diff options
Diffstat (limited to 'arch/arm/kernel/traps.c')
| -rw-r--r-- | arch/arm/kernel/traps.c | 63 |
1 files changed, 58 insertions, 5 deletions
diff --git a/arch/arm/kernel/traps.c b/arch/arm/kernel/traps.c index 3a001fe5540b..45d2a032d890 100644 --- a/arch/arm/kernel/traps.c +++ b/arch/arm/kernel/traps.c @@ -218,7 +218,8 @@ NORET_TYPE void die(const char *str, struct pt_regs *regs, int err) tsk->comm, tsk->pid, tsk->thread_info + 1); if (!user_mode(regs) || in_interrupt()) { - dump_mem("Stack: ", regs->ARM_sp, 8192+(unsigned long)tsk->thread_info); + dump_mem("Stack: ", regs->ARM_sp, + THREAD_SIZE + (unsigned long)tsk->thread_info); dump_backtrace(regs, tsk); dump_instr(regs); } @@ -450,9 +451,9 @@ asmlinkage int arm_syscall(int no, struct pt_regs *regs) case NR(set_tls): thread->tp_value = regs->ARM_r0; -#ifdef CONFIG_HAS_TLS_REG +#if defined(CONFIG_HAS_TLS_REG) asm ("mcr p15, 0, %0, c13, c0, 3" : : "r" (regs->ARM_r0) ); -#else +#elif !defined(CONFIG_TLS_REG_EMUL) /* * User space must never try to access this directly. * Expect your app to break eventually if you do so. @@ -463,6 +464,55 @@ asmlinkage int arm_syscall(int no, struct pt_regs *regs) #endif return 0; +#ifdef CONFIG_NEEDS_SYSCALL_FOR_CMPXCHG + /* + * Atomically store r1 in *r2 if *r2 is equal to r0 for user space. + * Return zero in r0 if *MEM was changed or non-zero if no exchange + * happened. Also set the user C flag accordingly. + * If access permissions have to be fixed up then non-zero is + * returned and the operation has to be re-attempted. + * + * *NOTE*: This is a ghost syscall private to the kernel. Only the + * __kuser_cmpxchg code in entry-armv.S should be aware of its + * existence. Don't ever use this from user code. + */ + case 0xfff0: + { + extern void do_DataAbort(unsigned long addr, unsigned int fsr, + struct pt_regs *regs); + unsigned long val; + unsigned long addr = regs->ARM_r2; + struct mm_struct *mm = current->mm; + pgd_t *pgd; pmd_t *pmd; pte_t *pte; + + regs->ARM_cpsr &= ~PSR_C_BIT; + spin_lock(&mm->page_table_lock); + pgd = pgd_offset(mm, addr); + if (!pgd_present(*pgd)) + goto bad_access; + pmd = pmd_offset(pgd, addr); + if (!pmd_present(*pmd)) + goto bad_access; + pte = pte_offset_map(pmd, addr); + if (!pte_present(*pte) || !pte_write(*pte)) + goto bad_access; + val = *(unsigned long *)addr; + val -= regs->ARM_r0; + if (val == 0) { + *(unsigned long *)addr = regs->ARM_r1; + regs->ARM_cpsr |= PSR_C_BIT; + } + spin_unlock(&mm->page_table_lock); + return val; + + bad_access: + spin_unlock(&mm->page_table_lock); + /* simulate a read access fault */ + do_DataAbort(addr, 15 + (1 << 11), regs); + return -1; + } +#endif + default: /* Calls 9f00xx..9f07ff are defined to return -ENOSYS if not implemented, rather than raising SIGILL. This @@ -497,11 +547,14 @@ asmlinkage int arm_syscall(int no, struct pt_regs *regs) return 0; } -#if defined(CONFIG_CPU_32v6) && !defined(CONFIG_HAS_TLS_REG) +#ifdef CONFIG_TLS_REG_EMUL /* * We might be running on an ARMv6+ processor which should have the TLS - * register, but for some reason we can't use it and have to emulate it. + * register but for some reason we can't use it, or maybe an SMP system + * using a pre-ARMv6 processor (there are apparently a few prototypes like + * that in existence) and therefore access to that register must be + * emulated. */ static int get_tp_trap(struct pt_regs *regs, unsigned int instr) |