MIPS: Calculate proper ebase value for 64-bit kernels
authorDavid Daney <ddaney@caviumnetworks.com>
Tue, 6 Apr 2010 20:29:50 +0000 (13:29 -0700)
committerRalf Baechle <ralf@linux-mips.org>
Mon, 12 Apr 2010 16:26:22 +0000 (17:26 +0100)
The ebase is relative to CKSEG0 not CAC_BASE.  On a 32-bit kernel they
are the same thing, for a 64-bit kernel they are not.

It happens to kind of work on a 64-bit kernel as they both reference
the same physical memory.  However since the CPU uses the CKSEG0 base,
determining if a J instruction will reach always gives the wrong result
unless we use the same number the CPU uses.

Signed-off-by: David Daney <ddaney@caviumnetworks.com>
To: linux-mips@linux-mips.org
Patchwork: http://patchwork.linux-mips.org/patch/1093/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
arch/mips/kernel/traps.c

index 4e00f9bc23ee99e333685f176800275941577a3c..1a4dd657ccb943b6abbf1ff200d263bd7ce61d5d 100644 (file)
@@ -1599,7 +1599,7 @@ void __init trap_init(void)
                ebase = (unsigned long)
                        __alloc_bootmem(size, 1 << fls(size), 0);
        } else {
-               ebase = CAC_BASE;
+               ebase = CKSEG0;
                if (cpu_has_mips_r2)
                        ebase += (read_c0_ebase() & 0x3ffff000);
        }