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 <jdike@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Jeff Dike
committed by
Linus Torvalds
Linus Torvalds
parent
189872f968
commit
a5f6096c80
@@ -144,85 +144,6 @@ int peek_user(struct task_struct *child, long addr, long data)
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return put_user(tmp, (unsigned long __user *) data);
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}
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struct i387_fxsave_struct {
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unsigned short cwd;
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unsigned short swd;
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unsigned short twd;
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unsigned short fop;
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long fip;
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long fcs;
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long foo;
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long fos;
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long mxcsr;
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long reserved;
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long st_space[32]; /* 8*16 bytes for each FP-reg = 128 bytes */
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long xmm_space[32]; /* 8*16 bytes for each XMM-reg = 128 bytes */
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long padding[56];
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};
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/*
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* FPU tag word conversions.
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*/
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static inline unsigned short twd_i387_to_fxsr( unsigned short twd )
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{
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unsigned int tmp; /* to avoid 16 bit prefixes in the code */
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/* Transform each pair of bits into 01 (valid) or 00 (empty) */
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tmp = ~twd;
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tmp = (tmp | (tmp>>1)) & 0x5555; /* 0V0V0V0V0V0V0V0V */
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/* and move the valid bits to the lower byte. */
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tmp = (tmp | (tmp >> 1)) & 0x3333; /* 00VV00VV00VV00VV */
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tmp = (tmp | (tmp >> 2)) & 0x0f0f; /* 0000VVVV0000VVVV */
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tmp = (tmp | (tmp >> 4)) & 0x00ff; /* 00000000VVVVVVVV */
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return tmp;
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}
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static inline unsigned long twd_fxsr_to_i387( struct i387_fxsave_struct *fxsave )
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{
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struct _fpxreg *st = NULL;
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unsigned long twd = (unsigned long) fxsave->twd;
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unsigned long tag;
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unsigned long ret = 0xffff0000;
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int i;
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#define FPREG_ADDR(f, n) ((char *)&(f)->st_space + (n) * 16);
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for ( i = 0 ; i < 8 ; i++ ) {
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if ( twd & 0x1 ) {
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st = (struct _fpxreg *) FPREG_ADDR( fxsave, i );
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switch ( st->exponent & 0x7fff ) {
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case 0x7fff:
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tag = 2; /* Special */
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break;
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case 0x0000:
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if ( !st->significand[0] &&
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!st->significand[1] &&
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!st->significand[2] &&
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!st->significand[3] ) {
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tag = 1; /* Zero */
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} else {
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tag = 2; /* Special */
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}
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break;
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default:
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if ( st->significand[3] & 0x8000 ) {
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tag = 0; /* Valid */
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} else {
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tag = 2; /* Special */
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}
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break;
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}
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} else {
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tag = 3; /* Empty */
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}
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ret |= (tag << (2 * i));
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twd = twd >> 1;
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}
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return ret;
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}
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static inline int convert_fxsr_to_user(struct _fpstate __user *buf,
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struct pt_regs *regs)
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{
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@@ -32,25 +32,186 @@ void copy_sc(struct uml_pt_regs *regs, void *from)
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REGS_SS(regs->gp) = sc->ss;
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}
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/*
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* FPU tag word conversions.
