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powerpc/bpf: Use bctrl for making function calls 

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
This commit is contained in:
Naveen N. Rao 2021-06-09 14:30:24 +05:30 committed by Michael Ellerman
parent b8ee3e6d6c
commit 20ccb004ba
2 changed files with 8 additions and 8 deletions
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4
arch/powerpc/net/bpf_jit_comp32.c
View File

@ -195,8 +195,8 @@ void bpf_jit_emit_func_call_rel(u32 *image, struct codegen_context *ctx, u64 fun
/* Load function address into r0 */
EMIT(PPC_RAW_LIS(_R0, IMM_H(func)));
EMIT(PPC_RAW_ORI(_R0, _R0, IMM_L(func)));
EMIT(PPC_RAW_MTLR(_R0));
EMIT(PPC_RAW_BLRL());
EMIT(PPC_RAW_MTCTR(_R0));
EMIT(PPC_RAW_BCTRL());
}
}

12
arch/powerpc/net/bpf_jit_comp64.c
View File

@ -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());
}
void bpf_jit_emit_func_call_rel(u32 *image, struct codegen_context *ctx, u64 func)
@ -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)