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-rw-r--r--arch/x86/include/asm/cacheflush.h5
-rw-r--r--arch/x86/kernel/ftrace.c17
-rw-r--r--arch/x86/kernel/vmiclock_32.c5
-rw-r--r--arch/x86/mm/init_32.c35
-rw-r--r--arch/x86/mm/init_64.c37
-rw-r--r--arch/x86/mm/pageattr.c15
-rw-r--r--include/linux/ftrace.h3
-rw-r--r--kernel/trace/ftrace.c33
8 files changed, 130 insertions, 20 deletions
diff --git a/arch/x86/include/asm/cacheflush.h b/arch/x86/include/asm/cacheflush.h
index 2f8466540fb..6145063cfe0 100644
--- a/arch/x86/include/asm/cacheflush.h
+++ b/arch/x86/include/asm/cacheflush.h
@@ -104,6 +104,11 @@ void clflush_cache_range(void *addr, unsigned int size);
#ifdef CONFIG_DEBUG_RODATA
void mark_rodata_ro(void);
extern const int rodata_test_data;
+void set_kernel_text_rw(void);
+void set_kernel_text_ro(void);
+#else
+static inline void set_kernel_text_rw(void) { }
+static inline void set_kernel_text_ro(void) { }
#endif
#ifdef CONFIG_DEBUG_RODATA_TEST
diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c
index c2e057d9f88..3925ec0184b 100644
--- a/arch/x86/kernel/ftrace.c
+++ b/arch/x86/kernel/ftrace.c
@@ -18,6 +18,7 @@
#include <linux/init.h>
#include <linux/list.h>
+#include <asm/cacheflush.h>
#include <asm/ftrace.h>
#include <linux/ftrace.h>
#include <asm/nops.h>
@@ -26,6 +27,18 @@
#ifdef CONFIG_DYNAMIC_FTRACE
+int ftrace_arch_code_modify_prepare(void)
+{
+ set_kernel_text_rw();
+ return 0;
+}
+
+int ftrace_arch_code_modify_post_process(void)
+{
+ set_kernel_text_ro();
+ return 0;
+}
+
union ftrace_code_union {
char code[MCOUNT_INSN_SIZE];
struct {
@@ -111,6 +124,10 @@ static void ftrace_mod_code(void)
*/
mod_code_status = probe_kernel_write(mod_code_ip, mod_code_newcode,
MCOUNT_INSN_SIZE);
+
+ /* if we fail, then kill any new writers */
+ if (mod_code_status)
+ mod_code_write = 0;
}
void ftrace_nmi_enter(void)
diff --git a/arch/x86/kernel/vmiclock_32.c b/arch/x86/kernel/vmiclock_32.c
index c4c1f9e0940..bde106cae0a 100644
--- a/arch/x86/kernel/vmiclock_32.c
+++ b/arch/x86/kernel/vmiclock_32.c
@@ -283,10 +283,13 @@ void __devinit vmi_time_ap_init(void)
#endif
/** vmi clocksource */
+static struct clocksource clocksource_vmi;
static cycle_t read_real_cycles(void)
{
- return vmi_timer_ops.get_cycle_counter(VMI_CYCLES_REAL);
+ cycle_t ret = (cycle_t)vmi_timer_ops.get_cycle_counter(VMI_CYCLES_REAL);
+ return ret >= clocksource_vmi.cycle_last ?
+ ret : clocksource_vmi.cycle_last;
}
static struct clocksource clocksource_vmi = {
diff --git a/arch/x86/mm/init_32.c b/arch/x86/mm/init_32.c
index 2cef0507441..3eb2ed188a4 100644
--- a/arch/x86/mm/init_32.c
+++ b/arch/x86/mm/init_32.c
@@ -1155,17 +1155,47 @@ static noinline int do_test_wp_bit(void)
const int rodata_test_data = 0xC3;
EXPORT_SYMBOL_GPL(rodata_test_data);
+static int kernel_set_to_readonly;
+
+void set_kernel_text_rw(void)
+{
+ unsigned long start = PFN_ALIGN(_text);
+ unsigned long size = PFN_ALIGN(_etext) - start;
+
+ if (!kernel_set_to_readonly)
+ return;
+
+ pr_debug("Set kernel text: %lx - %lx for read write\n",
+ start, start+size);
+
+ set_pages_rw(virt_to_page(start), size >> PAGE_SHIFT);
+}
+
+void set_kernel_text_ro(void)
+{
+ unsigned long start = PFN_ALIGN(_text);
+ unsigned long size = PFN_ALIGN(_etext) - start;
+
+ if (!kernel_set_to_readonly)
+ return;
+
+ pr_debug("Set kernel text: %lx - %lx for read only\n",
+ start, start+size);
+
+ set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT);
+}
+
void mark_rodata_ro(void)
{
unsigned long start = PFN_ALIGN(_text);
unsigned long size = PFN_ALIGN(_etext) - start;
-#ifndef CONFIG_DYNAMIC_FTRACE
- /* Dynamic tracing modifies the kernel text section */
set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT);
printk(KERN_INFO "Write protecting the kernel text: %luk\n",
size >> 10);
+ kernel_set_to_readonly = 1;
+
#ifdef CONFIG_CPA_DEBUG
printk(KERN_INFO "Testing CPA: Reverting %lx-%lx\n",
start, start+size);
@@ -1174,7 +1204,6 @@ void mark_rodata_ro(void)
printk(KERN_INFO "Testing CPA: write protecting again\n");
set_pages_ro(virt_to_page(start), size>>PAGE_SHIFT);
#endif
-#endif /* CONFIG_DYNAMIC_FTRACE */
start += size;
size = (unsigned long)__end_rodata - start;
diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
index e6d36b49025..63fdc531601 100644
