diff options
| author | Christophe Leroy <christophe.leroy@csgroup.eu> | 2021-03-22 16:37:53 +0000 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2021-04-03 21:22:21 +1100 |
| commit | 40272035e1d0edcd515ad45be297c4cce044536d (patch) | |
| tree | 4302a14a8374a0ebf88bb1a2924b2cb2e6d8d2ec /arch/powerpc/net/bpf_jit_comp64.c | |
| parent | 51c66ad849a703d9bbfd7704c941827aed0fd9fd (diff) | |
powerpc/bpf: Reallocate BPF registers to volatile registers when possible on PPC32
When the BPF routine doesn't call any function, the non volatile
registers can be reallocated to volatile registers in order to
avoid having to save them/restore on the stack.
Before this patch, the test #359 ADD default X is:
0: 7c 64 1b 78 mr r4,r3
4: 38 60 00 00 li r3,0
8: 94 21 ff b0 stwu r1,-80(r1)
c: 60 00 00 00 nop
10: 92 e1 00 2c stw r23,44(r1)
14: 93 01 00 30 stw r24,48(r1)
18: 93 21 00 34 stw r25,52(r1)
1c: 93 41 00 38 stw r26,56(r1)
20: 39 80 00 00 li r12,0
24: 39 60 00 00 li r11,0
28: 3b 40 00 00 li r26,0
2c: 3b 20 00 00 li r25,0
30: 7c 98 23 78 mr r24,r4
34: 7c 77 1b 78 mr r23,r3
38: 39 80 00 42 li r12,66
3c: 39 60 00 00 li r11,0
40: 7d 8c d2 14 add r12,r12,r26
44: 39 60 00 00 li r11,0
48: 7d 83 63 78 mr r3,r12
4c: 82 e1 00 2c lwz r23,44(r1)
50: 83 01 00 30 lwz r24,48(r1)
54: 83 21 00 34 lwz r25,52(r1)
58: 83 41 00 38 lwz r26,56(r1)
5c: 38 21 00 50 addi r1,r1,80
60: 4e 80 00 20 blr
After this patch, the same test has become:
0: 7c 64 1b 78 mr r4,r3
4: 38 60 00 00 li r3,0
8: 94 21 ff b0 stwu r1,-80(r1)
c: 60 00 00 00 nop
10: 39 80 00 00 li r12,0
14: 39 60 00 00 li r11,0
18: 39 00 00 00 li r8,0
1c: 38 e0 00 00 li r7,0
20: 7c 86 23 78 mr r6,r4
24: 7c 65 1b 78 mr r5,r3
28: 39 80 00 42 li r12,66
2c: 39 60 00 00 li r11,0
30: 7d 8c 42 14 add r12,r12,r8
34: 39 60 00 00 li r11,0
38: 7d 83 63 78 mr r3,r12
3c: 38 21 00 50 addi r1,r1,80
40: 4e 80 00 20 blr
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/b94562d7d2bb21aec89de0c40bb3cd91054b65a2.1616430991.git.christophe.leroy@csgroup.eu
Diffstat (limited to 'arch/powerpc/net/bpf_jit_comp64.c')
| -rw-r--r-- | arch/powerpc/net/bpf_jit_comp64.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/arch/powerpc/net/bpf_jit_comp64.c b/arch/powerpc/net/bpf_jit_comp64.c index 8a1f9fb00e78..57a8c1153851 100644 --- a/arch/powerpc/net/bpf_jit_comp64.c +++ b/arch/powerpc/net/bpf_jit_comp64.c @@ -64,6 +64,10 @@ static int bpf_jit_stack_offsetof(struct codegen_context *ctx, int reg) BUG(); } +void bpf_jit_realloc_regs(struct codegen_context *ctx) +{ +} + void bpf_jit_build_prologue(u32 *image, struct codegen_context *ctx) { int i; |