Re: [RESEND PATCH] arch: arm64: set __nocfi on swsusp_arch_resume

[Will Deacon <will@kernel.org>]

On Tue, Jan 20, 2026 at 02:06:19PM +0800, zhaoyang.huang wrote:
> From: Zhaoyang Huang <zhaoyang.huang@unisoc.com>
> 
> A DABT is reported[1] on an android based system when resume from hiberate,
> which is root caused as CFI will plant stub code[2] to verify the
> swsusp_arch_suspend_exit's authentication, where the hash value is stored
> before the page that alloced by create_safe_exec_page. We also have
> tried to copy the hash value together with the function but get failed since
> the value is not on the desired position(src_start - 4). So we solve
> this issue by setting __nocfi on swsusp_arch_resume and it works.
> 
> [1]
> [   22.991934][    T1] Unable to handle kernel paging request at virtual address 0000000109170ffc
> [   22.991934][    T1] Mem abort info:
> [   22.991934][    T1]   ESR = 0x0000000096000007
> [   22.991934][    T1]   EC = 0x25: DABT (current EL), IL = 32 bits
> [   22.991934][    T1]   SET = 0, FnV = 0
> [   22.991934][    T1]   EA = 0, S1PTW = 0
> [   22.991934][    T1]   FSC = 0x07: level 3 translation fault
> [   22.991934][    T1] Data abort info:
> [   22.991934][    T1]   ISV = 0, ISS = 0x00000007, ISS2 = 0x00000000
> [   22.991934][    T1]   CM = 0, WnR = 0, TnD = 0, TagAccess = 0
> [   22.991934][    T1]   GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0
> [   22.991934][    T1] [0000000109170ffc] user address but active_mm is swapper
> [   22.991934][    T1] Internal error: Oops: 0000000096000007 [#1] PREEMPT SMP
> [   22.991934][    T1] Dumping ftrace buffer:
> [   22.991934][    T1]    (ftrace buffer empty)
> [   22.991934][    T1] Modules linked in:
> [   22.991934][    T1] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 6.6.98-android15-8-g0b1d2aee7fc3-dirty-4k #1 688c7060a825a3ac418fe53881730b355915a419
> [   22.991934][    T1] Hardware name: Unisoc UMS9360-base Board (DT)
> [   22.991934][    T1] pstate: 804000c5 (Nzcv daIF +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
> [   22.991934][    T1] pc : swsusp_arch_resume+0x2ac/0x344
> [   22.991934][    T1] lr : swsusp_arch_resume+0x294/0x344
> [   22.991934][    T1] sp : ffffffc08006b960
> [   22.991934][    T1] x29: ffffffc08006b9c0 x28: 0000000000000000 x27: 0000000000000000
> [   22.991934][    T1] x26: 0000000000000000 x25: 0000000000000000 x24: 0000000000000820
> [   22.991934][    T1] x23: ffffffd0817e3000 x22: ffffffd0817e3000 x21: 0000000000000000
> [   22.991934][    T1] x20: ffffff8089171000 x19: ffffffd08252c8c8 x18: ffffffc080061058
> [   22.991934][    T1] x17: 00000000529c6ef0 x16: 00000000529c6ef0 x15: 0000000000000004
> [   22.991934][    T1] x14: ffffff8178c88000 x13: 0000000000000006 x12: 0000000000000000
> [   22.991934][    T1] x11: 0000000000000015 x10: 0000000000000001 x9 : ffffffd082533000
> [   22.991934][    T1] x8 : 0000000109171000 x7 : 205b5d3433393139 x6 : 392e32322020205b
> [   22.991934][    T1] x5 : 000000010916f000 x4 : 000000008164b000 x3 : ffffff808a4e0530
> [   22.991934][    T1] x2 : ffffffd08058e784 x1 : 0000000082326000 x0 : 000000010a283000
> [   22.991934][    T1] Call trace:
> [   22.991934][    T1]  swsusp_arch_resume+0x2ac/0x344
> [   22.991934][    T1]  hibernation_restore+0x158/0x18c
> [   22.991934][    T1]  load_image_and_restore+0xb0/0xec
> [   22.991934][    T1]  software_resume+0xf4/0x19c
> [   22.991934][    T1]  software_resume_initcall+0x34/0x78
> [   22.991934][    T1]  do_one_initcall+0xe8/0x370
> [   22.991934][    T1]  do_initcall_level+0xc8/0x19c
> [   22.991934][    T1]  do_initcalls+0x70/0xc0
> [   22.991934][    T1]  do_basic_setup+0x1c/0x28
> [   22.991934][    T1]  kernel_init_freeable+0xe0/0x148
> [   22.991934][    T1]  kernel_init+0x20/0x1a8
> [   22.991934][    T1]  ret_from_fork+0x10/0x20
> [   22.991934][    T1] Code: a9400a61 f94013e0 f9438923 f9400a64 (b85fc110)
> 
> [2]
> 0xffffffd08064a878 <swsusp_arch_resume+596>:	mov	x0, x24
> 0xffffffd08064a87c <swsusp_arch_resume+600>:	mov	x1, x20
> 0xffffffd08064a880 <swsusp_arch_resume+604>:	mov	x2, x21
> 0xffffffd08064a884 <swsusp_arch_resume+608>:	mov	x3, x22
> 0xffffffd08064a888 <swsusp_arch_resume+612>:	mov	x4, x23
> 0xffffffd08064a88c <swsusp_arch_resume+616>:	ldur	w16, [x25, #-4]
> 0xffffffd08064a890 <swsusp_arch_resume+620>:	movk	w17, #0x5d7b
> 0xffffffd08064a894 <swsusp_arch_resume+624>:	movk	w17, #0xb6ad, lsl #16
> 0xffffffd08064a898 <swsusp_arch_resume+628>:	cmp	w16, w17
> 0xffffffd08064a89c <swsusp_arch_resume+632>:	b.eq	0xffffffd08064a8a4 <swsusp_arch_resume+640>  // b.none
> 0xffffffd08064a8a0 <swsusp_arch_resume+636>:	brk	#0x8239
> 0xffffffd08064a8a4 <swsusp_arch_resume+640>:	blr	x25
> 
> co_developed-by: Jeson Gao <jeson.gao@unisoc.com>

This should be "Co-developed-by:" and you will also need Jeson's
Signed-off-by line in addition to your own.

> Signed-off-by: Zhaoyang Huang <zhaoyang.huang@unisoc.com>
> ---
>  arch/arm64/kernel/hibernate.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/arch/arm64/kernel/hibernate.c b/arch/arm64/kernel/hibernate.c
> index 18749e9a6c2d..9717568518ba 100644
> --- a/arch/arm64/kernel/hibernate.c
> +++ b/arch/arm64/kernel/hibernate.c
> @@ -402,7 +402,7 @@ int swsusp_arch_suspend(void)
>   * Memory allocated by get_safe_page() will be dealt with by the hibernate code,
>   * we don't need to free it here.
>   */
> -int swsusp_arch_resume(void)
> +int __nocfi swsusp_arch_resume(void)
>  {
>  	int rc;
>  	void *zero_page;

Why does is the '__nocfi' annotation here rather than on the
'hibernate_exit' pointer?

Will