From: "Björn Töpel" <bjorn.topel@gmail.com>
To: daniel@iogearbox.net, ast@kernel.org, netdev@vger.kernel.org
Cc: "Björn Töpel" <bjorn.topel@gmail.com>,
linux-riscv@lists.infradead.org, bpf@vger.kernel.org
Subject: [PATCH bpf-next 1/8] riscv, bpf: fix broken BPF tail calls
Date: Mon, 9 Dec 2019 18:31:29 +0100 [thread overview]
Message-ID: <20191209173136.29615-2-bjorn.topel@gmail.com> (raw)
In-Reply-To: <20191209173136.29615-1-bjorn.topel@gmail.com>
The BPF JIT incorrectly clobbered the a0 register, and did not flag
usage of s5 register when BPF stack was being used.
Fixes: 2353ecc6f91f ("bpf, riscv: add BPF JIT for RV64G")
Signed-off-by: Björn Töpel <bjorn.topel@gmail.com>
---
arch/riscv/net/bpf_jit_comp.c | 13 +++++++++++--
1 file changed, 11 insertions(+), 2 deletions(-)
diff --git a/arch/riscv/net/bpf_jit_comp.c b/arch/riscv/net/bpf_jit_comp.c
index 5451ef3845f2..1606ebd49666 100644
--- a/arch/riscv/net/bpf_jit_comp.c
+++ b/arch/riscv/net/bpf_jit_comp.c
@@ -120,6 +120,11 @@ static bool seen_reg(int reg, struct rv_jit_context *ctx)
return false;
}
+static void mark_fp(struct rv_jit_context *ctx)
+{
+ __set_bit(RV_CTX_F_SEEN_S5, &ctx->flags);
+}
+
static void mark_call(struct rv_jit_context *ctx)
{
__set_bit(RV_CTX_F_SEEN_CALL, &ctx->flags);
@@ -596,7 +601,8 @@ static void __build_epilogue(u8 reg, struct rv_jit_context *ctx)
emit(rv_addi(RV_REG_SP, RV_REG_SP, stack_adjust), ctx);
/* Set return value. */
- emit(rv_addi(RV_REG_A0, RV_REG_A5, 0), ctx);
+ if (reg == RV_REG_RA)
+ emit(rv_addi(RV_REG_A0, RV_REG_A5, 0), ctx);
emit(rv_jalr(RV_REG_ZERO, reg, 0), ctx);
}
@@ -1426,6 +1432,10 @@ static void build_prologue(struct rv_jit_context *ctx)
{
int stack_adjust = 0, store_offset, bpf_stack_adjust;
+ bpf_stack_adjust = round_up(ctx->prog->aux->stack_depth, 16);
+ if (bpf_stack_adjust)
+ mark_fp(ctx);
+
if (seen_reg(RV_REG_RA, ctx))
stack_adjust += 8;
stack_adjust += 8; /* RV_REG_FP */
@@ -1443,7 +1453,6 @@ static void build_prologue(struct rv_jit_context *ctx)
stack_adjust += 8;
stack_adjust = round_up(stack_adjust, 16);
- bpf_stack_adjust = round_up(ctx->prog->aux->stack_depth, 16);
stack_adjust += bpf_stack_adjust;
store_offset = stack_adjust - 8;
--
2.20.1
next prev parent reply other threads:[~2019-12-09 17:31 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-09 17:31 [PATCH bpf-next 0/8] riscv: BPF JIT fix, optimizations and far jumps support Björn Töpel
2019-12-09 17:31 ` Björn Töpel [this message]
2019-12-09 17:31 ` [PATCH bpf-next 2/8] riscv, bpf: add support for far branching Björn Töpel
2019-12-09 21:08 ` Luke Nelson
2019-12-09 21:27 ` Daniel Borkmann
2019-12-10 7:02 ` Luke Nelson
2019-12-10 5:32 ` Björn Töpel
2019-12-10 5:31 ` Björn Töpel
2019-12-09 17:31 ` [PATCH bpf-next 3/8] riscv, bpf: add support for far jumps and exits Björn Töpel
2019-12-09 21:15 ` Luke Nelson
2019-12-09 17:31 ` [PATCH bpf-next 4/8] riscv, bpf: optimize BPF tail calls Björn Töpel
2019-12-09 17:31 ` [PATCH bpf-next 5/8] riscv, bpf: provide RISC-V specific JIT image alloc/free Björn Töpel
2019-12-09 17:31 ` [PATCH bpf-next 6/8] riscv, bpf: optimize calls Björn Töpel
2019-12-09 17:31 ` [PATCH bpf-next 7/8] riscv, bpf: add missing uapi header for BPF_PROG_TYPE_PERF_EVENT programs Björn Töpel
2019-12-09 17:31 ` [PATCH bpf-next 8/8] riscv, perf: add arch specific perf_arch_bpf_user_pt_regs Björn Töpel
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