[PATCH 5/9] riscv: kprobes: Implement alloc_insn_page()

Jisheng Zhang
2021-03-29T18:30:12Z

From: Jisheng Zhang <jszhang@kernel.org>

Allocate PAGE_KERNEL_READ_EXEC(read only, executable) page for kprobes
insn page. This is to prepare for STRICT_MODULE_RWX.

Signed-off-by: Jisheng Zhang <jszhang@kernel.org>
---
arch/riscv/kernel/probes/kprobes.c | 8 ++++++++
1 file changed, 8 insertions(+)

diff --git a/arch/riscv/kernel/probes/kprobes.c b/arch/riscv/kernel/probes/kprobes.c
index 7e2c78e2ca6b..8c1f7a30aeed 100644
--- a/arch/riscv/kernel/probes/kprobes.c
+++ b/arch/riscv/kernel/probes/kprobes.c
@@ -84,6 +84,14 @@ int __kprobes arch_prepare_kprobe(struct kprobe *p)
return 0;
}

+void *alloc_insn_page(void)
+{
+ return __vmalloc_node_range(PAGE_SIZE, 1, VMALLOC_START, VMALLOC_END,
+ GFP_KERNEL, PAGE_KERNEL_READ_EXEC,
+ VM_FLUSH_RESET_PERMS, NUMA_NO_NODE,
+ __builtin_return_address(0));
+}
+
/* install breakpoint in text */
void __kprobes arch_arm_kprobe(struct kprobe *p)
{
--
2.31.0