From: "Mike Rapoport (Microsoft)" <rppt@xxxxxxxxxx>
x86::alloc_insn_page() always allocates ROX memory.
Instead of overriding this method, add EXECMEM_KPROBES entry in
execmem_info with pgprot set to PAGE_KERNEL_ROX and use ROX cache when
configuration and CPU features allow it.
Acked-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Signed-off-by: Mike Rapoport (Microsoft) <rppt@xxxxxxxxxx>
---
arch/x86/kernel/kprobes/core.c | 18 ------------------
arch/x86/mm/init.c | 9 ++++++++-
2 files changed, 8 insertions(+), 19 deletions(-)
diff --git a/arch/x86/kernel/kprobes/core.c b/arch/x86/kernel/kprobes/core.c
index 47cb8eb138ba..6079d15dab8c 100644
--- a/arch/x86/kernel/kprobes/core.c
+++ b/arch/x86/kernel/kprobes/core.c
@@ -481,24 +481,6 @@ static int prepare_singlestep(kprobe_opcode_t *buf, struct kprobe *p,
return len;
}
-/* Make page to RO mode when allocate it */
-void *alloc_insn_page(void)
-{
- void *page;
-
- page = execmem_alloc(EXECMEM_KPROBES, PAGE_SIZE);
- if (!page)
- return NULL;
-
- /*
- * TODO: Once additional kernel code protection mechanisms are set, ensure
- * that the page was not maliciously altered and it is still zeroed.
- */
- set_memory_rox((unsigned long)page, 1);
-
- return 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/arch/x86/mm/init.c b/arch/x86/mm/init.c
index dbc63f0d538f..442fafd8ff52 100644
--- a/arch/x86/mm/init.c
+++ b/arch/x86/mm/init.c
@@ -1098,7 +1098,14 @@ struct execmem_info __init *execmem_arch_setup(void)
.pgprot = pgprot,
.alignment = MODULE_ALIGN,
},
- [EXECMEM_KPROBES ... EXECMEM_BPF] = {
+ [EXECMEM_KPROBES] = {
+ .flags = flags,
+ .start = start,
+ .end = MODULES_END,
+ .pgprot = PAGE_KERNEL_ROX,
+ .alignment = MODULE_ALIGN,
+ },
+ [EXECMEM_FTRACE ... EXECMEM_BPF] = {
.flags = EXECMEM_KASAN_SHADOW,
.start = start,
.end = MODULES_END,
--
2.47.2
