diff mbox series

[v15,4/9] powerpc/kprobes: Mark newly allocated probes as ROX

Message ID 20210609013431.9805-5-jniethe5@gmail.com (mailing list archive)
State Accepted
Headers show
Series powerpc: Further Strict RWX support | expand
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Context Check Description
snowpatch_ozlabs/apply_patch success Successfully applied on branch powerpc/merge (c53db722ec7ab3ebf29ecf61e922820f31e5284b)
snowpatch_ozlabs/checkpatch success total: 0 errors, 0 warnings, 0 checks, 34 lines checked
snowpatch_ozlabs/needsstable success Patch has no Fixes tags

Commit Message

Jordan Niethe June 9, 2021, 1:34 a.m. UTC 
From: Russell Currey <ruscur@russell.cc>

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 <dja@axtens.net>
Signed-off-by: Russell Currey <ruscur@russell.cc>
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
[jpn: Reword commit message, switch to __vmalloc_node_range()]
Signed-off-by: Jordan Niethe <jniethe5@gmail.com>
---
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()
v14: Use strict_module_rwx_enabled()
---
 arch/powerpc/kernel/kprobes.c | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)
diff mbox series

Patch

diff --git a/arch/powerpc/kernel/kprobes.c b/arch/powerpc/kernel/kprobes.c
index 01ab2163659e..937e338053ff 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_module_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;