[daveh-devel:shstk-vmalloc 19/19] arch/x86/kernel/shstk_kunit.c:47: Error: `rdsspq' is only supported in 64-bit mode

[daveh-devel:shstk-vmalloc 19/19] arch/x86/kernel/shstk_kunit.c:47: Error: `rdsspq' is only supported in 64-bit mode

[kernel test robot]

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/daveh/devel.git shstk-vmalloc
head:   a820a994160883fea70750876fe26073766d831f
commit: a820a994160883fea70750876fe26073766d831f [19/19] kshstk-onoff-test
config: i386-allyesconfig (https://download.01.org/0day-ci/archive/20260908/202609080945.4fjnhYMA-lkp@intel.com/config)
compiler: gcc-14 (Debian 14.2.0-19) 14.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260908/202609080945.4fjnhYMA-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202609080945.4fjnhYMA-lkp@intel.com/

All errors (new ones prefixed by >>):

   arch/x86/kernel/shstk_kunit.c: In function 'enable_kernel_shstk_and_load_ssp':
   arch/x86/kernel/shstk_kunit.c:75:36: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast]
      75 |         __wrmsrq(MSR_IA32_PL0_SSP, (u64)token_addr);
         |                                    ^
   arch/x86/kernel/shstk_kunit.c: Assembler messages:
>> arch/x86/kernel/shstk_kunit.c:47: Error: `rdsspq' is only supported in 64-bit mode


vim +47 arch/x86/kernel/shstk_kunit.c

    37	
    38	/*
    39	 * Target function to call while S_CET is active.
    40	 * Marked noinline and notrace so compiler doesn't inline or instrument it.
    41	 */
    42	static noinline notrace void test_shstk_callee(unsigned long expected_ssp_base)
    43	{
    44		unsigned long current_ssp = 0;
    45	
    46		/* Read current SSP using RDSSPQ (returns 0 if shstk disabled) */
  > 47		asm volatile("rdsspq %0" : "=r" (current_ssp) : "0" (0UL));
    48	
    49		pr_info("CET Test: Inside callee, SSP = 0x%lx\n", current_ssp);
    50	
    51		if (current_ssp == 0)
    52			pr_err("CET Test: Error! SSP is zero (shadow stack inactive)\n");
    53	}
    54	

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