--- a/arch/x86/mm/init_64.c
+++ b/arch/x86/mm/init_64.c
@@ -986,21 +986,48 @@ void free_initmem(void)
const int rodata_test_data = 0xC3;
EXPORT_SYMBOL_GPL(rodata_test_data);
+static int kernel_set_to_readonly;
+
+void set_kernel_text_rw(void)
+{
+ unsigned long start = PFN_ALIGN(_stext);
+ unsigned long end = PFN_ALIGN(__start_rodata);
+
+ if (!kernel_set_to_readonly)
+ return;
+
+ pr_debug("Set kernel text: %lx - %lx for read write\n",
+ start, end);
+
+ set_memory_rw(start, (end - start) >> PAGE_SHIFT);
+}
+
+void set_kernel_text_ro(void)
+{
+ unsigned long start = PFN_ALIGN(_stext);
+ unsigned long end = PFN_ALIGN(__start_rodata);
+
+ if (!kernel_set_to_readonly)
+ return;
+
+ pr_debug("Set kernel text: %lx - %lx for read only\n",
+ start, end);
+
+ set_memory_ro(start, (end - start) >> PAGE_SHIFT);
+}
+
void mark_rodata_ro(void)
{
unsigned long start = PFN_ALIGN(_stext), end = PFN_ALIGN(__end_rodata);
unsigned long rodata_start =
((unsigned long)__start_rodata + PAGE_SIZE - 1) & PAGE_MASK;
-#ifdef CONFIG_DYNAMIC_FTRACE
- /* Dynamic tracing modifies the kernel text section */
- start = rodata_start;
-#endif
-
printk(KERN_INFO "Write protecting the kernel read-only data: %luk\n",
(end - start) >> 10);
set_memory_ro(start, (end - start) >> PAGE_SHIFT);
+ kernel_set_to_readonly = 1;
+
/*
* The rodata section (but not the kernel text!) should also be
* not-executable.
diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c
index 8ca0d8566fc..7be47d1a97e 100644
--- a/arch/x86/mm/pageattr.c
+++ b/arch/x86/mm/pageattr.c
@@ -508,18 +508,13 @@ static int split_large_page(pte_t *kpte, unsigned long address)
#endif
/*
- * Install the new, split up pagetable. Important details here:
+ * Install the new, split up pagetable.
*
- * On Intel the NX bit of all levels must be cleared to make a
- * page executable. See section 4.13.2 of Intel 64 and IA-32
- * Architectures Software Developer's Manual).
- *
- * Mark the entry present. The current mapping might be
- * set to not present, which we preserved above.
+ * We use the standard kernel pagetable protections for the new
+ * pagetable protections, the actual ptes set above control the
+ * primary protection behavior:
*/
- ref_prot = pte_pgprot(pte_mkexec(pte_clrhuge(*kpte)));
- pgprot_val(ref_prot) |= _PAGE_PRESENT;
- __set_pmd_pte(kpte, address, mk_pte(base, ref_prot));
+ __set_pmd_pte(kpte, address, mk_pte(base, __pgprot(_KERNPG_TABLE)));
base = NULL;
out_unlock:
diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
index 915f4723fc8..847bb3c48dd 100644
--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h
@@ -106,6 +106,9 @@ struct ftrace_func_command {
/* asm/ftrace.h must be defined for archs supporting dynamic ftrace */
#include <asm/ftrace.h>
+int ftrace_arch_code_modify_prepare(void);
+int ftrace_arch_code_modify_post_process(void);
+
struct seq_file;
struct ftrace_probe_ops {
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index cf59f4c5474..5a3a06b21ee 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -557,8 +557,11 @@ static void ftrace_replace_code(int enable)
if ((system_state == SYSTEM_BOOTING) ||
!core_kernel_text(rec->ip)) {
ftrace_free_rec(rec);
- } else
+ } else {
ftrace_bug(failed, rec->ip);
+ /* Stop processing */
+ return;
+ }
}
} while_for_each_ftrace_rec();
}
@@ -580,6 +583,24 @@ ftrace_code_disable(struct module *mod, struct dyn_ftrace *rec)
return 1;
}
+/*
+ * archs can override this function if they must do something
+ * before the modifying code is performed.
+ */
+int __weak ftrace_arch_code_modify_prepare(void)
+{
+ return 0;
+}
+
+/*
+ * archs can override this function if they must do something
+ * after the modifying code is performed.
+ */
+int __weak ftrace_arch_code_modify_post_process(void)
+{
+ return 0;
+}
+
static int __ftrace_modify_code(void *data)
{
int *command = data;
@@ -602,7 +623,17 @@ static int __ftrace_modify_code(void *data)
static void ftrace_run_update_code(int command)
{
+ int ret;
+
+ ret = ftrace_arch_code_modify_prepare();
+ FTRACE_WARN_ON(ret);
+ if (ret)
+ return;
+
stop_machine(__ftrace_modify_code, &command, NULL);
+
+ ret = ftrace_arch_code_modify_post_process();
+ FTRACE_WARN_ON(ret);
}
static ftrace_func_t saved_ftrace_func;
generated by cgit v1.2.3 (git 2.39.1) at 2024-07-04 21:04:57 +0000