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') diff --git a/drivers/misc/kgdbts.c b/drivers/misc/kgdbts.c index d087456ba08..3aa9a969b37 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 v1.2.3