kernel.git/arch/powerpc/kernel/ptrace.c, branch linux-3.12.y

powerpc/ptrace: Fix out of bounds array access warning

2016-10-06T06:22:00Z

commit 1e407ee3b21f981140491d5b8a36422979ca246f upstream. gcc-6 correctly warns about a out of bounds access arch/powerpc/kernel/ptrace.c:407:24: warning: index 32 denotes an offset greater than size of 'u64[32][1] {aka long long unsigned int[32][1]}' [-Warray-bounds] offsetof(struct thread_fp_state, fpr[32][0])); ^ check the end of array instead of beginning of next element to fix this Signed-off-by: Khem Raj Cc: Kees Cook Cc: Michael Ellerman Cc: Segher Boessenkool Tested-by: Aaro Koskinen Acked-by: Olof Johansson Signed-off-by: Michael Ellerman Signed-off-by: Jiri Slaby

ptrace/powerpc: revert "hw_breakpoints: Fix racy access to ptrace breakpoints"

2013-07-09T17:33:25Z

This reverts commit 07fa7a0a8a58 ("hw_breakpoints: Fix racy access to ptrace breakpoints") and removes ptrace_get/put_breakpoints() added by other commits. The patch was fine but we can no longer race with SIGKILL after commit 9899d11f6544 ("ptrace: ensure arch_ptrace/ptrace_request can never race with SIGKILL"), the __TASK_TRACED tracee can't be woken up and ->ptrace_bps[] can't go away. Signed-off-by: Oleg Nesterov Acked-by: Michael Neuling Cc: Benjamin Herrenschmidt Cc: Paul Mackerras Cc: Frederic Weisbecker Cc: Ingo Molnar Cc: Jan Kratochvil Cc: Paul Mundt Cc: Will Deacon Cc: Prasad Cc: Russell King Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

powerpc/hw_brk: Fix setting of length for exact mode breakpoints

2013-06-25T07:24:39Z

The smallest match region for both the DABR and DAWR is 8 bytes, so the kernel needs to filter matches when users want to look at regions smaller than this. Currently we set the length of PPC_BREAKPOINT_MODE_EXACT breakpoints to 8. This is wrong as in exact mode we should only match on 1 address, hence the length should be 1. This ensures that the kernel will filter out any exact mode hardware breakpoint matches on any addresses other than the requested one. Signed-off-by: Michael Neuling Reported-by: Edjunior Barbosa Machado Cc: stable@vger.kernel.org Signed-off-by: Benjamin Herrenschmidt

powerpc: Syscall hooks for context tracking subsystem

2013-05-14T06:00:19Z

This is the syscall slow path hooks for context tracking subsystem, corresponding to [PATCH] x86: Syscall hooks for userspace RCU extended QS commit bf5a3c13b939813d28ce26c01425054c740d6731 TIF_MEMDIE is moved to the second 16-bits (with value 17), as it seems there is no asm code using it. TIF_NOHZ is added to _TIF_SYCALL_T_OR_A, so it is better for it to be in the same 16 bits with others in the group, so in the asm code, andi. with this group could work. Signed-off-by: Li Zhong Acked-by: Frederic Weisbecker Signed-off-by: Benjamin Herrenschmidt

powerpc/ptrace: Add DAWR debug feature info for userspace

2013-04-18T05:59:55Z

This adds new debug feature information so that the DAWR can be identified by userspace tools like GDB. Unfortunately the DAWR doesn't sit nicely into the current description that ptrace provides to userspace via struct ppc_debug_info. It doesn't allow for specifying that only some ranges are possible or even the end alignment constraints (DAWR only allows 512 byte wide ranges which can't cross a 512 byte boundary). After talking to Edjunior Machado (GDB ppc developer), it was decided this was the best approach. Just mark it as debug feature DAWR and tools like GDB can internally decide the constraints. Signed-off-by: Michael Neuling Signed-off-by: Michael Ellerman

powerpc: fixing ptrace_get_reg to return an error

2013-04-18T03:03:57Z

Currently ptrace_get_reg returns error as a value what make impossible to tell whether it is a correct value or error code. The patch adds a parameter which points to the real return data and returns an error code. As get_user_msr() never fails and it is used in multiple places so it has not been changed by this patch. Signed-off-by: Alexey Kardashevskiy Acked-by: Michael Neuling Signed-off-by: Michael Ellerman

powerpc/ptrace: Fix brk.len used uninitialised

2013-03-17T01:35:06Z

With some CONFIGS it's possible that in ppc_set_hwdebug, brk.len is uninitialised before being used. It has been reported that GCC 4.2 will produce the following error in this case: arch/powerpc/kernel/ptrace.c:1479: warning: 'brk.len' is used uninitialized in this function arch/powerpc/kernel/ptrace.c:1381: note: 'brk.len' was declared here This patch corrects this. Signed-off-by: Michael Neuling Reported-by: Philippe De Muyter Signed-off-by: Benjamin Herrenschmidt

powerpc: Add DSCR support to ptrace

2013-01-15T18:25:46Z

The DSCR (aka Data Stream Control Register) is supported on some server PowerPC chips and allow some control over the prefetch of data streams. The kernel already supports DSCR value per thread but there is also a need in a ability to change it from an external process for the specific pid. The patch adds new register index PT_DSCR (index=44) which can be set/get by: ptrace(PTRACE_POKEUSER, traced_process, PT_DSCR << 3, dscr); dscr = ptrace(PTRACE_PEEKUSER, traced_process, PT_DSCR << 3, NULL); The patch does not increase PT_REGS_COUNT as the pt_regs struct has not been changed. Signed-off-by: Alexey Kardashevskiy Signed-off-by: Benjamin Herrenschmidt

powerpc: Hardware breakpoints rewrite to handle non DABR breakpoint registers

2013-01-10T06:01:44Z

This is a rewrite so that we don't assume we are using the DABR throughout the code. We now use the arch_hw_breakpoint to store the breakpoint in a generic manner in the thread_struct, rather than storing the raw DABR value. The ptrace GET/SET_DEBUGREG interface currently passes the raw DABR in from userspace. We keep this functionality, so that future changes (like the POWER8 DAWR), will still fake the DABR to userspace. Signed-off-by: Michael Neuling Signed-off-by: Benjamin Herrenschmidt

powerpc/ptrace: Enable hardware breakpoint upon re-registering

2012-11-15T02:01:13Z

On powerpc, ptrace will disable hardware breakpoint request once the breakpoint is hit. It is the responsibility of the caller to set it again. However, when the caller sets the hardware breakpoint again using ptrace(PTRACE_SET_DEBUGREG, child_pid, 0, addr), the hardware breakpoint is not enabled. While gdb's approach is to unregister and re-register the hardware breakpoint every time the breakpoint is hit - which is working fine, this could affect other programs trying to re-register hardware breakpoint without unregistering. This patch enables hardware breakpoint if the caller is re-registering. Signed-off-by: Aravinda Prasad Acked-by: Michael Neuling Signed-off-by: Benjamin Herrenschmidt