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scripts/decodecode: Add support for RISC-V 

RISC-V has some GNU disassembly quirks, e.g. it requires '-D' to
properly disassemble .2byte directives similar to Arm [1]. Further,
GNU objdump groups RISC-V instruction by 2 or 4 byte chunks, instead
doing byte-for-byte.

Add the required switches, and translate from short/word to bytes when
ARCH is "riscv".

An example how to invoke decodecode for RISC-V:
  $ echo 'Code: bf45 f793 1007 f7d9 50ef 37af d541 b7d9 7097 00c8 (80e7)
  6140' | AFLAGS="-march=rv64imac_zicbom_zihintpause"  \
  ARCH=riscv CROSS_COMPILE=riscv64-linux-gnu- ./scripts/decodecode
  Code: bf45 f793 1007 f7d9 50ef 37af d541 b7d9 7097 00c8 (80e7) 6140
  All code
  ========
     0:   bf45                    c.j     0xffffffffffffffb0
     2:   1007f793                andi    a5,a5,256
     6:   f7d9                    c.bnez  a5,0xffffffffffffff94
     8:   37af50ef                jal     ra,0xf5382
     c:   d541                    c.beqz  a0,0xffffffffffffff94
     e:   b7d9                    c.j     0xffffffffffffffd4
    10:   00c87097                auipc   ra,0xc87
    14:*  614080e7                jalr    ra,1556(ra) # 0xc87624          <-- trapping instruction

  Code starting with the faulting instruction
  ===========================================
     0:   614080e7                jalr    ra,1556(ra)

[1] https://sourceware.org/bugzilla/show_bug.cgi?id=10263

Signed-off-by: Björn Töpel <bjorn@rivosinc.com>
Tested-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Link: https://lore.kernel.org/r/20230119074738.708301-3-bjorn@kernel.org
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
This commit is contained in:
Björn Töpel 2023-01-19 08:47:38 +01:00 committed by Palmer Dabbelt
parent eb165bfa8e
commit 00b242509c
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GPG Key ID: 2E1319F35FBB1889
1 changed files with 11 additions and 1 deletions
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scripts/decodecode
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@ -93,6 +93,11 @@ disas() {
${CROSS_COMPILE}strip $t.o
fi
if [ "$ARCH" = "riscv" ]; then
OBJDUMPFLAGS="-M no-aliases --section=.text -D"
${CROSS_COMPILE}strip $t.o
fi
if [ $pc_sub -ne 0 ]; then
if [ $PC ]; then
adj_vma=$(( $PC - $pc_sub ))
@ -126,8 +131,13 @@ get_substr_opcode_bytes_num()
do
substr+="$opc"
opcode="$substr"
if [ "$ARCH" = "riscv" ]; then
opcode=$(echo $opcode | tr ' ' '\n' | tac | tr -d '\n')
fi
# return if opcode bytes do not match @opline anymore
if ! echo $opline | grep -q "$substr";
if ! echo $opline | grep -q "$opcode";
then
break
fi