The branch main has been updated by dchagin: URL: https://cgit.FreeBSD.org/src/commit/?id=cbbac560911521c0ded3e06e713107176855fae4
commit cbbac560911521c0ded3e06e713107176855fae4 Author: Dmitry Chagin <[email protected]> AuthorDate: 2023-06-08 22:33:26 +0000 Commit: Dmitry Chagin <[email protected]> CommitDate: 2023-06-08 22:33:26 +0000 linux(4): Preserve fpu xsave state across signal delivery on amd64 PR: 270247 Reviewed by: kib Differential Revision: https://reviews.freebsd.org/D40444 MFC after: 2 weeks --- sys/amd64/linux/linux_sysvec.c | 99 ++++++++++++++++++++++++++++++++++++-- sys/x86/linux/linux_x86_sigframe.h | 20 +++++++- 2 files changed, 114 insertions(+), 5 deletions(-) diff --git a/sys/amd64/linux/linux_sysvec.c b/sys/amd64/linux/linux_sysvec.c index acc7593308af..ba4aff6f0c15 100644 --- a/sys/amd64/linux/linux_sysvec.c +++ b/sys/amd64/linux/linux_sysvec.c @@ -295,6 +295,54 @@ linux_fxrstor(struct thread *td, mcontext_t *mcp, struct l_sigcontext *sc) return (set_fpcontext(td, mcp, NULL, 0)); } +static int +linux_xrstor(struct thread *td, mcontext_t *mcp, struct l_sigcontext *sc) +{ + struct savefpu *fp = (struct savefpu *)&mcp->mc_fpstate[0]; + char *xfpustate; + struct proc *p; + uint32_t magic2; + int error; + + p = td->td_proc; + mcp->mc_xfpustate_len = cpu_max_ext_state_size - sizeof(struct savefpu); + + /* Legacy region of an xsave area. */ + error = copyin(PTRIN(sc->sc_fpstate), fp, sizeof(mcp->mc_fpstate)); + if (error != 0) + return (error); + bzero(&fp->sv_pad[0], sizeof(fp->sv_pad)); + + /* Extended region of an xsave area. */ + sc->sc_fpstate += sizeof(mcp->mc_fpstate); + xfpustate = (char *)fpu_save_area_alloc(); + error = copyin(PTRIN(sc->sc_fpstate), xfpustate, mcp->mc_xfpustate_len); + if (error != 0) { + fpu_save_area_free((struct savefpu *)xfpustate); + uprintf("pid %d (%s): linux xrstor failed\n", p->p_pid, + td->td_name); + return (error); + } + + /* Linux specific end of xsave area marker. */ + sc->sc_fpstate += mcp->mc_xfpustate_len; + error = copyin(PTRIN(sc->sc_fpstate), &magic2, LINUX_FP_XSTATE_MAGIC2_SIZE); + if (error != 0 || magic2 != LINUX_FP_XSTATE_MAGIC2) { + fpu_save_area_free((struct savefpu *)xfpustate); + uprintf("pid %d (%s): sigreturn magic2 0x%x error %d\n", + p->p_pid, td->td_name, magic2, error); + return (error); + } + + error = set_fpcontext(td, mcp, xfpustate, mcp->mc_xfpustate_len); + fpu_save_area_free((struct savefpu *)xfpustate); + if (error != 0) { + uprintf("pid %d (%s): sigreturn set_fpcontext error %d\n", + p->p_pid, td->td_name, error); + } + return (error); +} + static int linux_copyin_fpstate(struct thread *td, struct l_ucontext *uc) { @@ -304,7 +352,10 @@ linux_copyin_fpstate(struct thread *td, struct l_ucontext *uc) mc.mc_ownedfp = _MC_FPOWNED_FPU; mc.mc_fpformat = _MC_FPFMT_XMM; - return (linux_fxrstor(td, &mc, &uc->uc_mcontext)); + if ((uc->uc_flags & LINUX_UC_FP_XSTATE) != 