[PATCH -tip 1/4] x86: Add in_entry_text() helper function

Masami Hiramatsu
2017-08-17T07:14:47Z

Add in_entry_text() helper function to cleanup
entry/irqentry section checking code in kprobes and
unwind_frame.

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
---
arch/x86/include/asm/sections.h | 15 +++++++++++++++
arch/x86/kernel/kprobes/opt.c | 5 +----
arch/x86/kernel/unwind_frame.c | 15 +--------------
3 files changed, 17 insertions(+), 18 deletions(-)

diff --git a/arch/x86/include/asm/sections.h b/arch/x86/include/asm/sections.h
index 2f75f30cb2f6..bb72ea0f4367 100644
--- a/arch/x86/include/asm/sections.h
+++ b/arch/x86/include/asm/sections.h
@@ -11,4 +11,19 @@ extern struct exception_table_entry __stop___ex_table[];
extern char __end_rodata_hpage_align[];
#endif

+/**
+ * in_entry_text - check if an address is in entry_text or irqentry_text
+ * @addr: virtual address to be checked
+ *
+ * Returns: true if the address specified by @addr is in the entry_text or
+ * irqentry_text, false otherwise.
+ */
+static inline bool in_entry_text(unsigned long addr)
+{
+ return memory_contains(__entry_text_start, __entry_text_end,
+ (void *)addr, 0) ||
+ memory_contains(__irqentry_text_start, __irqentry_text_end,
+ (void *)addr, 0);
+}
+
#endif /* _ASM_X86_SECTIONS_H */
diff --git a/arch/x86/kernel/kprobes/opt.c b/arch/x86/kernel/kprobes/opt.c
index 4f98aad38237..74c5ad55ba6a 100644
--- a/arch/x86/kernel/kprobes/opt.c
+++ b/arch/x86/kernel/kprobes/opt.c
@@ -254,10 +254,7 @@ static int can_optimize(unsigned long paddr)
* Do not optimize in the entry code due to the unstable
* stack handling and registers setup.
*/
- if (((paddr >= (unsigned long)__entry_text_start) &&
- (paddr < (unsigned long)__entry_text_end)) ||
- ((paddr >= (unsigned long)__irqentry_text_start) &&
- (paddr < (unsigned long)__irqentry_text_end)))
+ if (in_entry_text(paddr))
return 0;

/* Check there is enough space for a relative jump. */
diff --git a/arch/x86/kernel/unwind_frame.c b/arch/x86/kernel/unwind_frame.c
index d145a0b1f529..508cef8904f4 100644
--- a/arch/x86/kernel/unwind_frame.c
+++ b/arch/x86/kernel/unwind_frame.c
@@ -77,19 +77,6 @@ static size_t regs_size(struct pt_regs *regs)
return sizeof(*regs);
}

-static bool in_entry_code(unsigned long ip)
-{
- char *addr = (char *)ip;
-
- if (addr >= __entry_text_start && addr < __entry_text_end)
- return true;
-
- if (addr >= __irqentry_text_start && addr < __irqentry_text_end)
- return true;
-
- return false;
-}
-
static inline unsigned long *last_frame(struct unwind_state *state)
{
return (unsigned long *)task_pt_regs(state->task) - 2;
@@ -321,7 +308,7 @@ bool unwind_next_frame(struct unwind_state *state)
* Don't warn if the unwinder got lost due to an interrupt in entry
* code or in the C handler before the first frame pointer got set up:
*/
- if (state->got_irq && in_entry_code(state->ip))
+ if (state->got_irq && in_entry_text(state->ip))
goto the_end;
if (state->regs &&
state->regs->sp >= (unsigned long)last_aligned_frame(state) &&