From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from zen.linaro.local ([81.128.185.34]) by smtp.gmail.com with ESMTPSA id p29sm12821860wmf.3.2018.03.06.06.26.03 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 06 Mar 2018 06:26:03 -0800 (PST) Received: from zen (localhost [127.0.0.1]) by zen.linaro.local (Postfix) with ESMTPS id 648FB3E0270; Tue, 6 Mar 2018 14:26:03 +0000 (GMT) References: <20180303143823.27055-1-richard.henderson@linaro.org> <20180303143823.27055-5-richard.henderson@linaro.org> User-agent: mu4e 1.1.0; emacs 26.0.91 From: Alex =?utf-8?Q?Benn=C3=A9e?= To: Richard Henderson Cc: qemu-devel@nongnu.org, qemu-arm@nongnu.org Subject: Re: [Qemu-arm] [PATCH v4 4/5] aarch64-linux-user: Add support for EXTRA signal frame records In-reply-to: <20180303143823.27055-5-richard.henderson@linaro.org> Date: Tue, 06 Mar 2018 14:26:03 +0000 Message-ID: <87371dth50.fsf@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-TUID: 9w8WBzeXPl0q Richard Henderson writes: > The EXTRA record allows for additional space to be allocated > beyon what is currently reserved. Add code to emit and read > this record type. > > Nothing uses extra space yet. > > Signed-off-by: Richard Henderson Reviewed-by: Alex Benn=C3=A9e > --- > linux-user/signal.c | 74 +++++++++++++++++++++++++++++++++++++++++++++--= ------ > 1 file changed, 63 insertions(+), 11 deletions(-) > > diff --git a/linux-user/signal.c b/linux-user/signal.c > index f9eef3d753..c31cf0601d 100644 > --- a/linux-user/signal.c > +++ b/linux-user/signal.c > @@ -1443,6 +1443,15 @@ struct target_fpsimd_context { > uint64_t vregs[32 * 2]; /* really uint128_t vregs[32] */ > }; > > +#define TARGET_EXTRA_MAGIC 0x45585401 > + > +struct target_extra_context { > + struct target_aarch64_ctx head; > + uint64_t datap; /* 16-byte aligned pointer to extra space cast to __= u64 */ > + uint32_t size; /* size in bytes of the extra space */ > + uint32_t reserved[3]; > +}; > + > struct target_rt_sigframe { > struct target_siginfo info; > struct target_ucontext uc; > @@ -1502,6 +1511,15 @@ static void target_setup_fpsimd_record(struct targ= et_fpsimd_context *fpsimd, > } > } > > +static void target_setup_extra_record(struct target_extra_context *extra, > + uint64_t datap, uint32_t extra_siz= e) > +{ > + __put_user(TARGET_EXTRA_MAGIC, &extra->head.magic); > + __put_user(sizeof(struct target_extra_context), &extra->head.size); > + __put_user(datap, &extra->datap); > + __put_user(extra_size, &extra->size); > +} > + > static void target_setup_end_record(struct target_aarch64_ctx *end) > { > __put_user(0, &end->magic); > @@ -1554,48 +1572,74 @@ static void target_restore_fpsimd_record(CPUARMSt= ate *env, > static int target_restore_sigframe(CPUARMState *env, > struct target_rt_sigframe *sf) > { > - struct target_aarch64_ctx *ctx; > + struct target_aarch64_ctx *ctx, *extra =3D NULL; > struct target_fpsimd_context *fpsimd =3D NULL; > + uint64_t extra_datap =3D 0; > + bool used_extra =3D false; > + bool err =3D false; > > target_restore_general_frame(env, sf); > > ctx =3D (struct target_aarch64_ctx *)sf->uc.tuc_mcontext.__reserved; > while (ctx) { > - uint32_t magic, size; > + uint32_t magic, size, extra_size; > > __get_user(magic, &ctx->magic); > __get_user(size, &ctx->size); > switch (magic) { > case 0: > if (size !=3D 0) { > - return 1; > + err =3D true; > + goto exit; > + } > + if (used_extra) { > + ctx =3D NULL; > + } else { > + ctx =3D extra; > + used_extra =3D true; > } > - ctx =3D NULL; > continue; > > case TARGET_FPSIMD_MAGIC: > if (fpsimd || size !=3D sizeof(struct target_fpsimd_context)= ) { > - return 1; > + err =3D true; > + goto exit; > } > fpsimd =3D (struct target_fpsimd_context *)ctx; > break; > > + case TARGET_EXTRA_MAGIC: > + if (extra || size !=3D sizeof(struct target_extra_context)) { > + err =3D true; > + goto exit; > + } > + __get_user(extra_datap, > + &((struct target_extra_context *)ctx)->datap); > + __get_user(extra_size, > + &((struct target_extra_context *)ctx)->size); > + extra =3D lock_user(VERIFY_READ, extra_datap, extra_size, 0); > + break; > + > default: > /* Unknown record -- we certainly didn't generate it. > * Did we in fact get out of sync? > */ > - return 1; > + err =3D true; > + goto exit; > } > ctx =3D (void *)ctx + size; > } > > /* Require FPSIMD always. */ > - if (!fpsimd) { > - return 1; > + if (fpsimd) { > + target_restore_fpsimd_record(env, fpsimd); > + } else { > + err =3D true; > } > - target_restore_fpsimd_record(env, fpsimd); > > - return 0; > + exit: > + unlock_user(extra, extra_datap, 0); > + return err; > } > > static abi_ulong get_sigframe(struct target_sigaction *ka, CPUARMState *= env) > @@ -1621,7 +1665,8 @@ static void target_setup_frame(int usig, struct tar= get_sigaction *ka, > CPUARMState *env) > { > int size =3D offsetof(struct target_rt_sigframe, uc.tuc_mcontext.__r= eserved); > - int fpsimd_ofs, end1_ofs, fr_ofs; > + int fpsimd_ofs, end1_ofs, fr_ofs, end2_ofs =3D 0; > + int extra_ofs =3D 0, extra_base =3D 0, extra_size =3D 0; > struct target_rt_sigframe *frame; > struct target_rt_frame_record *fr; > abi_ulong frame_addr, return_addr; > @@ -1641,7 +1686,14 @@ static void target_setup_frame(int usig, struct ta= rget_sigaction *ka, > > target_setup_general_frame(frame, env, set); > target_setup_fpsimd_record((void *)frame + fpsimd_ofs, env); > + if (extra_ofs) { > + target_setup_extra_record((void *)frame + extra_ofs, > + frame_addr + extra_base, extra_size); > + } > target_setup_end_record((void *)frame + end1_ofs); > + if (end2_ofs) { > + target_setup_end_record((void *)frame + end2_ofs); > + } > > /* Set up the stack frame for unwinding. */ > fr =3D (void *)frame + fr_ofs; -- Alex Benn=C3=A9e