4.14-stable review patch. If anyone has any objections, please let me know.
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From: Max Filippov jcmvbkbc@gmail.com
commit 38a35a78c5e270cbe53c4fef6b0d3c2da90dd849 upstream.
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 Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- arch/xtensa/kernel/ptrace.c | 42 ++++++++++++++++++++++++++++++++++++++---- 1 file changed, 38 insertions(+), 4 deletions(-)
--- a/arch/xtensa/kernel/ptrace.c +++ b/arch/xtensa/kernel/ptrace.c @@ -127,12 +127,37 @@ static int ptrace_setregs(struct task_st }
+#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; @@ -140,8 +165,13 @@ static int ptrace_getxregs(struct task_s #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, ®s->xtregs_opt, sizeof(xtregs->opt)); @@ -157,6 +187,7 @@ static int ptrace_setxregs(struct task_s 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; @@ -166,8 +197,11 @@ static int ptrace_setxregs(struct task_s 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(®s->xtregs_opt, &xtregs->opt, sizeof(xtregs->opt));