linux-riscv.lists.infradead.org archive mirror
 help / color / mirror / Atom feed
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 v2 1/9] riscv, bpf: fix broken BPF tail calls
Date: Mon, 16 Dec 2019 10:13:35 +0100	[thread overview]
Message-ID: <20191216091343.23260-2-bjorn.topel@gmail.com> (raw)
In-Reply-To: <20191216091343.23260-1-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



  reply	other threads:[~2019-12-16  9:14 UTC|newest]

Thread overview: 33+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-12-16  9:13 [PATCH bpf-next v2 0/9] riscv: BPF JIT fix, optimizations and far jumps support Björn Töpel
2019-12-16  9:13 ` Björn Töpel [this message]
2019-12-16  9:13 ` [PATCH bpf-next v2 2/9] riscv, bpf: add support for far branching Björn Töpel
2019-12-16  9:13 ` [PATCH bpf-next v2 3/9] riscv, bpf: add support for far branching when emitting tail call Björn Töpel
2019-12-16  9:13 ` [PATCH bpf-next v2 4/9] riscv, bpf: add support for far jumps and exits Björn Töpel
2019-12-16  9:13 ` [PATCH bpf-next v2 5/9] riscv, bpf: optimize BPF tail calls Björn Töpel
2019-12-16  9:13 ` [PATCH bpf-next v2 6/9] riscv, bpf: provide RISC-V specific JIT image alloc/free Björn Töpel
2019-12-16 15:09   ` Daniel Borkmann
2019-12-18  6:23     ` Björn Töpel
2020-01-04  1:32       ` Paul Walmsley
2020-01-07 10:24         ` Björn Töpel
2020-01-07 10:47           ` Paul Walmsley
2020-02-02 13:37   ` Alex Ghiti
2020-02-03 12:28     ` Björn Töpel
2020-02-03 20:57       ` Alex Ghiti
2019-12-16  9:13 ` [PATCH bpf-next v2 7/9] riscv, bpf: optimize calls Björn Töpel
2019-12-16  9:13 ` [PATCH bpf-next v2 8/9] riscv, bpf: add missing uapi header for BPF_PROG_TYPE_PERF_EVENT programs Björn Töpel
2019-12-16  9:13 ` [PATCH bpf-next v2 9/9] riscv, perf: add arch specific perf_arch_bpf_user_pt_regs Björn Töpel
2019-12-19 15:07 ` [PATCH bpf-next v2 0/9] riscv: BPF JIT fix, optimizations and far jumps support Daniel Borkmann
2019-12-19 22:02 ` [PATCH bpf-next v2 1/9] riscv, bpf: fix broken BPF tail calls Palmer Dabbelt
2019-12-23 18:03 ` [PATCH bpf-next v2 2/9] riscv, bpf: add support for far branching Palmer Dabbelt
2020-01-07  8:13   ` Björn Töpel
2020-01-23  2:08   ` Palmer Dabbelt
2019-12-23 18:18 ` [PATCH bpf-next v2 3/9] riscv, bpf: add support for far branching when emitting tail call Palmer Dabbelt
2019-12-23 18:18 ` [PATCH bpf-next v2 4/9] riscv, bpf: add support for far jumps and exits Palmer Dabbelt
2019-12-23 18:29 ` [PATCH bpf-next v2 5/9] riscv, bpf: optimize BPF tail calls Palmer Dabbelt
2019-12-23 18:30 ` [PATCH bpf-next v2 6/9] riscv, bpf: provide RISC-V specific JIT image alloc/free Palmer Dabbelt
2019-12-23 18:58 ` [PATCH bpf-next v2 7/9] riscv, bpf: optimize calls Palmer Dabbelt
2020-01-07 10:14   ` Björn Töpel
2020-01-28  2:15   ` Palmer Dabbelt
2020-02-03 12:11     ` Björn Töpel
2019-12-23 18:58 ` [PATCH bpf-next v2 8/9] riscv, bpf: add missing uapi header for BPF_PROG_TYPE_PERF_EVENT programs Palmer Dabbelt
2019-12-23 18:58 ` [PATCH bpf-next v2 9/9] riscv, perf: add arch specific perf_arch_bpf_user_pt_regs Palmer Dabbelt

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20191216091343.23260-2-bjorn.topel@gmail.com \
    --to=bjorn.topel@gmail.com \
    --cc=ast@kernel.org \
    --cc=bpf@vger.kernel.org \
    --cc=daniel@iogearbox.net \
    --cc=linux-riscv@lists.infradead.org \
    --cc=netdev@vger.kernel.org \
    --subject='Re: [PATCH bpf-next v2 1/9] riscv, bpf: fix broken BPF tail calls' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).