MIPS: Add instrunction format for BREAK and SYSCALL
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From: David Daney on 3 Aug 2010 17:00 On 08/03/2010 01:54 PM, Maciej W. Rozycki wrote: > On Tue, 3 Aug 2010, David Daney wrote: > >> diff --git a/arch/mips/include/asm/inst.h b/arch/mips/include/asm/inst.h >> index 6489f00..444ff71 100644 >> --- a/arch/mips/include/asm/inst.h >> +++ b/arch/mips/include/asm/inst.h >> @@ -247,6 +247,12 @@ struct ma_format { /* FPU multipy and add format (MIPS IV) */ >> unsigned int fmt : 2; >> }; >> >> +struct b_format { /* BREAK and SYSCALL */ >> + unsigned int opcode:6; >> + unsigned int code:20; >> + unsigned int func:6; >> +}; >> + >> #elif defined(__MIPSEL__) >> >> struct j_format { /* Jump format */ > > Please note the code field of the BREAK instruction is by toolchain > convention (bug-compatibility with the original MIPS assembler or > suchlike) treated as a pair of swapped 10-bit fields -- you may want to > double-check consistency of interpretation with usage elsewhere. > Indeed, I am familiar with that fact. From patch 3/5 we have: .. .. .. +void __kprobes jprobe_return(void) +{ + /* Assembler quirk necessitates this '0,code' business. */ + asm volatile( + "break 0,%0\n\t" + ".globl jprobe_return_end\n" + "jprobe_return_end:\n" + : : "n" (BRK_KPROBE_BP) : "memory"); +} .. .. .. The 'break 0,code' construct causes gas to emit values that are compatible with the other use of struct b_format in the patch set. David Daney -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
From: Ralf Baechle on 4 Aug 2010 20:00
Thanks, applied. Ralf -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ |