Le 27/07/2021 à 08:55, Jordan Niethe a écrit :
Implement commit 40272035e1d0 ("powerpc/bpf: Reallocate BPF registers to
volatile registers when possible on PPC32") for PPC64.
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. To keep track of which
registers can be reallocated to make sure registers are set seen when
used.
Before this patch, the test #359 ADD default X is:
0: nop
4: nop
8: std r27,-40(r1)
c: std r28,-32(r1)
10: xor r8,r8,r8
14: rotlwi r8,r8,0
18: xor r28,r28,r28
1c: rotlwi r28,r28,0
20: mr r27,r3
24: li r8,66
28: add r8,r8,r28
2c: rotlwi r8,r8,0
30: ld r27,-40(r1)
34: ld r28,-32(r1)
38: mr r3,r8
3c: blr
After this patch, the same test has become:
0: nop
4: nop
8: xor r8,r8,r8
c: rotlwi r8,r8,0
10: xor r5,r5,r5
14: rotlwi r5,r5,0
18: mr r4,r3
1c: li r8,66
20: add r8,r8,r5
24: rotlwi r8,r8,0
28: mr r3,r8
2c: blr
Signed-off-by: Jordan Niethe <jniet...@gmail.com>
If this series is still applicable, it needs to be rebased of Naveen's
series https://patchwork.ozlabs.org/project/linuxppc-dev/list/?series=286000
Christophe
