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Message-Id: <1199916062.6424.60.camel@brick>
Date: Wed, 09 Jan 2008 14:01:02 -0800
From: Harvey Harrison <harvey.harrison@...il.com>
To: Heiko Carstens <heiko.carstens@...ibm.com>,
Christoph Hellwig <hch@...radead.org>,
Andrew Morton <akpm@...ux-foundation.org>
Cc: LKML <linux-kernel@...r.kernel.org>,
Masami Hiramatsu <mhiramat@...hat.com>,
Ananth N Mavinakayanahalli <ananth@...ibm.com>,
David Miller <davem@...emloft.net>, hskinnemoen@...el.com,
schwidefsky@...ibm.com, tony.luck@...el.com,
Ingo Molnar <mingo@...e.hu>, Paul Mackerras <paulus@...ba.org>
Subject: [PATCHv4] kprobes: Introduce kprobe_handle_fault()
Use a central kprobe_handle_fault() inline in kprobes.h to remove
all of the arch-dependant, practically identical implementations in
avr32, ia64, powerpc, s390, sparc64, and x86.
This patch removes the preempt_disable/enable pair around kprobe_running
which was originally added to avoid the assertion from smp_processor_id
which would be unreliable if preemption was enabled.
Kprobes can not be running if we are preemptible, so test explicitly
for preemption and bail out before hitting kprobe_running().
Style comments from Christoph Hellwig and Heiko Carstens included in
this version.
avr32 was the only arch without the preempt_disable/enable pair
in its notify_page_fault implementation.
This uncovered a possible bug in the s390 version as that purely
copied the x86 version unconditionally passing 14 as the trapnr
rather than the error_code parameter.
Signed-off-by: Harvey Harrison <harvey.harrison@...il.com>
---
arch/avr32/mm/fault.c | 21 +--------------------
arch/ia64/mm/fault.c | 24 +-----------------------
arch/powerpc/mm/fault.c | 25 +------------------------
arch/s390/mm/fault.c | 25 +------------------------
arch/sparc64/mm/fault.c | 23 +----------------------
arch/x86/mm/fault_64.c | 23 ++---------------------
include/linux/kprobes.h | 17 +++++++++++++++++
7 files changed, 24 insertions(+), 134 deletions(-)
diff --git a/arch/avr32/mm/fault.c b/arch/avr32/mm/fault.c
index 6560cb1..e41953e 100644
--- a/arch/avr32/mm/fault.c
+++ b/arch/avr32/mm/fault.c
@@ -20,25 +20,6 @@
#include <asm/tlb.h>
#include <asm/uaccess.h>
-#ifdef CONFIG_KPROBES
-static inline int notify_page_fault(struct pt_regs *regs, int trap)
-{
- int ret = 0;
-
- if (!user_mode(regs)) {
- if (kprobe_running() && kprobe_fault_handler(regs, trap))
- ret = 1;
- }
-
- return ret;
-}
-#else
-static inline int notify_page_fault(struct pt_regs *regs, int trap)
-{
- return 0;
-}
-#endif
-
int exception_trace = 1;
/*
@@ -66,7 +47,7 @@ asmlinkage void do_page_fault(unsigned long ecr, struct pt_regs *regs)
int code;
int fault;
- if (notify_page_fault(regs, ecr))
+ if (kprobe_handle_fault(regs, ecr))
return;
address = sysreg_read(TLBEAR);
diff --git a/arch/ia64/mm/fault.c b/arch/ia64/mm/fault.c
index 7571076..bfc83e8 100644
--- a/arch/ia64/mm/fault.c
+++ b/arch/ia64/mm/fault.c
@@ -18,28 +18,6 @@
extern void die (char *, struct pt_regs *, long);
-#ifdef CONFIG_KPROBES
-static inline int notify_page_fault(struct pt_regs *regs, int trap)
-{
- int ret = 0;
-
- if (!user_mode(regs)) {
- /* kprobe_running() needs smp_processor_id() */
- preempt_disable();
- if (kprobe_running() && kprobes_fault_handler(regs, trap))
- ret = 1;
- preempt_enable();
- }
-
- return ret;
-}
-#else
-static inline int notify_page_fault(struct pt_regs *regs, int trap)
-{
- return 0;
-}
-#endif
-
/*
* Return TRUE if ADDRESS points at a page in the kernel's mapped segment
* (inside region 5, on ia64) and that page is present.
