diff options
| author | Jason Wessel <jason.wessel@windriver.com> | 2012-03-23 09:35:05 -0500 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2012-04-13 08:33:48 -0700 |
| commit | fdf8d98d89726f435f4d7f89fc898340c2f47bc9 (patch) | |
| tree | aa35623a48796d23ba8861abeb28283aa57cff94 /drivers/misc | |
| parent | 706e51dedb8c4d05cf9f4feb1cfecc3d5618f2bf (diff) | |
x86,kgdb: Fix DEBUG_RODATA limitation using text_poke()
commit 3751d3e85cf693e10e2c47c03c8caa65e171099b upstream.
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 <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Inspried-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/misc')
| -rw-r--r-- | drivers/misc/kgdbts.c | 17 |
1 files changed, 0 insertions, 17 deletions
diff --git a/drivers/misc/kgdbts.c b/drivers/misc/kgdbts.c index d087456ba089..3aa9a969b373 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"); |