Currently core file of aarch32 process prstatus note has empty registers set. As result aarch32 core files create by V8 kernel are not very useful.

It happens because compat_gpr_get and compat_gpr_set functions can copy registers values to/from either kbuf or ubuf. ELF core file collection function fill_thread_core_info calls compat_gpr_get with kbuf set and ubuf set to 0. But current compat_gpr_get and compat_gpr_set function handle copy to/from only ubuf case.

Fix is to handle kbuf and ubuf as two separate cases in similar way as other functions like user_regset_copyout, user_regset_copyin do.

Signed-off-by: Victor Kamensky victor.kamensky@linaro.org Acked-by: Will Deacon will.deacon@arm.com Cc: stable@vger.kernel.org Cc: Catalin Marinas catalin.marinas@arm.com --- arch/arm64/kernel/ptrace.c | 28 +++++++++++++++++++--------- 1 file changed, 19 insertions(+), 9 deletions(-)

diff --git a/arch/arm64/kernel/ptrace.c b/arch/arm64/kernel/ptrace.c index 6a8928b..9c9c2b9 100644 --- a/arch/arm64/kernel/ptrace.c +++ b/arch/arm64/kernel/ptrace.c @@ -650,11 +650,16 @@ static int compat_gpr_get(struct task_struct *target, reg = task_pt_regs(target)->regs[idx]; }

- ret = copy_to_user(ubuf, &reg, sizeof(reg)); - if (ret) - break; - - ubuf += sizeof(reg); + if (kbuf) { + memcpy(kbuf, &reg, sizeof(reg)); + kbuf += sizeof(reg); + } else { + ret = copy_to_user(ubuf, &reg, sizeof(reg)); + if (ret) + break; + + ubuf += sizeof(reg); + } }

return ret; @@ -684,11 +689,16 @@ static int compat_gpr_set(struct task_struct *target, unsigned int idx = start + i; compat_ulong_t reg;

- ret = copy_from_user(&reg, ubuf, sizeof(reg)); - if (ret) - return ret; + if (kbuf) { + memcpy(&reg, kbuf, sizeof(reg)); + kbuf += sizeof(reg); + } else { + ret = copy_from_user(&reg, ubuf, sizeof(reg)); + if (ret) + return ret;

- ubuf += sizeof(reg); + ubuf += sizeof(reg); + }

switch (idx) { case 15: