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-rw-r--r--arch/x86/include/asm/tlbflush.h8
-rw-r--r--arch/x86/kernel/entry_64.S19
-rw-r--r--arch/x86/mm/kmmio.c104
-rw-r--r--arch/x86/mm/mmio-mod.c2
4 files changed, 70 insertions, 63 deletions
diff --git a/arch/x86/include/asm/tlbflush.h b/arch/x86/include/asm/tlbflush.h
index 16a5c84b0329..a5ecc9c33e92 100644
--- a/arch/x86/include/asm/tlbflush.h
+++ b/arch/x86/include/asm/tlbflush.h
@@ -17,7 +17,7 @@
static inline void __native_flush_tlb(void)
{
- write_cr3(read_cr3());
+ native_write_cr3(native_read_cr3());
}
static inline void __native_flush_tlb_global(void)
@@ -32,11 +32,11 @@ static inline void __native_flush_tlb_global(void)
*/
raw_local_irq_save(flags);
- cr4 = read_cr4();
+ cr4 = native_read_cr4();
/* clear PGE */
- write_cr4(cr4 & ~X86_CR4_PGE);
+ native_write_cr4(cr4 & ~X86_CR4_PGE);
/* write old PGE again and flush TLBs */
- write_cr4(cr4);
+ native_write_cr4(cr4);
raw_local_irq_restore(flags);
}
diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S
index 38946c6e8433..987f91f0f755 100644
--- a/arch/x86/kernel/entry_64.S
+++ b/arch/x86/kernel/entry_64.S
@@ -147,27 +147,14 @@ END(ftrace_graph_caller)
GLOBAL(return_to_handler)
subq $80, %rsp
+ /* Save the return values */
movq %rax, (%rsp)
- movq %rcx, 8(%rsp)
- movq %rdx, 16(%rsp)
- movq %rsi, 24(%rsp)
- movq %rdi, 32(%rsp)
- movq %r8, 40(%rsp)
- movq %r9, 48(%rsp)
- movq %r10, 56(%rsp)
- movq %r11, 64(%rsp)
+ movq %rdx, 8(%rsp)
call ftrace_return_to_handler
movq %rax, 72(%rsp)
- movq 64(%rsp), %r11
- movq 56(%rsp), %r10
- movq 48(%rsp), %r9
- movq 40(%rsp), %r8
- movq 32(%rsp), %rdi
- movq 24(%rsp), %rsi
- movq 16(%rsp), %rdx
- movq 8(%rsp), %rcx
+ movq 8(%rsp), %rdx
movq (%rsp), %rax
addq $72, %rsp
retq
diff --git a/arch/x86/mm/kmmio.c b/arch/x86/mm/kmmio.c
index 50dc802a1c46..16ccbd77917f 100644
--- a/arch/x86/mm/kmmio.c
+++ b/arch/x86/mm/kmmio.c
@@ -32,7 +32,7 @@ struct kmmio_fault_page {
struct list_head list;
struct kmmio_fault_page *release_next;
unsigned long page; /* location of the fault page */
- bool old_presence; /* page presence prior to arming */
+ pteval_t old_presence; /* page presence prior to arming */
bool armed;
/*
@@ -97,60 +97,62 @@ static struct kmmio_probe *get_kmmio_probe(unsigned long addr)
static struct kmmio_fault_page *get_kmmio_fault_page(unsigned long page)
{
struct list_head *head;
- struct kmmio_fault_page *p;
+ struct kmmio_fault_page *f;
page &= PAGE_MASK;
head = kmmio_page_list(page);
- list_for_each_entry_rcu(p, head, list) {
- if (p->page == page)
- return p;
+ list_for_each_entry_rcu(f, head, list) {
+ if (f->page == page)
+ return f;
}
return NULL;
}
-static void set_pmd_presence(pmd_t *pmd, bool present, bool *old)
+static void clear_pmd_presence(pmd_t *pmd, bool clear, pmdval_t *old)
{
pmdval_t v = pmd_val(*pmd);
- *old = !!(v & _PAGE_PRESENT);
