This is a note to let you know that I've just added the patch titled powerpc/sstep: Fix incorrect return from analyze_instr() to the 5.11-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: powerpc-sstep-fix-incorrect-return-from-analyze_inst.patch and it can be found in the queue-5.11 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 800836c7530a1b8e33fb7a95bc977d1670d0448e Author: Ananth N Mavinakayanahalli <ananth@xxxxxxxxxxxxx> Date: Mon Jan 25 18:36:43 2021 +0530 powerpc/sstep: Fix incorrect return from analyze_instr() [ Upstream commit 718aae916fa6619c57c348beaedd675835cf1aa1 ] 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 <ananth@xxxxxxxxxxxxx> Suggested-by: Michael Ellerman <mpe@xxxxxxxxxxxxxx> Tested-by: Naveen N. Rao <naveen.n.rao@xxxxxxxxxxxxxxxxxx> Reviewed-by: Sandipan Das <sandipan@xxxxxxxxxxxxx> Signed-off-by: Michael Ellerman <mpe@xxxxxxxxxxxxxx> Link: https://lore.kernel.org/r/161157999039.64773.14950289716779364766.stgit@thinktux.local Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/arch/powerpc/lib/sstep.c b/arch/powerpc/lib/sstep.c index 5e725ed24d772..33935869e4976 100644 --- a/arch/powerpc/lib/sstep.c +++ b/arch/powerpc/lib/sstep.c @@ -1447,6 +1447,11 @@ 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; @@ -1474,7 +1479,7 @@ 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 */