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ARM: net: bpf: improve 64-bit sign-extended immediate load
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Improve the 64-bit sign-extended immediate from:

  mov     r6, #1
  str     r6, [fp, #-52]  ; 0xffffffcc
  mov     r6, #0
  str     r6, [fp, #-48]  ; 0xffffffd0

to:

  mov     r6, #1
  mov     r7, #0
  strd    r6, [fp, #-52]  ; 0xffffffcc

Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
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Russell King authored and Daniel Borkmann committed Jul 13, 2018
1 parent f9ff501 commit 077513b
Showing 1 changed file with 3 additions and 4 deletions.
7 changes: 3 additions & 4 deletions arch/arm/net/bpf_jit_32.c
Original file line number Diff line number Diff line change
Expand Up @@ -613,12 +613,11 @@ static void emit_a32_mov_i64(const s8 dst[], u64 val, struct jit_ctx *ctx)
/* Sign extended move */
static inline void emit_a32_mov_se_i64(const bool is64, const s8 dst[],
const u32 val, struct jit_ctx *ctx) {
u32 hi = 0;
u64 val64 = val;

if (is64 && (val & (1<<31)))
hi = (u32)~0;
emit_a32_mov_i(dst_lo, val, ctx);
emit_a32_mov_i(dst_hi, hi, ctx);
val64 |= 0xffffffff00000000ULL;
emit_a32_mov_i64(dst, val64, ctx);
}

static inline void emit_a32_add_r(const u8 dst, const u8 src,
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