lkml.org 
[lkml]   [2021]   [Mar]   [1]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH 5.11 393/775] powerpc/sstep: Fix incorrect return from analyze_instr()
    Date
    From: Ananth N Mavinakayanahalli <ananth@linux.ibm.com>

    [ 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@linux.ibm.com>
    Suggested-by: Michael Ellerman <mpe@ellerman.id.au>
    Tested-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
    Reviewed-by: Sandipan Das <sandipan@linux.ibm.com>
    Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
    Link: https://lore.kernel.org/r/161157999039.64773.14950289716779364766.stgit@thinktux.local
    Signed-off-by: Sasha Levin <sashal@kernel.org>
    ---
    arch/powerpc/lib/sstep.c | 7 ++++++-
    1 file changed, 6 insertions(+), 1 deletion(-)

    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 */
    --
    2.27.0


    \
     
     \ /
      Last update: 2021-03-02 05:10    [W:2.174 / U:0.040 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site