mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2024-12-25 01:26:05 +07:00
7e923369b1
If multiple CPUs are patching code we need the spinlock to protect against parallel fixmap maps/unmap calls. Signed-off-by: Sven Schnelle <svens@stackframe.org> Signed-off-by: Helge Deller <deller@gmx.de>
134 lines
2.9 KiB
C
134 lines
2.9 KiB
C
// SPDX-License-Identifier: GPL-2.0
|
|
/*
|
|
* functions to patch RO kernel text during runtime
|
|
*
|
|
* Copyright (c) 2019 Sven Schnelle <svens@stackframe.org>
|
|
*/
|
|
|
|
#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/patch.h>
|
|
|
|
struct patch {
|
|
void *addr;
|
|
u32 *insn;
|
|
unsigned int len;
|
|
};
|
|
|
|
static DEFINE_RAW_SPINLOCK(patch_lock);
|
|
|
|
static void __kprobes *patch_map(void *addr, int fixmap, unsigned long *flags,
|
|
int *need_unmap)
|
|
{
|
|
unsigned long uintaddr = (uintptr_t) addr;
|
|
bool module = !core_kernel_text(uintaddr);
|
|
struct page *page;
|
|
|
|
*need_unmap = 0;
|
|
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;
|
|
|
|
*need_unmap = 1;
|
|
set_fixmap(fixmap, page_to_phys(page));
|
|
if (flags)
|
|
raw_spin_lock_irqsave(&patch_lock, *flags);
|
|
else
|
|
__acquire(&patch_lock);
|
|
|
|
return (void *) (__fix_to_virt(fixmap) + (uintaddr & ~PAGE_MASK));
|
|
}
|
|
|
|
static void __kprobes patch_unmap(int fixmap, unsigned long *flags)
|
|
{
|
|
clear_fixmap(fixmap);
|
|
|
|
if (flags)
|
|
raw_spin_unlock_irqrestore(&patch_lock, *flags);
|
|
else
|
|
__release(&patch_lock);
|
|
}
|
|
|
|
void __kprobes __patch_text_multiple(void *addr, u32 *insn, unsigned int len)
|
|
{
|
|
unsigned long start = (unsigned long)addr;
|
|
unsigned long end = (unsigned long)addr + len;
|
|
unsigned long flags;
|
|
u32 *p, *fixmap;
|
|
int mapped;
|
|
|
|
/* Make sure we don't have any aliases in cache */
|
|
flush_kernel_vmap_range(addr, len);
|
|
flush_icache_range(start, end);
|
|
|
|
p = fixmap = patch_map(addr, FIX_TEXT_POKE0, &flags, &mapped);
|
|
|
|
while (len >= 4) {
|
|
*p++ = *insn++;
|
|
addr += sizeof(u32);
|
|
len -= sizeof(u32);
|
|
if (len && offset_in_page(addr) == 0) {
|
|
/*
|
|
* We're crossing a page boundary, so
|
|
* need to remap
|
|
*/
|
|
flush_kernel_vmap_range((void *)fixmap,
|
|
(p-fixmap) * sizeof(*p));
|
|
if (mapped)
|
|
patch_unmap(FIX_TEXT_POKE0, &flags);
|
|
p = fixmap = patch_map(addr, FIX_TEXT_POKE0, &flags,
|
|
&mapped);
|
|
}
|
|
}
|
|
|
|
flush_kernel_vmap_range((void *)fixmap, (p-fixmap) * sizeof(*p));
|
|
if (mapped)
|
|
patch_unmap(FIX_TEXT_POKE0, &flags);
|
|
flush_icache_range(start, end);
|
|
}
|
|
|
|
void __kprobes __patch_text(void *addr, u32 insn)
|
|
{
|
|
__patch_text_multiple(addr, &insn, sizeof(insn));
|
|
}
|
|
|
|
static int __kprobes patch_text_stop_machine(void *data)
|
|
{
|
|
struct patch *patch = data;
|
|
|
|
__patch_text_multiple(patch->addr, patch->insn, patch->len);
|
|
return 0;
|
|
}
|
|
|
|
void __kprobes patch_text(void *addr, unsigned int insn)
|
|
{
|
|
struct patch patch = {
|
|
.addr = addr,
|
|
.insn = &insn,
|
|
.len = sizeof(insn),
|
|
};
|
|
|
|
stop_machine_cpuslocked(patch_text_stop_machine, &patch, NULL);
|
|
}
|
|
|
|
void __kprobes patch_text_multiple(void *addr, u32 *insn, unsigned int len)
|
|
{
|
|
|
|
struct patch patch = {
|
|
.addr = addr,
|
|
.insn = insn,
|
|
.len = len
|
|
};
|
|
|
|
stop_machine_cpuslocked(patch_text_stop_machine, &patch, NULL);
|
|
}
|