#include <linux/sched.h>
#include <linux/mutex.h>
#include <linux/list.h>
+#include <linux/stringify.h>
#include <linux/kprobes.h>
#include <linux/mm.h>
#include <linux/vmalloc.h>
+#include <linux/memory.h>
+#include <linux/stop_machine.h>
+#include <linux/slab.h>
#include <asm/alternative.h>
#include <asm/sections.h>
#include <asm/pgtable.h>
#include <asm/nmi.h>
#include <asm/vsyscall.h>
#include <asm/cacheflush.h>
+#include <asm/tlbflush.h>
#include <asm/io.h>
+#include <asm/fixmap.h>
#define MAX_PATCH_LEN (255-1)
#define smp_alt_once 1
#endif
-static int debug_alternative;
+static int __initdata_or_module debug_alternative;
static int __init debug_alt(char *str)
{
__setup("noreplace-smp", setup_noreplace_smp);
#ifdef CONFIG_PARAVIRT
-static int noreplace_paravirt = 0;
+static int __initdata_or_module noreplace_paravirt = 0;
static int __init setup_noreplace_paravirt(char *str)
{
#define DPRINTK(fmt, args...) if (debug_alternative) \
printk(KERN_DEBUG fmt, args)
-#ifdef GENERIC_NOP1
+#if defined(GENERIC_NOP1) && !defined(CONFIG_X86_64)
/* Use inline assembly to define this because the nops are defined
as inline assembly strings in the include files and we cannot
get them easily into strings. */
-asm("\t.section .rodata, \"a\"\nintelnops: "
+asm("\t" __stringify(__INITRODATA_OR_MODULE) "\nintelnops: "
GENERIC_NOP1 GENERIC_NOP2 GENERIC_NOP3 GENERIC_NOP4 GENERIC_NOP5 GENERIC_NOP6
GENERIC_NOP7 GENERIC_NOP8
"\t.previous");
extern const unsigned char intelnops[];
-static const unsigned char *const intel_nops[ASM_NOP_MAX+1] = {
+static const unsigned char *const __initconst_or_module
+intel_nops[ASM_NOP_MAX+1] = {
NULL,
intelnops,
intelnops + 1,
#endif
#ifdef K8_NOP1
-asm("\t.section .rodata, \"a\"\nk8nops: "
+asm("\t" __stringify(__INITRODATA_OR_MODULE) "\nk8nops: "
K8_NOP1 K8_NOP2 K8_NOP3 K8_NOP4 K8_NOP5 K8_NOP6
K8_NOP7 K8_NOP8
"\t.previous");
extern const unsigned char k8nops[];
-static const unsigned char *const k8_nops[ASM_NOP_MAX+1] = {
+static const unsigned char *const __initconst_or_module
+k8_nops[ASM_NOP_MAX+1] = {
NULL,
k8nops,
k8nops + 1,
};
#endif
-#ifdef K7_NOP1
-asm("\t.section .rodata, \"a\"\nk7nops: "
+#if defined(K7_NOP1) && !defined(CONFIG_X86_64)
+asm("\t" __stringify(__INITRODATA_OR_MODULE) "\nk7nops: "
K7_NOP1 K7_NOP2 K7_NOP3 K7_NOP4 K7_NOP5 K7_NOP6
K7_NOP7 K7_NOP8
"\t.previous");
extern const unsigned char k7nops[];
-static const unsigned char *const k7_nops[ASM_NOP_MAX+1] = {
+static const unsigned char *const __initconst_or_module
+k7_nops[ASM_NOP_MAX+1] = {
NULL,
k7nops,
k7nops + 1,
#endif
#ifdef P6_NOP1
-asm("\t.section .rodata, \"a\"\np6nops: "
+asm("\t" __stringify(__INITRODATA_OR_MODULE) "\np6nops: "
P6_NOP1 P6_NOP2 P6_NOP3 P6_NOP4 P6_NOP5 P6_NOP6
P6_NOP7 P6_NOP8
"\t.previous");
extern const unsigned char p6nops[];
-static const unsigned char *const p6_nops[ASM_NOP_MAX+1] = {
+static const unsigned char *const __initconst_or_module
+p6_nops[ASM_NOP_MAX+1] = {
NULL,
p6nops,
p6nops + 1,
#ifdef CONFIG_X86_64
extern char __vsyscall_0;
-const unsigned char *const *find_nop_table(void)
+static const unsigned char *const *__init_or_module find_nop_table(void)
{
if (boot_cpu_data.x86_vendor == X86_VENDOR_INTEL &&
boot_cpu_has(X86_FEATURE_NOPL))
#else /* CONFIG_X86_64 */
-const unsigned char *const *find_nop_table(void)
+static const unsigned char *const *__init_or_module find_nop_table(void)
{
if (boot_cpu_has(X86_FEATURE_K8))
return k8_nops;
#endif /* CONFIG_X86_64 */
/* Use this to add nops to a buffer, then text_poke the whole buffer. */
-void add_nops(void *insns, unsigned int len)
+static void __init_or_module add_nops(void *insns, unsigned int len)
{
const unsigned char *const *noptable = find_nop_table();
len -= noplen;
}
}
-EXPORT_SYMBOL_GPL(add_nops);
extern struct alt_instr __alt_instructions[], __alt_instructions_end[];
extern u8 *__smp_locks[], *__smp_locks_end[];
+static void *text_poke_early(void *addr, const void *opcode, size_t len);
/* Replace instructions with better alternatives for this CPU type.