0) + return (linux_xrstor(td, &mc, &uc->uc_mcontext)); + else + return (linux_fxrstor(td, &mc, &uc->uc_mcontext)); } /* @@ -411,20 +462,60 @@ linux_fxsave(mcontext_t *mcp, void *ufp) return (copyout(fx, ufp, sizeof(*fx))); } +static int +linux_xsave(mcontext_t *mcp, char *xfpusave, char *ufp) +{ + struct l_fpstate *fx = (struct l_fpstate *)&mcp->mc_fpstate[0]; + uint32_t magic2; + int error; + + /* Legacy region of an xsave area. */ + fx->sw_reserved.magic1 = LINUX_FP_XSTATE_MAGIC1; + fx->sw_reserved.xstate_size = mcp->mc_xfpustate_len + sizeof(*fx); + fx->sw_reserved.extended_size = fx->sw_reserved.xstate_size + + LINUX_FP_XSTATE_MAGIC2_SIZE; + fx->sw_reserved.xfeatures = xsave_mask; + + error = copyout(fx, ufp, sizeof(*fx)); + if (error != 0) + return (error); + ufp += sizeof(*fx); + + /* Extended region of an xsave area. */ + error = copyout(xfpusave, ufp, mcp->mc_xfpustate_len); + if (error != 0) + return (error); + + /* Linux specific end of xsave area marker. */ + ufp += mcp->mc_xfpustate_len; + magic2 = LINUX_FP_XSTATE_MAGIC2; + return (copyout(&magic2, ufp, LINUX_FP_XSTATE_MAGIC2_SIZE)); +} + static int linux_copyout_fpstate(struct thread *td, struct l_ucontext *uc, char **sp) { + size_t xfpusave_len; + char *xfpusave; mcontext_t mc; char *ufp = *sp; - get_fpcontext(td, &mc, NULL, NULL); + get_fpcontext(td, &mc, &xfpusave, &xfpusave_len); KASSERT(mc.mc_fpformat != _MC_FPFMT_NODEV, ("fpu not present")); - /* fxsave area */ + /* Room for fxsave area. */ ufp -= sizeof(struct l_fpstate); + if (xfpusave != NULL) { + /* Room for xsave area. */ + ufp -= (xfpusave_len + LINUX_FP_XSTATE_MAGIC2_SIZE); + uc->uc_flags |= LINUX_UC_FP_XSTATE; + } *sp = ufp = (char *)((unsigned long)ufp & ~0x3Ful); - return (linux_fxsave(&mc, ufp)); + if (xfpusave != NULL) + return (linux_xsave(&mc, xfpusave, ufp)); + else + return (linux_fxsave(&mc, ufp)); } /* diff --git a/sys/x86/linux/linux_x86_sigframe.h b/sys/x86/linux/linux_x86_sigframe.h index e5687069651f..c748073a3457 100644 --- a/sys/x86/linux/linux_x86_sigframe.h +++ b/sys/x86/linux/linux_x86_sigframe.h @@ -35,6 +35,20 @@ #ifndef _X86_LINUX_SIGFRAME_H_ #define _X86_LINUX_SIGFRAME_H_ +#define LINUX_UC_FP_XSTATE 0x1 + +#define LINUX_FP_XSTATE_MAGIC1 0x46505853U +#define LINUX_FP_XSTATE_MAGIC2 0x46505845U +#define LINUX_FP_XSTATE_MAGIC2_SIZE sizeof(uint32_t) + +struct l_fpx_sw_bytes { + uint32_t magic1; + uint32_t extended_size; + uint64_t xfeatures; + uint32_t xstate_size; + uint32_t padding[7]; +}; + #if defined(__i386__) || (defined(__amd64__) && defined(COMPAT_LINUX32)) /* The Linux sigcontext, pretty much a standard 386 trapframe. */ @@ -140,7 +154,11 @@ struct l_fpstate { u_int32_t mxcsr_mask; u_int8_t st[8][16]; u_int8_t xmm[16][16]; - u_int32_t reserved2[24]; + u_int32_t reserved2[12]; + union { + u_int32_t reserved3[12]; + struct l_fpx_sw_bytes sw_reserved; + }; } __aligned(16); struct l_sigcontext {
