_name_table)-1));
- } else {
- debug_kfree(knt1);
- knt1 = kdb_name_table[i];
- memmove(kdb_name_table+i, kdb_name_table+i+1,
- sizeof(kdb_name_table[0]) *
- (ARRAY_SIZE(kdb_name_table)-i-1));
- }
- i = ARRAY_SIZE(kdb_name_table) - 1;
- kdb_name_table[i] = knt1;
- symtab->sym_name = kdb_name_table[i];
- knt1 = NULL;
- }
-
if (symtab->mod_name == NULL)
symtab->mod_name = "kernel";
- if (KDB_DEBUG(AR))
- kdb_printf("kdbnearsym: 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);
-
+ 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:
- debug_kfree(knt1);
return ret;
}
-void kdbnearsym_cleanup(void)
-{
- int i;
- for (i = 0; i < ARRAY_SIZE(kdb_name_table); ++i) {
- if (kdb_name_table[i]) {
- debug_kfree(kdb_name_table[i]);
- kdb_name_table[i] = NULL;
- }
- }
-}
-
static char ks_namebuf[KSYM_NAME_LEN+1], ks_namebuf_prev[KSYM_NAME_LEN+1];
/*
@@ -325,10 +265,10 @@ char *kdb_strdup(const char *str, gfp_t type)
*/
int kdb_getarea_size(void *res, unsigned long addr, size_t size)
{
- int ret = probe_kernel_read((char *)res, (char *)addr, size);
+ int ret = copy_from_kernel_nofault((char *)res, (char *)addr, size);
if (ret) {
if (!KDB_STATE(SUPPRESS)) {
- kdb_printf("kdb_getarea: Bad address 0x%lx\n", addr);
+ kdb_func_printf("Bad address 0x%lx\n", addr);
KDB_STATE_SET(SUPPRESS);
}
ret = KDB_BADADDR;
@@ -350,10 +290,10 @@ int kdb_getarea_size(void *res, unsigned long addr, size_t size)
*/
int kdb_putarea_size(unsigned long addr, void *res, size_t size)
{
- int ret = probe_kernel_read((char *)addr, (char *)res, size);
+ int ret = copy_to_kernel_nofault((char *)addr, (char *)res, size);
if (ret) {
if (!KDB_STATE(SUPPRESS)) {
- kdb_printf("kdb_putarea: Bad address 0x%lx\n", addr);
+ kdb_func_printf("Bad address 0x%lx\n", addr);
KDB_STATE_SET(SUPPRESS);
}
ret = KDB_BADADDR;
@@ -432,10 +372,10 @@ int kdb_getphysword(unsigned long *word, unsigned long addr, size_t size)
*word = w8;
break;
}
- /* fall through */
+ fallthrough;
default:
diag = KDB_BADWIDTH;
- kdb_printf("kdb_getphysword: bad width %ld\n", (long) size);
+ kdb_func_printf("bad width %zu\n", size);
}
return diag;
}
@@ -481,10 +421,10 @@ int kdb_getword(unsigned long *word, unsigned long addr, size_t size)
*word = w8;
break;
}
- /* fall through */
+ fallthrough;
default:
diag = KDB_BADWIDTH;
- kdb_printf("kdb_getword: bad width %ld\n", (long) size);
+ kdb_func_printf("bad width %zu\n", size);
}
return diag;
}
@@ -525,91 +465,15 @@ int kdb_putword(unsigned long addr, unsigned long word, size_t size)
diag = kdb_putarea(addr, w8);
break;
}
- /* fall through */
+ fallthrough;
default:
diag = KDB_BADWIDTH;
- kdb_printf("kdb_putword: bad width %ld\n", (long) size);
+ kdb_func_printf("bad width %zu\n", size);
}
return diag;
}
-/*
- * kdb_task_state_string - Convert a string containing any of the
- * letters DRSTCZEUIMA to a mask for the process state field and
- * return the value. If no argument is supplied, return the mask
- * that corresponds to environment variable PS, DRSTCZEU by
- * default.
- * Inputs:
- * s String to convert
- * Returns:
- * Mask for process state.
