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-rw-r--r--arch/i386/kernel/alternative.c40
-rw-r--r--arch/i386/kernel/kprobes.c9
-rw-r--r--arch/i386/kernel/paravirt.c17
-rw-r--r--arch/i386/mm/init.c14
-rw-r--r--arch/x86_64/kernel/kprobes.c10
-rw-r--r--arch/x86_64/mm/init.c10
-rw-r--r--arch/x86_64/mm/pageattr.c2
-rw-r--r--include/asm-i386/alternative.h2
-rw-r--r--include/asm-x86_64/alternative.h2
-rw-r--r--include/asm-x86_64/pgtable.h2
10 files changed, 63 insertions, 45 deletions
diff --git a/arch/i386/kernel/alternative.c b/arch/i386/kernel/alternative.c
index 0695be5..206ea2c 100644
--- a/arch/i386/kernel/alternative.c
+++ b/arch/i386/kernel/alternative.c
@@ -2,8 +2,12 @@
#include <linux/sched.h>
#include <linux/spinlock.h>
#include <linux/list.h>
+#include <linux/kprobes.h>
+#include <linux/mm.h>
+#include <linux/vmalloc.h>
#include <asm/alternative.h>
#include <asm/sections.h>
+#include <asm/pgtable.h>
#ifdef CONFIG_HOTPLUG_CPU
static int smp_alt_once;
@@ -150,7 +154,7 @@ static void nop_out(void *insns, unsigned int len)
unsigned int noplen = len;
if (noplen > ASM_NOP_MAX)
noplen = ASM_NOP_MAX;
- memcpy(insns, noptable[noplen], noplen);
+ text_poke(insns, noptable[noplen], noplen);
insns += noplen;
len -= noplen;
}
@@ -202,7 +206,7 @@ static void alternatives_smp_lock(u8 **start, u8 **end, u8 *text, u8 *text_end)
continue;
if (*ptr > text_end)
continue;
- **ptr = 0xf0; /* lock prefix */
+ text_poke(*ptr, ((unsigned char []){0xf0}), 1); /* add lock prefix */
};
}
@@ -360,10 +364,6 @@ void apply_paravirt(struct paravirt_patch_site *start,
/* Pad the rest with nops */
nop_out(p->instr + used, p->len - used);
}
-
- /* Sync to be conservative, in case we patched following
- * instructions */
- sync_core();
}
extern struct paravirt_patch_site __start_parainstructions[],
__stop_parainstructions[];
@@ -406,3 +406,31 @@ void __init alternative_instructions(void)
apply_paravirt(__parainstructions, __parainstructions_end);
local_irq_restore(flags);
}
+
+/*
+ * Warning:
+ * When you use this code to patch more than one byte of an instruction
+ * you need to make sure that other CPUs cannot execute this code in parallel.
+ * Also no thread must be currently preempted in the middle of these instructions.
+ * And on the local CPU you need to be protected again NMI or MCE handlers
+ * seeing an inconsistent instruction while you patch.
