From a5f6096c805e6d2fa03ee932f8c70af34cee41a0 Mon Sep 17 00:00:00 2001 From: Jeff Dike Date: Tue, 16 Oct 2007 01:27:15 -0700 Subject: [PATCH] uml: floating point signal delivery fixes Handle floating point state in across signals correctly. UML/i386 needs to know whether the host does PTRACE_[GS]ETFPXREGS, so an arch_init_registers hook is added, which on x86_64 does nothing. UML doesn't save and restore floating point registers on kernel entry and exit, so they need to be copied between the host process and the sigcontext. save_fpx_registers and restore_fpx_registers are added for this purpose. save_fp_registers and restore_fp_registers already exist. There was a bunch of floating point state conversion code in arch/um/sys-i386/ptrace.c which isn't needed there, but is needed in signal.c, so it is moved over. The i386 code now distinguishes between fp and fpx state and handles them correctly. The x86_64 code just needs to copy state as-is between the host process and the stack. There are also some fixes there to pass the correct address of the floating point state around. Signed-off-by: Jeff Dike Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/um/include/registers.h | 2 + arch/um/include/sysdep-i386/ptrace.h | 2 + arch/um/include/sysdep-x86_64/ptrace.h | 4 + arch/um/os-Linux/registers.c | 2 + arch/um/os-Linux/sys-i386/registers.c | 35 +++- arch/um/sys-i386/ptrace.c | 79 --------- arch/um/sys-i386/signal.c | 223 ++++++++++++++++++++++--- arch/um/sys-x86_64/signal.c | 53 ++++-- 8 files changed, 284 insertions(+), 116 deletions(-) diff --git a/arch/um/include/registers.h b/arch/um/include/registers.h index 8e8ea9651189..0e27406a43a4 100644 --- a/arch/um/include/registers.h +++ b/arch/um/include/registers.h @@ -12,6 +12,8 @@ extern void init_thread_registers(struct uml_pt_regs *to); extern int save_fp_registers(int pid, unsigned long *fp_regs); extern int restore_fp_registers(int pid, unsigned long *fp_regs); +extern int save_fpx_registers(int pid, unsigned long *fp_regs); +extern int restore_fpx_registers(int pid, unsigned long *fp_regs); extern void save_registers(int pid, struct uml_pt_regs *regs); extern void restore_registers(int pid, struct uml_pt_regs *regs); extern void init_registers(int pid); diff --git a/arch/um/include/sysdep-i386/ptrace.h b/arch/um/include/sysdep-i386/ptrace.h index edb9393283b5..c16d739d2089 100644 --- a/arch/um/include/sysdep-i386/ptrace.h +++ b/arch/um/include/sysdep-i386/ptrace.h @@ -168,4 +168,6 @@ struct syscall_args { #define UPT_FAULTINFO(r) (&(r)->faultinfo) +extern void arch_init_registers(int pid); + #endif diff --git a/arch/um/include/sysdep-x86_64/ptrace.h b/arch/um/include/sysdep-x86_64/ptrace.h index 2ae04480ac81..7848b7dce715 100644 --- a/arch/um/include/sysdep-x86_64/ptrace.h +++ b/arch/um/include/sysdep-x86_64/ptrace.h @@ -234,4 +234,8 @@ struct syscall_args { #define UPT_FAULTINFO(r) (&(r)->faultinfo) +static inline void arch_init_registers(int pid) +{ +} + #endif diff --git a/arch/um/os-Linux/registers.c b/arch/um/os-Linux/registers.c index b06c780e8dba..a32ba6ab1211 100644 --- a/arch/um/os-Linux/registers.c +++ b/arch/um/os-Linux/registers.c @@ -47,6 +47,8 @@ void init_registers(int pid) if (err) panic("check_ptrace : PTRACE_GETREGS failed, errno = %d", errno); + + arch_init_registers(pid); } void get_safe_registers(unsigned long *regs) diff --git a/arch/um/os-Linux/sys-i386/registers.c b/arch/um/os-Linux/sys-i386/registers.c