This runs before SMP is initialized to avoid SMP problems with
APs have less capabilities than the boot processor are not handled.
Tough. Make sure you disable such features by hand. */
-void apply_alternatives(struct alt_instr *start, struct alt_instr *end)
+void __init_or_module apply_alternatives(struct alt_instr *start,
+ struct alt_instr *end)
{
struct alt_instr *a;
- char insnbuf[MAX_PATCH_LEN];
+ u8 insnbuf[MAX_PATCH_LEN];
DPRINTK("%s: alt table %p -> %p\n", __func__, start, end);
for (a = start; a < end; a++) {
}
#endif
memcpy(insnbuf, a->replacement, a->replacementlen);
+ if (*insnbuf == 0xe8 && a->replacementlen == 5)
+ *(s32 *)(insnbuf + 1) += a->replacement - a->instr;
add_nops(insnbuf + a->replacementlen,
a->instrlen - a->replacementlen);
text_poke_early(instr, insnbuf, a->instrlen);
{
u8 **ptr;
+ mutex_lock(&text_mutex);
for (ptr = start; ptr < end; ptr++) {
if (*ptr < text)
continue;
if (*ptr > text_end)
continue;
- text_poke(*ptr, ((unsigned char []){0xf0}), 1); /* add lock prefix */
+ /* turn DS segment override prefix into lock prefix */
+ text_poke(*ptr, ((unsigned char []){0xf0}), 1);
};
+ mutex_unlock(&text_mutex);
}
static void alternatives_smp_unlock(u8 **start, u8 **end, u8 *text, u8 *text_end)
{
u8 **ptr;
- char insn[1];
if (noreplace_smp)
return;
- add_nops(insn, 1);
+ mutex_lock(&text_mutex);
for (ptr = start; ptr < end; ptr++) {
if (*ptr < text)
continue;
if (*ptr > text_end)
continue;
- text_poke(*ptr, insn, 1);
+ /* turn lock prefix into DS segment override prefix */
+ text_poke(*ptr, ((unsigned char []){0x3E}), 1);
};
+ mutex_unlock(&text_mutex);
}
struct smp_alt_module {
static DEFINE_MUTEX(smp_alt);
static int smp_mode = 1; /* protected by smp_alt */
-void alternatives_smp_module_add(struct module *mod, char *name,
- void *locks, void *locks_end,
- void *text, void *text_end)
+void __init_or_module alternatives_smp_module_add(struct module *mod,
+ char *name,
+ void *locks, void *locks_end,
+ void *text, void *text_end)
{
struct smp_alt_module *smp;
mutex_unlock(&smp_alt);
}
-void alternatives_smp_module_del(struct module *mod)
+void __init_or_module alternatives_smp_module_del(struct module *mod)
{
struct smp_alt_module *item;
mutex_unlock(&smp_alt);
}
+/* Return 1 if the address range is reserved for smp-alternatives */
+int alternatives_text_reserved(void *start, void *end)
+{
+ struct smp_alt_module *mod;
+ u8 **ptr;
+ u8 *text_start = start;
+ u8 *text_end = end;
+
+ list_for_each_entry(mod, &smp_alt_modules, next) {
+ if (mod->text > text_end || mod->text_end < text_start)
+ continue;
+ for (ptr = mod->locks; ptr < mod->locks_end; ptr++)
+ if (text_start <= *ptr && text_end >= *ptr)
+ return 1;
+ }
+
+ return 0;
+}
#endif
#ifdef CONFIG_PARAVIRT
-void apply_paravirt(struct paravirt_patch_site *start,
- struct paravirt_patch_site *end)
+void __init_or_module apply_paravirt(struct paravirt_patch_site *start,
+ struct paravirt_patch_site *end)
{
struct paravirt_patch_site *p;
char insnbuf[MAX_PATCH_LEN];
that might execute the to be patched code.
Other CPUs are not running. */
stop_nmi();
-#ifdef CONFIG_X86_MCE
- stop_mce();
-#endif
+
+ /*
+ * Don't stop machine check exceptions while patching.
+ * MCEs only happen when something got corrupted and in this
+ * case we must do something about the corruption.
+ * Ignoring it is worse than a unlikely patching race.
