Layout of coprocessor registers in the elf_xtregs_t and xtregs_coprocessor_t may be different due to alignment. Thus it is not always possible to copy data between the xtregs_coprocessor_t structure and the elf_xtregs_t and get correct values for all registers. Use a table of offsets and sizes of individual coprocessor register groups to do coprocessor context copying in the ptrace_getxregs and ptrace_setxregs. This fixes incorrect coprocessor register values reading from the user process by the native gdb on an xtensa core with multiple coprocessors and registers with high alignment requirements.

Cc: stable@vger.kernel.org Signed-off-by: Max Filippov jcmvbkbc@gmail.com --- arch/xtensa/kernel/ptrace.c | 42 ++++++++++++++++++++++++++++++++++++++---- 1 file changed, 38 insertions(+), 4 deletions(-)

diff --git a/arch/xtensa/kernel/ptrace.c b/arch/xtensa/kernel/ptrace.c index f6585afa9cd9..7936b9368916 100644 --- a/arch/xtensa/kernel/ptrace.c +++ b/arch/xtensa/kernel/ptrace.c @@ -283,12 +283,37 @@ static int ptrace_setregs(struct task_struct *child, void __user *uregs) }

+#if XTENSA_HAVE_COPROCESSORS +#define CP_OFFSETS(cp) \ + { \ + .elf_xtregs_offset = offsetof(elf_xtregs_t, cp), \ + .ti_offset = offsetof(struct thread_info, xtregs_cp.cp), \ + .sz = sizeof(xtregs_ ## cp ## _t), \ + } + +static const struct { + size_t elf_xtregs_offset; + size_t ti_offset; + size_t sz; +} cp_offsets[] = { + CP_OFFSETS(cp0), + CP_OFFSETS(cp1), + CP_OFFSETS(cp2), + CP_OFFSETS(cp3), + CP_OFFSETS(cp4), + CP_OFFSETS(cp5), + CP_OFFSETS(cp6), + CP_OFFSETS(cp7), +}; +#endif + static int ptrace_getxregs(struct task_struct *child, void __user *uregs) { struct pt_regs *regs = task_pt_regs(child); struct thread_info *ti = task_thread_info(child); elf_xtregs_t __user *xtregs = uregs; int ret = 0; + int i __maybe_unused;

if (!access_ok(VERIFY_WRITE, uregs, sizeof(elf_xtregs_t))) return -EIO; @@ -296,8 +321,13 @@ static int ptrace_getxregs(struct task_struct *child, void __user *uregs) #if XTENSA_HAVE_COPROCESSORS /* Flush all coprocessor registers to memory. */ coprocessor_flush_all(ti); - ret |= __copy_to_user(&xtregs->cp0, &ti->xtregs_cp, - sizeof(xtregs_coprocessor_t)); + + for (i = 0; i < ARRAY_SIZE(cp_offsets); ++i) + ret |= __copy_to_user((char __user *)xtregs + + cp_offsets[i].elf_xtregs_offset, + (const char *)ti + + cp_offsets[i].ti_offset, + cp_offsets[i].sz); #endif ret |= __copy_to_user(&xtregs->opt, &regs->xtregs_opt, sizeof(xtregs->opt)); @@ -313,6 +343,7 @@ static int ptrace_setxregs(struct task_struct *child, void __user *uregs) struct pt_regs *regs = task_pt_regs(child); elf_xtregs_t *xtregs = uregs; int ret = 0; + int i __maybe_unused;

if (!access_ok(VERIFY_READ, uregs, sizeof(elf_xtregs_t))) return -EFAULT; @@ -322,8 +353,11 @@ static int ptrace_setxregs(struct task_struct *child, void __user *uregs) coprocessor_flush_all(ti); coprocessor_release_all(ti);

- ret |= __copy_from_user(&ti->xtregs_cp, &xtregs->cp0, - sizeof(xtregs_coprocessor_t)); + for (i = 0; i < ARRAY_SIZE(cp_offsets); ++i) + ret |= __copy_from_user((char *)ti + cp_offsets[i].ti_offset, + (const char __user *)xtregs + + cp_offsets[i].elf_xtregs_offset, + cp_offsets[i].sz); #endif ret |= __copy_from_user(&regs->xtregs_opt, &xtregs->opt, sizeof(xtregs->opt));