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*/
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static inline unsigned short twd_i387_to_fxsr(unsigned short twd)
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{
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unsigned int tmp; /* to avoid 16 bit prefixes in the code */
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/* Transform each pair of bits into 01 (valid) or 00 (empty) */
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tmp = ~twd;
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tmp = (tmp | (tmp>>1)) & 0x5555; /* 0V0V0V0V0V0V0V0V */
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/* and move the valid bits to the lower byte. */
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tmp = (tmp | (tmp >> 1)) & 0x3333; /* 00VV00VV00VV00VV */
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tmp = (tmp | (tmp >> 2)) & 0x0f0f; /* 0000VVVV0000VVVV */
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tmp = (tmp | (tmp >> 4)) & 0x00ff; /* 00000000VVVVVVVV */
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return tmp;
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}
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static inline unsigned long twd_fxsr_to_i387(struct user_fxsr_struct *fxsave)
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{
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struct _fpxreg *st = NULL;
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unsigned long twd = (unsigned long) fxsave->twd;
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unsigned long tag;
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unsigned long ret = 0xffff0000;
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int i;
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#define FPREG_ADDR(f, n) ((char *)&(f)->st_space + (n) * 16);
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for (i = 0; i < 8; i++) {
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if (twd & 0x1) {
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st = (struct _fpxreg *) FPREG_ADDR(fxsave, i);
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switch (st->exponent & 0x7fff) {
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case 0x7fff:
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tag = 2; /* Special */
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break;
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case 0x0000:
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if ( !st->significand[0] &&
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!st->significand[1] &&
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!st->significand[2] &&
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!st->significand[3] ) {
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tag = 1; /* Zero */
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} else {
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tag = 2; /* Special */
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}
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break;
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default:
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if (st->significand[3] & 0x8000) {
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tag = 0; /* Valid */
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} else {
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tag = 2; /* Special */
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}
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break;
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}
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} else {
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tag = 3; /* Empty */
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}
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ret |= (tag << (2 * i));
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twd = twd >> 1;
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}
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return ret;
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}
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static int convert_fxsr_to_user(struct _fpstate __user *buf,
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struct user_fxsr_struct *fxsave)
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{
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unsigned long env[7];
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struct _fpreg __user *to;
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struct _fpxreg *from;
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int i;
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env[0] = (unsigned long)fxsave->cwd | 0xffff0000ul;
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env[1] = (unsigned long)fxsave->swd | 0xffff0000ul;
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env[2] = twd_fxsr_to_i387(fxsave);
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env[3] = fxsave->fip;
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env[4] = fxsave->fcs | ((unsigned long)fxsave->fop << 16);
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env[5] = fxsave->foo;
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env[6] = fxsave->fos;
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if (__copy_to_user(buf, env, 7 * sizeof(unsigned long)))
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return 1;
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to = &buf->_st[0];
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from = (struct _fpxreg *) &fxsave->st_space[0];
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for (i = 0; i < 8; i++, to++, from++) {
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unsigned long __user *t = (unsigned long __user *)to;
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unsigned long *f = (unsigned long *)from;
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if (__put_user(*f, t) ||
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__put_user(*(f + 1), t + 1) ||
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__put_user(from->exponent, &to->exponent))
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return 1;
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}
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return 0;
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}
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static int convert_fxsr_from_user(struct user_fxsr_struct *fxsave,
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struct _fpstate __user *buf)
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{
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unsigned long env[7];
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struct _fpxreg *to;
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struct _fpreg __user *from;
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int i;
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if (copy_from_user( env, buf, 7 * sizeof(long)))
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return 1;
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fxsave->cwd = (unsigned short)(env[0] & 0xffff);
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fxsave->swd = (unsigned short)(env[1] & 0xffff);
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fxsave->twd = twd_i387_to_fxsr((unsigned short)(env[2] & 0xffff));
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fxsave->fip = env[3];
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fxsave->fop = (unsigned short)((env[4] & 0xffff0000ul) >> 16);
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fxsave->fcs = (env[4] & 0xffff);
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fxsave->foo = env[5];
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fxsave->fos = env[6];
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to = (struct _fpxreg *) &fxsave->st_space[0];
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from = &buf->_st[0];
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for (i = 0; i < 8; i++, to++, from++) {
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unsigned long *t = (unsigned long *)to;
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unsigned long __user *f = (unsigned long __user *)from;
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if (__get_user(*t, f) ||
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__get_user(*(t + 1), f + 1) ||
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__get_user(to->exponent, &from->exponent))