- * Notes:
- * The mask folds data from several sources into a single long value, so
- * be careful not to overlap the bits. TASK_* bits are in the LSB,
- * special cases like UNRUNNABLE are in the MSB. As of 2.6.10-rc1 there
- * is no overlap between TASK_* and EXIT_* but that may not always be
- * true, so EXIT_* bits are shifted left 16 bits before being stored in
- * the mask.
- */
-
-/* unrunnable is < 0 */
-#define UNRUNNABLE (1UL << (8*sizeof(unsigned long) - 1))
-#define RUNNING (1UL << (8*sizeof(unsigned long) - 2))
-#define IDLE (1UL << (8*sizeof(unsigned long) - 3))
-#define DAEMON (1UL << (8*sizeof(unsigned long) - 4))
-unsigned long kdb_task_state_string(const char *s)
-{
- long res = 0;
- if (!s) {
- s = kdbgetenv("PS");
- if (!s)
- s = "DRSTCZEU"; /* default value for ps */
- }
- while (*s) {
- switch (*s) {
- case 'D':
- res |= TASK_UNINTERRUPTIBLE;
- break;
- case 'R':
- res |= RUNNING;
- break;
- case 'S':
- res |= TASK_INTERRUPTIBLE;
- break;
- case 'T':
- res |= TASK_STOPPED;
- break;
- case 'C':
- res |= TASK_TRACED;
- break;
- case 'Z':
- res |= EXIT_ZOMBIE << 16;
- break;
- case 'E':
- res |= EXIT_DEAD << 16;
- break;
- case 'U':
- res |= UNRUNNABLE;
- break;
- case 'I':
- res |= IDLE;
- break;
- case 'M':
- res |= DAEMON;
- break;
- case 'A':
- res = ~0UL;
- break;
- default:
- kdb_printf("%s: unknown flag '%c' ignored\n",
- __func__, *s);
- break;
- }
- ++s;
- }
- return res;
-}
/*
* kdb_task_state_char - Return the character that represents the task state.
@@ -620,31 +484,26 @@ unsigned long kdb_task_state_string(const char *s)
*/
char kdb_task_state_char (const struct task_struct *p)
{
- int cpu;
- char state;
unsigned long tmp;
+ char state;
+ int cpu;
- if (!p || probe_kernel_read(&tmp, (char *)p, sizeof(unsigned long)))
+ if (!p ||
+ copy_from_kernel_nofault(&tmp, (char *)p, sizeof(unsigned long)))
return 'E';
- cpu = kdb_process_cpu(p);
- state = (p->state == 0) ? 'R' :
- (p->state < 0) ? 'U' :
- (p->state & TASK_UNINTERRUPTIBLE) ? 'D' :
- (p->state & TASK_STOPPED) ? 'T' :
- (p->state & TASK_TRACED) ? 'C' :
- (p->exit_state & EXIT_ZOMBIE) ? 'Z' :
- (p->exit_state & EXIT_DEAD) ? 'E' :
- (p->state & TASK_INTERRUPTIBLE) ? 'S' : '?';
+ 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 = 'I'; /* idle task */
+ state = '-'; /* idle task */
}
- } else if (!p->mm && state == 'S') {
- state = 'M'; /* sleeping system daemon */
+ } else if (!p->mm && strchr("IMS", state)) {
+ state = tolower(state); /* sleeping system daemon */
}
return state;
}
@@ -654,258 +513,28 @@ char kdb_task_state_char (const struct task_struct *p)
* given by the mask.
* Inputs:
* p struct task for the process
- * mask mask from kdb_task_state_string to select processes
+ * 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.
*/
-unsigned long kdb_task_state(const struct task_struct *p, unsigned long mask)
+bool kdb_task_state(const struct task_struct *p, const char *mask)
{
- char state[] = { kdb_task_state_char(p), '\0' };
- return (mask & kdb_task_state_string(state)) != 0;
-}
+ char state = kdb_task_state_char(p);
-/*
- * kdb_print_nameval - Print a name and its value, converting the
- * value to a symbol lookup if possible.
