diff options
| author | Chris Metcalf <cmetcalf@tilera.com> | 2012-04-28 18:51:43 -0400 |
|---|---|---|
| committer | Chris Metcalf <cmetcalf@tilera.com> | 2012-05-16 16:01:16 -0400 |
| commit | fc327e268fbef08e129ad51aa3a7113ee9bc6ba5 (patch) | |
| tree | ba75f2ac9509090c6896a4fbc6be7c3aaba1aaf6 /arch/tile/include/asm | |
| parent | 36be50515fe2aef61533b516fa2576a2c7fe7664 (diff) | |
arch/tile: fix up some issues in calling do_work_pending()
First, we were at risk of handling thread-info flags, in particular
do_signal(), when returning from kernel space. This could happen
after a failed kernel_execve(), or when forking a kernel thread.
The fix is to test in do_work_pending() for user_mode() and return
immediately if so; we already had this test for one of the flags,
so I just hoisted it to the top of the function.
Second, if a ptraced process updated the callee-saved registers
in the ptregs struct and then processed another thread-info flag, we
would overwrite the modifications with the original callee-saved
registers. To fix this, we add a register to note if we've already
saved the registers once, and skip doing it on additional passes
through the loop. To avoid a performance hit from the couple of
extra instructions involved, I modified the GET_THREAD_INFO() macro
to be guaranteed to be one instruction, then bundled it with adjacent
instructions, yielding an overall net savings.
Reported-By: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
Diffstat (limited to 'arch/tile/include/asm')
| -rw-r--r-- | arch/tile/include/asm/thread_info.h | 9 |
1 files changed, 7 insertions, 2 deletions
diff --git a/arch/tile/include/asm/thread_info.h b/arch/tile/include/asm/thread_info.h index bc4f562bd45..7594764d8a6 100644 --- a/arch/tile/include/asm/thread_info.h +++ b/arch/tile/include/asm/thread_info.h @@ -100,9 +100,14 @@ extern void cpu_idle_on_new_stack(struct thread_info *old_ti, #else /* __ASSEMBLY__ */ -/* how to get the thread information struct from ASM */ +/* + * How to get the thread information struct from assembly. + * Note that we use different macros since different architectures + * have different semantics in their "mm" instruction and we would + * like to guarantee that the macro expands to exactly one instruction. + */ #ifdef __tilegx__ -#define GET_THREAD_INFO(reg) move reg, sp; mm reg, zero, LOG2_THREAD_SIZE, 63 +#define EXTRACT_THREAD_INFO(reg) mm reg, zero, LOG2_THREAD_SIZE, 63 #else #define GET_THREAD_INFO(reg) mm reg, sp, zero, LOG2_THREAD_SIZE, 31 #endif |