diff options
| author | Russell King <rmk+kernel@armlinux.org.uk> | 2018-01-13 14:35:15 +0300 |
|---|---|---|
| committer | Russell King <rmk+kernel@armlinux.org.uk> | 2018-01-17 22:35:22 +0300 |
| commit | e9062481824384f00299971f923fecf6b3668001 (patch) | |
| tree | 9eb1a903130c504a325c754051c6be9c27c8088c /arch/arm | |
| parent | 36b0cb84ee858f02c256d26f0cb4229c78e3399e (diff) | |
| download | linux-e9062481824384f00299971f923fecf6b3668001.tar.xz | |
ARM: net: bpf: avoid 'bx' instruction on non-Thumb capable CPUs
Avoid the 'bx' instruction on CPUs that have no support for Thumb and
thus do not implement this instruction by moving the generation of this
opcode to a separate function that selects between:
bx reg
and
mov pc, reg
according to the capabilities of the CPU.
Fixes: 39c13c204bb1 ("arm: eBPF JIT compiler")
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Diffstat (limited to 'arch/arm')
| -rw-r--r-- | arch/arm/net/bpf_jit_32.c | 18 |
1 files changed, 11 insertions, 7 deletions
diff --git a/arch/arm/net/bpf_jit_32.c b/arch/arm/net/bpf_jit_32.c index c199990e12b6..4efb3743a89e 100644 --- a/arch/arm/net/bpf_jit_32.c +++ b/arch/arm/net/bpf_jit_32.c @@ -285,16 +285,20 @@ static inline void emit_mov_i(const u8 rd, u32 val, struct jit_ctx *ctx) emit_mov_i_no8m(rd, val, ctx); } -static inline void emit_blx_r(u8 tgt_reg, struct jit_ctx *ctx) +static void emit_bx_r(u8 tgt_reg, struct jit_ctx *ctx) { - ctx->seen |= SEEN_CALL; -#if __LINUX_ARM_ARCH__ < 5 - emit(ARM_MOV_R(ARM_LR, ARM_PC), ctx); - if (elf_hwcap & HWCAP_THUMB) emit(ARM_BX(tgt_reg), ctx); else emit(ARM_MOV_R(ARM_PC, tgt_reg), ctx); +} + +static inline void emit_blx_r(u8 tgt_reg, struct jit_ctx *ctx) +{ + ctx->seen |= SEEN_CALL; +#if __LINUX_ARM_ARCH__ < 5 + emit(ARM_MOV_R(ARM_LR, ARM_PC), ctx); + emit_bx_r(tgt_reg, ctx); #else emit(ARM_BLX_R(tgt_reg), ctx); #endif @@ -997,7 +1001,7 @@ static int emit_bpf_tail_call(struct jit_ctx *ctx) emit_a32_mov_i(tmp2[1], off, false, ctx); emit(ARM_LDR_R(tmp[1], tmp[1], tmp2[1]), ctx); emit(ARM_ADD_I(tmp[1], tmp[1], ctx->prologue_bytes), ctx); - emit(ARM_BX(tmp[1]), ctx); + emit_bx_r(tmp[1], ctx); /* out: */ if (out_offset == -1) @@ -1166,7 +1170,7 @@ static void build_epilogue(struct jit_ctx *ctx) emit(ARM_POP(reg_set), ctx); /* Return back to the callee function */ if (!(ctx->seen & SEEN_CALL)) - emit(ARM_BX(ARM_LR), ctx); + emit_bx_r(ARM_LR, ctx); #endif } |