Re: [PATCH v3] ARM: imx: Fix suspend/resume crash with Clang CFI

[Nathan Chancellor <nathan@kernel.org>]

On Tue, Jul 21, 2026 at 07:29:50AM +0200, Yo'av Moshe wrote:
> On 2026-07-20 9:29 PM, Sami Tolvanen wrote:
> > Would it be possible to just copy the 4-byte CFI hash prefix to OCRAM
> > when relocating the function? If not, the __nocfi approach seems
> > reasonable to me.
> > 
> > Sami
> 
> I gave this a try - I tried copying 4 bytes from before imx6_suspend
> into OCRAM, but when I tested it on physical hardware (Kobo Clara HD),
> it still crashed on suspend.
> 
> I suspect it's because imx6_suspend is written in assembly
> (suspend-imx6.S) rather than C, so Clang doesn't emit a CFI hash prefix
> before it in the first place.

Does using SYM_TYPED_FUNC_START for imx6_suspend() make that work?
Something like this builds fine for me and I see
__kcfi_typeid_imx6_suspend generated by Clang.

diff --git a/arch/arm/mach-imx/suspend-imx6.S b/arch/arm/mach-imx/suspend-imx6.S
index 63ccc2d0e920..6ded29a38c99 100644
--- a/arch/arm/mach-imx/suspend-imx6.S
+++ b/arch/arm/mach-imx/suspend-imx6.S
@@ -3,6 +3,7 @@
  * Copyright 2014 Freescale Semiconductor, Inc.
  */
 
+#include <linux/cfi_types.h>
 #include <linux/linkage.h>
 #include <asm/assembler.h>
 #include <asm/asm-offsets.h>
@@ -148,7 +149,7 @@
 
 	.endm
 
-ENTRY(imx6_suspend)
+SYM_TYPED_FUNC_START(imx6_suspend)
 	ldr	r1, [r0, #PM_INFO_PBASE_OFFSET]
 	ldr	r2, [r0, #PM_INFO_RESUME_ADDR_OFFSET]
 	ldr	r3, [r0, #PM_INFO_DDR_TYPE_OFFSET]
@@ -329,4 +330,4 @@ resume:
 	resume_mmdc
 
 	ret	lr
-ENDPROC(imx6_suspend)
+SYM_FUNC_END(imx6_suspend)

-- 
Cheers,
Nathan