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authorMichael Neuling <mikey@neuling.org>2008-06-25 14:07:18 +1000
committerPaul Mackerras <paulus@samba.org>2008-07-01 11:28:50 +1000
commitce48b2100785e5ca629fb3aa8e3b50aca808f692 (patch)
tree63532ff7cc68b18ca4902bd10e03fcbaaf01cade /arch/powerpc/kernel/signal_32.c
parent72ffff5b1792b0fa4d40a8e2f3276fff999820ec (diff)
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powerpc: Add VSX context save/restore, ptrace and signal support
This patch extends the floating point save and restore code to use the VSX load/stores when VSX is available. This will make FP context save/restore marginally slower on FP only code, when VSX is available, as it has to load/store 128bits rather than just 64bits. Mixing FP, VMX and VSX code will get constant architected state. The signals interface is extended to enable access to VSR 0-31 doubleword 1 after discussions with tool chain maintainers. Backward compatibility is maintained. The ptrace interface is also extended to allow access to VSR 0-31 full registers. Signed-off-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Paul Mackerras <paulus@samba.org>
Diffstat (limited to 'arch/powerpc/kernel/signal_32.c')
-rw-r--r--arch/powerpc/kernel/signal_32.c33
1 files changed, 33 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/signal_32.c b/arch/powerpc/kernel/signal_32.c
index f7fa395b9fb5..349d3487d920 100644
--- a/arch/powerpc/kernel/signal_32.c
+++ b/arch/powerpc/kernel/signal_32.c
@@ -378,6 +378,21 @@ static int save_user_regs(struct pt_regs *regs, struct mcontext __user *frame,
memcpy(&buf[i], &current->thread.fpscr, sizeof(double));
if (__copy_to_user(&frame->mc_fregs, buf, ELF_NFPREG * sizeof(double)))
return 1;
+ /*
+ * Copy VSR 0-31 upper half from thread_struct to local
+ * buffer, then write that to userspace. Also set MSR_VSX in
+ * the saved MSR value to indicate that frame->mc_vregs
+ * contains valid data
+ */
+ if (current->thread.used_vsr) {
+ flush_vsx_to_thread(current);
+ for (i = 0; i < 32 ; i++)
+ buf[i] = current->thread.fpr[i][TS_VSRLOWOFFSET];
+ if (__copy_to_user(&frame->mc_vsregs, buf,
+ ELF_NVSRHALFREG * sizeof(double)))
+ return 1;
+ msr |= MSR_VSX;
+ }
#else
/* save floating-point registers */
if (__copy_to_user(&frame->mc_fregs, current->thread.fpr,
@@ -482,6 +497,24 @@ static long restore_user_regs(struct pt_regs *regs,
for (i = 0; i < 32 ; i++)
current->thread.TS_FPR(i) = buf[i];
memcpy(&current->thread.fpscr, &buf[i], sizeof(double));
+ /*
+ * Force the process to reload the VSX registers from
+ * current->thread when it next does VSX instruction.
+ */
+ regs->msr &= ~MSR_VSX;
+ if (msr & MSR_VSX) {
+ /*
+ * Restore altivec registers from the stack to a local
+ * buffer, then write this out to the thread_struct
+ */
+ if (__copy_from_user(buf, &sr->mc_vsregs,
+ sizeof(sr->mc_vsregs)))
+ return 1;
+ for (i = 0; i < 32 ; i++)
+ current->thread.fpr[i][TS_VSRLOWOFFSET] = buf[i];
+ } else if (current->thread.used_vsr)
+ for (i = 0; i < 32 ; i++)
+ current->thread.fpr[i][TS_VSRLOWOFFSET] = 0;
#else
if (__copy_from_user(current->thread.fpr, &sr->mc_fregs,
sizeof(sr->mc_fregs)))