+ */
+void __kprobes text_poke(void *oaddr, unsigned char *opcode, int len)
+{
+ u8 *addr = oaddr;
+ if (!pte_write(*lookup_address((unsigned long)addr))) {
+ struct page *p[2] = { virt_to_page(addr), virt_to_page(addr+PAGE_SIZE) };
+ addr = vmap(p, 2, VM_MAP, PAGE_KERNEL);
+ if (!addr)
+ return;
+ addr += ((unsigned long)oaddr) % PAGE_SIZE;
+ }
+ memcpy(addr, opcode, len);
+ sync_core();
+ /* Not strictly needed, but can speed CPU recovery up. Ignore cross cacheline
+ case. */
+ if (cpu_has_clflush)
+ asm("clflush (%0) " :: "r" (oaddr) : "memory");
+ if (addr != oaddr)
+ vunmap(addr);
+}
diff --git a/arch/i386/kernel/kprobes.c b/arch/i386/kernel/kprobes.c
index dde828a..448a50b 100644
--- a/arch/i386/kernel/kprobes.c
+++ b/arch/i386/kernel/kprobes.c
@@ -35,6 +35,7 @@
#include <asm/cacheflush.h>
#include <asm/desc.h>
#include <asm/uaccess.h>
+#include <asm/alternative.h>
void jprobe_return_end(void);
@@ -169,16 +170,12 @@ int __kprobes arch_prepare_kprobe(struct kprobe *p)
void __kprobes arch_arm_kprobe(struct kprobe *p)
{
- *p->addr = BREAKPOINT_INSTRUCTION;
- flush_icache_range((unsigned long) p->addr,
- (unsigned long) p->addr + sizeof(kprobe_opcode_t));
+ text_poke(p->addr, ((unsigned char []){BREAKPOINT_INSTRUCTION}), 1);
}
void __kprobes arch_disarm_kprobe(struct kprobe *p)
{
- *p->addr = p->opcode;
- flush_icache_range((unsigned long) p->addr,
- (unsigned long) p->addr + sizeof(kprobe_opcode_t));
+ text_poke(p->addr, &p->opcode, 1);
}
void __kprobes arch_remove_kprobe(struct kprobe *p)
diff --git a/arch/i386/kernel/paravirt.c b/arch/i386/kernel/paravirt.c
index 53f07a8..79c167f 100644
--- a/arch/i386/kernel/paravirt.c
+++ b/arch/i386/kernel/paravirt.c
@@ -124,20 +124,28 @@ unsigned paravirt_patch_ignore(unsigned len)
return len;
}
+struct branch {
+ unsigned char opcode;
+ u32 delta;
+} __attribute__((packed));
+
unsigned paravirt_patch_call(void *target, u16 tgt_clobbers,
void *site, u16 site_clobbers,
unsigned len)
{
unsigned char *call = site;
unsigned long delta = (unsigned long)target - (unsigned long)(call+5);
+ struct branch b;
if (tgt_clobbers & ~site_clobbers)
return len; /* target would clobber too much for this site */
if (len < 5)
return len; /* call too long for patch site */
- *call++ = 0xe8; /* call */
- *(unsigned long *)call = delta;
+ b.opcode = 0xe8; /* call */
+ b.delta = delta;
+ BUILD_BUG_ON(sizeof(b) != 5);
+ text_poke(call, (unsigned char *)&b, 5);
return 5;
}
@@ -150,8 +158,9 @@ unsigned paravirt_patch_jmp(void *target, void *site, unsigned len)
if (len < 5)
return len; /* call too long for patch site */
- *jmp++ = 0xe9; /* jmp */
- *(unsigned long *)jmp = delta;
+ b.opcode = 0xe9; /* jmp */
+ b.delta = delta;
+ text_poke(call, (unsigned char *)&b, 5);
return 5;
}
diff --git a/arch/i386/mm/init.c b/arch/i386/mm/init.c
index e1a9a80..c3b9905 100644
--- a/arch/i386/mm/init.c
+++ b/arch/i386/mm/init.c
@@ -800,17 +800,9 @@ void mark_rodata_ro(void)
unsigned long start = PFN_ALIGN(_text);
unsigned long size = PFN_ALIGN(_etext) - start;
-#ifndef CONFIG_KPROBES
-#ifdef CONFIG_HOTPLUG_CPU
- /* It must still be possible to apply SMP alternatives. */
- if (num_possible_cpus() <= 1)
-#endif
- {
- change_page_attr(virt_to_page(start),
- size >> PAGE_SHIFT, PAGE_KERNEL_RX);
- printk("Write protecting the kernel text: %luk\n", size >> 10);
- }
-#endif
+ change_page_attr(virt_to_page(start),
+ size >> PAGE_SHIFT, PAGE_KERNEL_RX);
