[PATCH bpf-next v2 0/9] riscv: BPF JIT fix, optimizations and far jumps support · Björn Töpel <hidden> · 2019-12-16
[PATCH bpf-next v2 1/9] riscv, bpf: fix broken BPF tail calls · Björn Töpel <hidden> · 2019-12-16
[PATCH bpf-next v2 3/9] riscv, bpf: add support for far branching when emitting tail call · Björn Töpel <hidden> · 2019-12-16
Re: [PATCH bpf-next v2 3/9] riscv, bpf: add support for far branching when emitting tail call · Palmer Dabbelt <hidden> · 2019-12-23
[PATCH bpf-next v2 2/9] riscv, bpf: add support for far branching · Björn Töpel <hidden> · 2019-12-16
Re: [PATCH bpf-next v2 2/9] riscv, bpf: add support for far branching · Palmer Dabbelt <hidden> · 2019-12-23
Re: [PATCH bpf-next v2 2/9] riscv, bpf: add support for far branching · Björn Töpel <hidden> · 2020-01-07
Re: [PATCH bpf-next v2 2/9] riscv, bpf: add support for far branching · Palmer Dabbelt <hidden> · 2020-01-23
[PATCH bpf-next v2 4/9] riscv, bpf: add support for far jumps and exits · Björn Töpel <hidden> · 2019-12-16
Re: [PATCH bpf-next v2 4/9] riscv, bpf: add support for far jumps and exits · Palmer Dabbelt <hidden> · 2019-12-23
[PATCH bpf-next v2 5/9] riscv, bpf: optimize BPF tail calls · Björn Töpel <hidden> · 2019-12-16
Re: [PATCH bpf-next v2 5/9] riscv, bpf: optimize BPF tail calls · Palmer Dabbelt <hidden> · 2019-12-23
[PATCH bpf-next v2 6/9] riscv, bpf: provide RISC-V specific JIT image alloc/free · Björn Töpel <hidden> · 2019-12-16
Re: [PATCH bpf-next v2 6/9] riscv, bpf: provide RISC-V specific JIT image alloc/free · Daniel Borkmann <daniel@iogearbox.net> · 2019-12-16
Re: [PATCH bpf-next v2 6/9] riscv, bpf: provide RISC-V specific JIT image alloc/free · Björn Töpel <hidden> · 2019-12-18
Re: [PATCH bpf-next v2 6/9] riscv, bpf: provide RISC-V specific JIT image alloc/free · Paul Walmsley <hidden> · 2020-01-04
Re: [PATCH bpf-next v2 6/9] riscv, bpf: provide RISC-V specific JIT image alloc/free · Björn Töpel <hidden> · 2020-01-07
Re: [PATCH bpf-next v2 6/9] riscv, bpf: provide RISC-V specific JIT image alloc/free · Paul Walmsley <hidden> · 2020-01-07
Re: [PATCH bpf-next v2 6/9] riscv, bpf: provide RISC-V specific JIT image alloc/free · Palmer Dabbelt <hidden> · 2019-12-23
Re: [PATCH bpf-next v2 6/9] riscv, bpf: provide RISC-V specific JIT image alloc/free · Alex Ghiti <alex@ghiti.fr> · 2020-02-02
Re: [PATCH bpf-next v2 6/9] riscv, bpf: provide RISC-V specific JIT image alloc/free · Björn Töpel <hidden> · 2020-02-03
Re: [PATCH bpf-next v2 6/9] riscv, bpf: provide RISC-V specific JIT image alloc/free · Alex Ghiti <alex@ghiti.fr> · 2020-02-03
[PATCH bpf-next v2 7/9] riscv, bpf: optimize calls · Björn Töpel <hidden> · 2019-12-16
Re: [PATCH bpf-next v2 7/9] riscv, bpf: optimize calls · Palmer Dabbelt <hidden> · 2019-12-23
Re: [PATCH bpf-next v2 7/9] riscv, bpf: optimize calls · Björn Töpel <hidden> · 2020-01-07
Re: [PATCH bpf-next v2 7/9] riscv, bpf: optimize calls · Palmer Dabbelt <hidden> · 2020-01-28
Re: [PATCH bpf-next v2 7/9] riscv, bpf: optimize calls · Björn Töpel <hidden> · 2020-02-03
[PATCH bpf-next v2 8/9] riscv, bpf: add missing uapi header for BPF_PROG_TYPE_PERF_EVENT programs · Björn Töpel <hidden> · 2019-12-16
Re: [PATCH bpf-next v2 8/9] riscv, bpf: add missing uapi header for BPF_PROG_TYPE_PERF_EVENT programs · Palmer Dabbelt <hidden> · 2019-12-23
[PATCH bpf-next v2 9/9] riscv, perf: add arch specific perf_arch_bpf_user_pt_regs · Björn Töpel <hidden> · 2019-12-16
Re: [PATCH bpf-next v2 9/9] riscv, perf: add arch specific perf_arch_bpf_user_pt_regs · Palmer Dabbelt <hidden> · 2019-12-23
Re: [PATCH bpf-next v2 0/9] riscv: BPF JIT fix, optimizations and far jumps support · Daniel Borkmann <daniel@iogearbox.net> · 2019-12-19

STALE2362d LANDED

Revisions (2)

2019-12-09 v1 [diff vs current]
2019-12-16 v2 current

[PATCH bpf-next v2 1/9] riscv, bpf: fix broken BPF tail calls

From: Björn Töpel <hidden>
Date: 2019-12-16 09:13:56
Also in: bpf, linux-riscv
Subsystem: bpf jit for risc-v (32-bit), bpf jit for risc-v (64-bit), bpf [general] (safe dynamic programs and tools), risc-v architecture, the rest · Maintainers: Luke Nelson, Xi Wang, Björn Töpel, Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko, Eduard Zingerman, Kumar Kartikeya Dwivedi, Paul Walmsley, Palmer Dabbelt, Albert Ou, Linus Torvalds

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 <redacted>
---
 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