From 71e909c0cdad28a1df1fa14442929e68615dee45 Mon Sep 17 00:00:00 2001 From: "Maciej W. Rozycki" Date: Mon, 30 Apr 2018 15:56:47 +0100 Subject: 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 Signed-off-by: Maciej W. Rozycki Cc: Ralf Baechle Cc: linux-mips@linux-mips.org Cc: # 3.13+ Patchwork: https://patchwork.linux-mips.org/patch/19273/ Signed-off-by: James Hogan --- arch/mips/kernel/ptrace.c | 18 ++++++++++++++++-- 1 file changed, 16 insertions(+), 2 deletions(-) (limited to 'arch/mips/kernel/ptrace.c') 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; } -- cgit v1.2.3 From 9a3a92ccfe3620743d4ae57c987dc8e9c5f88996 Mon Sep 17 00:00:00 2001 From: "Maciej W. Rozycki" Date: Mon, 14 May 2018 16:49:43 +0100 Subject: MIPS: Fix ptrace(2) PTRACE_PEEKUSR and PTRACE_POKEUSR accesses to o32 FGRs Check the TIF_32BIT_FPREGS task setting of the tracee rather than the tracer in determining the layout of floating-point general registers in the floating-point context, correcting access to odd-numbered registers for o32 tracees where the setting disagrees between the two processes. Fixes: 597ce1723e0f ("MIPS: Support for 64-bit FP with O32 binaries") Signed-off-by: Maciej W. Rozycki Cc: Ralf Baechle Cc: linux-mips@linux-mips.org Cc: # 3.14+ Signed-off-by: James Hogan --- arch/mips/kernel/ptrace.c | 4 ++-- arch/mips/kernel/ptrace32.c | 4 ++-- 2 files changed, 4 insertions(+), 4 deletions(-) (limited to 'arch/mips/kernel/ptrace.c') diff --git a/arch/mips/kernel/ptrace.c b/arch/mips/kernel/ptrace.c index aede42990f08..8d098b9f395c 100644 --- a/arch/mips/kernel/ptrace.c +++ b/arch/mips/kernel/ptrace.c @@ -807,7 +807,7 @@ long arch_ptrace(struct task_struct *child, long request, fregs = get_fpu_regs(child); #ifdef CONFIG_32BIT - if (test_thread_flag(TIF_32BIT_FPREGS)) { + if (test_tsk_thread_flag(child, TIF_32BIT_FPREGS)) { /* * The odd registers are actually the high * order bits of the values stored in the even @@ -902,7 +902,7 @@ long arch_ptrace(struct task_struct *child, long request, init_fp_ctx(child); #ifdef CONFIG_32BIT - if (test_thread_flag(TIF_32BIT_FPREGS)) { + if (test_tsk_thread_flag(child, TIF_32BIT_FPREGS)) { /* * The odd registers are actually the high * order bits of the values stored in the even diff --git a/arch/mips/kernel/ptrace32.c b/arch/mips/kernel/ptrace32.c index 2b9260f92ccd..656a137c1fe2 100644 --- a/arch/mips/kernel/ptrace32.c +++ b/arch/mips/kernel/ptrace32.c @@ -99,7 +99,7 @@ long compat_arch_ptrace(struct task_struct *child, compat_long_t request, break; } fregs = get_fpu_regs(child); - if (test_thread_flag(TIF_32BIT_FPREGS)) { + if (test_tsk_thread_flag(child, TIF_32BIT_FPREGS)) { /* * The odd registers are actually the high * order bits of the values stored in the even @@ -212,7 +212,7 @@ long compat_arch_ptrace(struct task_struct *child, compat_long_t request, sizeof(child->thread.fpu)); child->thread.fpu.fcr31 = 0; } - if (test_thread_flag(TIF_32BIT_FPREGS)) { + if (test_tsk_thread_flag(child, TIF_32BIT_FPREGS)) { /* * The odd registers are actually the high * order bits of the values stored in the even -- cgit v1.2.3