- * Inputs:
- * name field name to print
- * val value of field
- */
-void kdb_print_nameval(const char *name, unsigned long val)
-{
- kdb_symtab_t symtab;
- kdb_printf(" %-11.11s ", name);
- if (kdbnearsym(val, &symtab))
- kdb_symbol_print(val, &symtab,
- KDB_SP_VALUE|KDB_SP_SYMSIZE|KDB_SP_NEWLINE);
- else
- kdb_printf("0x%lx\n", val);
-}
-
-/* Last ditch allocator for debugging, so we can still debug even when
- * the GFP_ATOMIC pool has been exhausted. The algorithms are tuned
- * for space usage, not for speed. One smallish memory pool, the free
- * chain is always in ascending address order to allow coalescing,
- * allocations are done in brute force best fit.
- */
-
-struct debug_alloc_header {
- u32 next; /* offset of next header from start of pool */
- u32 size;
- void *caller;
-};
-
-/* The memory returned by this allocator must be aligned, which means
- * so must the header size. Do not assume that sizeof(struct
- * debug_alloc_header) is a multiple of the alignment, explicitly
- * calculate the overhead of this header, including the alignment.
- * The rest of this code must not use sizeof() on any header or
- * pointer to a header.
- */
-#define dah_align 8
-#define dah_overhead ALIGN(sizeof(struct debug_alloc_header), dah_align)
-
-static u64 debug_alloc_pool_aligned[256*1024/dah_align]; /* 256K pool */
-static char *debug_alloc_pool = (char *)debug_alloc_pool_aligned;
-static u32 dah_first, dah_first_call = 1, dah_used, dah_used_max;
-
-/* Locking is awkward. The debug code is called from all contexts,
- * including non maskable interrupts. A normal spinlock is not safe
- * in NMI context. Try to get the debug allocator lock, if it cannot
- * be obtained after a second then give up. If the lock could not be
- * previously obtained on this cpu then only try once.
- *
- * sparse has no annotation for "this function _sometimes_ acquires a
- * lock", so fudge the acquire/release notation.
- */
-static DEFINE_SPINLOCK(dap_lock);
-static int get_dap_lock(void)
- __acquires(dap_lock)
-{
- static int dap_locked = -1;
- int count;
- if (dap_locked == smp_processor_id())
- count = 1;
- else
- count = 1000;
- while (1) {
- if (spin_trylock(&dap_lock)) {
- dap_locked = -1;
- return 1;
- }
- if (!count--)
- break;
- udelay(1000);
- }
- dap_locked = smp_processor_id();
- __acquire(dap_lock);
- return 0;
-}
-
-void *debug_kmalloc(size_t size, gfp_t flags)
-{
- unsigned int rem, h_offset;
- struct debug_alloc_header *best, *bestprev, *prev, *h;
- void *p = NULL;
- if (!get_dap_lock()) {
- __release(dap_lock); /* we never actually got it */
- return NULL;
- }
- h = (struct debug_alloc_header *)(debug_alloc_pool + dah_first);
- if (dah_first_call) {
- h->size = sizeof(debug_alloc_pool_aligned) - dah_overhead;
- dah_first_call = 0;
- }
- size = ALIGN(size, dah_align);
- prev = best = bestprev = NULL;
- while (1) {
- if (h->size >= size && (!best || h->size < best->size)) {
- best = h;
- bestprev = prev;
- if (h->size == size)
- break;
- }
- if (!h->next)
- break;
- prev = h;
- h = (struct debug_alloc_header *)(debug_alloc_pool + h->next);
- }
- if (!best)
- goto out;
- rem = best->size - size;
- /* The pool must always contain at least one header */
- if (best->next == 0 && bestprev == NULL && rem < dah_overhead)
- goto out;
- if (rem >= dah_overhead) {
- best->size = size;
- h_offset = ((char *)best - debug_alloc_pool) +
- dah_overhead + best->size;
- h = (struct debug_alloc_header *)(debug_alloc_pool + h_offset);
- h->size = rem - dah_overhead;
- h->next = best->next;
- } else
- h_offset = best->next;
- best->caller = __builtin_return_address(0);
- dah_used += best->size;
- dah_used_max = max(dah_used, dah_used_max);
- if (bestprev)