- v &= ~_PAGE_PRESENT;
- if (present)
- v |= _PAGE_PRESENT;
+ if (clear) {
+ *old = v & _PAGE_PRESENT;
+ v &= ~_PAGE_PRESENT;
+ } else /* presume this has been called with clear==true previously */
+ v |= *old;
set_pmd(pmd, __pmd(v));
}
-static void set_pte_presence(pte_t *pte, bool present, bool *old)
+static void clear_pte_presence(pte_t *pte, bool clear, pteval_t *old)
{
pteval_t v = pte_val(*pte);
- *old = !!(v & _PAGE_PRESENT);
- v &= ~_PAGE_PRESENT;
- if (present)
- v |= _PAGE_PRESENT;
+ if (clear) {
+ *old = v & _PAGE_PRESENT;
+ v &= ~_PAGE_PRESENT;
+ } else /* presume this has been called with clear==true previously */
+ v |= *old;
set_pte_atomic(pte, __pte(v));
}
-static int set_page_presence(unsigned long addr, bool present, bool *old)
+static int clear_page_presence(struct kmmio_fault_page *f, bool clear)
{
unsigned int level;
- pte_t *pte = lookup_address(addr, &level);
+ pte_t *pte = lookup_address(f->page, &level);
if (!pte) {
- pr_err("kmmio: no pte for page 0x%08lx\n", addr);
+ pr_err("kmmio: no pte for page 0x%08lx\n", f->page);
return -1;
}
switch (level) {
case PG_LEVEL_2M:
- set_pmd_presence((pmd_t *)pte, present, old);
+ clear_pmd_presence((pmd_t *)pte, clear, &f->old_presence);
break;
case PG_LEVEL_4K:
- set_pte_presence(pte, present, old);
+ clear_pte_presence(pte, clear, &f->old_presence);
break;
default:
pr_err("kmmio: unexpected page level 0x%x.\n", level);
return -1;
}
- __flush_tlb_one(addr);
+ __flush_tlb_one(f->page);
return 0;
}
@@ -171,9 +173,9 @@ static int arm_kmmio_fault_page(struct kmmio_fault_page *f)
WARN_ONCE(f->armed, KERN_ERR "kmmio page already armed.\n");
if (f->armed) {
pr_warning("kmmio double-arm: page 0x%08lx, ref %d, old %d\n",
- f->page, f->count, f->old_presence);
+ f->page, f->count, !!f->old_presence);
}
- ret = set_page_presence(f->page, false, &f->old_presence);
+ ret = clear_page_presence(f, true);
WARN_ONCE(ret < 0, KERN_ERR "kmmio arming 0x%08lx failed.\n", f->page);
f->armed = true;
return ret;
@@ -182,8 +184,7 @@ static int arm_kmmio_fault_page(struct kmmio_fault_page *f)
/** Restore the given page to saved presence state. */
static void disarm_kmmio_fault_page(struct kmmio_fault_page *f)
{
- bool tmp;
- int ret = set_page_presence(f->page, f->old_presence, &tmp);
+ int ret = clear_page_presence(f, false);
WARN_ONCE(ret < 0,
KERN_ERR "kmmio disarming 0x%08lx failed.\n", f->page);
f->armed = false;
@@ -310,7 +311,12 @@ static int post_kmmio_handler(unsigned long condition, struct pt_regs *regs)
struct kmmio_context *ctx = &get_cpu_var(kmmio_ctx);
if (!ctx->active) {
- pr_debug("kmmio: spurious debug trap on CPU %d.\n",
+ /*
+ * debug traps without an active context are due to either
+ * something external causing them (f.e. using a debugger while
+ * mmio tracing enabled), or erroneous behaviour
+ */
