diff options
Diffstat (limited to 'arch/arm64/kernel')
| -rw-r--r-- | arch/arm64/kernel/signal32.c | 47 |
1 files changed, 36 insertions, 11 deletions
diff --git a/arch/arm64/kernel/signal32.c b/arch/arm64/kernel/signal32.c index 948f0ad2de23..71ef6dc89ae5 100644 --- a/arch/arm64/kernel/signal32.c +++ b/arch/arm64/kernel/signal32.c @@ -212,14 +212,32 @@ int copy_siginfo_from_user32(siginfo_t *to, compat_siginfo_t __user *from) /* * VFP save/restore code. + * + * We have to be careful with endianness, since the fpsimd context-switch + * code operates on 128-bit (Q) register values whereas the compat ABI + * uses an array of 64-bit (D) registers. Consequently, we need to swap + * the two halves of each Q register when running on a big-endian CPU. */ +union __fpsimd_vreg { + __uint128_t raw; + struct { +#ifdef __AARCH64EB__ + u64 hi; + u64 lo; +#else + u64 lo; + u64 hi; +#endif + }; +}; + static int compat_preserve_vfp_context(struct compat_vfp_sigframe __user *frame) { struct fpsimd_state *fpsimd = ¤t->thread.fpsimd_state; compat_ulong_t magic = VFP_MAGIC; compat_ulong_t size = VFP_STORAGE_SIZE; compat_ulong_t fpscr, fpexc; - int err = 0; + int i, err = 0; /* * Save the hardware registers to the fpsimd_state structure. @@ -235,10 +253,15 @@ static int compat_preserve_vfp_context(struct compat_vfp_sigframe __user *frame) /* * Now copy the FP registers. Since the registers are packed, * we can copy the prefix we want (V0-V15) as it is. - * FIXME: Won't work if big endian. */ - err |= __copy_to_user(&frame->ufp.fpregs, fpsimd->vregs, - sizeof(frame->ufp.fpregs)); + for (i = 0; i < ARRAY_SIZE(frame->ufp.fpregs); i += 2) { + union __fpsimd_vreg vreg = { + .raw = fpsimd->vregs[i >> 1], + }; + + __put_user_error(vreg.lo, &frame->ufp.fpregs[i], err); + __put_user_error(vreg.hi, &frame->ufp.fpregs[i + 1], err); + } /* Create an AArch32 fpscr from the fpsr and the fpcr. */ fpscr = (fpsimd->fpsr & VFP_FPSCR_STAT_MASK) | @@ -263,7 +286,7 @@ static int compat_restore_vfp_context(struct compat_vfp_sigframe __user *frame) compat_ulong_t magic = VFP_MAGIC; compat_ulong_t size = VFP_STORAGE_SIZE; compat_ulong_t fpscr; - int err = 0; + int i, err = 0; __get_user_error(magic, &frame->magic, err); __get_user_error(size, &frame->size, err); @@ -273,12 +296,14 @@ static int compat_restore_vfp_context(struct compat_vfp_sigframe __user *frame) if (magic != VFP_MAGIC || size != VFP_STORAGE_SIZE) return -EINVAL; - /* - * Copy the FP registers into the start of the fpsimd_state. - * FIXME: Won't work if big endian. - */ - err |= __copy_from_user(fpsimd.vregs, frame->ufp.fpregs, - sizeof(frame->ufp.fpregs)); + /* Copy the FP registers into the start of the fpsimd_state. */ + for (i = 0; i < ARRAY_SIZE(frame->ufp.fpregs); i += 2) { + union __fpsimd_vreg vreg; + + __get_user_error(vreg.lo, &frame->ufp.fpregs[i], err); + __get_user_error(vreg.hi, &frame->ufp.fpregs[i + 1], err); + fpsimd.vregs[i >> 1] = vreg.raw; + } /* Extract the fpsr and the fpcr from the fpscr */ __get_user_error(fpscr, &frame->ufp.fpscr, err); |