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powerpc: Add VSX context save/restore, ptrace and signal support

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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>
This commit is contained in:
Michael Neuling
2008-06-25 14:07:18 +10:00
committed by Paul Mackerras
parent 72ffff5b17
commit ce48b21007
16 changed files with 451 additions and 8 deletions
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33
arch/powerpc/kernel/signal_32.c
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@ -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)))