[PATCH v13 3/8] powerpc/kprobes: Mark newly allocated probes as ROX
From: Jordan Niethe <hidden>
Date: 2021-05-10 01:20:41
Subsystem:
linux for powerpc (32-bit and 64-bit), the rest · Maintainers:
Madhavan Srinivasan, Linus Torvalds
From: Russell Currey <redacted>
Add the arch specific insn page allocator for powerpc. This allocates
ROX pages if STRICT_KERNEL_RWX is enabled. These pages are only written
to with patch_instruction() which is able to write RO pages.
Reviewed-by: Daniel Axtens <redacted>
Signed-off-by: Russell Currey <redacted>
Signed-off-by: Christophe Leroy <redacted>
[jpn: Reword commit message, switch to __vmalloc_node_range()]
Signed-off-by: Jordan Niethe <redacted>
---
v9: - vmalloc_exec() no longer exists
- Set the page to RW before freeing it
v10: - use __vmalloc_node_range()
v11: - Neaten up
v12: - Switch from __vmalloc_node_range() to module_alloc()
v13: Use strict_kernel_rwx_enabled()
---
arch/powerpc/kernel/kprobes.c | 17 +++++++++++++++++
1 file changed, 17 insertions(+)
diff --git a/arch/powerpc/kernel/kprobes.c b/arch/powerpc/kernel/kprobes.c
index 01ab2163659e..b517f3e6e7c5 100644
--- a/arch/powerpc/kernel/kprobes.c
+++ b/arch/powerpc/kernel/kprobes.c@@ -19,11 +19,13 @@ #include <linux/extable.h> #include <linux/kdebug.h> #include <linux/slab.h> +#include <linux/moduleloader.h> #include <asm/code-patching.h> #include <asm/cacheflush.h> #include <asm/sstep.h> #include <asm/sections.h> #include <asm/inst.h> +#include <asm/set_memory.h> #include <linux/uaccess.h> DEFINE_PER_CPU(struct kprobe *, current_kprobe) = NULL;
@@ -103,6 +105,21 @@ kprobe_opcode_t *kprobe_lookup_name(const char *name, unsigned int offset) return addr; } +void *alloc_insn_page(void) +{ + void *page; + + page = module_alloc(PAGE_SIZE); + if (!page) + return NULL; + + if (strict_kernel_rwx_enabled()) { + set_memory_ro((unsigned long)page, 1); + set_memory_x((unsigned long)page, 1); + } + return page; +} + int arch_prepare_kprobe(struct kprobe *p) { int ret = 0;
--
2.25.1