From 456ca7ff24841bf2d2a2dfd690fe7d42ef70d932 Mon Sep 17 00:00:00 2001 From: Jason Wessel Date: Thu, 29 Mar 2012 06:55:44 -0500 Subject: kgdbts: Fix kernel oops with CONFIG_DEBUG_RODATA On x86 the kgdb test suite will oops when the kernel is compiled with CONFIG_DEBUG_RODATA and you run the tests after boot time. This is regression has existed since 2.6.26 by commit: b33cb815 (kgdbts: Use HW breakpoints with CONFIG_DEBUG_RODATA). The test suite can use hw breakpoints for all the tests, but it has to execute the hardware breakpoint specific tests first in order to determine that the hw breakpoints actually work. Specifically the very first test causes an oops: # echo V1I1 > /sys/module/kgdbts/parameters/kgdbts kgdb: Registered I/O driver kgdbts. kgdbts:RUN plant and detach test Entering kdb (current=0xffff880017aa9320, pid 1078) on processor 0 due to Keyboard Entry [0]kdb> kgdbts: ERROR PUT: end of test buffer on 'plant_and_detach_test' line 1 expected OK got $E14#aa WARNING: at drivers/misc/kgdbts.c:730 run_simple_test+0x151/0x2c0() [...oops clipped...] This commit re-orders the running of the tests and puts the RODATA check into its own function so as to correctly avoid the kernel oops by detecting and using the hw breakpoints. Cc: # >= 2.6.26 Signed-off-by: Jason Wessel --- drivers/misc/kgdbts.c | 52 +++++++++++++++++++++++++++------------------------ 1 file changed, 28 insertions(+), 24 deletions(-) (limited to 'drivers/misc/kgdbts.c') diff --git a/drivers/misc/kgdbts.c b/drivers/misc/kgdbts.c index 3f7ad83..997e94d 100644 --- a/drivers/misc/kgdbts.c +++ b/drivers/misc/kgdbts.c @@ -885,6 +885,22 @@ static void run_singlestep_break_test(void) kgdbts_break_test(); } +static void test_debug_rodata(void) +{ +#ifdef CONFIG_DEBUG_RODATA + /* Until there is an api to write to read-only text segments, use + * HW breakpoints for the remainder of any tests, else print a + * failure message if hw breakpoints do not work. + */ + if (!(arch_kgdb_ops.flags & KGDB_HW_BREAKPOINT && hwbreaks_ok)) { + eprintk("kgdbts: HW breakpoints BROKEN, ending tests\n"); + return; + } + force_hwbrks = 1; + v1printk("kgdbts:Using HW breakpoints for SW breakpoint tests\n"); +#endif /* CONFIG_DEBUG_RODATA */ +} + static void kgdbts_run_tests(void) { char *ptr; @@ -907,6 +923,18 @@ static void kgdbts_run_tests(void) if (ptr) sstep_test = simple_strtol(ptr+1, NULL, 10); + /* All HW break point tests */ + if (arch_kgdb_ops.flags & KGDB_HW_BREAKPOINT) { + hwbreaks_ok = 1; + v1printk("kgdbts:RUN hw breakpoint test\n"); + run_breakpoint_test(1); + v1printk("kgdbts:RUN hw write breakpoint test\n"); + run_hw_break_test(1); + v1printk("kgdbts:RUN access write breakpoint test\n"); + run_hw_break_test(0); + } + test_debug_rodata(); + /* required internal KGDB tests */ v1printk("kgdbts:RUN plant and detach test\n"); run_plant_and_detach_test(0); @@ -924,35 +952,11 @@ static void kgdbts_run_tests(void) /* ===Optional tests=== */ - /* All HW break point tests */ - if (arch_kgdb_ops.flags & KGDB_HW_BREAKPOINT) { - hwbreaks_ok = 1; - v1printk("kgdbts:RUN hw breakpoint test\n"); - run_breakpoint_test(1); - v1printk("kgdbts:RUN hw write breakpoint test\n"); - run_hw_break_test(1); - v1printk("kgdbts:RUN access write breakpoint test\n"); - run_hw_break_test(0); - } - if (nmi_sleep) { v1printk("kgdbts:RUN NMI sleep %i seconds test\n", nmi_sleep); run_nmi_sleep_test(nmi_sleep); } -#ifdef CONFIG_DEBUG_RODATA - /* Until there is an api to write to read-only text segments, use - * HW breakpoints for the remainder of any tests, else print a - * failure message if hw breakpoints do not work. - */ - if (!