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Peter Anvin" , , Subject: [PATCH] x86/entry/32: pass cr2 to do_async_page_fault Date: Tue, 23 Jul 2019 21:20:58 -0700 Message-ID: <20190724042058.24506-1-mmullins@fb.com> X-Mailer: git-send-email 2.17.1 MIME-Version: 1.0 Content-Type: text/plain X-Originating-IP: [2620:10d:c081:10::13] X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2019-07-24_01:,, signatures=0 X-Proofpoint-Spam-Details: rule=fb_default_notspam policy=fb_default score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1011 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1906280000 definitions=main-1907240047 X-FB-Internal: deliver Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit a0d14b8909de ("x86/mm, tracing: Fix CR2 corruption") added the address parameter to do_async_page_fault, but does not pass it from the 32-bit entry point. To plumb it through, factor-out common_exception_read_cr2 in the same fashion as common_exception, and uses it from both page_fault and async_page_fault. For a 32-bit KVM guest, this fixes: [ 1.148669][ T1] Run /sbin/init as init process [ 1.153328][ T1] Starting init: /sbin/init exists but couldn't execute it (error -14) Fixes: a0d14b8909de ("x86/mm, tracing: Fix CR2 corruption") Signed-off-by: Matt Mullins --- arch/x86/entry/entry_32.S | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-) diff --git a/arch/x86/entry/entry_32.S b/arch/x86/entry/entry_32.S index 2bb986f305ac..4f86928246e7 100644 --- a/arch/x86/entry/entry_32.S +++ b/arch/x86/entry/entry_32.S @@ -1443,8 +1443,12 @@ BUILD_INTERRUPT3(hv_stimer0_callback_vector, HYPERV_STIMER0_VECTOR, ENTRY(page_fault) ASM_CLAC - pushl $0; /* %gs's slot on the stack */ + pushl $do_page_fault + jmp common_exception_read_cr2 +END(page_fault) +common_exception_read_cr2: + /* the function address is in %gs's slot on the stack */ SAVE_ALL switch_stacks=1 skip_gs=1 ENCODE_FRAME_POINTER @@ -1452,6 +1456,7 @@ ENTRY(page_fault) /* fixup %gs */ GS_TO_REG %ecx + movl PT_GS(%esp), %edi REG_TO_PTGS %ecx SET_KERNEL_GS %ecx @@ -1463,9 +1468,9 @@ ENTRY(page_fault) TRACE_IRQS_OFF movl %esp, %eax # pt_regs pointer - call do_page_fault + CALL_NOSPEC %edi jmp ret_from_exception -END(page_fault) +END(common_exception_read_cr2) common_exception: /* the function address is in %gs's slot on the stack */ @@ -1595,7 +1600,7 @@ END(general_protection) ENTRY(async_page_fault) ASM_CLAC pushl $do_async_page_fault - jmp common_exception + jmp common_exception_read_cr2 END(async_page_fault) #endif -- 2.17.1