In preparation to fix a commit 72b22bbad1e7 ("MIPS: Don't assume 64-bit FP registers for FP regset") FCSR access regression factor out NT_PRFPREG regset access helpers for the non-MSA and the MSA variants respectively, to avoid having to deal with excessive indentation in the actual fix.
No functional change, however use `target->thread.fpu.fpr[0]' rather than `target->thread.fpu.fpr[i]' for FGR holding type size determination as there's no `i' variable to refer to anymore, and for the factored out `i' variable declaration use `unsigned int' rather than `unsigned' as its type, following the common style.
Cc: stable@vger.kernel.org # v3.15+ Fixes: 72b22bbad1e7 ("MIPS: Don't assume 64-bit FP registers for FP regset") Signed-off-by: Maciej W. Rozycki macro@mips.com --- arch/mips/kernel/ptrace.c | 108 +++++++++++++++++++++++++++++++++++----------- 1 file changed, 83 insertions(+), 25 deletions(-)
linux-mips-nt-prfpreg-factor-out.diff Index: linux-sfr-test/arch/mips/kernel/ptrace.c =================================================================== --- linux-sfr-test.orig/arch/mips/kernel/ptrace.c 2017-11-23 19:18:08.831530000 +0000 +++ linux-sfr-test/arch/mips/kernel/ptrace.c 2017-11-28 22:44:11.537151000 +0000 @@ -410,25 +410,36 @@ static int gpr64_set(struct task_struct
#endif /* CONFIG_64BIT */
-static int fpr_get(struct task_struct *target, - const struct user_regset *regset, - unsigned int pos, unsigned int count, - void *kbuf, void __user *ubuf) +/* + * Copy the floating-point context to the supplied NT_PRFPREG buffer, + * !CONFIG_CPU_HAS_MSA variant. FP context's general register slots + * correspond 1:1 to buffer slots. + */ +static int fpr_get_fpa(struct task_struct *target, + unsigned int *pos, unsigned int *count, + void **kbuf, void __user **ubuf) { - unsigned i; - int err; - u64 fpr_val; - - /* XXX fcr31 */ + return user_regset_copyout(pos, count, kbuf, ubuf, + &target->thread.fpu, + 0, sizeof(elf_fpregset_t)); +}
- if (sizeof(target->thread.fpu.fpr[i]) == sizeof(elf_fpreg_t)) - return user_regset_copyout(&pos, &count, &kbuf, &ubuf, - &target->thread.fpu, - 0, sizeof(elf_fpregset_t)); +/* + * Copy the floating-point context to the supplied NT_PRFPREG buffer, + * CONFIG_CPU_HAS_MSA variant. Only lower 64 bits of FP context's + * general register slots are copied to buffer slots. + */ +static int fpr_get_msa(struct task_struct *target, + unsigned int *pos, unsigned int *count, + void **kbuf, void __user **ubuf) +{ + unsigned int i; + u64 fpr_val; + int err;
for (i = 0; i < NUM_FPU_REGS; i++) { fpr_val = get_fpr64(&target->thread.fpu.fpr[i], 0); - err = user_regset_copyout(&pos, &count, &kbuf, &ubuf, + err = user_regset_copyout(pos, count, kbuf, ubuf, &fpr_val, i * sizeof(elf_fpreg_t), (i + 1) * sizeof(elf_fpreg_t)); if (err) @@ -438,27 +449,54 @@ static int fpr_get(struct task_struct *t return 0; }
-static int fpr_set(struct task_struct *target, +/* Copy the floating-point context to the supplied NT_PRFPREG buffer. */ +static int fpr_get(struct task_struct *target, const struct user_regset *regset, unsigned int pos, unsigned int count, - const void *kbuf, const void __user *ubuf) + void *kbuf, void __user *ubuf) { - unsigned i; int err; - u64 fpr_val;
/* XXX fcr31 */
- init_fp_ctx(target); + if (sizeof(target->thread.fpu.fpr[0]) == sizeof(elf_fpreg_t)) + err = fpr_get_fpa(target, &pos, &count, &kbuf, &ubuf); + else + err = fpr_get_msa(target, &pos, &count, &kbuf, &ubuf);
- if (sizeof(target->thread.fpu.fpr[i]) == sizeof(elf_fpreg_t)) - return user_regset_copyin(&pos, &count, &kbuf, &ubuf, - &target->thread.fpu, - 0, sizeof(elf_fpregset_t)); + return err; +} + +/* + * Copy the supplied NT_PRFPREG buffer to the floating-point context, + * !CONFIG_CPU_HAS_MSA variant. Buffer slots correspond 1:1 to FP + * context's general register slots. + */ +static int fpr_set_fpa(struct task_struct *target, + unsigned int *pos, unsigned int *count, + const void **kbuf, const void __user **ubuf) +{ + return user_regset_copyin(pos, count, kbuf, ubuf, + &target->thread.fpu, + 0, sizeof(elf_fpregset_t)); +} + +/* + * Copy the supplied NT_PRFPREG buffer to the floating-point context, + * CONFIG_CPU_HAS_MSA variant. Buffer slots are copied to lower 64 + * bits only of FP context's general register slots. + */ +static int fpr_set_msa(struct task_struct *target, + unsigned int *pos, unsigned int *count, + const void **kbuf, const void __user **ubuf) +{ + unsigned int i; + u64 fpr_val; + int err;
BUILD_BUG_ON(sizeof(fpr_val) != sizeof(elf_fpreg_t)); - for (i = 0; i < NUM_FPU_REGS && count >= sizeof(elf_fpreg_t); i++) { - err = user_regset_copyin(&pos, &count, &kbuf, &ubuf, + for (i = 0; i < NUM_FPU_REGS && *count >= sizeof(elf_fpreg_t); i++) { + err = user_regset_copyin(pos, count, kbuf, ubuf, &fpr_val, i * sizeof(elf_fpreg_t), (i + 1) * sizeof(elf_fpreg_t)); if (err) @@ -469,6 +507,26 @@ static int fpr_set(struct task_struct *t return 0; }
+/* Copy the supplied NT_PRFPREG buffer to the floating-point context. */ +static int fpr_set(struct task_struct *target, + const struct user_regset *regset, + unsigned int pos, unsigned int count, + const void *kbuf, const void __user *ubuf) +{ + int err; + + /* XXX fcr31 */ + + init_fp_ctx(target); + + if (sizeof(target->thread.fpu.fpr[0]) == sizeof(elf_fpreg_t)) + err = fpr_set_fpa(target, &pos, &count, &kbuf, &ubuf); + else + err = fpr_set_msa(target, &pos, &count, &kbuf, &ubuf); + + return err; +} + enum mips_regset { REGSET_GPR, REGSET_FPR,