From ef713951c571c8490ca57c17c88785c6df1ed840 Mon Sep 17 00:00:00 2001 From: Yao Qi Date: Fri, 10 Apr 2015 10:33:01 +0100 Subject: [PATCH] [arm] Fix displaced stepping for thumb alu reg instruction Recent patch series "V2 All-stop on top of non-stop" causes a SIGSEGV in the test case, > -PASS: gdb.base/info-shared.exp: continue to breakpoint: library function #4 > +FAIL: gdb.base/info-shared.exp: continue to breakpoint: library function #4 > > continue^M > Continuing.^M > ^M > Program received signal SIGSEGV, Segmentation fault.^M > 0x40021564 in ?? () gdb/testsuite/gdb.base/info-shared-solib1.so^M > (gdb) FAIL: gdb.base/info-shared.exp: continue to breakpoint: library function #4 and an ARM displaced stepping bug is exposed. It can be reproduced by the modified gdb.arch/arm-disp-step.exp as below, continue^M Continuing.^M ^M Program received signal SIGSEGV, Segmentation fault.^M 0xa713cfcc in ?? ()^M (gdb) FAIL: gdb.arch/arm-disp-step.exp: continue to breakpoint: continue to test_add_rn_pc_end This patch is to fix it. gdb: 2015-04-10 Yao Qi * arm-tdep.c (install_alu_reg): Update comment. (thumb_copy_alu_reg): Remove local variable rn. Update debugging message. Use r2 instead of r1 in the modified instruction. gdb/testsuite: 2015-04-10 Yao Qi * gdb.arch/arm-disp-step.S (main): Call test_add_rn_pc. (test_add_rn_pc): New function. * gdb.arch/arm-disp-step.exp (test_add_rn_pc): New proc. (top level): Invoke test_add_rn_pc. --- gdb/ChangeLog | 7 ++++++ gdb/arm-tdep.c | 19 +++++++-------- gdb/testsuite/ChangeLog | 7 ++++++ gdb/testsuite/gdb.arch/arm-disp-step.S | 19 +++++++++++++++ gdb/testsuite/gdb.arch/arm-disp-step.exp | 41 ++++++++++++++++++++++++++++++++ 5 files changed, 83 insertions(+), 10 deletions(-) diff --git a/gdb/ChangeLog b/gdb/ChangeLog index cedf0c5..be8eabb 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,3 +1,10 @@ +2015-04-10 Yao Qi + + * arm-tdep.c (install_alu_reg): Update comment. + (thumb_copy_alu_reg): Remove local variable rn. Update + debugging message. Use r2 instead of r1 in the modified + instruction. + 2015-04-10 Pedro Alves PR gdb/13858 diff --git a/gdb/arm-tdep.c b/gdb/arm-tdep.c index 630a207..8181f25 100644 --- a/gdb/arm-tdep.c +++ b/gdb/arm-tdep.c @@ -6407,7 +6407,7 @@ install_alu_reg (struct gdbarch *gdbarch, struct regcache *regs, Preparation: tmp1, tmp2, tmp3 <- r0, r1, r2; r0, r1, r2 <- rd, rn, rm - Insn: r0, r1, r2 [, ] + Insn: r0, [r1,] r2 [, ] Cleanup: rd <- r0; r0, r1, r2 <- tmp1, tmp2, tmp3 */ @@ -6454,22 +6454,21 @@ thumb_copy_alu_reg (struct gdbarch *gdbarch, uint16_t insn, struct regcache *regs, struct displaced_step_closure *dsc) { - unsigned rn, rm, rd; + unsigned rm, rd; - rd = bits (insn, 3, 6); - rn = (bit (insn, 7) << 3) | bits (insn, 0, 2); - rm = 2; + rm = bits (insn, 3, 6); + rd = (bit (insn, 7) << 3) | bits (insn, 0, 2); - if (rd != ARM_PC_REGNUM && rn != ARM_PC_REGNUM) + if (rd != ARM_PC_REGNUM && rm != ARM_PC_REGNUM) return thumb_copy_unmodified_16bit (gdbarch, insn, "ALU reg", dsc); if (debug_displaced) - fprintf_unfiltered (gdb_stdlog, "displaced: copying reg %s insn %.4x\n", - "ALU", (unsigned short) insn); + fprintf_unfiltered (gdb_stdlog, "displaced: copying ALU reg insn %.4x\n", + (unsigned short) insn); - dsc->modinsn[0] = ((insn & 0xff00) | 0x08); + dsc->modinsn[0] = ((insn & 0xff00) | 0x10); - install_alu_reg (gdbarch, regs, dsc, rd, rn, rm); + install_alu_reg (gdbarch, regs, dsc, rd, rd, rm); return 0; } diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog index 39f2f69..2d19d45 100644 --- a/gdb/testsuite/ChangeLog +++ b/gdb/testsuite/ChangeLog @@ -1,3 +1,10 @@ +2015-04-10 Yao Qi + + * gdb.arch/arm-disp-step.S (main): Call test_add_rn_pc. + (test_add_rn_pc): New function. + * gdb.arch/arm-disp-step.exp (test_add_rn_pc): New proc. + (top level): Invoke test_add_rn_pc. + 2015-04-10 Pedro Alves PR gdb/13858 diff --git a/gdb/testsuite/gdb.arch/arm-disp-step.S b/gdb/testsuite/gdb.arch/arm-disp-step.S index c9c9447..c3b1088 100644 --- a/gdb/testsuite/gdb.arch/arm-disp-step.S +++ b/gdb/testsuite/gdb.arch/arm-disp-step.S @@ -78,6 +78,11 @@ test_ret_end: #if !defined(__thumb__) bl test_str_pc #endif + + /* Test add with pc in Thumb and Thumb-2 */ +#if defined(__thumb__) + bl test_add_rn_pc +#endif /* Return */ mov sp, r7 sub sp, sp, #4 @@ -372,3 +377,17 @@ pc_offset_wrong: test_str_pc_end: bx lr #endif + +#if defined(__thumb__) + .global test_add_rn_pc + .code 16 + .thumb_func +test_add_rn_pc: + mov r3, 4 +test_add_rn_pc_start: + add r3, pc + .global test_add_rn_pc_end +test_add_rn_pc_end: + bx lr + .size test_add_rn_pc, .-test_add_rn_pc +#endif diff --git a/gdb/testsuite/gdb.arch/arm-disp-step.exp b/gdb/testsuite/gdb.arch/arm-disp-step.exp index 7eac4d1..e191f73 100644 --- a/gdb/testsuite/gdb.arch/arm-disp-step.exp +++ b/gdb/testsuite/gdb.arch/arm-disp-step.exp @@ -371,6 +371,45 @@ proc test_str_pc {} { ".*bx lr.*" } +# Test 16 bit thumb instruction 'add rd, pc'. + +proc test_add_rn_pc {} { + global srcfile gdb_prompt + + set test "break test_add_rn_pc" + gdb_test_multiple "break *test_add_rn_pc" $test { + -re "Breakpoint.*at.* file .*$srcfile, line.*\r\n$gdb_prompt $" { + pass $test + } + -re "No symbol.*\r\n$gdb_prompt $" { + return + } + } + + gdb_continue_to_breakpoint "continue to test_add_rn_pc" \ + ".*mov.*r3, 4.*" + + gdb_test "break *test_add_rn_pc_start" \ + "Breakpoint.*at.* file .*$srcfile, line.*" \ + "break test_add_rn_pc_start" + + gdb_continue_to_breakpoint "continue to test_add_rn_pc_start" \ + ".*add.*r3,.*pc.*" + + set pc_val [get_integer_valueof "\$pc" 0] + + gdb_test "break *test_add_rn_pc_end" \ + "Breakpoint.*at.* file .*$srcfile, line.*" \ + "break test_add_rn_pc_end" + + gdb_continue_to_breakpoint "continue to test_add_rn_pc_end" \ + ".*bx lr.*" + + set r3_val [get_integer_valueof "\$r3" 0] + # Test the value in r3 is correct. + gdb_assert { [expr {$pc_val + 4 + 4} == $r3_val] } +} + # Get things started. clean_restart ${testfile} @@ -410,6 +449,8 @@ test_pop_pc test_str_pc +test_add_rn_pc + ########################################## # Done, run program to exit. -- 2.7.4