| Message ID | 20200827052659.24922-3-cmr@codefail.de (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | Use per-CPU temporary mappings for patching | expand |
| Context | Check | Description |
|---|---|---|
| snowpatch_ozlabs/apply_patch | success | Successfully applied on branch powerpc/merge (d4ecce4dcc8f8820286cf4e0859850c555e89854) |
| snowpatch_ozlabs/checkpatch | success | total: 0 errors, 0 warnings, 0 checks, 21 lines checked |
| snowpatch_ozlabs/needsstable | success | Patch has no Fixes tags |
diff --git a/arch/x86/include/asm/text-patching.h b/arch/x86/include/asm/text-patching.h index 6593b42cb379..f67b4dd30bf8 100644 --- a/arch/x86/include/asm/text-patching.h +++ b/arch/x86/include/asm/text-patching.h @@ -148,4 +148,8 @@ void int3_emulate_call(struct pt_regs *regs, unsigned long func) } #endif /* !CONFIG_UML_X86 */ +#ifdef CONFIG_LKDTM +unsigned long read_cpu_patching_addr(unsigned int cpu); +#endif + #endif /* _ASM_X86_TEXT_PATCHING_H */ diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c index c3daf0aaa0ee..c16833f35a1f 100644 --- a/arch/x86/kernel/alternative.c +++ b/arch/x86/kernel/alternative.c @@ -843,6 +843,13 @@ static inline void unuse_temporary_mm(temp_mm_state_t prev_state) __ro_after_init struct mm_struct *poking_mm; __ro_after_init unsigned long poking_addr; +#ifdef CONFIG_LKDTM +unsigned long read_cpu_patching_addr(unsigned int cpu) +{ + return poking_addr; +} +#endif + static void *__text_poke(void *addr, const void *opcode, size_t len) { bool cross_page_boundary = offset_in_page(addr) + len > PAGE_SIZE;
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 <cmr@codefail.de> --- arch/x86/include/asm/text-patching.h | 4 ++++ arch/x86/kernel/alternative.c | 7 +++++++ 2 files changed, 11 insertions(+)