From: Ananth N Mavinakayanahalli Date: Mon, 25 Jan 2021 13:06:43 +0000 (+0530) Subject: powerpc/sstep: Fix incorrect return from analyze_instr() X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=718aae916fa6619c57c348beaedd675835cf1aa1;p=linux.git powerpc/sstep: Fix incorrect return from analyze_instr() We currently just percolate the return value from analyze_instr() to the caller of emulate_step(), especially if it is a -1. For one particular case (opcode = 4) for instructions that aren't currently emulated, we are returning 'should not be single-stepped' while we should have returned 0 which says 'did not emulate, may have to single-step'. Fixes: 930d6288a26787 ("powerpc: sstep: Add support for maddhd, maddhdu, maddld instructions") Signed-off-by: Ananth N Mavinakayanahalli Suggested-by: Michael Ellerman Tested-by: Naveen N. Rao Reviewed-by: Sandipan Das Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/161157999039.64773.14950289716779364766.stgit@thinktux.local --- diff --git a/arch/powerpc/lib/sstep.c b/arch/powerpc/lib/sstep.c index f859cbbb6375a..e96cff845ef79 100644 --- a/arch/powerpc/lib/sstep.c +++ b/arch/powerpc/lib/sstep.c @@ -1445,6 +1445,11 @@ int analyse_instr(struct instruction_op *op, const struct pt_regs *regs, #ifdef __powerpc64__ case 4: + /* + * There are very many instructions with this primary opcode + * introduced in the ISA as early as v2.03. However, the ones + * we currently emulate were all introduced with ISA 3.0 + */ if (!cpu_has_feature(CPU_FTR_ARCH_300)) goto unknown_opcode; @@ -1472,7 +1477,7 @@ int analyse_instr(struct instruction_op *op, const struct pt_regs *regs, * There are other instructions from ISA 3.0 with the same * primary opcode which do not have emulation support yet. */ - return -1; + goto unknown_opcode; #endif case 7: /* mulli */