On Mon, Jan 27, 2014 at 09:06:52PM +0300, Sergei Shtylyov wrote:
> Hello.
>
> On 01/27/2014 06:23 PM, Paul Burton wrote:
>
> >The upper bits of an FP register are architecturally defined as
> >unpredictable following an instructions which only writes the lower
> >bits. The prior behaviour of the kernel is to leave them unmodified.
> >This patch modifies that to clear the upper bits to zero. This is what
> >the MSA architecture reference manual specifies should happen for its
> >wider registers and is still permissible for scalar FP instructions
> >given the bits unpredictability there.
>
> >Signed-off-by: Paul Burton <paul.burton@xxxxxxxxxx>
> >---
> > arch/mips/math-emu/cp1emu.c | 25 ++++++++++++++++++++-----
> > 1 file changed, 20 insertions(+), 5 deletions(-)
>
> >diff --git a/arch/mips/math-emu/cp1emu.c b/arch/mips/math-emu/cp1emu.c
> >index 9144842..c484f5f 100644
> >--- a/arch/mips/math-emu/cp1emu.c
> >+++ b/arch/mips/math-emu/cp1emu.c
> >@@ -884,20 +884,35 @@ static inline int cop1_64bit(struct pt_regs *xcp)
> > } while (0)
> >
> > #define SITOREG(si, x) do { \
> >- if (cop1_64bit(xcp)) \
> >+ if (cop1_64bit(xcp)) { \
> >+ unsigned i; \
> > set_fpr32(&ctx->fpr[x], 0, si); \
> >- else \
> >+ for (i = 1; i < ARRAY_SIZE(ctx->fpr[x].val32); i++) \
> >+ set_fpr32(&ctx->fpr[x], i, 0); \
> >+ } else { \
> > set_fpr32(&ctx->fpr[(x) & ~1], (x) & 1, si); \
> >+ } \
> > } while (0)
> >
> > #define SIFROMHREG(si, x) ((si) = get_fpr32(&ctx->fpr[x], 1))
> >-#define SITOHREG(si, x) set_fpr32(&ctx->fpr[x], 1, si)
> >+
> >+#define SITOHREG(si, x) do { \
> >+ unsigned i; \
> >+ set_fpr32(&ctx->fpr[x], 1, si); \
> >+ for (i = 2; i < ARRAY_SIZE(ctx->fpr[x].val32); i++) \
> >+ set_fpr32(&ctx->fpr[x], i, 0); \
>
> This line is over-indented, no? Compare the loop below...
>
Indeed it is, well spotted :)
Thanks,
Paul
> >+} while (0)
> >
> > #define DIFROMREG(di, x) \
> > ((di) = get_fpr64(&ctx->fpr[(x) & ~(cop1_64bit(xcp) == 0)], 0))
> >
> >-#define DITOREG(di, x) \
> >- set_fpr64(&ctx->fpr[(x) & ~(cop1_64bit(xcp) == 0)], 0, di)
> >+#define DITOREG(di, x) do { \
> >+ unsigned fpr, i; \
> >+ fpr = (x) & ~(cop1_64bit(xcp) == 0); \
> >+ set_fpr64(&ctx->fpr[fpr], 0, di); \
> >+ for (i = 1; i < ARRAY_SIZE(ctx->fpr[x].val64); i++) \
> >+ set_fpr64(&ctx->fpr[fpr], i, 0); \
> >+} while (0)
>
> WBR, Sergei
>