@@ -106,7 +84,7 @@ ia64_do_page_fault (unsigned long address, unsigned long isr, struct pt_regs *re
/*
* This is to handle the kprobes on user space access instructions
*/
- if (notify_page_fault(regs, TRAP_BRKPT))
+ if (kprobe_handle_fault(regs, TRAP_BRKPT))
return;
down_read(&mm->mmap_sem);
diff --git a/arch/powerpc/mm/fault.c b/arch/powerpc/mm/fault.c
index 8135da0..ff64bd3 100644
--- a/arch/powerpc/mm/fault.c
+++ b/arch/powerpc/mm/fault.c
@@ -39,29 +39,6 @@
#include <asm/tlbflush.h>
#include <asm/siginfo.h>
-
-#ifdef CONFIG_KPROBES
-static inline int notify_page_fault(struct pt_regs *regs)
-{
- int ret = 0;
-
- /* kprobe_running() needs smp_processor_id() */
- if (!user_mode(regs)) {
- preempt_disable();
- if (kprobe_running() && kprobe_fault_handler(regs, 11))
- ret = 1;
- preempt_enable();
- }
-
- return ret;
-}
-#else
-static inline int notify_page_fault(struct pt_regs *regs)
-{
- return 0;
-}
-#endif
-
/*
* Check whether the instruction at regs->nip is a store using
* an update addressing form which will update r1.
@@ -164,7 +141,7 @@ int __kprobes do_page_fault(struct pt_regs *regs, unsigned long address,
is_write = error_code & ESR_DST;
#endif /* CONFIG_4xx || CONFIG_BOOKE */
- if (notify_page_fault(regs))
+ if (kprobe_handle_fault(regs, 11))
return 0;
if (trap == 0x300) {
diff --git a/arch/s390/mm/fault.c b/arch/s390/mm/fault.c
index 2456b52..a9033cf 100644
--- a/arch/s390/mm/fault.c
+++ b/arch/s390/mm/fault.c
@@ -51,29 +51,6 @@ extern int sysctl_userprocess_debug;
extern void die(const char *,struct pt_regs *,long);
-#ifdef CONFIG_KPROBES
-static inline int notify_page_fault(struct pt_regs *regs, long err)
-{
- int ret = 0;
-
- /* kprobe_running() needs smp_processor_id() */
- if (!user_mode(regs)) {
- preempt_disable();
- if (kprobe_running() && kprobe_fault_handler(regs, 14))
- ret = 1;
- preempt_enable();
- }
-
- return ret;
-}
-#else
-static inline int notify_page_fault(struct pt_regs *regs, long err)
-{
- return 0;
-}
-#endif
-
-
/*
* Unlock any spinlocks which will prevent us from getting the
* message out.
@@ -309,7 +286,7 @@ do_exception(struct pt_regs *regs, unsigned long error_code, int write)
int si_code;
int fault;
- if (notify_page_fault(regs, error_code))
+ if (kprobe_handle_fault(regs, 14))
return;
tsk = current;
diff --git a/arch/sparc64/mm/fault.c b/arch/sparc64/mm/fault.c
index e2027f2..8467dd6 100644
--- a/arch/sparc64/mm/fault.c
+++ b/arch/sparc64/mm/fault.c
@@ -31,27 +31,6 @@
#include <asm/sections.h>
#include <asm/mmu_context.h>
-#ifdef CONFIG_KPROBES
-static inline int notify_page_fault(struct pt_regs *regs)
-{
- int ret = 0;
-
- /* kprobe_running() needs smp_processor_id() */
- if (!user_mode(regs)) {
- preempt_disable();
- if (kprobe_running() && kprobe_fault_handler(regs, 0))
- ret = 1;
- preempt_enable();
- }
- return ret;
-}
-#else
-static inline int notify_page_fault(struct pt_regs *regs)
-{
- return 0;
-}
-#endif
-
/*
* To debug kernel to catch accesses to certain virtual/physical addresses.