(arch_kgdb_ops.flags & KGDB_HW_BREAKPOINT && hwbreaks_ok)) { - eprintk("kgdbts: HW breakpoints do not work," - "skipping remaining tests\n"); - return; - } - force_hwbrks = 1; -#endif /* CONFIG_DEBUG_RODATA */ - /* If the do_fork test is run it will be the last test that is * executed because a kernel thread will be spawned at the very * end to unregister the debug hooks. -- cgit v1.1 From 486c5987a00a89d56c2c04c506417ef8f823ca2e Mon Sep 17 00:00:00 2001 From: Jason Wessel Date: Thu, 29 Mar 2012 17:41:24 -0500 Subject: kgdbts: (1 of 2) fix single step awareness to work correctly with SMP The do_fork and sys_open tests have never worked properly on anything other than a UP configuration with the kgdb test suite. This is because the test suite did not fully implement the behavior of a real debugger. A real debugger tracks the state of what thread it asked to single step and can correctly continue other threads of execution or conditionally stop while waiting for the original thread single step request to return. Below is a simple method to cause a fatal kernel oops with the kgdb test suite on a 4 processor x86 system: while [ 1 ] ; do ls > /dev/null 2> /dev/null; done& while [ 1 ] ; do ls > /dev/null 2> /dev/null; done& while [ 1 ] ; do ls > /dev/null 2> /dev/null; done& while [ 1 ] ; do ls > /dev/null 2> /dev/null; done& echo V1I1F1000 > /sys/module/kgdbts/parameters/kgdbts Very soon after starting the test the kernel will oops with a message like: kgdbts: BP mismatch 3b7da66480 expected ffffffff8106a590 WARNING: at drivers/misc/kgdbts.c:303 check_and_rewind_pc+0xe0/0x100() Call Trace: [] check_and_rewind_pc+0xe0/0x100 [] validate_simple_test+0x25/0xc0 [] run_simple_test+0x107/0x2c0 [] kgdbts_put_char+0x18/0x20 The warn will turn to a hard kernel crash shortly after that because the pc will not get properly rewound to the right value after hitting a breakpoint leading to a hard lockup. This change is broken up into 2 pieces because archs that have hw single stepping (2.6.26 and up) need different changes than archs that do not have hw single stepping (3.0 and up). This change implements the correct behavior for an arch that supports hw single stepping. A minor defect was fixed where sys_open should be do_sys_open for the sys_open break point test. This solves the problem of running a 64 bit with a 32 bit user space. The sys_open() never gets called when using the 32 bit file system for the kgdb testsuite because the 32 bit binaries invoke the compat_sys_open() call leading to the test never completing. In order to mimic a real debugger, the kgdb test suite now tracks the most recent thread that was continued (cont_thread_id), with the intent to single step just this thread. When the response to the single step request stops in a different thread that hit the original break point that thread will now get continued, while the debugger waits for the thread with the single step pending. Here is a high level description of the sequence of events. cont_instead_of_sstep = 0; 1) set breakpoint at do_fork 2) continue 3) Save the thread id where we stop to cont_thread_id 4) Remove breakpoint at do_fork 5) Reset the PC if