x86/boot/64: Strip percpu address space when setting up GDT descriptors

init_per_cpu_var() returns a pointer in the percpu address space while
rip_rel_ptr() expects a pointer in the generic address space.

When strict address space checks are enabled, GCC's named address space
checks fail:

  asm.h:124:63: error: passing argument 1 of 'rip_rel_ptr' from
                       pointer to non-enclosed address space

Add a explicit cast to remove address space of the returned pointer.

Fixes: 11e36b0f7c21 ("x86/boot/64: Load the final kernel GDT during early boot directly, remove startup_gdt[]")
Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/20240819083334.148536-1-ubizjak@gmail.com

diff --git a/arch/x86/kernel/head64.c b/arch/x86/kernel/head64.c
index a817ed0724d1e76bb110c7fa8ff7239e4bfa72d2..4b9d4557fc94a46defab68cba0e56b2776148552 100644 (file)
--- a/arch/x86/kernel/head64.c
+++ b/arch/x86/kernel/head64.c
@@ -559,10 +559,11 @@ void early_setup_idt(void)
  */
 void __head startup_64_setup_gdt_idt(void)
 {
+       struct desc_struct *gdt = (void *)(__force unsigned long)init_per_cpu_var(gdt_page.gdt);
        void *handler = NULL;
 
        struct desc_ptr startup_gdt_descr = {
-               .address = (unsigned long)&RIP_REL_REF(init_per_cpu_var(gdt_page.gdt)),
+               .address = (unsigned long)&RIP_REL_REF(*gdt),
                .size    = GDT_SIZE - 1,
        };