index f171204caa4e..8f1f0ab639b9 100644 --- a/arch/um/os-Linux/sys-i386/registers.c +++ b/arch/um/os-Linux/sys-i386/registers.c @@ -8,9 +8,6 @@ #include "longjmp.h" #include "user.h" -/* XXX These need to use [GS]ETFPXREGS and copy_sc_{to,from}_user_skas needs - * to pass in a sufficiently large buffer - */ int save_fp_registers(int pid, unsigned long *fp_regs) { if(ptrace(PTRACE_GETFPREGS, pid, 0, fp_regs) < 0) @@ -25,6 +22,20 @@ int restore_fp_registers(int pid, unsigned long *fp_regs) return 0; } +int save_fpx_registers(int pid, unsigned long *fp_regs) +{ + if(ptrace(PTRACE_GETFPXREGS, pid, 0, fp_regs) < 0) + return -errno; + return 0; +} + +int restore_fpx_registers(int pid, unsigned long *fp_regs) +{ + if(ptrace(PTRACE_SETFPXREGS, pid, 0, fp_regs) < 0) + return -errno; + return 0; +} + unsigned long get_thread_reg(int reg, jmp_buf *buf) { switch(reg){ @@ -36,3 +47,21 @@ unsigned long get_thread_reg(int reg, jmp_buf *buf) return 0; } } + +int have_fpx_regs = 1; + +void arch_init_registers(int pid) +{ + unsigned long fpx_regs[HOST_XFP_SIZE]; + int err; + + err = ptrace(PTRACE_GETFPXREGS, pid, 0, fpx_regs); + if(!err) + return; + + if(errno != EIO) + panic("check_ptrace : PTRACE_GETFPXREGS failed, errno = %d", + errno); + + have_fpx_regs = 0; +} diff --git a/arch/um/sys-i386/ptrace.c b/arch/um/sys-i386/ptrace.c index 178f894384f4..cb899dd1c6b5 100644 --- a/arch/um/sys-i386/ptrace.c +++ b/arch/um/sys-i386/ptrace.c @@ -144,85 +144,6 @@ int peek_user(struct task_struct *child, long addr, long data) return put_user(tmp, (unsigned long __user *) data); } -struct i387_fxsave_struct { - unsigned short cwd; - unsigned short swd; - unsigned short twd; - unsigned short fop; - long fip; - long fcs; - long foo; - long fos; - long mxcsr; - long reserved; - long st_space[32]; /* 8*16 bytes for each FP-reg = 128 bytes */ - long xmm_space[32]; /* 8*16 bytes for each XMM-reg = 128 bytes */ - long padding[56]; -}; - -/* - * FPU tag word conversions. - */ - -static inline unsigned short twd_i387_to_fxsr( unsigned short twd ) -{ - unsigned int tmp; /* to avoid 16 bit prefixes in the code */ - - /* Transform each pair of bits into 01 (valid) or 00 (empty) */ - tmp = ~twd; - tmp = (tmp | (tmp>>1)) & 0x5555; /* 0V0V0V0V0V0V0V0V */ - /* and move the valid bits to the lower byte. */ - tmp = (tmp | (tmp >> 1)) & 0x3333; /* 00VV00VV00VV00VV */ - tmp = (tmp | (tmp >> 2)) & 0x0f0f; /* 0000VVVV0000VVVV */ - tmp = (tmp | (tmp >> 4)) & 0x00ff; /* 00000000VVVVVVVV */ - return tmp; -} - -static inline unsigned long twd_fxsr_to_i387( struct i387_fxsave_struct *fxsave ) -{ - struct _fpxreg *st = NULL; - unsigned long twd = (unsigned long) fxsave->twd; - unsigned long tag; - unsigned long ret = 0xffff0000; - int i; - -#define FPREG_ADDR(f, n) ((char *)&(f)->st_space + (n) * 16); - - for ( i = 0 ; i < 8 ; i++ ) { - if ( twd & 0x1 ) { - st = (struct _fpxreg *) FPREG_ADDR( fxsave, i ); - - switch ( st->exponent & 0x7fff ) { - case 0x7fff: - tag = 2; /* Special */ - break; - case 0x0000: - if ( !st->significand[0] && - !st->significand[1] && - !st->significand[2] && - !st->significand[3] ) { - tag = 1; /* Zero */ - } else { - tag = 2; /* Special */ - } - break; - default: - if ( st->significand[3] & 0x8000 ) { - tag = 0; /* Valid */ - } else { - tag = 2; /* Special */ - } - break; - } - } else { - tag = 3; /* Empty */ - } - ret |= (tag << (2 * i)); - twd = twd >> 1; - } - return ret; -} - static inline int