#endif
ENTRY(stext)
- mov x21, x0 // x21=FDT
+ bl preserve_boot_args
bl el2_setup // Drop to EL1, w20=cpu_boot_mode
adrp x24, __PHYS_OFFSET
bl set_cpu_boot_mode_flag
b __cpu_setup // initialise processor
ENDPROC(stext)
+/*
+ * Preserve the arguments passed by the bootloader in x0 .. x3
+ */
+preserve_boot_args:
+ mov x21, x0 // x21=FDT
+
+ adr_l x0, boot_args // record the contents of
+ stp x21, x1, [x0] // x0 .. x3 at kernel entry
+ stp x2, x3, [x0, #16]
+
+ dmb sy // needed before dc ivac with
+ // MMU off
+
+ add x1, x0, #0x20 // 4 x 8 bytes
+ b __inval_cache_range // tail call
+ENDPROC(preserve_boot_args)
+
/*
* Determine validity of the x21 FDT pointer.
* The dtb must be 8-byte aligned and live in the first 512M of memory.
printk("%s", buf);
}
+/*
+ * The recorded values of x0 .. x3 upon kernel entry.
+ */
+u64 __cacheline_aligned boot_args[4];
+
void __init smp_setup_processor_id(void)
{
u64 mpidr = read_cpuid_mpidr() & MPIDR_HWID_BITMASK;
conswitchp = &dummy_con;
#endif
#endif
+ if (boot_args[1] || boot_args[2] || boot_args[3]) {
+ pr_err("WARNING: x1-x3 nonzero in violation of boot protocol:\n"
+ "\tx1: %016llx\n\tx2: %016llx\n\tx3: %016llx\n"
+ "This indicates a broken bootloader or old kernel\n",
+ boot_args[1], boot_args[2], boot_args[3]);
+ }
}
static int __init arm64_device_init(void)