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authorMaciej W. Rozycki <macro@mips.com>2018-05-16 01:40:18 +0300
committerPaul Burton <paul.burton@mips.com>2018-07-19 23:58:44 +0300
commit1ae22a0e35636efceab83728ba30b013df761592 (patch)
tree731483ca0394e955c233c3d944881e6fbc12155f /arch
parent44109c60176ae73924a42a6bef64ef151aba9095 (diff)
downloadlinux-1ae22a0e35636efceab83728ba30b013df761592.tar.xz
MIPS: Add FP_MODE regset support
Define an NT_MIPS_FP_MODE core file note and implement a corresponding regset holding the state handled by PR_SET_FP_MODE and PR_GET_FP_MODE prctl(2) requests. This lets debug software correctly interpret the contents of floating-point general registers both in live debugging and in core files, and also switch floating-point modes of a live process. [paul.burton@mips.com: - Changed NT_MIPS_FP_MODE to 0x801 to match first nibble of NT_MIPS_DSP, which was also changed to avoid a conflict.] Signed-off-by: Maciej W. Rozycki <macro@mips.com> Signed-off-by: Paul Burton <paul.burton@mips.com> Patchwork: https://patchwork.linux-mips.org/patch/19331/ Cc: James Hogan <jhogan@kernel.org> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org
Diffstat (limited to 'arch')
-rw-r--r--arch/mips/kernel/ptrace.c63
1 files changed, 63 insertions, 0 deletions
diff --git a/arch/mips/kernel/ptrace.c b/arch/mips/kernel/ptrace.c
index a536271ba084..e5ba56c01ee0 100644
--- a/arch/mips/kernel/ptrace.c
+++ b/arch/mips/kernel/ptrace.c
@@ -759,10 +759,57 @@ static int dsp_active(struct task_struct *target,
return cpu_has_dsp ? NUM_DSP_REGS + 1 : -ENODEV;
}
+/* Copy the FP mode setting to the supplied NT_MIPS_FP_MODE buffer. */
+static int fp_mode_get(struct task_struct *target,
+ const struct user_regset *regset,
+ unsigned int pos, unsigned int count,
+ void *kbuf, void __user *ubuf)
+{
+ int fp_mode;
+
+ fp_mode = mips_get_process_fp_mode(target);
+ return user_regset_copyout(&pos, &count, &kbuf, &ubuf, &fp_mode, 0,
+ sizeof(fp_mode));
+}
+
+/*
+ * Copy the supplied NT_MIPS_FP_MODE buffer to the FP mode setting.
+ *
+ * We optimize for the case where `count % sizeof(int) == 0', which
+ * is supposed to have been guaranteed by the kernel before calling
+ * us, e.g. in `ptrace_regset'. We enforce that requirement, so
+ * that we can safely avoid preinitializing temporaries for partial
+ * mode writes.
+ */
+static int fp_mode_set(struct task_struct *target,
+ const struct user_regset *regset,
+ unsigned int pos, unsigned int count,
+ const void *kbuf, const void __user *ubuf)
+{
+ int fp_mode;
+ int err;
+
+ BUG_ON(count % sizeof(int));
+
+ if (pos + count > sizeof(fp_mode))
+ return -EIO;
+
+ err = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &fp_mode, 0,
+ sizeof(fp_mode));
+ if (err)
+ return err;
+
+ if (count > 0)
+ err = mips_set_process_fp_mode(target, fp_mode);
+
+ return err;
+}
+
enum mips_regset {
REGSET_GPR,
REGSET_FPR,
REGSET_DSP,
+ REGSET_FP_MODE,
};
struct pt_regs_offset {
@@ -877,6 +924,14 @@ static const struct user_regset mips_regsets[] = {
.set = dsp32_set,
.active = dsp_active,
},
+ [REGSET_FP_MODE] = {
+ .core_note_type = NT_MIPS_FP_MODE,
+ .n = 1,
+ .size = sizeof(int),
+ .align = sizeof(int),
+ .get = fp_mode_get,
+ .set = fp_mode_set,
+ },
};
static const struct user_regset_view user_mips_view = {
@@ -917,6 +972,14 @@ static const struct user_regset mips64_regsets[] = {
.set = dsp64_set,
.active = dsp_active,
},
+ [REGSET_FP_MODE] = {
+ .core_note_type = NT_MIPS_FP_MODE,
+ .n = 1,
+ .size = sizeof(int),
+ .align = sizeof(int),
+ .get = fp_mode_get,
+ .set = fp_mode_set,
+ },
};
static const struct user_regset_view user_mips64_view = {