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Wed, 10 Nov 2021 10:35:38 +0000 Subject: Re: [PATCH v2 11/23] x86,xen: Remove .fixup usage To: Peter Zijlstra , x86@kernel.org Cc: linux-kernel@vger.kernel.org, jpoimboe@redhat.com, mark.rutland@arm.com, dvyukov@google.com, seanjc@google.com, pbonzini@redhat.com, mbenes@suse.cz References: <20211110100102.250793167@infradead.org> <20211110101325.545019822@infradead.org> From: Juergen Gross Message-ID: <42933d6b-c6f4-7420-1d0f-7f5d6ec17d8e@suse.com> Date: Wed, 10 Nov 2021 11:35:37 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.12.0 MIME-Version: 1.0 In-Reply-To: <20211110101325.545019822@infradead.org> Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="gb60vylI2gV7LlMOI2PrPGc54DAOjHNjp" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --gb60vylI2gV7LlMOI2PrPGc54DAOjHNjp Content-Type: multipart/mixed; boundary="RfDTTybY0OmbF4RlJn8t2lqLzXpqeL7FX"; protected-headers="v1" From: Juergen Gross To: Peter Zijlstra , x86@kernel.org Cc: linux-kernel@vger.kernel.org, jpoimboe@redhat.com, mark.rutland@arm.com, dvyukov@google.com, seanjc@google.com, pbonzini@redhat.com, mbenes@suse.cz Message-ID: <42933d6b-c6f4-7420-1d0f-7f5d6ec17d8e@suse.com> Subject: Re: [PATCH v2 11/23] x86,xen: Remove .fixup usage References: <20211110100102.250793167@infradead.org> <20211110101325.545019822@infradead.org> In-Reply-To: <20211110101325.545019822@infradead.org> --RfDTTybY0OmbF4RlJn8t2lqLzXpqeL7FX Content-Type: multipart/mixed; boundary="------------35DC811F2D7BB6811DBE992C" Content-Language: en-US This is a multi-part message in MIME format. --------------35DC811F2D7BB6811DBE992C Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: quoted-printable On 10.11.21 11:01, Peter Zijlstra wrote: > Employ the fancy new EX_TYPE_IMM_REG to store -EFAULT in the return > register and use this to remove some Xen .fixup usage. >=20 > All callers of these functions only test for 0 return, so the actual > return value change from -1 to -EFAULT is immaterial. >=20 > Signed-off-by: Peter Zijlstra (Intel) > --- > arch/x86/include/asm/xen/page.h | 14 +++----------- > 1 file changed, 3 insertions(+), 11 deletions(-) >=20 > --- a/arch/x86/include/asm/xen/page.h > +++ b/arch/x86/include/asm/xen/page.h > @@ -96,11 +96,7 @@ static inline int xen_safe_write_ulong(u > =20 > asm volatile("1: mov %[val], %[ptr]\n" > "2:\n" > - ".section .fixup, \"ax\"\n" > - "3: sub $1, %[ret]\n" > - " jmp 2b\n" > - ".previous\n" > - _ASM_EXTABLE(1b, 