convert_fxsr_to_user(struct _fpstate __user *buf, struct pt_regs *regs) { diff --git a/arch/um/sys-i386/signal.c b/arch/um/sys-i386/signal.c index 1eb21a023e33..0147227ce18d 100644 --- a/arch/um/sys-i386/signal.c +++ b/arch/um/sys-i386/signal.c @@ -32,25 +32,186 @@ void copy_sc(struct uml_pt_regs *regs, void *from) REGS_SS(regs->gp) = sc->ss; } +/* + * FPU tag word conversions. + */ + +static inline unsigned short twd_i387_to_fxsr(unsigned short twd) +{ + unsigned int tmp; /* to avoid 16 bit prefixes in the code */ + + /* Transform each pair of bits into 01 (valid) or 00 (empty) */ + tmp = ~twd; + tmp = (tmp | (tmp>>1)) & 0x5555; /* 0V0V0V0V0V0V0V0V */ + /* and move the valid bits to the lower byte. */ + tmp = (tmp | (tmp >> 1)) & 0x3333; /* 00VV00VV00VV00VV */ + tmp = (tmp | (tmp >> 2)) & 0x0f0f; /* 0000VVVV0000VVVV */ + tmp = (tmp | (tmp >> 4)) & 0x00ff; /* 00000000VVVVVVVV */ + return tmp; +} + +static inline unsigned long twd_fxsr_to_i387(struct user_fxsr_struct *fxsave) +{ + struct _fpxreg *st = NULL; + unsigned long twd = (unsigned long) fxsave->twd; + unsigned long tag; + unsigned long ret = 0xffff0000; + int i; + +#define FPREG_ADDR(f, n) ((char *)&(f)->st_space + (n) * 16); + + for (i = 0; i < 8; i++) { + if (twd & 0x1) { + st = (struct _fpxreg *) FPREG_ADDR(fxsave, i); + + switch (st->exponent & 0x7fff) { + case 0x7fff: + tag = 2; /* Special */ + break; + case 0x0000: + if ( !st->significand[0] && + !st->significand[1] && + !st->significand[2] && + !st->significand[3] ) { + tag = 1; /* Zero */ + } else { + tag = 2; /* Special */ + } + break; + default: + if (st->significand[3] & 0x8000) { + tag = 0; /* Valid */ + } else { + tag = 2; /* Special */ + } + break; + } + } else { + tag = 3; /* Empty */ + } + ret |= (tag << (2 * i)); + twd = twd >> 1; + } + return ret; +} + +static int convert_fxsr_to_user(struct _fpstate __user *buf, + struct user_fxsr_struct *fxsave) +{ + unsigned long env[7]; + struct _fpreg __user *to; + struct _fpxreg *from; + int i; + + env[0] = (unsigned long)fxsave->cwd | 0xffff0000ul; + env[1] = (unsigned long)fxsave->swd | 0xffff0000ul; + env[2] = twd_fxsr_to_i387(fxsave); + env[3] = fxsave->fip; + env[4] = fxsave->fcs | ((unsigned long)fxsave->fop << 16); + env[5] = fxsave->foo; + env[6] = fxsave->fos; + + if (__copy_to_user(buf, env, 7 * sizeof(unsigned long))) + return 1; + + to = &buf->_st[0]; + from = (struct _fpxreg *) &fxsave->st_space[0]; + for (i = 0; i < 8; i++, to++, from++) { + unsigned long __user *t = (unsigned long __user *)to; + unsigned long *f = (unsigned long *)from; + + if (__put_user(*f, t) || + __put_user(*(f + 1), t + 1) || + __put_user(from->exponent, &to->exponent)) + return 1; + } + return 0; +} + +static int convert_fxsr_from_user(struct user_fxsr_struct *fxsave, + struct _fpstate __user *buf) +{ + unsigned long env[7]; + struct _fpxreg *to; + struct _fpreg __user *from; + int i; + + if (copy_from_user( env, buf, 7 * sizeof(long))) + return 1; + + fxsave->cwd = (unsigned short)(env[0] & 0xffff); + fxsave->swd = (unsigned short)(env[1] & 0xffff); + fxsave->twd = twd_i387_to_fxsr((unsigned short)(env[2] & 0xffff)); + fxsave->fip = env[3]; + fxsave->fop = (unsigned short)((env[4] & 0xffff0000ul) >> 16); + fxsave->fcs = (env[4] & 0xffff); + fxsave->foo = env[5]; + fxsave->fos = env[6]; + + to = (struct _fpxreg *) &fxsave->st_space[0]; + from = &buf->_st[0]; + for (i = 0; i < 8; i++, to++, from++) { + unsigned long *t = (unsigned