+ pr_warning("kmmio: unexpected debug trap on CPU %d.\n",
smp_processor_id());
goto out;
}
@@ -439,12 +445,12 @@ static void rcu_free_kmmio_fault_pages(struct rcu_head *head)
head,
struct kmmio_delayed_release,
rcu);
- struct kmmio_fault_page *p = dr->release_list;
- while (p) {
- struct kmmio_fault_page *next = p->release_next;
- BUG_ON(p->count);
- kfree(p);
- p = next;
+ struct kmmio_fault_page *f = dr->release_list;
+ while (f) {
+ struct kmmio_fault_page *next = f->release_next;
+ BUG_ON(f->count);
+ kfree(f);
+ f = next;
}
kfree(dr);
}
@@ -453,19 +459,19 @@ static void remove_kmmio_fault_pages(struct rcu_head *head)
{
struct kmmio_delayed_release *dr =
container_of(head, struct kmmio_delayed_release, rcu);
- struct kmmio_fault_page *p = dr->release_list;
+ struct kmmio_fault_page *f = dr->release_list;
struct kmmio_fault_page **prevp = &dr->release_list;
unsigned long flags;
spin_lock_irqsave(&kmmio_lock, flags);
- while (p) {
- if (!p->count) {
- list_del_rcu(&p->list);
- prevp = &p->release_next;
+ while (f) {
+ if (!f->count) {
+ list_del_rcu(&f->list);
+ prevp = &f->release_next;
} else {
- *prevp = p->release_next;
+ *prevp = f->release_next;
}
- p = p->release_next;
+ f = f->release_next;
}
spin_unlock_irqrestore(&kmmio_lock, flags);
@@ -528,8 +534,8 @@ void unregister_kmmio_probe(struct kmmio_probe *p)
}
EXPORT_SYMBOL(unregister_kmmio_probe);
-static int kmmio_die_notifier(struct notifier_block *nb, unsigned long val,
- void *args)
+static int
+kmmio_die_notifier(struct notifier_block *nb, unsigned long val, void *args)
{
struct die_args *arg = args;
@@ -544,11 +550,23 @@ static struct notifier_block nb_die = {
.notifier_call = kmmio_die_notifier
};
-static int __init init_kmmio(void)
+int kmmio_init(void)
{
int i;
+
for (i = 0; i < KMMIO_PAGE_TABLE_SIZE; i++)
INIT_LIST_HEAD(&kmmio_page_table[i]);
+
return register_die_notifier(&nb_die);
}
-fs_initcall(init_kmmio); /* should be before device_initcall() */
+
+void kmmio_cleanup(void)
+{
+ int i;
+
+ unregister_die_notifier(&nb_die);
+ for (i = 0; i < KMMIO_PAGE_TABLE_SIZE; i++) {
+ WARN_ONCE(!list_empty(&kmmio_page_table[i]),
+ KERN_ERR "kmmio_page_table not empty at cleanup, any further tracing will leak memory.\n");
+ }
+}
diff --git a/arch/x86/mm/mmio-mod.c b/arch/x86/mm/mmio-mod.c
index c9342ed8b402..132772a8ec57 100644
--- a/arch/x86/mm/mmio-mod.c
+++ b/arch/x86/mm/mmio-mod.c
@@ -451,6 +451,7 @@ void enable_mmiotrace(void)
if (nommiotrace)
pr_info(NAME "MMIO tracing disabled.\n");
+ kmmio_init();
enter_uniprocessor();
spin_lock_irq(&trace_lock);
atomic_inc(&mmiotrace_enabled);
@@ -473,6 +474,7 @@ void disable_mmiotrace(void)
clear_trace_list(); /* guarantees: no more kmmio callbacks */
leave_uniprocessor();
+ kmmio_cleanup();
pr_info(NAME "disabled.\n");
out:
mutex_unlock(&mmiotrace_mutex);
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.