From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 14681 invoked by alias); 28 Dec 2010 16:42:07 -0000 Received: (qmail 14671 invoked by uid 22791); 28 Dec 2010 16:42:04 -0000 X-SWARE-Spam-Status: No, hits=-1.9 required=5.0 tests=AWL,BAYES_00,T_RP_MATCHES_RCVD X-Spam-Check-By: sourceware.org Received: from mail.codesourcery.com (HELO mail.codesourcery.com) (38.113.113.100) by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Tue, 28 Dec 2010 16:41:55 +0000 Received: (qmail 26574 invoked from network); 28 Dec 2010 16:41:52 -0000 Received: from unknown (HELO ?192.168.0.101?) (yao@127.0.0.2) by mail.codesourcery.com with ESMTPA; 28 Dec 2010 16:41:52 -0000 Message-ID: <4D1A1343.8020204@codesourcery.com> Date: Tue, 28 Dec 2010 17:24:00 -0000 From: Yao Qi User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.2.13) Gecko/20101208 Thunderbird/3.1.7 MIME-Version: 1.0 To: gdb-patches@sourceware.org Subject: [patch] Fix PR tdep/12352: Handle str pc, [Rd, #imm] in displaced stepping Content-Type: multipart/mixed; boundary="------------040107080602090804060708" X-IsSubscribed: yes Mailing-List: contact gdb-patches-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-patches-owner@sourceware.org X-SW-Source: 2010-12/txt/msg00516.txt.bz2 This is a multi-part message in MIME format. --------------040107080602090804060708 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Content-length: 662 When I read arm-tdep.c:copy_ldr_str_ldrb_strb, I feel pretty hard to understand two lines of code, dsc->modinsn[0] = 0xe58ff014; /* str pc, [pc, #20]. */ dsc->modinsn[1] = 0xe59f4010; /* ldr r4, [pc, #16]. */ Shall program get SIGSEGV when executing `str pc, [pc, #20]' during displaced stepping? A simple test case confirmed my guess, which is included in arm-disp-step.S in this patch. If it is a bug here, this patch is to address it. These two lines of code is to compute the offset of `str pc'. In this patch, we can do this in a different way, str pc, [sp, #-4] ldr r4, [sp, #-4] OK for mainline and 7.2 branch? -- Yao (齐尧) --------------040107080602090804060708 Content-Type: text/x-patch; name="pr12352.patch" Content-Transfer-Encoding: 7bit Content-Disposition: attachment; filename="pr12352.patch" Content-length: 3332 gdb/ PR tdep/12352 * arm-tdep.c (copy_ldr_str_ldrb_strb): Replace PC with SP in order to store PC value on stack instead of text section. gdb/testsuite/ PR tdep/12352 * gdb.arch/arm-disp-step.S : New test for str instruction. * gdb.arch/arm-disp-step.exp : Likewise. diff --git a/gdb/arm-tdep.c b/gdb/arm-tdep.c index 1f05b7a..ad9b1f4 100644 --- a/gdb/arm-tdep.c +++ b/gdb/arm-tdep.c @@ -5152,7 +5152,7 @@ copy_ldr_str_ldrb_strb (struct gdbarch *gdbarch, uint32_t insn, scratch+12: add r4, r4, #8 (r4 = offset) scratch+16: add r0, r0, r4 scratch+20: str r0, [r2, #imm] (or str r0, [r2, r3]) - scratch+24: + temp can be [sp, -4] Otherwise we don't know what value to write for PC, since the offset is architecture-dependent (sometimes PC+8, sometimes PC+12). */ @@ -5177,8 +5177,8 @@ copy_ldr_str_ldrb_strb (struct gdbarch *gdbarch, uint32_t insn, /* We need to use r4 as scratch. Make sure it's restored afterwards. */ dsc->u.ldst.restore_r4 = 1; - dsc->modinsn[0] = 0xe58ff014; /* str pc, [pc, #20]. */ - dsc->modinsn[1] = 0xe59f4010; /* ldr r4, [pc, #16]. */ + dsc->modinsn[0] = 0xe50df004; /* str pc, [sp, #-4]*/ + dsc->modinsn[1] = 0xe51d4004; /* ldr r4, [sp, #-4]*/ dsc->modinsn[2] = 0xe044400f; /* sub r4, r4, pc. */ dsc->modinsn[3] = 0xe2844008; /* add r4, r4, #8. */ dsc->modinsn[4] = 0xe0800004; /* add r0, r0, r4. */ diff --git a/gdb/testsuite/gdb.arch/arm-disp-step.S b/gdb/testsuite/gdb.arch/arm-disp-step.S index d748718..1aa7df1 100644 --- a/gdb/testsuite/gdb.arch/arm-disp-step.S +++ b/gdb/testsuite/gdb.arch/arm-disp-step.S @@ -48,6 +48,10 @@ test_ret_end: bl test_ldm_stm_pc #endif + /* Test str in ARM mode and Thumb-2 */ +#if !defined(__thumb__) + bl test_str_pc +#endif /* Return */ mov sp, r7 sub sp, sp, #4 @@ -118,3 +122,17 @@ test_ldm_stm_pc_ret: .word test_ldm_stm_pc_ret .size test_ldm_stm_pc, .-test_ldm_stm_pc #endif + +#if !defined(__thumb__) +#if defined (__thumb2__) + .code 16 + .thumb_func +#endif + .global test_str_pc + .type test_str_pc, %function +test_str_pc: + str pc, [sp, #-4] + .global test_str_pc_end +test_str_pc_end: + bx lr +#endif diff --git a/gdb/testsuite/gdb.arch/arm-disp-step.exp b/gdb/testsuite/gdb.arch/arm-disp-step.exp index 826f728..f2df388 100644 --- a/gdb/testsuite/gdb.arch/arm-disp-step.exp +++ b/gdb/testsuite/gdb.arch/arm-disp-step.exp @@ -126,6 +126,29 @@ proc test_ldr_from_pc {} { ".*bx lr.*" } +########################################### + +proc test_str_pc {} { + global srcfile + gdb_test_multiple "break *test_str_pc" "break test_str_pc" { + -re "Breakpoint.*at.* file .*$srcfile, line.*" { + pass "break test_str_pc" + } + -re "No symbol.*" { + pass "break test_str_pc" + return + } + } + gdb_test "break *test_str_pc_end" \ + "Breakpoint.*at.* file .*$srcfile, line.*" \ + "break test_str_pc_end" + + gdb_continue_to_breakpoint "continue to test_str_pc" \ + ".*str.*pc\,.*\[sp, #-4\].*" + gdb_continue_to_breakpoint "continue to test_str_pc_end" \ + ".*bx lr.*" +} + # Get things started. clean_restart ${testfile} @@ -165,6 +188,7 @@ test_ldr_from_pc test_ldm_stm_pc +test_str_pc ########################################## # Done, run program to exit. --------------040107080602090804060708--