needed depending on kernel exception type 6) if (cont_instead_of_sstep) { continue } else { single step } 7) Check where we stopped if current thread != cont_thread_id { cont_instead_of_sstep = 1; goto step 5 } else { cont_instead_of_sstep = 0; } 8) clean up and run test again if needed Cc: stable@vger.kernel.org # >= 2.6.26 Signed-off-by: Jason Wessel --- drivers/misc/kgdbts.c | 54 ++++++++++++++++++++++++++++++++++++++++----------- 1 file changed, 43 insertions(+), 11 deletions(-) (limited to 'drivers/misc/kgdbts.c') diff --git a/drivers/misc/kgdbts.c b/drivers/misc/kgdbts.c index 997e94d..3cad9fc 100644 --- a/drivers/misc/kgdbts.c +++ b/drivers/misc/kgdbts.c @@ -134,6 +134,9 @@ static int force_hwbrks; static int hwbreaks_ok; static int hw_break_val; static int hw_break_val2; +static int cont_instead_of_sstep; +static unsigned long cont_thread_id; +static unsigned long sstep_thread_id; #if defined(CONFIG_ARM) || defined(CONFIG_MIPS) || defined(CONFIG_SPARC) static int arch_needs_sstep_emulation = 1; #else @@ -211,7 +214,7 @@ static unsigned long lookup_addr(char *arg) if (!strcmp(arg, "kgdbts_break_test")) addr = (unsigned long)kgdbts_break_test; else if (!strcmp(arg, "sys_open")) - addr = (unsigned long)sys_open; + addr = (unsigned long)do_sys_open; else if (!strcmp(arg, "do_fork")) addr = (unsigned long)do_fork; else if (!strcmp(arg, "hw_break_val")) @@ -283,6 +286,16 @@ static void hw_break_val_write(void) hw_break_val++; } +static int get_thread_id_continue(char *put_str, char *arg) +{ + char *ptr = &put_str[11]; + + if (put_str[1] != 'T' || put_str[2] != '0') + return 1; + kgdb_hex2long(&ptr, &cont_thread_id); + return 0; +} + static int check_and_rewind_pc(char *put_str, char *arg) { unsigned long addr = lookup_addr(arg); @@ -324,6 +337,18 @@ static int check_single_step(char *put_str, char *arg) gdb_regs_to_pt_regs(kgdbts_gdb_regs, &kgdbts_regs); v2printk("Singlestep stopped at IP: %lx\n", instruction_pointer(&kgdbts_regs)); + + if (sstep_thread_id != cont_thread_id && !arch_needs_sstep_emulation) { + /* + * Ensure we stopped in the same thread id as before, else the + * debugger should continue until the original thread that was + * single stepped is scheduled again, emulating gdb's behavior. + */ + v2printk("ThrID does not match: %lx\n", cont_thread_id); + cont_instead_of_sstep = 1; + ts.idx -= 4; + return 0; + } if (instruction_pointer(&kgdbts_regs) == addr) { eprintk("kgdbts: SingleStep failed at %lx\n", instruction_pointer(&kgdbts_regs)); @@ -368,7 +393,12 @@ static int got_break(char *put_str, char *arg) static void emul_sstep_get(char *arg) { if (!arch_needs_sstep_emulation) { - fill_get_buf(arg); + if (cont_instead_of_sstep) { + cont_instead_of_sstep = 0; + fill_get_buf("c"); + } else { + fill_get_buf(arg); + } return; } switch (sstep_state) { @@ -398,9 +428,11 @@ static void emul_sstep_get(char *arg) static int emul_sstep_put(char *put_str, char *arg) { if (!arch_needs_sstep_emulation) { - if (!strncmp(put_str+1, arg, 2)) - return 0; - return 1; + char *ptr = &put_str[11]; + if (put_str[1] != 'T' || put_str[2] != '0') + return 1; + kgdb_hex2long(&ptr, &sstep_thread_id); + return 0; } switch (sstep_state) { case 1: @@ -502,10 +534,10 @@ static struct test_struct bad_read_test[] = { static struct test_struct singlestep_break_test[] = { { "?", "S0*" }, /* Clear break points */ { "kgdbts_break_test", "OK", sw_break, }, /* set