forked from Minki/linux
9489cc8f37
The text patching functions which are invoked from jump_label and kprobes code are protected against cpu hotplug at the call sites. Use stop_machine_cpuslocked() to avoid recursion on the cpu hotplug rwsem. stop_machine_cpuslocked() contains a lockdep assertion to catch any unprotected callers. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Ingo Molnar <mingo@kernel.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Sebastian Siewior <bigeasy@linutronix.de> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Russell King <linux@armlinux.org.uk> Cc: linux-arm-kernel@lists.infradead.org Link: http://lkml.kernel.org/r/20170524081549.275871311@linutronix.de
129 lines
2.8 KiB
C
129 lines
2.8 KiB
C
#include <linux/kernel.h>
|
|
#include <linux/spinlock.h>
|
|
#include <linux/kprobes.h>
|
|
#include <linux/mm.h>
|
|
#include <linux/stop_machine.h>
|
|
|
|
#include <asm/cacheflush.h>
|
|
#include <asm/fixmap.h>
|
|
#include <asm/smp_plat.h>
|
|
#include <asm/opcodes.h>
|
|
#include <asm/patch.h>
|
|
|
|
struct patch {
|
|
void *addr;
|
|
unsigned int insn;
|
|
};
|
|
|
|
static DEFINE_SPINLOCK(patch_lock);
|
|
|
|
static void __kprobes *patch_map(void *addr, int fixmap, unsigned long *flags)
|
|
__acquires(&patch_lock)
|
|
{
|
|
unsigned int uintaddr = (uintptr_t) addr;
|
|
bool module = !core_kernel_text(uintaddr);
|
|
struct page *page;
|
|
|
|
if (module && IS_ENABLED(CONFIG_STRICT_MODULE_RWX))
|
|
page = vmalloc_to_page(addr);
|
|
else if (!module && IS_ENABLED(CONFIG_STRICT_KERNEL_RWX))
|
|
page = virt_to_page(addr);
|
|
else
|
|
return addr;
|
|
|
|
if (flags)
|
|
spin_lock_irqsave(&patch_lock, *flags);
|
|
else
|
|
__acquire(&patch_lock);
|
|
|
|
set_fixmap(fixmap, page_to_phys(page));
|
|
|
|
return (void *) (__fix_to_virt(fixmap) + (uintaddr & ~PAGE_MASK));
|
|
}
|
|
|
|
static void __kprobes patch_unmap(int fixmap, unsigned long *flags)
|
|
__releases(&patch_lock)
|
|
{
|
|
clear_fixmap(fixmap);
|
|
|
|
if (flags)
|
|
spin_unlock_irqrestore(&patch_lock, *flags);
|
|
else
|
|
__release(&patch_lock);
|
|
}
|
|
|
|
void __kprobes __patch_text_real(void *addr, unsigned int insn, bool remap)
|
|
{
|
|
bool thumb2 = IS_ENABLED(CONFIG_THUMB2_KERNEL);
|
|
unsigned int uintaddr = (uintptr_t) addr;
|
|
bool twopage = false;
|
|
unsigned long flags;
|
|
void *waddr = addr;
|
|
int size;
|
|
|
|
if (remap)
|
|
waddr = patch_map(addr, FIX_TEXT_POKE0, &flags);
|
|
else
|
|
__acquire(&patch_lock);
|
|
|
|
if (thumb2 && __opcode_is_thumb16(insn)) {
|
|
*(u16 *)waddr = __opcode_to_mem_thumb16(insn);
|
|
size = sizeof(u16);
|
|
} else if (thumb2 && (uintaddr & 2)) {
|
|
u16 first = __opcode_thumb32_first(insn);
|
|
u16 second = __opcode_thumb32_second(insn);
|
|
u16 *addrh0 = waddr;
|
|
u16 *addrh1 = waddr + 2;
|
|
|
|
twopage = (uintaddr & ~PAGE_MASK) == PAGE_SIZE - 2;
|
|
if (twopage && remap)
|
|
addrh1 = patch_map(addr + 2, FIX_TEXT_POKE1, NULL);
|
|
|
|
*addrh0 = __opcode_to_mem_thumb16(first);
|
|
*addrh1 = __opcode_to_mem_thumb16(second);
|
|
|
|
if (twopage && addrh1 != addr + 2) {
|
|
flush_kernel_vmap_range(addrh1, 2);
|
|
patch_unmap(FIX_TEXT_POKE1, NULL);
|
|
}
|
|
|
|
size = sizeof(u32);
|
|
} else {
|
|
if (thumb2)
|
|
insn = __opcode_to_mem_thumb32(insn);
|
|
else
|
|
insn = __opcode_to_mem_arm(insn);
|
|
|
|
*(u32 *)waddr = insn;
|
|
size = sizeof(u32);
|
|
}
|
|
|
|
if (waddr != addr) {
|
|
flush_kernel_vmap_range(waddr, twopage ? size / 2 : size);
|
|
patch_unmap(FIX_TEXT_POKE0, &flags);
|
|
} else
|
|
__release(&patch_lock);
|
|
|
|
flush_icache_range((uintptr_t)(addr),
|
|
(uintptr_t)(addr) + size);
|
|
}
|
|
|
|
static int __kprobes patch_text_stop_machine(void *data)
|
|
{
|
|
struct patch *patch = data;
|
|
|
|
__patch_text(patch->addr, patch->insn);
|
|
|
|
return 0;
|
|
}
|
|
|
|
void __kprobes patch_text(void *addr, unsigned int insn)
|
|
{
|
|
struct patch patch = {
|
|
.addr = addr,
|
|
.insn = insn,
|
|
};
|
|
|
|
stop_machine_cpuslocked(patch_text_stop_machine, &patch, NULL);
|
|
}
|