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return 1;
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}
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return 0;
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}
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extern int have_fpx_regs;
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static int copy_sc_from_user(struct pt_regs *regs,
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struct sigcontext __user *from)
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{
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struct sigcontext sc;
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unsigned long fpregs[HOST_FP_SIZE];
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struct sigcontext sc;
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int err;
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err = copy_from_user(&sc, from, sizeof(sc));
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err |= copy_from_user(fpregs, sc.fpstate, sizeof(fpregs));
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if (err)
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return err;
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copy_sc(®s->regs, &sc);
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if (have_fpx_regs) {
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struct user_fxsr_struct fpx;
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err = restore_fp_registers(userspace_pid[0], fpregs);
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if (err < 0) {
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printk(KERN_ERR "copy_sc_from_user_skas - PTRACE_SETFPREGS "
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"failed, errno = %d\n", -err);
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return err;
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err = copy_from_user(&fpx, &sc.fpstate->_fxsr_env[0],
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sizeof(struct user_fxsr_struct));
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if (err)
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return 1;
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err = convert_fxsr_from_user(&fpx, sc.fpstate);
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if (err)
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return 1;
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err = restore_fpx_registers(userspace_pid[current_thread->cpu],
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(unsigned long *) &fpx);
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if (err < 0) {
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printk(KERN_ERR "copy_sc_from_user - "
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"restore_fpx_registers failed, errno = %d\n",
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-err);
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return 1;
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}
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}
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else {
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struct user_i387_struct fp;
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err = copy_from_user(&fp, sc.fpstate,
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sizeof(struct user_i387_struct));
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if (err)
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return 1;
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err = restore_fp_registers(userspace_pid[current_thread->cpu],
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(unsigned long *) &fp);
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if (err < 0) {
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printk(KERN_ERR "copy_sc_from_user - "
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"restore_fp_registers failed, errno = %d\n",
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-err);
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return 1;
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}
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}
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return 0;
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@@ -61,7 +222,6 @@ static int copy_sc_to_user(struct sigcontext __user *to,
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unsigned long sp)
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{
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struct sigcontext sc;
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unsigned long fpregs[HOST_FP_SIZE];
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struct faultinfo * fi = ¤t->thread.arch.faultinfo;
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int err;
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@@ -86,20 +246,43 @@ static int copy_sc_to_user(struct sigcontext __user *to,
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sc.err = fi->error_code;
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sc.trapno = fi->trap_no;
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err = save_fp_registers(userspace_pid[0], fpregs);
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if (err < 0) {
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printk(KERN_ERR "copy_sc_to_user_skas - PTRACE_GETFPREGS "
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"failed, errno = %d\n", err);
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return 1;
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}
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to_fp = (to_fp ? to_fp : (struct _fpstate __user *) (to + 1));
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sc.fpstate = to_fp;
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if (err)
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return err;
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if (have_fpx_regs) {
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struct user_fxsr_struct fpx;
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return copy_to_user(to, &sc, sizeof(sc)) ||
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copy_to_user(to_fp, fpregs, sizeof(fpregs));
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err = save_fpx_registers(userspace_pid[current_thread->cpu],
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(unsigned long *) &fpx);
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if (err < 0){
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printk(KERN_ERR "copy_sc_to_user - save_fpx_registers "
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"failed, errno = %d\n", err);
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return 1;
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}
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err = convert_fxsr_to_user(to_fp, &fpx);
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if (err)
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return 1;
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err |= __put_user(fpx.swd, &to_fp->status);
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err |= __put_user(X86_FXSR_MAGIC, &to_fp->magic);
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if (err)
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return 1;
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if (copy_to_user(&to_fp->_fxsr_env[0], &fpx,
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sizeof(struct user_fxsr_struct)))
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return 1;
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}
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else {
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struct user_i387_struct fp;
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err = save_fp_registers(userspace_pid[current_thread->cpu],
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(unsigned long *) &fp);
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if (copy_to_user(to_fp, &fp, sizeof(struct user_i387_struct)))
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return 1;
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}
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return copy_to_user(to, &sc, sizeof(sc));
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}
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static int copy_ucontext_to_user(struct ucontext __user *uc,
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