parisc: Add runtime check to prevent PA2.0 kernels on PA1.x machines

If a 32-bit kernel was compiled for PA2.0 CPUs, it won't be able to run
on machines with PA1.x CPUs. Add a check and bail out early if a PA1.x
machine is detected.

Signed-off-by: Helge Deller <deller@gmx.de>

diff --git a/arch/parisc/kernel/head.S b/arch/parisc/kernel/head.S
index e0a9e96576221a614522acc63e45f13e5248462e..fd15fd4bbb61b8f4cd7567b20a7b6d29f36b7864 100644 (file)
--- a/arch/parisc/kernel/head.S
+++ b/arch/parisc/kernel/head.S
@@ -22,7 +22,7 @@
 #include <linux/init.h>
 #include <linux/pgtable.h>
 
-       .level  PA_ASM_LEVEL
+       .level  1.1
 
        __INITDATA
 ENTRY(boot_args)
@@ -70,6 +70,47 @@ $bss_loop:
        stw,ma          %arg2,4(%r1)
        stw,ma          %arg3,4(%r1)
 
+#if !defined(CONFIG_64BIT) && defined(CONFIG_PA20)
+       /* This 32-bit kernel was compiled for PA2.0 CPUs. Check current CPU
+        * and halt kernel if we detect a PA1.x CPU. */
+       ldi             32,%r10
+       mtctl           %r10,%cr11
+       .level 2.0
+       mfctl,w         %cr11,%r10
+       .level 1.1
+       comib,<>,n      0,%r10,$cpu_ok
+
+       load32          PA(msg1),%arg0
+       ldi             msg1_end-msg1,%arg1
+$iodc_panic:
+       copy            %arg0, %r10
+       copy            %arg1, %r11
+       load32          PA(init_stack),%sp
+#define MEM_CONS 0x3A0
+       ldw             MEM_CONS+32(%r0),%arg0  // HPA
+       ldi             ENTRY_IO_COUT,%arg1
+       ldw             MEM_CONS+36(%r0),%arg2  // SPA
+       ldw             MEM_CONS+8(%r0),%arg3   // layers
+       load32          PA(__bss_start),%r1
+       stw             %r1,-52(%sp)            // arg4
+       stw             %r0,-56(%sp)            // arg5
+       stw             %r10,-60(%sp)           // arg6 = ptr to text
+       stw             %r11,-64(%sp)           // arg7 = len
+       stw             %r0,-68(%sp)            // arg8
+       load32          PA(.iodc_panic_ret), %rp
+       ldw             MEM_CONS+40(%r0),%r1    // ENTRY_IODC
+       bv,n            (%r1)
+.iodc_panic_ret:
+       b .                             /* wait endless with ... */
+       or              %r10,%r10,%r10  /* qemu idle sleep */
+msg1:  .ascii "Can't boot kernel which was built for PA8x00 CPUs on this machine.\r\n"
+msg1_end:
+
+$cpu_ok:
+#endif
+
+       .level  PA_ASM_LEVEL
+
        /* Initialize startup VM. Just map first 16/32 MB of memory */
        load32          PA(swapper_pg_dir),%r4
        mtctl           %r4,%cr24       /* Initialize kernel root pointer */