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Message-ID: <alpine.DEB.2.00.1711290212440.31156@tp.orcam.me.uk>
Date: Wed, 29 Nov 2017 15:17:59 +0000
From: "Maciej W. Rozycki" <macro@...s.com>
To: Ralf Baechle <ralf@...ux-mips.org>,
James Hogan <james.hogan@...s.com>
CC: Paul Burton <Paul.Burton@...s.com>,
Alex Smith <alex@...x-smith.me.uk>,
Dave Martin <Dave.Martin@....com>, <linux-mips@...ux-mips.org>,
<linux-kernel@...r.kernel.org>, <stable@...r.kernel.org>
Subject: [PATCH 1/5] MIPS: Factor out NT_PRFPREG regset access helpers
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@...r.kernel.org # v3.15+
Fixes: 72b22bbad1e7 ("MIPS: Don't assume 64-bit FP registers for FP regset")
Signed-off-by: Maciej W. Rozycki <macro@...s.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,
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