| Message ID | 1301489184-4112-2-git-send-email-dave.martin@linaro.org |
|---|---|
| State | Rejected |
| Headers | show |
On Wed, Mar 30, 2011 at 01:46:24PM +0100, Dave Martin wrote: > The fpmx_state field was presumably used in the past, when > FSTMX/FLDMX were used to save and resture the VFP state. > > This was been deprecated since ARMv6, the context switch code > has been ported to use the double-precision load/store variants > many years ago, and now it appears that nothing in the kernel > references this field any more. Wrong. .macro VFPFSTMIA, base, tmp #if __LINUX_ARM_ARCH__ < 6 STC p11, cr0, [\base],#33*4 @ FSTMIAX \base!, {d0-d15} #else STC p11, cr0, [\base],#32*4 @ FSTMIAD \base!, {d0-d15} #endif So, building for pre-ARMv6, it's still used.
On Wed, Mar 30, 2011 at 6:52 PM, Russell King - ARM Linux <linux@arm.linux.org.uk> wrote: > On Wed, Mar 30, 2011 at 01:46:24PM +0100, Dave Martin wrote: >> The fpmx_state field was presumably used in the past, when >> FSTMX/FLDMX were used to save and resture the VFP state. >> >> This was been deprecated since ARMv6, the context switch code >> has been ported to use the double-precision load/store variants >> many years ago, and now it appears that nothing in the kernel >> references this field any more. > > Wrong. > > .macro VFPFSTMIA, base, tmp > #if __LINUX_ARM_ARCH__ < 6 > STC p11, cr0, [\base],#33*4 @ FSTMIAX \base!, {d0-d15} > #else > STC p11, cr0, [\base],#32*4 @ FSTMIAD \base!, {d0-d15} > #endif > > So, building for pre-ARMv6, it's still used. > Fair point -- looks like my grepping missed those. Oops. While I'm looking at this file though... vfpmacros.h starts with: @ Macros to allow building with old toolkits (with no VFP support) I don't think we support building the kernel with such old binutils any more. Maybe this file could be simplified? arch/arm/vfp/ seems to be built with -mfpu=softvfp+vfp, which appears to enable most of the affected mnemonics. vfpmacros.h also contains some oddities such as: #ifdef CONFIG_VFPv3 #if __LINUX_ARM_ARCH__ <= 6 /*...*/ Since we don't support building a single kernel across ARMv5 and ARMv7, are these blocks effectively dead code? Cheers ---Dave
diff --git a/arch/arm/include/asm/fpstate.h b/arch/arm/include/asm/fpstate.h index ee5e03e..08bb836 100644 --- a/arch/arm/include/asm/fpstate.h +++ b/arch/arm/include/asm/fpstate.h @@ -18,7 +18,6 @@ * VFP storage area has: * - FPEXC, FPSCR, FPINST and FPINST2. * - 16 or 32 double precision data registers - * - an implementation-dependant word of state for FLDMX/FSTMX (pre-ARMv6) * * FPEXC will always be non-zero once the VFP has been used in this process. */ @@ -29,9 +28,6 @@ struct vfp_hard_struct { #else __u64 fpregs[16]; #endif -#if __LINUX_ARM_ARCH__ < 6 - __u32 fpmx_state; -#endif __u32 fpexc; __u32 fpscr; /*
The fpmx_state field was presumably used in the past, when FSTMX/FLDMX were used to save and resture the VFP state. This was been deprecated since ARMv6, the context switch code has been ported to use the double-precision load/store variants many years ago, and now it appears that nothing in the kernel references this field any more. Signed-off-by: Dave Martin <dave.martin@linaro.org> --- arch/arm/include/asm/fpstate.h | 4 ---- 1 files changed, 0 insertions(+), 4 deletions(-)