2008-04-27 19:56:19 +03:00
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Change the default alingment handling to not be silent failure
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2009-02-08 21:36:13 +02:00
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--- a/arch/arm/mm/alignment.c
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+++ b/arch/arm/mm/alignment.c
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2008-04-27 19:56:19 +03:00
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@@ -797,6 +797,8 @@ static int __init alignment_init(void)
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res->write_proc = proc_alignment_write;
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#endif
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+ ai_usermode = CONFIG_ALIGNMENT_HANDLING;
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+
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hook_fault_code(1, do_alignment, SIGILL, "alignment exception");
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hook_fault_code(3, do_alignment, SIGILL, "alignment exception");
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2009-02-08 21:36:13 +02:00
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--- a/arch/arm/Kconfig
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+++ b/arch/arm/Kconfig
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2008-04-27 19:56:19 +03:00
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@@ -709,6 +709,19 @@ config ALIGNMENT_TRAP
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correct operation of some network protocols. With an IP-only
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configuration it is safe to say N, otherwise say Y.
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+config ALIGNMENT_HANDLING
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+ hex "Userspace alignment trap handling"
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+ default "0x3"
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+ depends on ALIGNMENT_TRAP
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+ help
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+ How should we handle alignment errors in userspace by default? This is a bitfield where:
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+ 0 - silently ignore alignment errors (will lead to unexpected results)
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+ 1 - report alignment errors through printk (will lead to unexpected results, but you'll know about them)
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+ 2 - fix the alignment and make things work properly (performance degradation for un-aligned code)
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+ 4 - raise SIGBUS on alignment traps
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+ A good number to choose is probably either 3 (work slowly but log message) or 5 (log message and SIGBUS).
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+ You can change the behavior at runtime through /proc/cpu/alignment if you have PROC_FS enabled.
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+
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endmenu
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menu "Boot options"
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