| H A D | uprobes.h | 60f07e22 Fri Dec 02 01:11:10 CST 2022 junhua huang <huang.junhua@zte.com.cn> arm64:uprobe fix the uprobe SWBP_INSN in big-endian
We use uprobe in aarch64_be, which we found the tracee task would exit
due to SIGILL when we enable the uprobe trace.
We can see the replace inst from uprobe is not correct in aarch big-endian.
As in Armv8-A, instruction fetches are always treated as little-endian,
we should treat the UPROBE_SWBP_INSN as little-endian。
The test case is as following。
bash-4.4# ./mqueue_test_aarchbe 1 1 2 1 10 > /dev/null &
bash-4.4# cd /sys/kernel/debug/tracing/
bash-4.4# echo 'p:test /mqueue_test_aarchbe:0xc30 %x0 %x1' > uprobe_events
bash-4.4# echo 1 > events/uprobes/enable
bash-4.4#
bash-4.4# ps
PID TTY TIME CMD
140 ? 00:00:01 bash
237 ? 00:00:00 ps
[1]+ Illegal instruction ./mqueue_test_aarchbe 1 1 2 1 100 > /dev/null
which we debug use gdb as following:
bash-4.4# gdb attach 155
(gdb) disassemble send
Dump of assembler code for function send:
0x0000000000400c30 <+0>: .inst 0xa00020d4 ; undefined
0x0000000000400c34 <+4>: mov x29, sp
0x0000000000400c38 <+8>: str w0, [sp, #28]
0x0000000000400c3c <+12>: strb w1, [sp, #27]
0x0000000000400c40 <+16>: str xzr, [sp, #40]
0x0000000000400c44 <+20>: str xzr, [sp, #48]
0x0000000000400c48 <+24>: add x0, sp, #0x1b
0x0000000000400c4c <+28>: mov w3, #0x0 // #0
0x0000000000400c50 <+32>: mov x2, #0x1 // #1
0x0000000000400c54 <+36>: mov x1, x0
0x0000000000400c58 <+40>: ldr w0, [sp, #28]
0x0000000000400c5c <+44>: bl 0x405e10 <mq_send>
0x0000000000400c60 <+48>: str w0, [sp, #60]
0x0000000000400c64 <+52>: ldr w0, [sp, #60]
0x0000000000400c68 <+56>: ldp x29, x30, [sp], #64
0x0000000000400c6c <+60>: ret
End of assembler dump.
(gdb) info b
No breakpoints or watchpoints.
(gdb) c
Continuing.
Program received signal SIGILL, Illegal instruction.
0x0000000000400c30 in send ()
(gdb) x/10x 0x400c30
0x400c30 <send>: 0xd42000a0 0xfd030091 0xe01f00b9 0xe16f0039
0x400c40 <send+16>: 0xff1700f9 0xff1b00f9 0xe06f0091 0x03008052
0x400c50 <send+32>: 0x220080d2 0xe10300aa
(gdb) disassemble 0x400c30
Dump of assembler code for function send:
=> 0x0000000000400c30 <+0>: .inst 0xa00020d4 ; undefined
0x0000000000400c34 <+4>: mov x29, sp
0x0000000000400c38 <+8>: str w0, [sp, #28]
0x0000000000400c3c <+12>: strb w1, [sp, #27]
0x0000000000400c40 <+16>: str xzr, [sp, #40]
Signed-off-by: junhua huang <huang.junhua@zte.com.cn>
Link: https://lore.kernel.org/r/202212021511106844809@zte.com.cn
Signed-off-by: Will Deacon <will@kernel.org>
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