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Subject[RFC PATCH 5/6] uprobes: add bp_vaddr argument to consumer handler
Date
Add argument to handler() to pass the breakpoint address(bp_vaddr). This makes
uprobes consistent, doesn't require users to calculate the pre-breakpoint
address themselves as well as remove uprobes.h import(see the cuts in
trace_event.c here). It also simplifies implementation of the return
probes(uretprobes).

I can't foresee whether anything else from the u[ret]probes should be exposed
the same way as breakpoint address and bet on it as unlikely, so I think
anything heavier than just a sufficient to pass an address variable is overkill.
Any input are welcome though.

Signed-off-by: Anton Arapov <anton@redhat.com>
---
include/linux/uprobes.h | 2 +-
kernel/events/uprobes.c | 9 +++++----
kernel/trace/trace_uprobe.c | 20 +++++++++++---------
3 files changed, 17 insertions(+), 14 deletions(-)

diff --git a/include/linux/uprobes.h b/include/linux/uprobes.h
index 1222a2c..741cc77 100644
--- a/include/linux/uprobes.h
+++ b/include/linux/uprobes.h
@@ -39,7 +39,7 @@ struct inode;
#endif

struct uprobe_consumer {
- int (*handler)(struct uprobe_consumer *self, struct pt_regs *regs);
+ int (*handler)(struct uprobe_consumer *self, unsigned long bp_vaddr, struct pt_regs *regs);

struct uprobe_consumer *next;
};
diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
index a3b3a60..d4016282 100644
--- a/kernel/events/uprobes.c
+++ b/kernel/events/uprobes.c
@@ -454,7 +454,8 @@ static struct uprobe *alloc_uprobe(struct inode *inode, loff_t offset)
return uprobe;
}

-static void handler_chain(struct uprobe *uprobe, struct pt_regs *regs)
+static void
+handler_chain(struct uprobe *uprobe, unsigned long bp_vaddr, struct pt_regs *regs)
{
struct uprobe_consumer *uc;

@@ -463,7 +464,7 @@ static void handler_chain(struct uprobe *uprobe, struct pt_regs *regs)
prepare_uretprobe(uprobe, regs);

for (uc = uprobe->consumers; uc; uc = uc->next)
- uc->handler(uc, regs);
+ uc->handler(uc, bp_vaddr, regs);
up_read(&uprobe->register_rwsem);
}

@@ -473,7 +474,7 @@ static void uretprobe_handler_chain(struct uprobe *uprobe, unsigned long bp_vadd

down_read(&uprobe->register_rwsem);
for (uc = uprobe->return_consumers; uc; uc = uc->next)
- uc->handler(uc, regs);
+ uc->handler(uc, bp_vaddr, regs);
up_read(&uprobe->register_rwsem);
}

@@ -1676,7 +1677,7 @@ static void handle_swbp(struct pt_regs *regs)
goto restart;
}

- handler_chain(uprobe, regs);
+ handler_chain(uprobe, bp_vaddr, regs);
if (can_skip_sstep(uprobe, regs))
goto out;

diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c
index 920dfd0..999da12 100644
--- a/kernel/trace/trace_uprobe.c
+++ b/kernel/trace/trace_uprobe.c
@@ -20,7 +20,6 @@

#include <linux/module.h>
#include <linux/uaccess.h>
-#include <linux/uprobes.h>
#include <linux/namei.h>
#include <linux/string.h>

@@ -62,7 +61,7 @@ static void unregister_uprobe_event(struct trace_uprobe *tu);
static DEFINE_MUTEX(uprobe_lock);
static LIST_HEAD(uprobe_list);

-static int uprobe_dispatcher(struct uprobe_consumer *con, struct pt_regs *regs);
+static int uprobe_dispatcher(struct uprobe_consumer *con, unsigned long bp_vaddr, struct pt_regs *regs);

/*
* Allocate new trace_uprobe and initialize it (including uprobes).
@@ -465,7 +464,8 @@ static const struct file_operations uprobe_profile_ops = {
};

/* uprobe handler */
-static void uprobe_trace_func(struct trace_uprobe *tu, struct pt_regs *regs)
+static void
+uprobe_trace_func(struct trace_uprobe *tu, unsigned long bp_vaddr, struct pt_regs *regs)
{
struct uprobe_trace_entry_head *entry;
struct ring_buffer_event *event;
@@ -488,7 +488,7 @@ static void uprobe_trace_func(struct trace_uprobe *tu, struct pt_regs *regs)
return;

entry = ring_buffer_event_data(event);
- entry->ip = uprobe_get_swbp_addr(task_pt_regs(current));
+ entry->ip = bp_vaddr;
data = (u8 *)&entry[1];
for (i = 0; i < tu->nr_args; i++)
call_fetch(&tu->args[i].fetch, regs, data + tu->args[i].offset);
@@ -642,7 +642,8 @@ static int set_print_fmt(struct trace_uprobe *tu)

#ifdef CONFIG_PERF_EVENTS
/* uprobe profile handler */
-static void uprobe_perf_func(struct trace_uprobe *tu, struct pt_regs *regs)
+static void
+uprobe_perf_func(struct trace_uprobe *tu, unsigned long bp_vaddr, struct pt_regs *regs)
{
struct ftrace_event_call *call = &tu->call;
struct uprobe_trace_entry_head *entry;
@@ -663,7 +664,7 @@ static void uprobe_perf_func(struct trace_uprobe *tu, struct pt_regs *regs)
if (!entry)
goto out;

- entry->ip = uprobe_get_swbp_addr(task_pt_regs(current));
+ entry->ip = bp_vaddr;
data = (u8 *)&entry[1];
for (i = 0; i < tu->nr_args; i++)
call_fetch(&tu->args[i].fetch, regs, data + tu->args[i].offset);
@@ -703,7 +704,8 @@ int trace_uprobe_register(struct ftrace_event_call *event, enum trace_reg type,
return 0;
}

-static int uprobe_dispatcher(struct uprobe_consumer *con, struct pt_regs *regs)
+static int
+uprobe_dispatcher(struct uprobe_consumer *con, unsigned long bp_vaddr, struct pt_regs *regs)
{
struct uprobe_trace_consumer *utc;
struct trace_uprobe *tu;
@@ -714,11 +716,11 @@ static int uprobe_dispatcher(struct uprobe_consumer *con, struct pt_regs *regs)
return 0;

if (tu->flags & TP_FLAG_TRACE)
- uprobe_trace_func(tu, regs);
+ uprobe_trace_func(tu, bp_vaddr, regs);

#ifdef CONFIG_PERF_EVENTS
if (tu->flags & TP_FLAG_PROFILE)
- uprobe_perf_func(tu, regs);
+ uprobe_perf_func(tu, bp_vaddr, regs);
#endif
return 0;
}
--
1.8.0.2


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