3b) > + _ASM_EXTABLE_TYPE_REG(1b, 2b, EX_TYPE_EFAULT_REG, %[ret]) > : [ret] "+r" (ret), [ptr] "=3Dm" (*addr) > : [val] "r" (val)); > =20 > @@ -110,16 +106,12 @@ static inline int xen_safe_write_ulong(u > static inline int xen_safe_read_ulong(const unsigned long *addr, > unsigned long *val) > { > - int ret =3D 0; > unsigned long rval =3D ~0ul; > + int ret =3D 0; Spurious change. > =20 > asm volatile("1: mov %[ptr], %[rval]\n" > "2:\n" > - ".section .fixup, \"ax\"\n" > - "3: sub $1, %[ret]\n" > - " jmp 2b\n" > - ".previous\n" > - _ASM_EXTABLE(1b, 3b) > + _ASM_EXTABLE_TYPE_REG(1b, 2b, EX_TYPE_EFAUL_REG, %[ret]) I guess you didn't compile that? There is a typo: s/EFAUL/EFAULT/ > : [ret] "+r" (ret), [rval] "+r" (rval) > : [ptr] "m" (*addr)); > *val =3D rval; >=20 >=20 Juergen --------------35DC811F2D7BB6811DBE992C Content-Type: application/pgp-keys; name="OpenPGP_0xB0DE9DD628BF132F.asc" Content-Transfer-Encoding: quoted-printable Content-Description: OpenPGP public key Content-Disposition: attachment; filename="OpenPGP_0xB0DE9DD628BF132F.asc" -----BEGIN PGP PUBLIC KEY BLOCK----- xsBNBFOMcBYBCACgGjqjoGvbEouQZw/ToiBg9W98AlM2QHV+iNHsEs7kxWhKMjrioyspZKOBy= cWx w3ie3j9uvg9EOB3aN4xiTv4qbnGiTr3oJhkB1gsb6ToJQZ8uxGq2kaV2KL9650I1SJvedYm8O= f8Z d621lSmoKOwlNClALZNew72NjJLEzTalU1OdT7/i1TXkH09XSSI8mEQ/ouNcMvIJNwQpd369y= 9bf IhWUiVXEK7MlRgUG6MvIj6Y3Am/BBLUVbDa4+gmzDC9ezlZkTZG2t14zWPvxXP3FAp2pkW0xq= G7/ 377qptDmrk42GlSKN4z76ELnLxussxc7I2hx18NUcbP8+uty4bMxABEBAAHNHEp1ZXJnZW4gR= 3Jv c3MgPGpnQHBmdXBmLm5ldD7CwHkEEwECACMFAlOMcBYCGwMHCwkIBwMCAQYVCAIJCgsEFgIDA= QIe AQIXgAAKCRCw3p3WKL8TL0KdB/93FcIZ3GCNwFU0u3EjNbNjmXBKDY4FUGNQH2lvWAUy+dnyT= hpw dtF/jQ6j9RwE8VP0+NXcYpGJDWlNb9/JmYqLiX2Q3TyevpB0CA3dbBQp0OW0fgCetToGIQrg0= MbD 1C/sEOv8Mr4NAfbauXjZlvTj30H2jO0u+6WGM6nHwbh2l5O8ZiHkH32iaSTfN7Eu5RnNVUJbv= oPH Z8SlM4KWm8rG+lIkGurqqu5gu8q8ZMKdsdGC4bBxdQKDKHEFExLJK/nRPFmAuGlId1E3fe10v= 5QL +qHI3EIPtyfE7i9Hz6rVwi7lWKgh7pe0ZvatAudZ+JNIlBKptb64FaiIOAWDCx1SzR9KdWVyZ= 2Vu IEdyb3NzIDxqZ3Jvc3NAc3VzZS5jb20+wsB5BBMBAgAjBQJTjHCvAhsDBwsJCAcDAgEGFQgCC= QoL BBYCAwECHgECF4AACgkQsN6d1ii/Ey/HmQf/RtI7kv5A2PS4RF7HoZhPVPogNVbC4YA6lW7Dr= Wf0 teC0RR3MzXfy6pJ+7KLgkqMlrAbN/8Dvjoz78X+5vhH/rDLa9BuZQlhFmvcGtCF8eR0T1v0nC= /nu AFVGy+67q2DH8As3KPu0344TBDpAvr2uYM4tSqxK4DURx5INz4ZZ0WNFHcqsfvlGJALDeE0Lh= ITT d9jLzdDad1pQSToCnLl6SBJZjDOX9QQcyUigZFtCXFst4dlsvddrxyqT1f17+2cFSdu7+ynLm= XBK 7abQ3rwJY8SbRO2iRulogc5vr/RLMMlscDAiDkaFQWLoqHHOdfO9rURssHNN8WkMnQfvUewRz= 80h SnVlcmdlbiBHcm9zcyA8amdyb3NzQG5vdmVsbC5jb20+wsB5BBMBAgAjBQJTjHDXAhsDBwsJC= AcD AgEGFQgCCQoLBBYCAwECHgECF4AACgkQsN6d1ii/Ey8PUQf/ehmgCI9jB9hlgexLvgOtf7PJn= FOX gMLdBQgBlVPO3/D9R8LtF9DBAFPNhlrsfIG/SqICoRCqUcJ96Pn3P7UUinFG/I0ECGF4EvTE1= jnD kfJZr6jrbjgyoZHiw/4BNwSTL9rWASyLgqlA8u1mf+c2yUwcGhgkRAd1gOwungxcwzwqgljf0= N51 N5JfVRHRtyfwq/ge+YEkDGcTU6Y0sPOuj4Dyfm8fJzdfHNQsWq3PnczLVELStJNdapwPOoE+l= otu fe3AM2vAEYJ9rTz3Cki4JFUsgLkHFqGZarrPGi1eyQcXeluldO3m91NK/1xMI3/+8jbO0tsn1= tqS EUGIJi7ox80eSnVlcmdlbiBHcm9zcyA8amdyb3NzQHN1c2UuZGU+wsB5BBMBAgAjBQJTjHDrA= hsD BwsJCAcDAgEGFQgCCQoLBBYCAwECHgECF4AACgkQsN6d1ii/Ey+LhQf9GL45eU5vOowA2u5N3= g3O ZUEBmDHVVbqMtzwlmNC4k9Kx39r5s2vcFl4tXqW7g9/ViXYuiDXb0RfUpZiIUW89siKrkzmQ5= dM7 wRqzgJpJwK8Bn2MIxAKArekWpiCKvBOB/Cc+3EXE78XdlxLyOi/NrmSGRIov0karw2RzMNOu5= D+j LRZQd1Sv27AR+IP3I8U4aqnhLpwhK7MEy9oCILlgZ1QZe49kpcumcZKORmzBTNh30FVKK1Evm= V2x AKDoaEOgQB4iFQLhJCdP1I5aSgM5IVFdn7v5YgEYuJYx37IoN1EblHI//x/e2AaIHpzK5h88N= Eaw QsaNRpNSrcfbFmAg987ATQRTjHAWAQgAyzH6AOODMBjgfWE9VeCgsrwH3exNAU32gLq2xvjpW= nHI s98ndPUDpnoxWQugJ6MpMncr0xSwFmHEgnSEjK/PAjppgmyc57BwKII3sV4on+gDVFJR6Y8ZR= wgn BC5mVM6JjQ5xDk8WRXljExRfUX9pNhdE5eBOZJrDRoLUmmjDtKzWaDhIg/+1Hzz93X4fCQkNV= bVF LELU9bMaLPBG/x5q4iYZ2k2ex6d47YE1ZFdMm6YBYMOljGkZKwYde5ldM9mo45mmwe0icXKLk= pEd IXKTZeKDO+Hdv1aqFuAcccTg9RXDQjmwhC3yEmrmcfl0+rPghO0Iv3OOImwTEe4co3c1mwARA= QAB wsBfBBgBAgAJBQJTjHAWAhsMAAoJELDendYovxMvQ/gH/1ha96vm4P/L+bQpJwrZ/dneZcmEw= Tbe 8YFsw2V/Buv6Z4Mysln3nQK5ZadD534CF7TDVft7fC4tU4PONxF5D+/tvgkPfDAfF77zy2AH1= vJz Q1fOU8lYFpZXTXIHb+559UqvIB8AdgR3SAJGHHt4RKA0F7f5ipYBBrC6cyXJyyoprT10EMvU8= VGi wXvTyJz3fjoYsdFzpWPlJEBRMedCot60g5dmbdrZ5DWClAr0yau47zpWj3enf1tLWaqcsuylW= svi uGjKGw7KHQd3bxALOknAp4dN3QwBYCKuZ7AddY9yjynVaD5X7nF9nO5BjR/i1DG86lem3iBDX= zXs ZDn8R38=3D =3D2wuH -----END PGP PUBLIC KEY BLOCK----- --------------35DC811F2D7BB6811DBE992C-- --RfDTTybY0OmbF4RlJn8t2lqLzXpqeL7FX-- --gb60vylI2gV7LlMOI2PrPGc54DAOjHNjp Content-Type: application/pgp-signature; name="OpenPGP_signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="OpenPGP_signature" -----BEGIN PGP SIGNATURE----- wsB5BAABCAAjFiEEhRJncuj2BJSl0Jf3sN6d1ii/Ey8FAmGLoHkFAwAAAAAACgkQsN6d1ii/Ey8O uQf8Cd9NWDAoThFPF4+tbc2vpwest+nNAb2aRsuKzTbEOAMdm8OcZxF+OtMaMxhRuM6Np9Yhnyr8 6B0c4th9rLWopAnT/Gf50r+xfgczqL3zhZ+KnM8nUA7aZAyklVdBUodS0P0bsjpR7iqIaG38PyL/ cEMZ6Z0bpAjvit1z38+QrbNq/zp+OKFztsNpAp/OuJ8DkuY/al1G33lyDxjmwsHpg4O/GKwJU2ip LitF8/Qwh/acIN4yKv6N7hpK4nawzMS40HvcAhFk04q2dIoFXgK7ooLJ1gUmm79xLLQoqDUGjCkF 03bmcuVc2Wftz6avclzIpU7hc1S0jb3As4j3ffcJ0A== =/xKJ -----END PGP SIGNATURE----- --gb60vylI2gV7LlMOI2PrPGc54DAOjHNjp--