Re: [PATCH 4/5] powerpc/lib: Add LKDTM accessor for patching addr
From: Christophe Leroy <hidden>
Date: 2020-06-03 07:17:04
Le 03/06/2020 à 07:19, Christopher M. Riedl a écrit :
quoted hunk ↗ jump to hunk
When live patching a STRICT_RWX kernel, a mapping is installed at a "patching address" with temporary write permissions. Provide a LKDTM-only accessor function for this address in preparation for a LKDTM test which attempts to "hijack" this mapping by writing to it from another CPU. Signed-off-by: Christopher M. Riedl <redacted> --- arch/powerpc/lib/code-patching.c | 7 +++++++ 1 file changed, 7 insertions(+)diff --git a/arch/powerpc/lib/code-patching.c b/arch/powerpc/lib/code-patching.c index df0765845204..c23453049116 100644 --- a/arch/powerpc/lib/code-patching.c +++ b/arch/powerpc/lib/code-patching.c@@ -52,6 +52,13 @@ int raw_patch_instruction(struct ppc_inst *addr, struct ppc_inst instr) static struct mm_struct *patching_mm __ro_after_init; static unsigned long patching_addr __ro_after_init; +#ifdef CONFIG_LKDTM +unsigned long read_cpu_patching_addr(unsigned int cpu)
If this fonction is not static, it means it is intended to be used from some other C file, so it should be declared in a .h too. Christophe
+{
+ return patching_addr;
+}
+#endif
+
void __init poking_init(void)
{
spinlock_t *ptl; /* for protecting pte table */