mirror of
https://github.com/torvalds/linux.git
synced 2024-12-27 13:22:23 +00:00
143c2a89e0
When running kprobe on -rt kernel, the below bug is caught: |BUG: sleeping function called from invalid context at kernel/locking/rtmutex.c:931 |in_atomic(): 1, irqs_disabled(): 128, pid: 14, name: migration/0 |Preemption disabled at:[<802f2b98>] cpu_stopper_thread+0xc0/0x140 |CPU: 0 PID: 14 Comm: migration/0 Tainted: G O 4.8.3-rt2 #1 |Hardware name: Freescale LS1021A |[<8025a43c>] (___might_sleep) |[<80b5b324>] (rt_spin_lock) |[<80b5c31c>] (__patch_text_real) |[<80b5c3ac>] (patch_text_stop_machine) |[<802f2920>] (multi_cpu_stop) Since patch_text_stop_machine() is called in stop_machine() which disables IRQ, sleepable lock should be not used in this atomic context, so replace patch_lock to raw lock. Signed-off-by: Yang Shi <yang.shi@linaro.org> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Reviewed-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
130 lines
2.9 KiB
C
130 lines
2.9 KiB
C
// SPDX-License-Identifier: GPL-2.0
|
|
#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_RAW_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)
|
|
raw_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)
|
|
raw_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);
|
|
}
|