+ * Also machine checks tend to be broadcast and if one CPU
+ * goes into machine check the others follow quickly, so we don't
+ * expect a machine check to cause undue problems during to code
+ * patching.
+ */
apply_alternatives(__alt_instructions, __alt_instructions_end);
_text, _etext);
/* Only switch to UP mode if we don't immediately boot others */
- if (num_possible_cpus() == 1 || setup_max_cpus <= 1)
+ if (num_present_cpus() == 1 || setup_max_cpus <= 1)
alternatives_smp_switch(0);
}
#endif
(unsigned long)__smp_locks_end);
restart_nmi();
-#ifdef CONFIG_X86_MCE
- restart_mce();
-#endif
}
/**
* instructions. And on the local CPU you need to be protected again NMI or MCE
* handlers seeing an inconsistent instruction while you patch.
*/
-void *text_poke_early(void *addr, const void *opcode, size_t len)
+static void *__init_or_module text_poke_early(void *addr, const void *opcode,
+ size_t len)
{
unsigned long flags;
local_irq_save(flags);
memcpy(addr, opcode, len);
- local_irq_restore(flags);
sync_core();
+ local_irq_restore(flags);
/* Could also do a CLFLUSH here to speed up CPU recovery; but
that causes hangs on some VIA CPUs. */
return addr;
* It means the size must be writable atomically and the address must be aligned
* in a way that permits an atomic write. It also makes sure we fit on a single
* page.
+ *
+ * Note: Must be called under text_mutex.
*/
void *__kprobes text_poke(void *addr, const void *opcode, size_t len)
{
unsigned long flags;
char *vaddr;
- int nr_pages = 2;
struct page *pages[2];
int i;
pages[1] = virt_to_page(addr + PAGE_SIZE);
}
BUG_ON(!pages[0]);
- if (!pages[1])
- nr_pages = 1;
- vaddr = vmap(pages, nr_pages, VM_MAP, PAGE_KERNEL);
- BUG_ON(!vaddr);
local_irq_save(flags);
+ set_fixmap(FIX_TEXT_POKE0, page_to_phys(pages[0]));
+ if (pages[1])
+ set_fixmap(FIX_TEXT_POKE1, page_to_phys(pages[1]));
+ vaddr = (char *)fix_to_virt(FIX_TEXT_POKE0);
memcpy(&vaddr[(unsigned long)addr & ~PAGE_MASK], opcode, len);
- local_irq_restore(flags);
- vunmap(vaddr);
+ clear_fixmap(FIX_TEXT_POKE0);
+ if (pages[1])
+ clear_fixmap(FIX_TEXT_POKE1);
+ local_flush_tlb();
sync_core();
/* Could also do a CLFLUSH here to speed up CPU recovery; but
that causes hangs on some VIA CPUs. */
for (i = 0; i < len; i++)
BUG_ON(((char *)addr)[i] != ((char *)opcode)[i]);
+ local_irq_restore(flags);
+ return addr;
+}
+
+/*
+ * Cross-modifying kernel text with stop_machine().
+ * This code originally comes from immediate value.
+ */
+static atomic_t stop_machine_first;
+static int wrote_text;
+
+struct text_poke_params {
+ void *addr;
+ const void *opcode;
+ size_t len;
+};
+
+static int __kprobes stop_machine_text_poke(void *data)
+{
+ struct text_poke_params *tpp = data;
+
+ if (atomic_dec_and_test(&stop_machine_first)) {
+ text_poke(tpp->addr, tpp->opcode, tpp->len);
+ smp_wmb(); /* Make sure other cpus see that this has run */
+ wrote_text = 1;
+ } else {
+ while (!wrote_text)
+ cpu_relax();
+ smp_mb(); /* Load wrote_text before following execution */
+ }
+
+ flush_icache_range((unsigned long)tpp->addr,
+ (unsigned long)tpp->addr + tpp->len);
+ return 0;
+}
+
+/**
+ * text_poke_smp - Update instructions on a live kernel on SMP
+ * @addr: address to modify
+ * @opcode: source of the copy
+ * @len: length to copy
+ *
+ * Modify multi-byte instruction by using stop_machine() on SMP. This allows
+ * user to poke/set multi-byte text on SMP. Only non-NMI/MCE code modifying
+ * should be allowed, since stop_machine() does _not_ protect code against
+ * NMI and MCE.
+ *
+ * Note: Must be called under get_online_cpus() and text_mutex.
+ */
+void *__kprobes text_poke_smp(void *addr, const void *opcode, size_t len)
+{
+ struct text_poke_params tpp;
+
+ tpp.addr = addr;
+ tpp.opcode = opcode;
+ tpp.len = len;
+ atomic_set(&stop_machine_first, 1);
+ wrote_text = 0;
+ stop_machine(stop_machine_text_poke, (void *)&tpp, NULL);
return addr;
}
+
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff