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Peter Anvin" , , , , , Kefeng Wang , Xie XiuQi , Guohanjun References: <20220528065056.1034168-1-tongtiangen@huawei.com> <20220528065056.1034168-3-tongtiangen@huawei.com> From: Tong Tiangen In-Reply-To: Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 8bit X-Originating-IP: [10.174.179.234] X-ClientProxiedBy: dggems704-chm.china.huawei.com (10.3.19.181) To kwepemm600017.china.huawei.com (7.193.23.234) X-CFilter-Loop: Reflected X-Spam-Status: No, score=-6.4 required=5.0 tests=BAYES_00,NICE_REPLY_A, RCVD_IN_DNSWL_MED,SPF_HELO_NONE,SPF_PASS,T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 在 2022/6/17 16:24, Mark Rutland 写道: > On Sat, May 28, 2022 at 06:50:50AM +0000, Tong Tiangen wrote: >> Currnetly, the extable type used by __arch_copy_from/to_user() is >> EX_TYPE_FIXUP. In fact, It is more clearly to use meaningful >> EX_TYPE_UACCESS_*. >> >> Suggested-by: Mark Rutland >> Signed-off-by: Tong Tiangen >> --- >> arch/arm64/include/asm/asm-extable.h | 8 ++++++++ >> arch/arm64/include/asm/asm-uaccess.h | 12 ++++++------ >> 2 files changed, 14 insertions(+), 6 deletions(-) >> >> diff --git a/arch/arm64/include/asm/asm-extable.h b/arch/arm64/include/asm/asm-extable.h >> index 56ebe183e78b..9c94ac1f082c 100644 >> --- a/arch/arm64/include/asm/asm-extable.h >> +++ b/arch/arm64/include/asm/asm-extable.h >> @@ -28,6 +28,14 @@ >> __ASM_EXTABLE_RAW(\insn, \fixup, EX_TYPE_FIXUP, 0) >> .endm >> >> +/* >> + * Create an exception table entry for uaccess `insn`, which will branch to `fixup` >> + * when an unhandled fault is taken. >> + * ex->data = ~0 means both reg_err and reg_zero is set to wzr(x31). >> + */ >> + .macro _asm_extable_uaccess, insn, fixup >> + __ASM_EXTABLE_RAW(\insn, \fixup, EX_TYPE_UACCESS_ERR_ZERO, ~0) >> + .endm > > I'm not too keen on using `~0` here, since that also sets other bits in the > data field, and its somewhat opaque. > > How painful is it to generate the data fields as with the C version of this > macro, so that we can pass in wzr explciitly for the two sub-fields? > > Other than that, this looks good to me. > > Thanks, > Mark. ok, will fix next version. Thanks, Tong. > >> /* >> * Create an exception table entry for `insn` if `fixup` is provided. Otherwise >> * do nothing. >> diff --git a/arch/arm64/include/asm/asm-uaccess.h b/arch/arm64/include/asm/asm-uaccess.h >> index 0557af834e03..75b211c98dea 100644 >> --- a/arch/arm64/include/asm/asm-uaccess.h >> +++ b/arch/arm64/include/asm/asm-uaccess.h >> @@ -61,7 +61,7 @@ alternative_else_nop_endif >> >> #define USER(l, x...) \ >> 9999: x; \ >> - _asm_extable 9999b, l >> + _asm_extable_uaccess 9999b, l >> >> /* >> * Generate the assembly for LDTR/STTR with exception table entries. >> @@ -73,8 +73,8 @@ alternative_else_nop_endif >> 8889: ldtr \reg2, [\addr, #8]; >> add \addr, \addr, \post_inc; >> >> - _asm_extable 8888b,\l; >> - _asm_extable 8889b,\l; >> + _asm_extable_uaccess 8888b, \l; >> + _asm_extable_uaccess 8889b, \l; >> .endm >> >> .macro user_stp l, reg1, reg2, addr, post_inc >> @@ -82,14 +82,14 @@ alternative_else_nop_endif >> 8889: sttr \reg2, [\addr, #8]; >> add \addr, \addr, \post_inc; >> >> - _asm_extable 8888b,\l; >> - _asm_extable 8889b,\l; >> + _asm_extable_uaccess 8888b,\l; >> + _asm_extable_uaccess 8889b,\l; >> .endm >> >> .macro user_ldst l, inst, reg, addr, post_inc >> 8888: \inst \reg, [\addr]; >> add \addr, \addr, \post_inc; >> >> - _asm_extable 8888b,\l; >> + _asm_extable_uaccess 8888b, \l; >> .endm >> #endif >> -- >> 2.25.1 >> > .