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authorIngo Molnar <mingo@kernel.org>2012-12-08 15:50:23 +0100
committerIngo Molnar <mingo@kernel.org>2012-12-08 15:51:10 +0100
commit7e0dd574cd6b1bcc818ed4251e5ceda7d8bee08f (patch)
tree04f5630e361083ab53da43a46d6c47a52e8b87ca
parentf0b9abfb044649bc452fb2fb975ff2fd599cc6a3 (diff)
parent32cdba1e05418909708a17e52505e8b2ba4381d1 (diff)
Merge branch 'uprobes/core' of git://git.kernel.org/pub/scm/linux/kernel/git/oleg/misc into perf/core
Pull uprobes fixes, cleanups and preparation for the ARM port from Oleg Nesterov. Signed-off-by: Ingo Molnar <mingo@kernel.org>
-rw-r--r--arch/powerpc/kernel/signal.c4
-rw-r--r--arch/powerpc/kernel/uprobes.c6
-rw-r--r--arch/x86/kernel/uprobes.c54
-rw-r--r--include/linux/uprobes.h10
-rw-r--r--kernel/events/uprobes.c43
-rw-r--r--kernel/fork.c2
-rw-r--r--kernel/trace/trace_uprobe.c2
7 files changed, 65 insertions, 56 deletions
diff --git a/arch/powerpc/kernel/signal.c b/arch/powerpc/kernel/signal.c
index a2dc75793bd..3b997118df5 100644
--- a/arch/powerpc/kernel/signal.c
+++ b/arch/powerpc/kernel/signal.c
@@ -158,10 +158,8 @@ static int do_signal(struct pt_regs *regs)
void do_notify_resume(struct pt_regs *regs, unsigned long thread_info_flags)
{
- if (thread_info_flags & _TIF_UPROBE) {
- clear_thread_flag(TIF_UPROBE);
+ if (thread_info_flags & _TIF_UPROBE)
uprobe_notify_resume(regs);
- }
if (thread_info_flags & _TIF_SIGPENDING)
do_signal(regs);
diff --git a/arch/powerpc/kernel/uprobes.c b/arch/powerpc/kernel/uprobes.c
index d2d46d1014f..bc77834dbf4 100644
--- a/arch/powerpc/kernel/uprobes.c
+++ b/arch/powerpc/kernel/uprobes.c
@@ -64,6 +64,8 @@ int arch_uprobe_pre_xol(struct arch_uprobe *auprobe, struct pt_regs *regs)
autask->saved_trap_nr = current->thread.trap_nr;
current->thread.trap_nr = UPROBE_TRAP_NR;
regs->nip = current->utask->xol_vaddr;
+
+ user_enable_single_step(current);
return 0;
}
@@ -119,6 +121,8 @@ int arch_uprobe_post_xol(struct arch_uprobe *auprobe, struct pt_regs *regs)
* to be executed.
*/
regs->nip = utask->vaddr + MAX_UINSN_BYTES;
+
+ user_disable_single_step(current);
return 0;
}
@@ -162,6 +166,8 @@ void arch_uprobe_abort_xol(struct arch_uprobe *auprobe, struct pt_regs *regs)
current->thread.trap_nr = utask->autask.saved_trap_nr;
instruction_pointer_set(regs, utask->vaddr);
+
+ user_disable_single_step(current);
}
/*
diff --git a/arch/x86/kernel/uprobes.c b/arch/x86/kernel/uprobes.c
index aafa5557b39..c71025b6746 100644
--- a/arch/x86/kernel/uprobes.c
+++ b/arch/x86/kernel/uprobes.c
@@ -478,6 +478,11 @@ int arch_uprobe_pre_xol(struct arch_uprobe *auprobe, struct pt_regs *regs)
regs->ip = current->utask->xol_vaddr;
pre_xol_rip_insn(auprobe, regs, autask);
+ autask->saved_tf = !!(regs->flags & X86_EFLAGS_TF);
+ regs->flags |= X86_EFLAGS_TF;
+ if (test_tsk_thread_flag(current, TIF_BLOCKSTEP))
+ set_task_blockstep(current, false);
+
return 0;
}
@@ -603,6 +608,16 @@ int arch_uprobe_post_xol(struct arch_uprobe *auprobe, struct pt_regs *regs)
if (auprobe->fixups & UPROBE_FIX_CALL)
result = adjust_ret_addr(regs->sp, correction);
+ /*
+ * arch_uprobe_pre_xol() doesn't save the state of TIF_BLOCKSTEP
+ * so we can get an extra SIGTRAP if we do not clear TF. We need
+ * to examine the opcode to make it right.
