diff options
Diffstat (limited to 'arch/arm/mm/alignment.c')
| -rw-r--r-- | arch/arm/mm/alignment.c | 27 |
1 files changed, 24 insertions, 3 deletions
diff --git a/arch/arm/mm/alignment.c b/arch/arm/mm/alignment.c index 133e65d166b3..3a398befed41 100644 --- a/arch/arm/mm/alignment.c +++ b/arch/arm/mm/alignment.c @@ -17,6 +17,7 @@ #include <linux/string.h> #include <linux/proc_fs.h> #include <linux/init.h> +#include <linux/sched.h> #include <linux/uaccess.h> #include <asm/unaligned.h> @@ -70,6 +71,10 @@ static unsigned long ai_dword; static unsigned long ai_multi; static int ai_usermode; +#define UM_WARN (1 << 0) +#define UM_FIXUP (1 << 1) +#define UM_SIGNAL (1 << 2) + #ifdef CONFIG_PROC_FS static const char *usermode_action[] = { "ignored", @@ -754,7 +759,7 @@ do_alignment(unsigned long addr, unsigned int fsr, struct pt_regs *regs) user: ai_user += 1; - if (ai_usermode & 1) + if (ai_usermode & UM_WARN) printk("Alignment trap: %s (%d) PC=0x%08lx Instr=0x%0*lx " "Address=0x%08lx FSR 0x%03x\n", current->comm, task_pid_nr(current), instrptr, @@ -762,10 +767,10 @@ do_alignment(unsigned long addr, unsigned int fsr, struct pt_regs *regs) thumb_mode(regs) ? tinstr : instr, addr, fsr); - if (ai_usermode & 2) + if (ai_usermode & UM_FIXUP) goto fixup; - if (ai_usermode & 4) + if (ai_usermode & UM_SIGNAL) force_sig(SIGBUS, current); else set_cr(cr_no_alignment); @@ -796,6 +801,22 @@ static int __init alignment_init(void) res->write_proc = proc_alignment_write; #endif + /* + * ARMv6 and later CPUs can perform unaligned accesses for + * most single load and store instructions up to word size. + * LDM, STM, LDRD and STRD still need to be handled. + * + * Ignoring the alignment fault is not an option on these + * CPUs since we spin re-faulting the instruction without + * making any progress. + */ + if (cpu_architecture() >= CPU_ARCH_ARMv6 && (cr_alignment & CR_U)) { + cr_alignment &= ~CR_A; + cr_no_alignment &= ~CR_A; + set_cr(cr_alignment); + ai_usermode = UM_FIXUP; + } + hook_fault_code(1, do_alignment, SIGILL, "alignment exception"); hook_fault_code(3, do_alignment, SIGILL, "alignment exception"); |