From 235754834b6818e727d6b8e240c4ec7f79e2f457 Mon Sep 17 00:00:00 2001 From: Michal Simek Date: Mon, 24 Aug 2009 13:26:04 +0200 Subject: microblaze: Support ptrace syscall tracing. Signed-off-by: Edgar E. Iglesias Signed-off-by: Michal Simek --- arch/microblaze/kernel/entry.S | 72 ++++++++++++++++++++++++++++++++++------- arch/microblaze/kernel/ptrace.c | 62 +++++++++++++++++++++++++++++++++++ 2 files changed, 122 insertions(+), 12 deletions(-) diff --git a/arch/microblaze/kernel/entry.S b/arch/microblaze/kernel/entry.S index c7353e79f4a..acc1f05d1e2 100644 --- a/arch/microblaze/kernel/entry.S +++ b/arch/microblaze/kernel/entry.S @@ -308,38 +308,69 @@ C_ENTRY(_user_exception): swi r12, r1, PTO+PT_R0; tovirt(r1,r1) - la r15, r0, ret_from_trap-8 /* where the trap should return need -8 to adjust for rtsd r15, 8*/ /* Jump to the appropriate function for the system call number in r12 * (r12 is not preserved), or return an error if r12 is not valid. The LP * register should point to the location where * the called function should return. [note that MAKE_SYS_CALL uses label 1] */ - /* See if the system call number is valid. */ + + # Step into virtual mode. + set_vms; + addik r11, r0, 3f + rtid r11, 0 + nop +3: + add r11, r0, CURRENT_TASK /* Get current task ptr into r11 */ + lwi r11, r11, TS_THREAD_INFO /* get thread info */ + lwi r11, r11, TI_FLAGS /* get flags in thread info */ + andi r11, r11, _TIF_WORK_SYSCALL_MASK + beqi r11, 4f + + addik r3, r0, -ENOSYS + swi r3, r1, PTO + PT_R3 + brlid r15, do_syscall_trace_enter + addik r5, r1, PTO + PT_R0 + + # do_syscall_trace_enter returns the new syscall nr. + addk r12, r0, r3 + lwi r5, r1, PTO+PT_R5; + lwi r6, r1, PTO+PT_R6; + lwi r7, r1, PTO+PT_R7; + lwi r8, r1, PTO+PT_R8; + lwi r9, r1, PTO+PT_R9; + lwi r10, r1, PTO+PT_R10; +4: +/* Jump to the appropriate function for the system call number in r12 + * (r12 is not preserved), or return an error if r12 is not valid. + * The LP register should point to the location where the called function + * should return. [note that MAKE_SYS_CALL uses label 1] */ + /* See if the system call number is valid */ addi r11, r12, -__NR_syscalls; - bgei r11,1f; + bgei r11,5f; /* Figure out which function to use for this system call. */ /* Note Microblaze barrel shift is optional, so don't rely on it */ add r12, r12, r12; /* convert num -> ptr */ add r12, r12, r12; /* Trac syscalls and stored them to r0_ram */ - lwi r3, r12, 0x400 + TOPHYS(r0_ram) + lwi r3, r12, 0x400 + r0_ram addi r3, r3, 1 - swi r3, r12, 0x400 + TOPHYS(r0_ram) + swi r3, r12, 0x400 + r0_ram + + # Find and jump into the syscall handler. + lwi r12, r12, sys_call_table + /* where the trap should return need -8 to adjust for rtsd r15, 8 */ + la r15, r0, ret_from_trap-8 + bra r12 - lwi r12, r12, TOPHYS(sys_call_table); /* Function ptr */ - /* Make the system call. to r12*/ - set_vms; - rtid r12, 0; - nop; /* The syscall number is invalid, return an error. */ -1: VM_ON; /* RETURN() expects virtual mode*/ +5: addi r3, r0, -ENOSYS; rtsd r15,8; /* looks like a normal subroutine return */ or r0, r0, r0 -/* Entry point used to return from a syscall/trap. */ +/* Entry point used to return from a syscall/trap */ /* We re-enable BIP bit before state restore */ C_ENTRY(ret_from_trap): set_bip; /* Ints masked for state restore*/ @@ -347,6 +378,23 @@ C_ENTRY(ret_from_trap): /* See if returning to kernel mode, if so, skip resched &c. */ bnei r11, 2f; + /* We're returning to user mode, so check for various conditions that + * trigger rescheduling. */ + # FIXME: Restructure all these flag checks. + add r11, r0, CURRENT_TASK; /* Get current task ptr into r11 */ + lwi r11, r11, TS_THREAD_INFO; /* get thread info */ + lwi r11, r11, TI_FLAGS; /* get flags in thread info */ + andi r11, r11, _TIF_WORK_SYSCALL_MASK + beqi r11, 1f + + swi r3, r1, PTO + PT_R3 + swi r4, r1, PTO + PT_R4 + brlid r15, do_syscall_trace_leave + addik r5, r1, PTO + PT_R0 + lwi r3, r1, PTO + PT_R3 + lwi r4, r1, PTO + PT_R4 +1: + /* We're returning to user mode, so check for various conditions that * trigger rescheduling. */ /* Get current task ptr into r11 */ diff --git a/arch/microblaze/kernel/ptrace.c b/arch/microblaze/kernel/ptrace.c index 53ff39af6a5..4b3ac32754d 100644 --- a/arch/microblaze/kernel/ptrace.c +++ b/arch/microblaze/kernel/ptrace.c @@ -29,6 +29,10 @@ #include #include #include +#include +#include +#include +#include #include #include @@ -174,6 +178,64 @@ long arch_ptrace(struct task_struct *child, long request, long addr, long data) return rval; } +asmlinkage long do_syscall_trace_enter(struct pt_regs *regs) +{ + long ret = 0; + + secure_computing(regs->r12); + + if (test_thread_flag(TIF_SYSCALL_TRACE) && + tracehook_report_syscall_entry(regs)) + /* + * Tracing decided this syscall should not happen. + * We'll return a bogus call number to get an ENOSYS + * error, but leave the original number in regs->regs[0]. + */ + ret = -1L; + + if (unlikely(current->audit_context)) + audit_syscall_entry(EM_XILINX_MICROBLAZE, regs->r12, + regs->r5, regs->r6, + regs->r7, regs->r8); + + return ret ?: regs->r12; +} + +asmlinkage void do_syscall_trace_leave(struct pt_regs *regs) +{ + int step; + + if (unlikely(current->audit_context)) + audit_syscall_exit(AUDITSC_RESULT(regs->r3), regs->r3); + + step = test_thread_flag(TIF_SINGLESTEP); + if (step || test_thread_flag(TIF_SYSCALL_TRACE)) + tracehook_report_syscall_exit(regs, step); +} + +#if 0 +static asmlinkage void syscall_trace(void) +{ + if (!test_thread_flag(TIF_SYSCALL_TRACE)) + return; + if (!(current->ptrace & PT_PTRACED)) + return; + /* The 0x80 provides a way for the tracing parent to distinguish + between a syscall stop and SIGTRAP delivery */ + ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD) + ? 0x80 : 0)); + /* + * this isn't the same as continuing with a signal, but it will do + * for normal use. strace only continues with a signal if the + * stopping signal is not SIGTRAP. -brl + */ + if (current->exit_code) { + send_sig(current->exit_code, current, 1); + current->exit_code = 0; + } +} +#endif + void ptrace_disable(struct task_struct *child) { /* nothing to do */ -- cgit v1.2.3