+ */
+ if (utask->autask.saved_tf)
+ send_sig(SIGTRAP, current, 0);
+ else if (!(auprobe->fixups & UPROBE_FIX_SETF))
+ regs->flags &= ~X86_EFLAGS_TF;
+
return result;
}
@@ -647,6 +662,10 @@ void arch_uprobe_abort_xol(struct arch_uprobe *auprobe, struct pt_regs *regs)
current->thread.trap_nr = utask->autask.saved_trap_nr;
handle_riprel_post_xol(auprobe, regs, NULL);
instruction_pointer_set(regs, utask->vaddr);
+
+ /* clear TF if it was set by us in arch_uprobe_pre_xol() */
+ if (!utask->autask.saved_tf)
+ regs->flags &= ~X86_EFLAGS_TF;
}
/*
@@ -676,38 +695,3 @@ bool arch_uprobe_skip_sstep(struct arch_uprobe *auprobe, struct pt_regs *regs)
send_sig(SIGTRAP, current, 0);
return ret;
}
-
-void arch_uprobe_enable_step(struct arch_uprobe *auprobe)
-{
- struct task_struct *task = current;
- struct arch_uprobe_task *autask = &task->utask->autask;
- struct pt_regs *regs = task_pt_regs(task);
-
- autask->saved_tf = !!(regs->flags & X86_EFLAGS_TF);
-
- regs->flags |= X86_EFLAGS_TF;
- if (test_tsk_thread_flag(task, TIF_BLOCKSTEP))
- set_task_blockstep(task, false);
-}
-
-void arch_uprobe_disable_step(struct arch_uprobe *auprobe)
-{
- struct task_struct *task = current;
- struct arch_uprobe_task *autask = &task->utask->autask;
- bool trapped = (task->utask->state == UTASK_SSTEP_TRAPPED);
- struct pt_regs *regs = task_pt_regs(task);
- /*
- * The state of TIF_BLOCKSTEP was not saved so we can get an extra
- * SIGTRAP if we do not clear TF. We need to examine the opcode to
- * make it right.
- */
- if (unlikely(trapped)) {
- if (!autask->saved_tf)
- regs->flags &= ~X86_EFLAGS_TF;
- } else {
- if (autask->saved_tf)
- send_sig(SIGTRAP, task, 0);
- else if (!(auprobe->fixups & UPROBE_FIX_SETF))
- regs->flags &= ~X86_EFLAGS_TF;
- }
-}
diff --git a/include/linux/uprobes.h b/include/linux/uprobes.h
index 24594571c5a..4f628a6fc5b 100644
--- a/include/linux/uprobes.h
+++ b/include/linux/uprobes.h
@@ -97,12 +97,12 @@ extern int uprobe_register(struct inode *inode, loff_t offset, struct uprobe_con
extern void uprobe_unregister(struct inode *inode, loff_t offset, struct uprobe_consumer *uc);
extern int uprobe_mmap(struct vm_area_struct *vma);
extern void uprobe_munmap(struct vm_area_struct *vma, unsigned long start, unsigned long end);
+extern void uprobe_start_dup_mmap(void);
+extern void uprobe_end_dup_mmap(void);
extern void uprobe_dup_mmap(struct mm_struct *oldmm, struct mm_struct *newmm);
extern void uprobe_free_utask(struct task_struct *t);
extern void uprobe_copy_process(struct task_struct *t);
extern unsigned long __weak uprobe_get_swbp_addr(struct pt_regs *regs);
-extern void __weak arch_uprobe_enable_step(struct arch_uprobe *arch);
-extern void __weak arch_uprobe_disable_step(struct arch_uprobe *arch);
extern int uprobe_post_sstep_notifier(struct pt_regs *regs);
extern int uprobe_pre_sstep_notifier(struct pt_regs *regs);
extern void uprobe_notify_resume(struct pt_regs *regs);
@@ -129,6 +129,12 @@ static inline void
uprobe_munmap(struct vm_area_struct *vma, unsigned long start, unsigned long end)
{
}
+static inline void uprobe_start_dup_mmap(void)
+{
+}
+static inline void uprobe_end_dup_mmap(void)
+{
+}
static inline void
uprobe_dup_mmap(struct mm_struct *oldmm, struct mm_struct *newmm)
{
diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
index 5cc4e7e42e6..dea7acfbb07 100644
--- a/kernel/events/uprobes.c
+++ b/kernel/events/uprobes.c
@@ -33,6 +33,7 @@
#include <linux/ptrace.h> /* user_enable_single_step */
#include <linux/kdebug.h> /* notifier mechanism */
#include "../../mm/internal.h" /* munlock_vma_page */
+#include <linux/percpu-rwsem.h>
#include <linux/uprobes.h>
@@ -71,6 +72,8 @@ static struct mutex uprobes_mutex[UPROBES_HASH_SZ];
static struct mutex uprobes_mmap_mutex[UPROBES_HASH_SZ];
