diff options
Diffstat (limited to 'arch/powerpc/include/asm/ppc_asm.h')
| -rw-r--r-- | arch/powerpc/include/asm/ppc_asm.h | 31 |
1 files changed, 30 insertions, 1 deletions
diff --git a/arch/powerpc/include/asm/ppc_asm.h b/arch/powerpc/include/asm/ppc_asm.h index 0c51fb4fd2aa..ce05bba0bfc6 100644 --- a/arch/powerpc/include/asm/ppc_asm.h +++ b/arch/powerpc/include/asm/ppc_asm.h @@ -845,6 +845,35 @@ END_FTR_SECTION_NESTED(CPU_FTR_HAS_PPR,CPU_FTR_HAS_PPR,946) #define N_SLINE 68 #define N_SO 100 -#endif /* __ASSEMBLY__ */ +/* + * Create an endian fixup trampoline + * + * This starts with a "tdi 0,0,0x48" instruction which is + * essentially a "trap never", and thus akin to a nop. + * + * The opcode for this instruction read with the wrong endian + * however results in a b . + 8 + * + * So essentially we use that trick to execute the following + * trampoline in "reverse endian" if we are running with the + * MSR_LE bit set the "wrong" way for whatever endianness the + * kernel is built for. + */ +#ifdef CONFIG_PPC_BOOK3E +#define FIXUP_ENDIAN +#else +#define FIXUP_ENDIAN \ + tdi 0,0,0x48; /* Reverse endian of b . + 8 */ \ + b $+36; /* Skip trampoline if endian is good */ \ + .long 0x05009f42; /* bcl 20,31,$+4 */ \ + .long 0xa602487d; /* mflr r10 */ \ + .long 0x1c004a39; /* addi r10,r10,28 */ \ + .long 0xa600607d; /* mfmsr r11 */ \ + .long 0x01006b69; /* xori r11,r11,1 */ \ + .long 0xa6035a7d; /* mtsrr0 r10 */ \ + .long 0xa6037b7d; /* mtsrr1 r11 */ \ + .long 0x2400004c /* rfid */ +#endif /* !CONFIG_PPC_BOOK3E */ +#endif /* __ASSEMBLY__ */ #endif /* _ASM_POWERPC_PPC_ASM_H */ |