long *)to; + unsigned long __user *f = (unsigned long __user *)from; + + if (__get_user(*t, f) || + __get_user(*(t + 1), f + 1) || + __get_user(to->exponent, &from->exponent)) + return 1; + } + return 0; +} + +extern int have_fpx_regs; + static int copy_sc_from_user(struct pt_regs *regs, struct sigcontext __user *from) { - struct sigcontext sc; - unsigned long fpregs[HOST_FP_SIZE]; + struct sigcontext sc; int err; err = copy_from_user(&sc, from, sizeof(sc)); - err |= copy_from_user(fpregs, sc.fpstate, sizeof(fpregs)); if (err) return err; copy_sc(®s->regs, &sc); - - err = restore_fp_registers(userspace_pid[0], fpregs); - if (err < 0) { - printk(KERN_ERR "copy_sc_from_user_skas - PTRACE_SETFPREGS " - "failed, errno = %d\n", -err); - return err; + if (have_fpx_regs) { + struct user_fxsr_struct fpx; + + err = copy_from_user(&fpx, &sc.fpstate->_fxsr_env[0], + sizeof(struct user_fxsr_struct)); + if (err) + return 1; + + err = convert_fxsr_from_user(&fpx, sc.fpstate); + if (err) + return 1; + + err = restore_fpx_registers(userspace_pid[current_thread->cpu], + (unsigned long *) &fpx); + if (err < 0) { + printk(KERN_ERR "copy_sc_from_user - " + "restore_fpx_registers failed, errno = %d\n", + -err); + return 1; + } + } + else { + struct user_i387_struct fp; + + err = copy_from_user(&fp, sc.fpstate, + sizeof(struct user_i387_struct)); + if (err) + return 1; + + err = restore_fp_registers(userspace_pid[current_thread->cpu], + (unsigned long *) &fp); + if (err < 0) { + printk(KERN_ERR "copy_sc_from_user - " + "restore_fp_registers failed, errno = %d\n", + -err); + return 1; + } } return 0; @@ -61,7 +222,6 @@ static int copy_sc_to_user(struct sigcontext __user *to, unsigned long sp) { struct sigcontext sc; - unsigned long fpregs[HOST_FP_SIZE]; struct faultinfo * fi = ¤t->thread.arch.faultinfo; int err; @@ -86,20 +246,43 @@ static int copy_sc_to_user(struct sigcontext __user *to, sc.err = fi->error_code; sc.trapno = fi->trap_no; - err = save_fp_registers(userspace_pid[0], fpregs); - if (err < 0) { - printk(KERN_ERR "copy_sc_to_user_skas - PTRACE_GETFPREGS " - "failed, errno = %d\n", err); - return 1; - } to_fp = (to_fp ? to_fp : (struct _fpstate __user *) (to + 1)); sc.fpstate = to_fp; - if (err) - return err; + if (have_fpx_regs) { + struct user_fxsr_struct fpx; + + err = save_fpx_registers(userspace_pid[current_thread->cpu], + (unsigned long *) &fpx); + if (err < 0){ + printk(KERN_ERR "copy_sc_to_user - save_fpx_registers " + "failed, errno = %d\n", err); + return 1; + } + + err = convert_fxsr_to_user(to_fp, &fpx); + if (err) + return 1; + + err |= __put_user(fpx.swd, &to_fp->status); + err |= __put_user(X86_FXSR_MAGIC, &to_fp->magic); + if (err) + return 1; + + if (copy_to_user(&to_fp->_fxsr_env[0], &fpx, + sizeof(struct user_fxsr_struct))) + return 1; + } + else { + struct user_i387_struct fp; + + err = save_fp_registers(userspace_pid[current_thread->cpu], + (unsigned long *) &fp); + if (copy_to_user(to_fp, &fp, sizeof(struct user_i387_struct))) + return 1; + } - return copy_to_user(to, &sc, sizeof(sc)) || - copy_to_user(to_fp, fpregs, sizeof(fpregs)); + return copy_to_user(to, &sc, sizeof(sc)); } static int copy_ucontext_to_user(struct ucontext __user *uc, diff --git a/arch/um/sys-x86_64/signal.c b/arch/um/sys-x86_64/signal.c index c98dd7f31396..a8e5fd7b2adb 100644 --- a/arch/um/sys-x86_64/signal.c +++ b/arch/um/sys-x86_64/signal.c @@ -42,8 +42,10 @@ void copy_sc(struct uml_pt_regs *regs, void *from) } static int copy_sc_from_user(struct pt_regs *regs, - struct sigcontext __user *from) + struct sigcontext __user *from, + struct _fpstate __user *fpp) { + struct user_i387_struct fp; int err = 0; #define GETREG(regs, regno, sc, regname) \ @@ -69,10 +71,25 @@ static int copy_sc_from_user(struct pt_regs *regs, err |= GETREG(regs, RIP, from, rip); err |= GETREG(regs, EFLAGS, from, eflags); err |= GETREG(regs, CS, from, cs); + if (err) + return 1; #undef GETREG - return err; + err = copy_from_user(&fp, fpp, sizeof(struct user_i387_struct)); + if (err) + return 1; + + err = restore_fp_registers(userspace_pid[current_thread->cpu], + (unsigned long *) &fp); + if (err < 0) { + printk(KERN_ERR "copy_sc_from_user - " + "restore_fp_registers failed, errno = %d\n", + -err); + return 1; + } + + return 0; } static int copy_sc_to_user(struct sigcontext __user *to, @@ -80,6 +97,7 @@ static int copy_sc_to_user(struct sigcontext __user *to, unsigned long mask, unsigned long sp) { struct faultinfo * fi = ¤t->thread.arch.faultinfo; + struct user_i387_struct fp; int err = 0; err |= __put_user(0, &to->gs); @@ -120,6 +138,19 @@ static int copy_sc_to_user(struct sigcontext __user *to, #undef PUTREG err |= __put_user(mask, &to->oldmask); + if (err) + return 1; + + err = save_fp_registers(userspace_pid[current_thread->cpu], + (unsigned long *) &fp); + if (err < 0) { + printk(KERN_ERR "copy_sc_from_user - restore_fp_registers " + "failed, errno = %d\n", -err); + return 1; + } + + if (copy_to_user(to_fp, &fp, sizeof(struct user_i387_struct))) + return 1; return(err); } @@ -129,6 +160,7 @@ struct rt_sigframe char __user *pretcode; struct ucontext uc; struct siginfo info; + struct _fpstate fpstate; }; #define round_down(m, n) (((m) / (n)) * (n)) @@ -138,7 +170,6 @@ int setup_signal_stack_si(unsigned long stack_top, int sig, siginfo_t *info, sigset_t *set) { struct rt_sigframe __user *frame; - struct _fpstate __user *fp = NULL; unsigned long save_sp = PT_REGS_RSP(regs); int err = 0; struct task_struct *me = current; @@ -148,13 +179,6 @@ int setup_signal_stack_si(unsigned long stack_top, int sig, /* Subtract 128 for a red zone and 8 for proper alignment */ frame = (struct rt_sigframe __user *) ((unsigned long) frame - 128 - 8); - if (!access_ok(VERIFY_WRITE, fp, sizeof(struct _fpstate))) - goto out; - -#if 0 /* XXX */ - if (save_i387(fp) < 0) - err |= -1; -#endif if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame))) goto out; @@ -181,9 +205,9 @@ int setup_signal_stack_si(unsigned long stack_top, int sig, err |= __put_user(sas_ss_flags(save_sp), &frame->uc.uc_stack.ss_flags); err |= __put_user(me->sas_ss_size, &frame->uc.uc_stack.ss_size); - err |= copy_sc_to_user(&frame->uc.uc_mcontext, fp, regs, set->sig[0], - save_sp); - err |= __put_user(fp, &frame->uc.uc_mcontext.fpstate); + err |= copy_sc_to_user(&frame->uc.uc_mcontext, &frame->fpstate, regs, + set->sig[0], save_sp); + err |= __put_user(&frame->fpstate, &frame->uc.uc_mcontext.fpstate); if (sizeof(*set) == 16) { __put_user(set->sig[0], &frame->uc.uc_sigmask.sig[0]); __put_user(set->sig[1], &frame->uc.uc_sigmask.sig[1]); @@ -246,7 +270,8 @@ long sys_rt_sigreturn(struct pt_regs *regs) recalc_sigpending(); spin_unlock_irq(¤t->sighand->siglock); - if (copy_sc_from_user(¤t->thread.regs, &uc->uc_mcontext)) + if (copy_sc_from_user(¤t->thread.regs, &uc->uc_mcontext, + &frame->fpstate)) goto segfault; /* Avoid ERESTART handling */ -- GitLab