Use the `unsigned long' rather than `__u32' type for DSP accumulator registers, like with the regular MIPS multiply/divide accumulator and general-purpose registers, as all are 64-bit in 64-bit implementations and using a 32-bit data type leads to contents truncation on context saving.

Update `arch_ptrace' and `compat_arch_ptrace' accordingly, removing casts that are similarly not used with multiply/divide accumulator or general-purpose register accesses.

Cc: stable@vger.kernel.org # 2.6.15+ Fixes: e50c0a8fa60d ("Support the MIPS32 / MIPS64 DSP ASE.") Signed-off-by: Maciej W. Rozycki macro@mips.com --- Hi,

I have no 64-bit DSP hardware handy to verify this change, however some surely exists and is used to run Linux, as indicated by GDB PR gdb/22286, https://sourceware.org/bugzilla/show_bug.cgi?id=22286, so we better get it right before people start screaming.

Maciej --- arch/mips/include/asm/processor.h | 2 +- arch/mips/kernel/ptrace.c | 2 +- arch/mips/kernel/ptrace32.c | 2 +- 3 files changed, 3 insertions(+), 3 deletions(-)

linux-mips-dsp64.diff Index: linux-jhogan-test/arch/mips/include/asm/processor.h =================================================================== --- linux-jhogan-test.orig/arch/mips/include/asm/processor.h 2018-03-21 17:13:52.000000000 +0000 +++ linux-jhogan-test/arch/mips/include/asm/processor.h 2018-05-09 22:35:33.248559000 +0100 @@ -141,7 +141,7 @@ struct mips_fpu_struct {

#define NUM_DSP_REGS 6

-typedef __u32 dspreg_t; +typedef unsigned long dspreg_t;

struct mips_dsp_state { dspreg_t dspr[NUM_DSP_REGS]; Index: linux-jhogan-test/arch/mips/kernel/ptrace.c =================================================================== --- linux-jhogan-test.orig/arch/mips/kernel/ptrace.c 2018-05-09 22:34:00.000000000 +0100 +++ linux-jhogan-test/arch/mips/kernel/ptrace.c 2018-05-09 22:37:45.416608000 +0100 @@ -856,7 +856,7 @@ long arch_ptrace(struct task_struct *chi goto out; } dregs = __get_dsp_regs(child); - tmp = (unsigned long) (dregs[addr - DSP_BASE]); + tmp = dregs[addr - DSP_BASE]; break; } case DSP_CONTROL: Index: linux-jhogan-test/arch/mips/kernel/ptrace32.c =================================================================== --- linux-jhogan-test.orig/arch/mips/kernel/ptrace32.c 2018-03-21 17:13:52.000000000 +0000 +++ linux-jhogan-test/arch/mips/kernel/ptrace32.c 2018-05-09 22:45:50.924418000 +0100 @@ -142,7 +142,7 @@ long compat_arch_ptrace(struct task_stru goto out; } dregs = __get_dsp_regs(child); - tmp = (unsigned long) (dregs[addr - DSP_BASE]); + tmp = dregs[addr - DSP_BASE]; break; } case DSP_CONTROL: