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Merge branch 'tip/x86/ftrace' of git://git.kernel.org/pub/scm/linux/k…
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…ernel/git/rostedt/linux-2.6-trace into tracing/ftrace

Conflicts:
	include/linux/ftrace.h
	kernel/trace/ftrace.c
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Ingo Molnar committed Feb 22, 2009
2 parents 843adf2 + 4377245 commit c478f87
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Showing 8 changed files with 130 additions and 20 deletions.
5 changes: 5 additions & 0 deletions arch/x86/include/asm/cacheflush.h
Original file line number Diff line number Diff line change
Expand Up @@ -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
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17 changes: 17 additions & 0 deletions arch/x86/kernel/ftrace.c
Original file line number Diff line number Diff line change
Expand Up @@ -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>
Expand All @@ -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 {
Expand Down Expand Up @@ -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)
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5 changes: 4 additions & 1 deletion arch/x86/kernel/vmiclock_32.c
Original file line number Diff line number Diff line change
Expand Up @@ -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 = {
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35 changes: 32 additions & 3 deletions arch/x86/mm/init_32.c
Original file line number Diff line number Diff line change
Expand Up @@ -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);
Expand All @@ -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;
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37 changes: 32 additions & 5 deletions arch/x86/mm/init_64.c
Original file line number Diff line number Diff line change
Expand Up @@ -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.
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15 changes: 5 additions & 10 deletions arch/x86/mm/pageattr.c
Original file line number Diff line number Diff line change
Expand Up @@ -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:
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3 changes: 3 additions & 0 deletions include/linux/ftrace.h
Original file line number Diff line number Diff line change
Expand Up @@ -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 {
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33 changes: 32 additions & 1 deletion kernel/trace/ftrace.c
Original file line number Diff line number Diff line change
Expand Up @@ -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();
}
Expand All @@ -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;
Expand All @@ -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;
Expand Down

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