* Mode = 0 selects physical watchpoints, mode = 1 selects virtual watchpoints.
@@ -280,7 +259,7 @@ asmlinkage void __kprobes do_sparc64_fault(struct pt_regs *regs)
fault_code = get_thread_fault_code();
- if (notify_page_fault(regs))
+ if (kprobe_handle_fault(regs, 0))
return;
si_code = SEGV_MAPERR;
diff --git a/arch/x86/mm/fault_64.c b/arch/x86/mm/fault_64.c
index f681ff8..f81660f 100644
--- a/arch/x86/mm/fault_64.c
+++ b/arch/x86/mm/fault_64.c
@@ -45,25 +45,6 @@
#define PF_RSVD (1<<3)
#define PF_INSTR (1<<4)
-static inline int notify_page_fault(struct pt_regs *regs)
-{
-#ifdef CONFIG_KPROBES
- int ret = 0;
-
- /* kprobe_running() needs smp_processor_id() */
- if (!user_mode(regs)) {
- preempt_disable();
- if (kprobe_running() && kprobe_fault_handler(regs, 14))
- ret = 1;
- preempt_enable();
- }
-
- return ret;
-#else
- return 0;
-#endif
-}
-
#ifdef CONFIG_X86_32
/*
* Return EIP plus the CS segment base. The segment limit is also
@@ -468,7 +449,7 @@ asmlinkage void __kprobes do_page_fault(struct pt_regs *regs,
if (vmalloc_fault(address) >= 0)
return;
}
- if (notify_page_fault(regs))
+ if (kprobe_handle_fault(regs, 14))
return;
/*
* Don't take the mm semaphore here. If we fixup a prefetch
@@ -477,7 +458,7 @@ asmlinkage void __kprobes do_page_fault(struct pt_regs *regs,
goto bad_area_nosemaphore;
}
- if (notify_page_fault(regs))
+ if (kprobe_handle_fault(regs, 14))
return;
if (likely(regs->flags & X86_EFLAGS_IF))
diff --git a/include/linux/kprobes.h b/include/linux/kprobes.h
index 6168c0a..e099426 100644
--- a/include/linux/kprobes.h
+++ b/include/linux/kprobes.h
@@ -36,6 +36,7 @@
#include <linux/spinlock.h>
#include <linux/rcupdate.h>
#include <linux/mutex.h>
+#include <linux/hardirq.h>
#ifdef CONFIG_KPROBES
#include <asm/kprobes.h>
@@ -212,6 +213,18 @@ static inline struct kprobe *kprobe_running(void)
return (__get_cpu_var(current_kprobe));
}
+/*
+ * If it is a kprobe pagefault we can not be preemptible so return before
+ * calling kprobe_running() as it will assert on smp_processor_id if
+ * preemption is enabled.
+ */
+static inline int kprobe_handle_fault(struct pt_regs *regs, int trapnr)
+{
+ if (!user_mode(regs) && !preemptible() && kprobe_running())
+ return kprobe_fault_handler(regs, trapnr);
+ return 0;
+}
+
static inline void reset_current_kprobe(void)
{
__get_cpu_var(current_kprobe) = NULL;
@@ -247,6 +260,10 @@ static inline struct kprobe *kprobe_running(void)
{
return NULL;
}
+static inline int kprobe_handle_fault(struct pt_regs *regs, int trapnr)
+{
+ return 0;
+}
static inline int register_kprobe(struct kprobe *p)
{
return -ENOSYS;
--
1.5.4.rc2.1164.g6451
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