({ \
efi_virtmap_load(); \
__efi_fpsimd_begin(); \
+ spin_lock(&efi_rt_lock); \
})
#undef arch_efi_call_virt
#define arch_efi_call_virt_teardown() \
({ \
+ spin_unlock(&efi_rt_lock); \
__efi_fpsimd_end(); \
efi_virtmap_unload(); \
})
+extern spinlock_t efi_rt_lock;
efi_status_t __efi_rt_asm_wrapper(void *, const char *, ...);
#define ARCH_EFI_IRQ_FLAGS_MASK (PSR_D_BIT | PSR_A_BIT | PSR_I_BIT | PSR_F_BIT)
*/
stp x1, x18, [sp, #16]
+ ldr_l x16, efi_rt_stack_top
+ mov sp, x16
+#ifdef CONFIG_SHADOW_CALL_STACK
+ str x18, [sp, #-16]!
+#endif
+
/*
* We are lucky enough that no EFI runtime services take more than
* 5 arguments, so all are passed in registers rather than via the
mov x4, x6
blr x8
+ mov sp, x29
ldp x1, x2, [sp, #16]
cmp x2, x18
ldp x29, x30, [sp], #32
* called with preemption disabled and a separate shadow stack is used
* for interrupts.
*/
- mov x18, x2
+#ifdef CONFIG_SHADOW_CALL_STACK
+ ldr_l x18, efi_rt_stack_top
+ ldr x18, [x18, #-16]
+#endif
+
b efi_handle_corrupted_x18 // tail call
SYM_FUNC_END(__efi_rt_asm_wrapper)
pr_err_ratelimited(FW_BUG "register x18 corrupted by EFI %s\n", f);
return s;
}
+
+DEFINE_SPINLOCK(efi_rt_lock);
+
+asmlinkage u64 *efi_rt_stack_top __ro_after_init;
+
+/* EFI requires 8 KiB of stack space for runtime services */
+static_assert(THREAD_SIZE >= SZ_8K);
+
+static int __init arm64_efi_rt_init(void)
+{
+ void *p;
+
+ if (!efi_enabled(EFI_RUNTIME_SERVICES))
+ return 0;
+
+ p = __vmalloc_node(THREAD_SIZE, THREAD_ALIGN, GFP_KERNEL,
+ NUMA_NO_NODE, &&l);
+l: if (!p) {
+ pr_warn("Failed to allocate EFI runtime stack\n");
+ clear_bit(EFI_RUNTIME_SERVICES, &efi.flags);
+ return -ENOMEM;
+ }
+
+ efi_rt_stack_top = p + THREAD_SIZE;
+ return 0;
+}
+core_initcall(arm64_efi_rt_init);