sw breakpoint */ - { "c", "T0*", }, /* Continue */ + { "c", "T0*", NULL, get_thread_id_continue }, /* Continue */ + { "kgdbts_break_test", "OK", sw_rem_break }, /*remove breakpoint */ { "g", "kgdbts_break_test", NULL, check_and_rewind_pc }, { "write", "OK", write_regs }, /* Write registers */ - { "kgdbts_break_test", "OK", sw_rem_break }, /*remove breakpoint */ { "s", "T0*", emul_sstep_get, emul_sstep_put }, /* Single step */ { "g", "kgdbts_break_test", NULL, check_single_step }, { "kgdbts_break_test", "OK", sw_break, }, /* set sw breakpoint */ @@ -523,10 +555,10 @@ static struct test_struct singlestep_break_test[] = { static struct test_struct do_fork_test[] = { { "?", "S0*" }, /* Clear break points */ { "do_fork", "OK", sw_break, }, /* set sw breakpoint */ - { "c", "T0*", }, /* Continue */ + { "c", "T0*", NULL, get_thread_id_continue }, /* Continue */ + { "do_fork", "OK", sw_rem_break }, /*remove breakpoint */ { "g", "do_fork", NULL, check_and_rewind_pc }, /* check location */ { "write", "OK", write_regs }, /* Write registers */ - { "do_fork", "OK", sw_rem_break }, /*remove breakpoint */ { "s", "T0*", emul_sstep_get, emul_sstep_put }, /* Single step */ { "g", "do_fork", NULL, check_single_step }, { "do_fork", "OK", sw_break, }, /* set sw breakpoint */ @@ -541,10 +573,10 @@ static struct test_struct do_fork_test[] = { static struct test_struct sys_open_test[] = { { "?", "S0*" }, /* Clear break points */ { "sys_open", "OK", sw_break, }, /* set sw breakpoint */ - { "c", "T0*", }, /* Continue */ + { "c", "T0*", NULL, get_thread_id_continue }, /* Continue */ + { "sys_open", "OK", sw_rem_break }, /*remove breakpoint */ { "g", "sys_open", NULL, check_and_rewind_pc }, /* check location */ { "write", "OK", write_regs }, /* Write registers */ - { "sys_open", "OK", sw_rem_break }, /*remove breakpoint */ { "s", "T0*", emul_sstep_get, emul_sstep_put }, /* Single step */ { "g", "sys_open", NULL, check_single_step }, { "sys_open", "OK", sw_break, }, /* set sw breakpoint */ -- cgit v1.1 From 23bbd8e346f1ef3fc1219c79cea53d8d52b207d8 Mon Sep 17 00:00:00 2001 From: Jason Wessel Date: Thu, 29 Mar 2012 17:41:24 -0500 Subject: kgdbts: (2 of 2) fix single step awareness to work correctly with SMP The do_fork and sys_open tests have never worked properly on anything other than a UP configuration with the kgdb test suite. This is because the test suite did not fully implement the behavior of a real debugger. A real debugger tracks the state of what thread it asked to single step and can correctly continue other threads of execution or conditionally stop while waiting for the original thread single step request to return. Below is a simple method to cause a fatal kernel oops with the kgdb test suite on a 2 processor ARM system: while [ 1 ] ; do ls > /dev/null 2> /dev/null; done& while [ 1 ] ; do ls > /dev/null 2> /dev/null; done& echo V1I1F100 > /sys/module/kgdbts/parameters/kgdbts Very soon after starting the test the kernel will start warning with messages like: kgdbts: BP mismatch c002487c expected c0024878 ------------[ cut here ]------------ WARNING: at drivers/misc/kgdbts.c:317 check_and_rewind_pc+0x9c/0xc4() [] (check_and_rewind_pc+0x9c/0xc4) [] (validate_simple_test+0x3c/0xc4) [] (run_simple_test+0x1e8/0x274) The kernel will eventually recovers, but the test suite has completely failed to test anything useful. This patch implements behavior