#define uprobes_mmap_hash(v) (&uprobes_mmap_mutex[((unsigned long)(v)) % UPROBES_HASH_SZ])
+static struct percpu_rw_semaphore dup_mmap_sem;
+
/*
* uprobe_events allows us to skip the uprobe_mmap if there are no uprobe
* events active at this time. Probably a fine grained per inode count is
@@ -766,10 +769,13 @@ static int register_for_each_vma(struct uprobe *uprobe, bool is_register)
struct map_info *info;
int err = 0;
+ percpu_down_write(&dup_mmap_sem);
info = build_map_info(uprobe->inode->i_mapping,
uprobe->offset, is_register);
- if (IS_ERR(info))
- return PTR_ERR(info);
+ if (IS_ERR(info)) {
+ err = PTR_ERR(info);
+ goto out;
+ }
while (info) {
struct mm_struct *mm = info->mm;
@@ -799,7 +805,8 @@ static int register_for_each_vma(struct uprobe *uprobe, bool is_register)
mmput(mm);
info = free_map_info(info);
}
-
+ out:
+ percpu_up_write(&dup_mmap_sem);
return err;
}
@@ -1131,6 +1138,16 @@ void uprobe_clear_state(struct mm_struct *mm)
kfree(area);
}
+void uprobe_start_dup_mmap(void)
+{
+ percpu_down_read(&dup_mmap_sem);
+}
+
+void uprobe_end_dup_mmap(void)
+{
+ percpu_up_read(&dup_mmap_sem);
+}
+
void uprobe_dup_mmap(struct mm_struct *oldmm, struct mm_struct *newmm)
{
newmm->uprobes_state.xol_area = NULL;
@@ -1199,6 +1216,11 @@ static unsigned long xol_get_insn_slot(struct uprobe *uprobe, unsigned long slot
vaddr = kmap_atomic(area->page);
memcpy(vaddr + offset, uprobe->arch.insn, MAX_UINSN_BYTES);
kunmap_atomic(vaddr);
+ /*
+ * We probably need flush_icache_user_range() but it needs vma.
+ * This should work on supported architectures too.
+ */
+ flush_dcache_page(area->page);
return current->utask->xol_vaddr;
}
@@ -1430,16 +1452,6 @@ static struct uprobe *find_active_uprobe(unsigned long bp_vaddr, int *is_swbp)
return uprobe;
}
-void __weak arch_uprobe_enable_step(struct arch_uprobe *arch)
-{
- user_enable_single_step(current);
-}
-
-void __weak arch_uprobe_disable_step(struct arch_uprobe *arch)
-{
- user_disable_single_step(current);
-}
-
/*
* Run handler and ask thread to singlestep.
* Ensure all non-fatal signals cannot interrupt thread while it singlesteps.
@@ -1493,7 +1505,6 @@ static void handle_swbp(struct pt_regs *regs)
goto out;
if (!pre_ssout(uprobe, regs, bp_vaddr)) {
- arch_uprobe_enable_step(&uprobe->arch);
utask->active_uprobe = uprobe;
utask->state = UTASK_SSTEP;
return;
@@ -1525,7 +1536,6 @@ static void handle_singlestep(struct uprobe_task *utask, struct pt_regs *regs)
else
WARN_ON_ONCE(1);
- arch_uprobe_disable_step(&uprobe->arch);
put_uprobe(uprobe);
utask->active_uprobe = NULL;
utask->state = UTASK_RUNNING;
@@ -1604,6 +1614,9 @@ static int __init init_uprobes(void)
mutex_init(&uprobes_mmap_mutex[i]);
}
+ if (percpu_init_rwsem(&dup_mmap_sem))
+ return -ENOMEM;
+
return register_die_notifier(&uprobe_exception_nb);
}
module_init(init_uprobes);
diff --git a/kernel/fork.c b/kernel/fork.c
index 8b20ab7d3aa..c497e57aa65 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -352,6 +352,7 @@ static int dup_mmap(struct mm_struct *mm, struct mm_struct *oldmm)
unsigned long charge;
struct mempolicy *pol;
+ uprobe_start_dup_mmap();
down_write(&oldmm->mmap_sem);
flush_cache_dup_mm(oldmm);
uprobe_dup_mmap(oldmm, mm);
@@ -469,6 +470,7 @@ out:
up_write(&mm->mmap_sem);
flush_tlb_mm(oldmm);
up_write(&oldmm->mmap_sem);
+ uprobe_end_dup_mmap();
return retval;
fail_nomem_anon_vma_fork:
mpol_put(pol);
diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c
index 4ff9ca4f359..9614db8b0f8 100644
--- a/kernel/trace/trace_uprobe.c
+++ b/kernel/trace/trace_uprobe.c
@@ -189,7 +189,7 @@ static int create_trace_uprobe(int argc, char **argv)
if (argv[0][0] == '-')
is_delete = true;
else if (argv[0][0] != 'p') {
- pr_info("Probe definition must be started with 'p', 'r' or" " '-'.\n");
+ pr_info("Probe definition must be started with 'p' or '-'.\n");
return -EINVAL;
}