mirror of
https://github.com/torvalds/linux.git
synced 2024-12-28 13:51:44 +00:00
6651ee070b
bpf_tail_call() arguments:
- ctx......: Context pointer
- jmp_table: One of BPF_MAP_TYPE_PROG_ARRAY maps used as the jump table
- index....: Index in the jump table
In this implementation s390x JIT does stack unwinding and jumps into the
callee program prologue. Caller and callee use the same stack.
With this patch a tail call generates the following code on s390x:
if (index >= array->map.max_entries)
goto out
000003ff8001c7e4: e31030100016 llgf %r1,16(%r3)
000003ff8001c7ea: ec41001fa065 clgrj %r4,%r1,10,3ff8001c828
if (tail_call_cnt++ > MAX_TAIL_CALL_CNT)
goto out;
000003ff8001c7f0: a7080001 lhi %r0,1
000003ff8001c7f4: eb10f25000fa laal %r1,%r0,592(%r15)
000003ff8001c7fa: ec120017207f clij %r1,32,2,3ff8001c828
prog = array->prog[index];
if (prog == NULL)
goto out;
000003ff8001c800: eb140003000d sllg %r1,%r4,3
000003ff8001c806: e31310800004 lg %r1,128(%r3,%r1)
000003ff8001c80c: ec18000e007d clgij %r1,0,8,3ff8001c828
Restore registers before calling function
000003ff8001c812: eb68f2980004 lmg %r6,%r8,664(%r15)
000003ff8001c818: ebbff2c00004 lmg %r11,%r15,704(%r15)
goto *(prog->bpf_func + tail_call_start);
000003ff8001c81e: e31100200004 lg %r1,32(%r1,%r0)
000003ff8001c824: 47f01006 bc 15,6(%r1)
Reviewed-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Alexei Starovoitov <ast@plumgrid.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
|
||
|---|---|---|
| .. | ||
| alpha | ||
| arc | ||
| arm | ||
| arm64 | ||
| avr32 | ||
| blackfin | ||
| c6x | ||
| cris | ||
| frv | ||
| hexagon | ||
| ia64 | ||
| m32r | ||
| m68k | ||
| metag | ||
| microblaze | ||
| mips | ||
| mn10300 | ||
| nios2 | ||
| openrisc | ||
| parisc | ||
| powerpc | ||
| s390 | ||
| score | ||
| sh | ||
| sparc | ||
| tile | ||
| um | ||
| unicore32 | ||
| x86 | ||
| xtensa | ||
| .gitignore | ||
| Kconfig | ||