similar to a real debugger that does not rely on hardware single stepping by using only software planted breakpoints. In order to mimic a real debugger, the kgdb test suite now tracks the most recent thread that was continued (cont_thread_id), with the intent to single step just this thread. When the response to the single step request stops in a different thread that hit the original break point that thread will now get continued, while the debugger waits for the thread with the single step pending. Here is a high level description of the sequence of events. cont_instead_of_sstep = 0; 1) set breakpoint at do_fork 2) continue 3) Save the thread id where we stop to cont_thread_id 4) Remove breakpoint at do_fork 5) Reset the PC if needed depending on kernel exception type 6) soft single step 7) Check where we stopped if current thread != cont_thread_id { if (here for more than 2 times for the same thead) { ### must be a really busy system, start test again ### goto step 1 } goto step 5 } else { cont_instead_of_sstep = 0; } 8) clean up and run test again if needed 9) Clear out any threads that were waiting on a break point at the point in time the test is ended with get_cont_catch(). This happens sometimes because breakpoints are used in place of single stepping and some threads could have been in the debugger exception handling queue because breakpoints were hit concurrently on different CPUs. This also means we wait at least one second before unplumbing the debugger connection at the very end, so as respond to any debug threads waiting to be serviced. Cc: stable@vger.kernel.org # >= 3.0 Signed-off-by: Jason Wessel --- drivers/misc/kgdbts.c | 73 +++++++++++++++++++++++++++++++++++++++++++-------- 1 file changed, 62 insertions(+), 11 deletions(-) (limited to 'drivers/misc/kgdbts.c') diff --git a/drivers/misc/kgdbts.c b/drivers/misc/kgdbts.c index 3cad9fc..d087456 100644 --- a/drivers/misc/kgdbts.c +++ b/drivers/misc/kgdbts.c @@ -142,7 +142,9 @@ static int arch_needs_sstep_emulation = 1; #else static int arch_needs_sstep_emulation; #endif +static unsigned long cont_addr; static unsigned long sstep_addr; +static int restart_from_top_after_write; static int sstep_state; /* Storage for the registers, in GDB format. */ @@ -190,7 +192,8 @@ static int kgdbts_unreg_thread(void *ptr) */ while (!final_ack) msleep_interruptible(1500); - + /* Pause for any other threads to exit after final ack. */ + msleep_interruptible(1000); if (configured) kgdb_unregister_io_module(&kgdbts_io_ops); configured = 0; @@ -312,13 +315,21 @@ static int check_and_rewind_pc(char *put_str, char *arg) if (addr + BREAK_INSTR_SIZE == ip) offset = -BREAK_INSTR_SIZE; #endif - if (strcmp(arg, "silent") && ip + offset != addr) { + + if (arch_needs_sstep_emulation && sstep_addr && + ip + offset == sstep_addr && + ((!strcmp(arg, "sys_open") || !strcmp(arg, "do_fork")))) { + /* This is special case for emulated single step */ + v2printk("Emul: rewind hit single step bp\n"); + restart_from_top_after_write = 1; + } else if (strcmp(arg, "silent") && ip + offset != addr) { eprintk("kgdbts: BP mismatch %lx expected %lx\n", ip + offset, addr); return 1; } /* Readjust the instruction pointer if needed */ ip += offset; + cont_addr = ip; #ifdef GDB_ADJUSTS_BREAK_OFFSET instruction_pointer_set(&kgdbts_regs, ip); #endif @@ -328,6 +339,8 @@ static int check_and_rewind_pc(char *put_str, char *arg) static int check_single_step(char *put_str, char *arg) { unsigned long addr = lookup_addr(arg); + static int matched_id; + /* * From an arch indepent point of view the instruction pointer * should be on a different instruction @@ -338,17 +351,28 @@ static int check_single_step(char *put_str, char *arg) v2printk("Singlestep stopped at IP: %lx\n", instruction_pointer(&kgdbts_regs)); - if (sstep_thread_id != cont_thread_id && !arch_needs_sstep_emulation) { + if (sstep_thread_id != cont_thread_id) { /* * Ensure we stopped in the same thread id as before, else the * debugger should continue until the original thread that was * single stepped is scheduled again, emulating gdb's behavior. */ v2printk("ThrID does not match: %lx\n", cont_thread_id); + if (arch_needs_sstep_emulation) { + if (matched_id && + instruction_pointer(&kgdbts_regs) != addr) + goto continue_test; + matched_id++; + ts.idx -= 2; + sstep_state = 0; + return 0; + } cont_instead_of_sstep = 1; ts.idx -= 4; return 0; } +continue_test: + matched_id = 0; if (instruction_pointer(&kgdbts_regs) == addr) { eprintk("kgdbts: SingleStep failed at %lx\n", instruction_pointer(&kgdbts_regs)); @@ -390,6 +414,31 @@ static int got_break(char *put_str, char *arg) return 1; } +static void get_cont_catch(char *arg) +{ + /* Always send detach because the test is completed at this point */ + fill_get_buf("D"); +} + +static int put_cont_catch(char *put_str, char *arg) +{ + /* This is at the end of the test and we catch any and all input */ + v2printk("kgdbts: cleanup task: %lx\n", sstep_thread_id); + ts.idx--; + return 0; +} + +static int emul_reset(char *put_str, char *arg) +{ + if (strncmp(put_str, "$OK", 3)) + return 1; + if (restart_from_top_after_write) { + restart_from_top_after_write = 0; + ts.idx = -1; + } + return 0; +} + static void emul_sstep_get(char *arg) { if (!arch_needs_sstep_emulation) { @@ -443,8 +492,7 @@ static int emul_sstep_put(char *put_str, char *arg) v2printk("Stopped at IP: %lx\n", instruction_pointer(&kgdbts_regs)); /* Want to stop at IP + break instruction size by default */ - sstep_addr = instruction_pointer(&kgdbts_regs) + - BREAK_INSTR_SIZE; + sstep_addr = cont_addr + BREAK_INSTR_SIZE; break; case 2: if (strncmp(put_str, "$OK", 3)) { @@ -456,6 +504,9 @@ static int emul_sstep_put(char *put_str, char *arg) if (strncmp(put_str, "$T0", 3)) { eprintk("kgdbts: failed continue sstep\n"); return 1; + } else { + char *ptr = &put_str[11]; + kgdb_hex2long(&ptr, &sstep_thread_id); } break; case 4: @@ -558,13 +609,13 @@ static struct test_struct do_fork_test[] = { { "c", "T0*", NULL, get_thread_id_continue }, /* Continue */ { "do_fork", "OK", sw_rem_break }, /*remove breakpoint */ { "g", "do_fork", NULL, check_and_rewind_pc }, /* check location */ - { "write", "OK", write_regs }, /* Write registers */ + { "write", "OK", write_regs, emul_reset }, /* Write registers */ { "s", "T0*", emul_sstep_get, emul_sstep_put }, /* Single step */ { "g", "do_fork", NULL, check_single_step }, { "do_fork", "OK", sw_break, }, /* set sw breakpoint */ { "7", "T0*", skip_back_repeat_test }, /* Loop based on repeat_test */ { "D", "OK", NULL, final_ack_set }, /* detach and unregister I/O */ - { "", "" }, + { "", "", get_cont_catch, put_cont_catch }, }; /* Test for hitting a breakpoint at sys_open for what ever the number @@ -576,13 +627,13 @@ static struct test_struct