Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760667Ab3JPLW4 (ORCPT ); Wed, 16 Oct 2013 07:22:56 -0400 Received: from cam-admin0.cambridge.arm.com ([217.140.96.50]:51408 "EHLO cam-admin0.cambridge.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1760492Ab3JPLWz (ORCPT ); Wed, 16 Oct 2013 07:22:55 -0400 Date: Wed, 16 Oct 2013 12:22:22 +0100 From: Will Deacon To: Jiang Liu Cc: Steven Rostedt , Catalin Marinas , Sandeepa Prabhu , Jiang Liu , "linux-arm-kernel@lists.infradead.org" , "linux-kernel@vger.kernel.org" Subject: Re: [PATCH v3 3/7] arm64: move encode_insn_immediate() from module.c to insn.c Message-ID: <20131016112222.GG5403@mudshark.cambridge.arm.com> References: <1381893492-7135-1-git-send-email-liuj97@gmail.com> <1381893492-7135-4-git-send-email-liuj97@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1381893492-7135-4-git-send-email-liuj97@gmail.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3847 Lines: 94 On Wed, Oct 16, 2013 at 04:18:08AM +0100, Jiang Liu wrote: > From: Jiang Liu > > Function encode_insn_immediate() will be used by other instruction > manipulate related functions, so move it into insn.c and rename it > as aarch64_insn_encode_immediate(). > > Signed-off-by: Jiang Liu > Cc: Jiang Liu > --- > arch/arm64/include/asm/insn.h | 14 ++++ > arch/arm64/kernel/insn.c | 77 +++++++++++++++++++++ > arch/arm64/kernel/module.c | 151 +++++++++--------------------------------- > 3 files changed, 123 insertions(+), 119 deletions(-) > > diff --git a/arch/arm64/include/asm/insn.h b/arch/arm64/include/asm/insn.h > index 2dfcdb4..8dc0a91 100644 > --- a/arch/arm64/include/asm/insn.h > +++ b/arch/arm64/include/asm/insn.h > @@ -28,6 +28,18 @@ enum aarch64_insn_class { > * system instructions */ > }; > > +enum aarch64_insn_imm_type { > + AARCH64_INSN_IMM_MOVNZ, > + AARCH64_INSN_IMM_MOVK, > + AARCH64_INSN_IMM_ADR, > + AARCH64_INSN_IMM_26, > + AARCH64_INSN_IMM_19, > + AARCH64_INSN_IMM_16, > + AARCH64_INSN_IMM_14, > + AARCH64_INSN_IMM_12, > + AARCH64_INSN_IMM_9, > +}; > + > #define __AARCH64_INSN_FUNCS(abbr, mask, val) \ > static __always_inline bool aarch64_insn_is_##abbr(u32 code) \ > { return (code & (mask)) == (val); } \ > @@ -47,6 +59,8 @@ __AARCH64_INSN_FUNCS(nop, 0xFFFFFFFF, 0xD503201F) > #undef __AARCH64_INSN_FUNCS > > enum aarch64_insn_class aarch64_get_insn_class(u32 insn); > +u32 aarch64_insn_encode_immediate(enum aarch64_insn_imm_type type, > + u32 insn, u64 imm); > u32 aarch64_insn_read(void *addr); > void aarch64_insn_write(void *addr, u32 insn); > bool aarch64_insn_hotpatch_safe(u32 old_insn, u32 new_insn); > diff --git a/arch/arm64/kernel/insn.c b/arch/arm64/kernel/insn.c > index ad4185f..90cc312 100644 > --- a/arch/arm64/kernel/insn.c > +++ b/arch/arm64/kernel/insn.c > @@ -179,3 +179,80 @@ int __kprobes aarch64_insn_patch_text(void *addrs[], u32 insns[], int cnt) > else > return aarch64_insn_patch_text_sync(addrs, insns, cnt); > } > + > +u32 aarch64_insn_encode_immediate(enum aarch64_insn_imm_type type, > + u32 insn, u64 imm) > +{ > + u32 immlo, immhi, lomask, himask, mask; > + int shift; > + > + switch (type) { > + case AARCH64_INSN_IMM_MOVNZ: > + /* > + * For signed MOVW relocations, we have to manipulate the > + * instruction encoding depending on whether or not the > + * immediate is less than zero. > + */ > + insn &= ~(3 << 29); > + if ((s64)imm >= 0) { > + /* >=0: Set the instruction to MOVZ (opcode 10b). */ > + insn |= 2 << 29; > + } else { > + /* > + * <0: Set the instruction to MOVN (opcode 00b). > + * Since we've masked the opcode already, we > + * don't need to do anything other than > + * inverting the new immediate field. > + */ > + imm = ~imm; > + } I'm really not comfortable with this. This code is performing static relocations and re-encoding instructions as required by the AArch64 ELF spec. That's not really what you'd expect from a generic instruction encoder! Will -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/