ARM: net: bpf: imm12 constant conversion (1ca3b17b) · Commits · 戴 / test

arch/arm/net/bpf_jit_32.c

+49 −1

Original line number	Diff line number	Diff line
		@@ -236,10 +236,56 @@ static inline void emit(u32 inst, struct jit_ctx *ctx)
		_emit(ARM_COND_AL, inst, ctx);
		}

		/*
		* This is rather horrid, but necessary to convert an integer constant
		* to an immediate operand for the opcodes, and be able to detect at
		* build time whether the constant can't be converted (iow, usable in
		* BUILD_BUG_ON()).
		*/
		#define imm12val(v, s) (rol32(v, (s)) \| (s) << 7)
		#define const_imm8m(x) \
		({ int r; \
		u32 v = (x); \
		if (!(v & ~0x000000ff)) \
		r = imm12val(v, 0); \
		else if (!(v & ~0xc000003f)) \
		r = imm12val(v, 2); \
		else if (!(v & ~0xf000000f)) \
		r = imm12val(v, 4); \
		else if (!(v & ~0xfc000003)) \
		r = imm12val(v, 6); \
		else if (!(v & ~0xff000000)) \
		r = imm12val(v, 8); \
		else if (!(v & ~0x3fc00000)) \
		r = imm12val(v, 10); \
		else if (!(v & ~0x0ff00000)) \
		r = imm12val(v, 12); \
		else if (!(v & ~0x03fc0000)) \
		r = imm12val(v, 14); \
		else if (!(v & ~0x00ff0000)) \
		r = imm12val(v, 16); \
		else if (!(v & ~0x003fc000)) \
		r = imm12val(v, 18); \
		else if (!(v & ~0x000ff000)) \
		r = imm12val(v, 20); \
		else if (!(v & ~0x0003fc00)) \
		r = imm12val(v, 22); \
		else if (!(v & ~0x0000ff00)) \
		r = imm12val(v, 24); \
		else if (!(v & ~0x00003fc0)) \
		r = imm12val(v, 26); \
		else if (!(v & ~0x00000ff0)) \
		r = imm12val(v, 28); \
		else if (!(v & ~0x000003fc)) \
		r = imm12val(v, 30); \
		else \
		r = -1; \
		r; })

		/*
		* Checks if immediate value can be converted to imm12(12 bits) value.
		*/
		static int16_t imm8m(u32 x)
		static int imm8m(u32 x)
		{
		u32 rot;

		@@ -249,6 +295,8 @@ static int16_t imm8m(u32 x)
		return -1;
		}

		#define imm8m(x) (__builtin_constant_p(x) ? const_imm8m(x) : imm8m(x))

		static u32 arm_bpf_ldst_imm12(u32 op, u8 rt, u8 rn, s16 imm12)
		{
		op \|= rt << 12 \| rn << 16;

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