diff options
| author | Vineet Gupta <vgupta@synopsys.com> | 2013-01-18 13:42:19 +0400 |
|---|---|---|
| committer | Vineet Gupta <vgupta@synopsys.com> | 2013-02-15 21:33:30 +0400 |
| commit | c3581039b6c51a778a70accec53a9bb7ad9a4d32 (patch) | |
| tree | 6816e82f1a59fe3d4fbf8c291d3f52598531c50c /arch/arc/include/asm/entry.h | |
| parent | d8005e6b95268cbb50db3773d5f180c32a9434fe (diff) | |
| download | linux-c3581039b6c51a778a70accec53a9bb7ad9a4d32.tar.xz | |
ARC: Signal handling
Includes following fixes courtesy review by Al-Viro
* Tracer poke to Callee-regs were lost
Before going off into do_signal( ) we save the user-mode callee regs
(as they are not saved by default as part of pt_regs). This is to make
sure that that a Tracer (if tracing related signal) is able to do likes
of PEEKUSR(callee-reg).
However in return path we were simply discarding the user-mode callee
regs, which would break a POKEUSR(callee-reg) from a tracer.
* Issue related to multiple syscall restarts are addressed in next patch
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Acked-by: Jonas Bonn <jonas@southpole.se>
Diffstat (limited to 'arch/arc/include/asm/entry.h')
| -rw-r--r-- | arch/arc/include/asm/entry.h | 35 |
1 files changed, 35 insertions, 0 deletions
diff --git a/arch/arc/include/asm/entry.h b/arch/arc/include/asm/entry.h index 63705b12d911..6b42bf5c45ec 100644 --- a/arch/arc/include/asm/entry.h +++ b/arch/arc/include/asm/entry.h @@ -166,6 +166,41 @@ .endm /*-------------------------------------------------------------- + * RESTORE_CALLEE_SAVED_USER: + * This is called after do_signal where tracer might have changed callee regs + * thus we need to restore the reg file. + * Special case handling is required for r25 in case it is used by kernel + * for caching task ptr. Ptrace would have modified on-kernel-stack value of + * r25, which needs to be shoved back into task->thread.user_r25 where from + * Low level exception/ISR return code will retrieve to populate with rest of + * callee reg-file. + *-------------------------------------------------------------*/ +.macro RESTORE_CALLEE_SAVED_USER + + add sp, sp, 4 /* skip "callee_regs->stack_place_holder" */ + +#ifdef CONFIG_ARC_CURR_IN_REG + ld.ab r12, [sp, 4] + st r12, [r25, TASK_THREAD + THREAD_USER_R25] +#else + ld.ab r25, [sp, 4] +#endif + + ld.ab r24, [sp, 4] + ld.ab r23, [sp, 4] + ld.ab r22, [sp, 4] + ld.ab r21, [sp, 4] + ld.ab r20, [sp, 4] + ld.ab r19, [sp, 4] + ld.ab r18, [sp, 4] + ld.ab r17, [sp, 4] + ld.ab r16, [sp, 4] + ld.ab r15, [sp, 4] + ld.ab r14, [sp, 4] + ld.ab r13, [sp, 4] +.endm + +/*-------------------------------------------------------------- * Super FAST Restore callee saved regs by simply re-adjusting SP *-------------------------------------------------------------*/ .macro DISCARD_CALLEE_SAVED_USER |