diff options
author | Maciej W. Rozycki <macro@mips.com> | 2018-04-30 17:56:47 +0300 |
---|---|---|
committer | James Hogan <jhogan@kernel.org> | 2018-05-15 01:54:25 +0300 |
commit | 71e909c0cdad28a1df1fa14442929e68615dee45 (patch) | |
tree | 7b01e10ca233ba665dc4b2c883e661ff68cc4d23 /arch/mips | |
parent | c60128ce97674fd05adb8b5ae79eb6745a03192e (diff) | |
download | linux-71e909c0cdad28a1df1fa14442929e68615dee45.tar.xz |
MIPS: ptrace: Expose FIR register through FP regset
Correct commit 7aeb753b5353 ("MIPS: Implement task_user_regset_view.")
and expose the FIR register using the unused 4 bytes at the end of the
NT_PRFPREG regset. Without that register included clients cannot use
the PTRACE_GETREGSET request to retrieve the complete FPU register set
and have to resort to one of the older interfaces, either PTRACE_PEEKUSR
or PTRACE_GETFPREGS, to retrieve the missing piece of data. Also the
register is irreversibly missing from core dumps.
This register is architecturally hardwired and read-only so the write
path does not matter. Ignore data supplied on writes then.
Fixes: 7aeb753b5353 ("MIPS: Implement task_user_regset_view.")
Signed-off-by: James Hogan <jhogan@kernel.org>
Signed-off-by: Maciej W. Rozycki <macro@mips.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: <stable@vger.kernel.org> # 3.13+
Patchwork: https://patchwork.linux-mips.org/patch/19273/
Signed-off-by: James Hogan <jhogan@kernel.org>
Diffstat (limited to 'arch/mips')
-rw-r--r-- | arch/mips/kernel/ptrace.c | 18 |
1 files changed, 16 insertions, 2 deletions
diff --git a/arch/mips/kernel/ptrace.c b/arch/mips/kernel/ptrace.c index 0b23b1ad99e6..aede42990f08 100644 --- a/arch/mips/kernel/ptrace.c +++ b/arch/mips/kernel/ptrace.c @@ -463,7 +463,7 @@ static int fpr_get_msa(struct task_struct *target, /* * Copy the floating-point context to the supplied NT_PRFPREG buffer. * Choose the appropriate helper for general registers, and then copy - * the FCSR register separately. + * the FCSR and FIR registers separately. */ static int fpr_get(struct task_struct *target, const struct user_regset *regset, @@ -471,6 +471,7 @@ static int fpr_get(struct task_struct *target, void *kbuf, void __user *ubuf) { const int fcr31_pos = NUM_FPU_REGS * sizeof(elf_fpreg_t); + const int fir_pos = fcr31_pos + sizeof(u32); int err; if (sizeof(target->thread.fpu.fpr[0]) == sizeof(elf_fpreg_t)) @@ -483,6 +484,12 @@ static int fpr_get(struct task_struct *target, err = user_regset_copyout(&pos, &count, &kbuf, &ubuf, &target->thread.fpu.fcr31, fcr31_pos, fcr31_pos + sizeof(u32)); + if (err) + return err; + + err = user_regset_copyout(&pos, &count, &kbuf, &ubuf, + &boot_cpu_data.fpu_id, + fir_pos, fir_pos + sizeof(u32)); return err; } @@ -531,7 +538,8 @@ static int fpr_set_msa(struct task_struct *target, /* * Copy the supplied NT_PRFPREG buffer to the floating-point context. * Choose the appropriate helper for general registers, and then copy - * the FCSR register separately. + * the FCSR register separately. Ignore the incoming FIR register + * contents though, as the register is read-only. * * We optimize for the case where `count % sizeof(elf_fpreg_t) == 0', * which is supposed to have been guaranteed by the kernel before @@ -545,6 +553,7 @@ static int fpr_set(struct task_struct *target, const void *kbuf, const void __user *ubuf) { const int fcr31_pos = NUM_FPU_REGS * sizeof(elf_fpreg_t); + const int fir_pos = fcr31_pos + sizeof(u32); u32 fcr31; int err; @@ -572,6 +581,11 @@ static int fpr_set(struct task_struct *target, ptrace_setfcr31(target, fcr31); } + if (count > 0) + err = user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf, + fir_pos, + fir_pos + sizeof(u32)); + return err; } |