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authorVineet Gupta <vgupta@synopsys.com>2013-10-10 19:33:57 +0530
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2013-10-18 07:45:45 -0700
commit4b3ea63f5af44f93bd28d94a93508bbd3186be89 (patch)
tree67c9f9eddaedff1df14eb08a9576e847a62697bc /arch
parent19a420033da02200c424adfa3a7b9eed6e3a6dc2 (diff)
downloadvexpress-lsk-4b3ea63f5af44f93bd28d94a93508bbd3186be89.tar.gz
ARC: Ignore ptrace SETREGSET request for synthetic register "stop_pc"
commit 5b24282846c064ee90d40fcb3a8f63b8e754fd28 upstream. ARCompact TRAP_S insn used for breakpoints, commits before exception is taken (updating architectural PC). So ptregs->ret contains next-PC and not the breakpoint PC itself. This is different from other restartable exceptions such as TLB Miss where ptregs->ret has exact faulting PC. gdb needs to know exact-PC hence ARC ptrace GETREGSET provides for @stop_pc which returns ptregs->ret vs. EFA depending on the situation. However, writing stop_pc (SETREGSET request), which updates ptregs->ret doesn't makes sense stop_pc doesn't always correspond to that reg as described above. This was not an issue so far since user_regs->ret / user_regs->stop_pc had same value and both writing to ptregs->ret was OK, needless, but NOT broken, hence not observed. With gdb "jump", they diverge, and user_regs->ret updating ptregs is overwritten immediately with stop_pc, which this patch fixes. Reported-by: Anton Kolesov <akolesov@synopsys.com> Signed-off-by: Vineet Gupta <vgupta@synopsys.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch')
-rw-r--r--arch/arc/kernel/ptrace.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/arc/kernel/ptrace.c b/arch/arc/kernel/ptrace.c
index c6a81c58d0f..0851604bb9c 100644
--- a/arch/arc/kernel/ptrace.c
+++ b/arch/arc/kernel/ptrace.c
@@ -92,7 +92,7 @@ static int genregs_set(struct task_struct *target,
REG_IN_CHUNK(scratch, callee, ptregs); /* pt_regs[bta..orig_r8] */
REG_IN_CHUNK(callee, efa, cregs); /* callee_regs[r25..r13] */
REG_IGNORE_ONE(efa); /* efa update invalid */
- REG_IN_ONE(stop_pc, &ptregs->ret); /* stop_pc: PC update */
+ REG_IGNORE_ONE(stop_pc); /* PC updated via @ret */
return ret;
}