- bestprev->next = h_offset;
- else
- dah_first = h_offset;
- p = (char *)best + dah_overhead;
- memset(p, POISON_INUSE, best->size - 1);
- *((char *)p + best->size - 1) = POISON_END;
-out:
- spin_unlock(&dap_lock);
- return 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);
-void debug_kfree(void *p)
-{
- struct debug_alloc_header *h;
- unsigned int h_offset;
- if (!p)
- return;
- if ((char *)p < debug_alloc_pool ||
- (char *)p >= debug_alloc_pool + sizeof(debug_alloc_pool_aligned)) {
- kfree(p);
- return;
- }
- if (!get_dap_lock()) {
- __release(dap_lock); /* we never actually got it */
- return; /* memory leak, cannot be helped */
- }
- h = (struct debug_alloc_header *)((char *)p - dah_overhead);
- memset(p, POISON_FREE, h->size - 1);
- *((char *)p + h->size - 1) = POISON_END;
- h->caller = NULL;
- dah_used -= h->size;
- h_offset = (char *)h - debug_alloc_pool;
- if (h_offset < dah_first) {
- h->next = dah_first;
- dah_first = h_offset;
- } else {
- struct debug_alloc_header *prev;
- unsigned int prev_offset;
- prev = (struct debug_alloc_header *)(debug_alloc_pool +
- dah_first);
- while (1) {
- if (!prev->next || prev->next > h_offset)
- break;
- prev = (struct debug_alloc_header *)
- (debug_alloc_pool + prev->next);
- }
- prev_offset = (char *)prev - debug_alloc_pool;
- if (prev_offset + dah_overhead + prev->size == h_offset) {
- prev->size += dah_overhead + h->size;
- memset(h, POISON_FREE, dah_overhead - 1);
- *((char *)h + dah_overhead - 1) = POISON_END;
- h = prev;
- h_offset = prev_offset;
- } else {
- h->next = prev->next;
- prev->next = h_offset;
- }
- }
- if (h_offset + dah_overhead + h->size == h->next) {
- struct debug_alloc_header *next;
- next = (struct debug_alloc_header *)
- (debug_alloc_pool + h->next);
- h->size += dah_overhead + next->size;
- h->next = next->next;
- memset(next, POISON_FREE, dah_overhead - 1);
- *((char *)next + dah_overhead - 1) = POISON_END;
- }
- spin_unlock(&dap_lock);
-}
+ /* A is a special case that matches all states */
+ if (strchr(mask, 'A'))
+ return true;
-void debug_kusage(void)
-{
- struct debug_alloc_header *h_free, *h_used;
-#ifdef CONFIG_IA64
- /* FIXME: using dah for ia64 unwind always results in a memory leak.
- * Fix that memory leak first, then set debug_kusage_one_time = 1 for
- * all architectures.
- */
- static int debug_kusage_one_time;
-#else
- static int debug_kusage_one_time = 1;
-#endif
- if (!get_dap_lock()) {
- __release(dap_lock); /* we never actually got it */
- return;
- }
- h_free = (struct debug_alloc_header *)(debug_alloc_pool + dah_first);
- if (dah_first == 0 &&
- (h_free->size == sizeof(debug_alloc_pool_aligned) - dah_overhead ||
- dah_first_call))
- goto out;
- if (!debug_kusage_one_time)
- goto out;
- debug_kusage_one_time = 0;
- kdb_printf("%s: debug_kmalloc memory leak dah_first %d\n",
- __func__, dah_first);
- if (dah_first) {
- h_used = (struct debug_alloc_header *)debug_alloc_pool;
- kdb_printf("%s: h_used %px size %d\n", __func__, h_used,
- h_used->size);
- }
- do {
- h_used = (struct debug_alloc_header *)
- ((char *)h_free + dah_overhead + h_free->size);
- kdb_printf("%s: h_used %px size %d caller %px\n",
- __func__, h_used, h_used->size, h_used->caller);
- h_free = (struct debug_alloc_header *)
- (debug_alloc_pool + h_free->next);
- } while (h_free->next);
- h_used = (struct debug_alloc_header *)
- ((char *)h_free + dah_overhead + h_free->size);
- if ((char *)h_used - debug_alloc_pool !=
- sizeof(debug_alloc_pool_aligned))
- kdb_printf("%s: h_used %px size %d caller %px\n",
- __func__, h_used, h_used->size, h_used->caller);
-out:
- spin_unlock(&dap_lock);
+ return strchr(mask, state);
}
/* Maintain a small stack of kdb_flags to allow recursion without disturbing