From: Xiao Wang <xiao.w.wang@intel.com>
To: paul.walmsley@sifive.com, palmer@dabbelt.com,
aou@eecs.berkeley.edu, luke.r.nels@gmail.com, xi.wang@gmail.com,
bjorn@kernel.org
Cc: ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org,
martin.lau@linux.dev, eddyz87@gmail.com, song@kernel.org,
yonghong.song@linux.dev, john.fastabend@gmail.com,
kpsingh@kernel.org, sdf@google.com, haoluo@google.com,
jolsa@kernel.org, linux-riscv@lists.infradead.org,
linux-kernel@vger.kernel.org, bpf@vger.kernel.org,
pulehui@huawei.com, haicheng.li@intel.com, conor@kernel.org,
Xiao Wang <xiao.w.wang@intel.com>
Subject: [PATCH v2] riscv, bpf: Optimize zextw insn with Zba extension
Date: Sat, 11 May 2024 10:34:36 +0800 [thread overview]
Message-ID: <20240511023436.3282285-1-xiao.w.wang@intel.com> (raw)
The Zba extension provides add.uw insn which can be used to implement
zext.w with rs2 set as ZERO.
Signed-off-by: Xiao Wang <xiao.w.wang@intel.com>
---
v2:
* Add Zba description in the Kconfig. (Lehui)
* Reword the Kconfig help message to make it clearer. (Conor)
---
arch/riscv/Kconfig | 22 ++++++++++++++++++++++
arch/riscv/net/bpf_jit.h | 18 ++++++++++++++++++
2 files changed, 40 insertions(+)
diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index 6bec1bce6586..e262a8668b41 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -586,6 +586,14 @@ config RISCV_ISA_V_PREEMPTIVE
preemption. Enabling this config will result in higher memory
consumption due to the allocation of per-task's kernel Vector context.
+config TOOLCHAIN_HAS_ZBA
+ bool
+ default y
+ depends on !64BIT || $(cc-option,-mabi=lp64 -march=rv64ima_zba)
+ depends on !32BIT || $(cc-option,-mabi=ilp32 -march=rv32ima_zba)
+ depends on LLD_VERSION >= 150000 || LD_VERSION >= 23900
+ depends on AS_HAS_OPTION_ARCH
+
config TOOLCHAIN_HAS_ZBB
bool
default y
@@ -601,6 +609,20 @@ config TOOLCHAIN_HAS_VECTOR_CRYPTO
def_bool $(as-instr, .option arch$(comma) +v$(comma) +zvkb)
depends on AS_HAS_OPTION_ARCH
+config RISCV_ISA_ZBA
+ bool "Zba extension support for bit manipulation instructions"
+ depends on TOOLCHAIN_HAS_ZBA
+ depends on RISCV_ALTERNATIVE
+ default y
+ help
+ Add support for enabling optimisations in the kernel when the Zba
+ extension is detected at boot.
+
+ The Zba extension provides instructions to accelerate the generation
+ of addresses that index into arrays of basic data types.
+
+ If you don't know what to do here, say Y.
+
config RISCV_ISA_ZBB
bool "Zbb extension support for bit manipulation instructions"
depends on TOOLCHAIN_HAS_ZBB
diff --git a/arch/riscv/net/bpf_jit.h b/arch/riscv/net/bpf_jit.h
index f4b6b3b9edda..18a7885ba95e 100644
--- a/arch/riscv/net/bpf_jit.h
+++ b/arch/riscv/net/bpf_jit.h
@@ -18,6 +18,11 @@ static inline bool rvc_enabled(void)
return IS_ENABLED(CONFIG_RISCV_ISA_C);
}
+static inline bool rvzba_enabled(void)
+{
+ return IS_ENABLED(CONFIG_RISCV_ISA_ZBA) && riscv_has_extension_likely(RISCV_ISA_EXT_ZBA);
+}
+
static inline bool rvzbb_enabled(void)
{
return IS_ENABLED(CONFIG_RISCV_ISA_ZBB) && riscv_has_extension_likely(RISCV_ISA_EXT_ZBB);
@@ -937,6 +942,14 @@ static inline u16 rvc_sdsp(u32 imm9, u8 rs2)
return rv_css_insn(0x7, imm, rs2, 0x2);
}
+/* RV64-only ZBA instructions. */
+
+static inline u32 rvzba_zextw(u8 rd, u8 rs1)
+{
+ /* add.uw rd, rs1, ZERO */
+ return rv_r_insn(0x04, RV_REG_ZERO, rs1, 0, rd, 0x3b);
+}
+
#endif /* __riscv_xlen == 64 */
/* Helper functions that emit RVC instructions when possible. */
@@ -1159,6 +1172,11 @@ static inline void emit_zexth(u8 rd, u8 rs, struct rv_jit_context *ctx)
static inline void emit_zextw(u8 rd, u8 rs, struct rv_jit_context *ctx)
{
+ if (rvzba_enabled()) {
+ emit(rvzba_zextw(rd, rs), ctx);
+ return;
+ }
+
emit_slli(rd, rs, 32, ctx);
emit_srli(rd, rd, 32, ctx);
}
--
2.25.1
next reply other threads:[~2024-05-11 2:31 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-05-11 2:34 Xiao Wang [this message]
2024-05-13 16:53 ` [PATCH v2] riscv, bpf: Optimize zextw insn with Zba extension Andrew Jones
2024-05-14 7:36 ` Wang, Xiao W
2024-05-14 13:37 ` Andrew Jones
2024-05-15 7:38 ` Wang, Xiao W
2024-05-15 8:19 ` Conor Dooley
2024-05-15 9:32 ` Conor Dooley
2024-05-15 11:31 ` Wang, Xiao W
2024-05-15 11:51 ` Conor Dooley
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