sys_open_test[] = { { "c", "T0*", NULL, get_thread_id_continue }, /* Continue */ { "sys_open", "OK", sw_rem_break }, /*remove breakpoint */ { "g", "sys_open", NULL, check_and_rewind_pc }, /* check location */ - { "write", "OK", write_regs }, /* Write registers */ + { "write", "OK", write_regs, emul_reset }, /* Write registers */ { "s", "T0*", emul_sstep_get, emul_sstep_put }, /* Single step */ { "g", "sys_open", NULL, check_single_step }, { "sys_open", "OK", sw_break, }, /* set sw breakpoint */ { "7", "T0*", skip_back_repeat_test }, /* Loop based on repeat_test */ { "D", "OK", NULL, final_ack_set }, /* detach and unregister I/O */ - { "", "" }, + { "", "", get_cont_catch, put_cont_catch }, }; /* @@ -725,8 +776,8 @@ static int run_simple_test(int is_get_char, int chr) /* This callback is a put char which is when kgdb sends data to * this I/O module. */ - if (ts.tst[ts.idx].get[0] == '\0' && - ts.tst[ts.idx].put[0] == '\0') { + if (ts.tst[ts.idx].get[0] == '\0' && ts.tst[ts.idx].put[0] == '\0' && + !ts.tst[ts.idx].get_handler) { eprintk("kgdbts: ERROR: beyond end of test on" " '%s' line %i\n", ts.name, ts.idx); return 0; -- cgit v1.1 From 3751d3e85cf693e10e2c47c03c8caa65e171099b Mon Sep 17 00:00:00 2001 From: Jason Wessel Date: Fri, 23 Mar 2012 09:35:05 -0500 Subject: x86,kgdb: Fix DEBUG_RODATA limitation using text_poke() There has long been a limitation using software breakpoints with a kernel compiled with CONFIG_DEBUG_RODATA going back to 2.6.26. For this particular patch, it will apply cleanly and has been tested all the way back to 2.6.36. The kprobes code uses the text_poke() function which accommodates writing a breakpoint into a read-only page. The x86 kgdb code can solve the problem similarly by overriding the default breakpoint set/remove routines and using text_poke() directly. The x86 kgdb code will first attempt to use the traditional probe_kernel_write(), and next try using a the text_poke() function. The break point install method is tracked such that the correct break point removal routine will get called later on. Cc: x86@kernel.org Cc: Thomas Gleixner Cc: Ingo Molnar Cc: H. Peter Anvin Cc: stable@vger.kernel.org # >= 2.6.36 Inspried-by: Masami Hiramatsu Signed-off-by: Jason Wessel --- drivers/misc/kgdbts.c | 17 ----------------- 1 file changed, 17 deletions(-) (limited to 'drivers/misc/kgdbts.c') diff --git a/drivers/misc/kgdbts.c b/drivers/misc/kgdbts.c index d087456..3aa9a96 100644 --- a/drivers/misc/kgdbts.c +++ b/drivers/misc/kgdbts.c @@ -968,22 +968,6 @@ static void run_singlestep_break_test(void) kgdbts_break_test(); } -static void test_debug_rodata(void) -{ -#ifdef CONFIG_DEBUG_RODATA - /* Until there is an api to write to read-only text segments, use - * HW breakpoints for the remainder of any tests, else print a - * failure message if hw breakpoints do not work. - */ - if (!(arch_kgdb_ops.flags & KGDB_HW_BREAKPOINT && hwbreaks_ok)) { - eprintk("kgdbts: HW breakpoints BROKEN, ending tests\n"); - return; - } - force_hwbrks = 1; - v1printk("kgdbts:Using HW breakpoints for SW breakpoint tests\n"); -#endif /* CONFIG_DEBUG_RODATA */ -} - static void kgdbts_run_tests(void) { char *ptr; @@ -1016,7 +1000,6 @@ static void kgdbts_run_tests(void) v1printk("kgdbts:RUN access write breakpoint test\n"); run_hw_break_test(0); } - test_debug_rodata(); /* required internal KGDB tests */ v1printk("kgdbts:RUN plant and detach test\n"); -- cgit v1.1