mips: reloc: Change R_MIPS_NONE to catch pre-reloc BSS usage

This patch changes the R_MIPS_NONE define from 0 to a magic value. This
makes it possible to better detect any forbidden pre-relocation usage
of BSS variables, as they are often zero'ed and then relocation is
stopped too early.

Additionally the error message is improved to also print the faulting
address. This helps finding the root-cause for this breakage by
comparing this address with the values in System.map.

This patch helps a lot when working on pre-relocation code, like the
Octeon DDR init code, where such variables have hit me multiple times
now.

Signed-off-by: Stefan Roese <sr@denx.de>
Cc: Daniel Schwierzeck <daniel.schwierzeck@gmail.com>
Cc: Aaron Williams <awilliams@marvell.com>
Cc: Chandrakala Chavva <cchavva@marvell.com>

diff --git a/arch/mips/include/asm/relocs.h b/arch/mips/include/asm/relocs.h
index 0987c4bb136f3a39f7cbd40a5283d2180e8fc370..b9b0261f6240d76661c5416db2bf441069c85e47 100644 (file)
--- a/arch/mips/include/asm/relocs.h
+++ b/arch/mips/include/asm/relocs.h
@@ -8,7 +8,7 @@
 #ifndef __ASM_MIPS_RELOCS_H__
 #define __ASM_MIPS_RELOCS_H__
 
-#define R_MIPS_NONE            0
+#define R_MIPS_NONE            0xbeef7531
 #define R_MIPS_32              2
 #define R_MIPS_26              4
 #define R_MIPS_HI16            5

diff --git a/arch/mips/lib/reloc.c b/arch/mips/lib/reloc.c
index ffc8c7a1b724aeafb7c45da008760bf02a54f6a3..67c8af2f35a5722a1facc7126f1b2017bb0f92f5 100644 (file)
--- a/arch/mips/lib/reloc.c
+++ b/arch/mips/lib/reloc.c
@@ -67,7 +67,7 @@ static unsigned long read_uint(uint8_t **buf)
  * intentionally simple, and does the bare minimum needed to fixup the
  * relocated U-Boot - in particular, it does not check for overflows.
  */
-static void apply_reloc(unsigned int type, void *addr, long off)
+static void apply_reloc(unsigned int type, void *addr, long off, uint8_t *buf)
 {
        uint32_t u32;
 
@@ -92,7 +92,8 @@ static void apply_reloc(unsigned int type, void *addr, long off)
                break;
 
        default:
-               panic("Unhandled reloc type %u\n", type);
+               panic("Unhandled reloc type %u (@ %p), bss used before relocation?\n",
+                     type, buf);
        }
 }
 
@@ -137,7 +138,7 @@ void relocate_code(ulong start_addr_sp, gd_t *new_gd, ulong relocaddr)
                        break;
 
                addr += read_uint(&buf) << 2;
-               apply_reloc(type, (void *)addr, off);
+               apply_reloc(type, (void *)addr, off, buf);
        }
 
        /* Ensure the icache is coherent */