* [PATCH bpf-next] mips, bpf: Optimize loading of 64-bit constants
@ 2021-10-07 14:28 Johan Almbladh
2021-10-07 20:00 ` patchwork-bot+netdevbpf
0 siblings, 1 reply; 2+ messages in thread
From: Johan Almbladh @ 2021-10-07 14:28 UTC (permalink / raw)
To: ast, daniel, andrii, paulburton
Cc: kafai, songliubraving, yhs, john.fastabend, kpsingh,
tony.ambardar, bpf, netdev, Johan Almbladh
This patch shaves off a few instructions when loading sparse 64-bit
constants to register. The change is covered by additional tests in
lib/test_bpf.c.
Signed-off-by: Johan Almbladh <johan.almbladh@anyfinetworks.com>
---
arch/mips/net/bpf_jit_comp64.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)
diff --git a/arch/mips/net/bpf_jit_comp64.c b/arch/mips/net/bpf_jit_comp64.c
index 1f1f7b87f213..815ade724227 100644
--- a/arch/mips/net/bpf_jit_comp64.c
+++ b/arch/mips/net/bpf_jit_comp64.c
@@ -131,19 +131,25 @@ static void emit_mov_i64(struct jit_context *ctx, u8 dst, u64 imm64)
emit(ctx, ori, dst, dst, (u16)imm64 & 0xffff);
} else {
u8 acc = MIPS_R_ZERO;
+ int shift = 0;
int k;
for (k = 0; k < 4; k++) {
u16 half = imm64 >> (48 - 16 * k);
if (acc == dst)
- emit(ctx, dsll, dst, dst, 16);
+ shift += 16;
if (half) {
+ if (shift)
+ emit(ctx, dsll_safe, dst, dst, shift);
emit(ctx, ori, dst, acc, half);
acc = dst;
+ shift = 0;
}
}
+ if (shift)
+ emit(ctx, dsll_safe, dst, dst, shift);
}
clobber_reg(ctx, dst);
}
--
2.30.2
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH bpf-next] mips, bpf: Optimize loading of 64-bit constants
2021-10-07 14:28 [PATCH bpf-next] mips, bpf: Optimize loading of 64-bit constants Johan Almbladh
@ 2021-10-07 20:00 ` patchwork-bot+netdevbpf
0 siblings, 0 replies; 2+ messages in thread
From: patchwork-bot+netdevbpf @ 2021-10-07 20:00 UTC (permalink / raw)
To: Johan Almbladh
Cc: ast, daniel, andrii, paulburton, kafai, songliubraving, yhs,
john.fastabend, kpsingh, tony.ambardar, bpf, netdev
Hello:
This patch was applied to bpf/bpf-next.git (master)
by Daniel Borkmann <daniel@iogearbox.net>:
On Thu, 7 Oct 2021 16:28:28 +0200 you wrote:
> This patch shaves off a few instructions when loading sparse 64-bit
> constants to register. The change is covered by additional tests in
> lib/test_bpf.c.
>
> Signed-off-by: Johan Almbladh <johan.almbladh@anyfinetworks.com>
> ---
> arch/mips/net/bpf_jit_comp64.c | 8 +++++++-
> 1 file changed, 7 insertions(+), 1 deletion(-)
Here is the summary with links:
- [bpf-next] mips, bpf: Optimize loading of 64-bit constants
https://git.kernel.org/bpf/bpf-next/c/612ff31f7672
You are awesome, thank you!
--
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