[PATCH v2] kprobes: remove duplicated strong free_insn_page in x86 and s390

From: Barry Song
Date: Mon Jun 07 2021 - 05:19:13 EST


free_insn_page() in x86 and s390 are same with the common weak function
in kernel/kprobes.c.
Plus, the comment "Recover page to RW mode before releasing it" in x86
seems insensible to be there since resetting mapping is done by common
code in vfree() of module_memfree().
So drop these two duplicated strong functions and related comment, then
mark the common one in kernel/kprobes.c strong.

Cc: Christoph Hellwig <hch@xxxxxxxxxxxxx>
Signed-off-by: Barry Song <song.bao.hua@xxxxxxxxxxxxx>
---
-v2:
remove free_insn_page in s390 as well and remove the __weak in common
code according to Christoph's comment;

arch/s390/kernel/kprobes.c | 5 -----
arch/x86/kernel/kprobes/core.c | 6 ------
kernel/kprobes.c | 2 +-
3 files changed, 1 insertion(+), 12 deletions(-)

diff --git a/arch/s390/kernel/kprobes.c b/arch/s390/kernel/kprobes.c
index aae24dc75df6..60cfbd24229b 100644
--- a/arch/s390/kernel/kprobes.c
+++ b/arch/s390/kernel/kprobes.c
@@ -44,11 +44,6 @@ void *alloc_insn_page(void)
return page;
}

-void free_insn_page(void *page)
-{
- module_memfree(page);
-}
-
static void *alloc_s390_insn_page(void)
{
if (xchg(&insn_page_in_use, 1) == 1)
diff --git a/arch/x86/kernel/kprobes/core.c b/arch/x86/kernel/kprobes/core.c
index d3d65545cb8b..3bce67d3a03c 100644
--- a/arch/x86/kernel/kprobes/core.c
+++ b/arch/x86/kernel/kprobes/core.c
@@ -422,12 +422,6 @@ void *alloc_insn_page(void)
return page;
}

-/* Recover page to RW mode before releasing it */
-void free_insn_page(void *page)
-{
- module_memfree(page);
-}
-
/* Kprobe x86 instruction emulation - only regs->ip or IF flag modifiers */

static void kprobe_emulate_ifmodifiers(struct kprobe *p, struct pt_regs *regs)
diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index 745f08fdd7a6..ddb643f3879f 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -106,7 +106,7 @@ void __weak *alloc_insn_page(void)
return module_alloc(PAGE_SIZE);
}

-void __weak free_insn_page(void *page)
+void free_insn_page(void *page)
{
module_memfree(page);
}
--
2.25.1