+ printk("Write protecting the kernel text: %luk\n", size >> 10);
start += size;
size = (unsigned long)__end_rodata - start;
change_page_attr(virt_to_page(start),
diff --git a/arch/x86_64/kernel/kprobes.c b/arch/x86_64/kernel/kprobes.c
index d4a0d0a..a30e004 100644
--- a/arch/x86_64/kernel/kprobes.c
+++ b/arch/x86_64/kernel/kprobes.c
@@ -39,9 +39,9 @@
#include <linux/module.h>
#include <linux/kdebug.h>
-#include <asm/cacheflush.h>
#include <asm/pgtable.h>
#include <asm/uaccess.h>
+#include <asm/alternative.h>
void jprobe_return_end(void);
static void __kprobes arch_copy_kprobe(struct kprobe *p);
@@ -209,16 +209,12 @@ static void __kprobes arch_copy_kprobe(struct kprobe *p)
void __kprobes arch_arm_kprobe(struct kprobe *p)
{
- *p->addr = BREAKPOINT_INSTRUCTION;
- flush_icache_range((unsigned long) p->addr,
- (unsigned long) p->addr + sizeof(kprobe_opcode_t));
+ text_poke(p->addr, ((unsigned char []){BREAKPOINT_INSTRUCTION}), 1);
}
void __kprobes arch_disarm_kprobe(struct kprobe *p)
{
- *p->addr = p->opcode;
- flush_icache_range((unsigned long) p->addr,
- (unsigned long) p->addr + sizeof(kprobe_opcode_t));
+ text_poke(p->addr, &p->opcode, 1);
}
void __kprobes arch_remove_kprobe(struct kprobe *p)
diff --git a/arch/x86_64/mm/init.c b/arch/x86_64/mm/init.c
index 2044fa9..314e12b 100644
--- a/arch/x86_64/mm/init.c
+++ b/arch/x86_64/mm/init.c
@@ -600,16 +600,6 @@ void mark_rodata_ro(void)
{
unsigned long start = (unsigned long)_stext, end;
-#ifdef CONFIG_HOTPLUG_CPU
- /* It must still be possible to apply SMP alternatives. */
- if (num_possible_cpus() > 1)
- start = (unsigned long)_etext;
-#endif
-
-#ifdef CONFIG_KPROBES
- start = (unsigned long)__start_rodata;
-#endif
-
end = (unsigned long)__end_rodata;
start = (start + PAGE_SIZE - 1) & PAGE_MASK;
end &= PAGE_MASK;
diff --git a/arch/x86_64/mm/pageattr.c b/arch/x86_64/mm/pageattr.c
index 36377b6..7e161c6 100644
--- a/arch/x86_64/mm/pageattr.c
+++ b/arch/x86_64/mm/pageattr.c
@@ -13,7 +13,7 @@
#include <asm/tlbflush.h>
#include <asm/io.h>
-static inline pte_t *lookup_address(unsigned long address)
+pte_t *lookup_address(unsigned long address)
{
pgd_t *pgd = pgd_offset_k(address);
pud_t *pud;
diff --git a/include/asm-i386/alternative.h b/include/asm-i386/alternative.h
index eb7da54..bda6c81 100644
--- a/include/asm-i386/alternative.h
+++ b/include/asm-i386/alternative.h
@@ -149,4 +149,6 @@ apply_paravirt(struct paravirt_patch_site *start,
#define __parainstructions_end NULL
#endif
+extern void text_poke(void *addr, unsigned char *opcode, int len);
+
#endif /* _I386_ALTERNATIVE_H */
diff --git a/include/asm-x86_64/alternative.h b/include/asm-x86_64/alternative.h
index eea7aec..ab161e8 100644
--- a/include/asm-x86_64/alternative.h
+++ b/include/asm-x86_64/alternative.h
@@ -154,4 +154,6 @@ apply_paravirt(struct paravirt_patch *start, struct paravirt_patch *end)
#define __parainstructions_end NULL
#endif
+extern void text_poke(void *addr, unsigned char *opcode, int len);
+
#endif /* _X86_64_ALTERNATIVE_H */
diff --git a/include/asm-x86_64/pgtable.h b/include/asm-x86_64/pgtable.h
index 60cff1e..c9d8764 100644
--- a/include/asm-x86_64/pgtable.h
+++ b/include/asm-x86_64/pgtable.h
@@ -403,6 +403,8 @@ extern struct list_head pgd_list;
extern int kern_addr_valid(unsigned long addr);
+pte_t *lookup_address(unsigned long addr);
+
#define io_remap_pfn_range(vma, vaddr, pfn, size, prot) \
remap_pfn_range(vma, vaddr, pfn, size, prot)
generated by cgit v1.1 at 2024-10-30 17:19:57 +0000