From 20ccb004bad659c186f9091015a956da220d615d Mon Sep 17 00:00:00 2001
From: "Naveen N. Rao" <naveen.n.rao@linux.vnet.ibm.com>
Date: Wed, 9 Jun 2021 14:30:24 +0530
Subject: [PATCH] powerpc/bpf: Use bctrl for making function calls
References: bsc#1065729
Patch-mainline: v5.14-rc1
Git-commit: 20ccb004bad659c186f9091015a956da220d615d
blrl corrupts the link stack. Instead use bctrl when making function
calls from BPF programs.
Reported-by: Anton Blanchard <anton@ozlabs.org>
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210609090024.1446800-1-naveen.n.rao@linux.vnet.ibm.com
Acked-by: Michal Suchanek <msuchanek@suse.de>
---
arch/powerpc/net/bpf_jit_comp32.c | 4 ++--
arch/powerpc/net/bpf_jit_comp64.c | 12 ++++++------
2 files changed, 8 insertions(+), 8 deletions(-)
diff --git a/arch/powerpc/net/bpf_jit_comp64.c b/arch/powerpc/net/bpf_jit_comp64.c
--- a/arch/powerpc/net/bpf_jit_comp64.c
+++ b/arch/powerpc/net/bpf_jit_comp64.c
@@ -153,8 +153,8 @@ static void bpf_jit_emit_func_call_hlp(u32 *image, struct codegen_context *ctx,
PPC_LI64(b2p[TMP_REG_2], func);
/* Load actual entry point from function descriptor */
PPC_BPF_LL(b2p[TMP_REG_1], b2p[TMP_REG_2], 0);
- /* ... and move it to LR */
- EMIT(PPC_RAW_MTLR(b2p[TMP_REG_1]));
+ /* ... and move it to CTR */
+ EMIT(PPC_RAW_MTCTR(b2p[TMP_REG_1]));
/*
* Load TOC from function descriptor at offset 8.
* We can clobber r2 since we get called through a
@@ -165,9 +165,9 @@ static void bpf_jit_emit_func_call_hlp(u32 *image, struct codegen_context *ctx,
#else
/* We can clobber r12 */
PPC_FUNC_ADDR(12, func);
- EMIT(PPC_RAW_MTLR(12));
+ EMIT(PPC_RAW_MTCTR(12));
#endif
- EMIT(PPC_RAW_BLRL());
+ EMIT(PPC_RAW_BCTRL());
}
static void bpf_jit_emit_func_call_rel(u32 *image, struct codegen_context *ctx,
@@ -202,8 +202,8 @@ void bpf_jit_emit_func_call_rel(u32 *image, struct codegen_context *ctx, u64 fun
PPC_BPF_LL(12, 12, 0);
#endif
- EMIT(PPC_RAW_MTLR(12));
- EMIT(PPC_RAW_BLRL());
+ EMIT(PPC_RAW_MTCTR(12));
+ EMIT(PPC_RAW_BCTRL());
}
static void bpf_jit_emit_tail_call(u32 *image, struct codegen_context *ctx, u32 out)
--
2.31.1