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Preserve VFP state across signal delivery.

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We don't have enouch space to store full VFP context within mcontext
stucture. Due to this:
 - follow i386/amd64 way and store VFP state outside of the mcontext_t
   but point to it. Use the size of VFP state structure as an 'magic'
   indicator of the saved VFP state presence.
 - teach set_mcontext() about this external storage.
 - for signal delivery, store VFP state to expanded 'struct sigframe'.

Submited by:	Andrew Gierth (initial version)
PR:		217611
MFC after:	2 weeks
This commit is contained in:
Michal Meloun 2017-03-26 08:36:56 +00:00
parent d9d7354968
commit 6fc9f4dbc8
4 changed files with 193 additions and 103 deletions
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4
lib/libthread_db/arch/arm/libpthread_md.c
View File

@ -90,7 +90,9 @@ pt_fpreg_to_ucontext(const struct fpreg *r __unused, ucontext_t *uc)
mcontext_t *mc = &uc->uc_mcontext;
/* XXX */
memset(&mc->mc_spare, 0, sizeof(mc->mc_spare));
mc->mc_vfp_size = 0;
mc->mc_vfp_ptr = NULL;
memset(mc->mc_spare, 0, sizeof(mc->mc_spare));
}
void

278
sys/arm/arm/machdep.c
View File

@ -146,105 +146,6 @@ static delay_func *delay_impl;
static void *delay_arg;
#endif
void
sendsig(catcher, ksi, mask)
sig_t catcher;
ksiginfo_t *ksi;
sigset_t *mask;
{
struct thread *td;
struct proc *p;
struct trapframe *tf;
struct sigframe *fp, frame;
struct sigacts *psp;
struct sysentvec *sysent;
int onstack;
int sig;
int code;
td = curthread;
p = td->td_proc;
PROC_LOCK_ASSERT(p, MA_OWNED);
sig = ksi->ksi_signo;
code = ksi->ksi_code;
psp = p->p_sigacts;
mtx_assert(&psp->ps_mtx, MA_OWNED);
tf = td->td_frame;
onstack = sigonstack(tf->tf_usr_sp);
CTR4(KTR_SIG, "sendsig: td=%p (%s) catcher=%p sig=%d", td, p->p_comm,
catcher, sig);
/* Allocate and validate space for the signal handler context. */
if ((td->td_pflags & TDP_ALTSTACK) != 0 && !(onstack) &&
SIGISMEMBER(psp->ps_sigonstack, sig)) {
fp = (struct sigframe *)((uintptr_t)td->td_sigstk.ss_sp +
td->td_sigstk.ss_size);
#if defined(COMPAT_43)
td->td_sigstk.ss_flags |= SS_ONSTACK;
#endif
} else
fp = (struct sigframe *)td->td_frame->tf_usr_sp;
/* make room on the stack */
fp--;
/* make the stack aligned */
fp = (struct sigframe *)STACKALIGN(fp);
/* Populate the siginfo frame. */
get_mcontext(td, &frame.sf_uc.uc_mcontext, 0);
frame.sf_si = ksi->ksi_info;
frame.sf_uc.uc_sigmask = *mask;
frame.sf_uc.uc_stack.ss_flags = (td->td_pflags & TDP_ALTSTACK )
? ((onstack) ? SS_ONSTACK : 0) : SS_DISABLE;
frame.sf_uc.uc_stack = td->td_sigstk;
mtx_unlock(&psp->ps_mtx);
PROC_UNLOCK(td->td_proc);
/* Copy the sigframe out to the user's stack. */
if (copyout(&frame, fp, sizeof(*fp)) != 0) {
/* Process has trashed its stack. Kill it. */
CTR2(KTR_SIG, "sendsig: sigexit td=%p fp=%p", td, fp);
PROC_LOCK(p);
sigexit(td, SIGILL);
}
/*
* Build context to run handler in. We invoke the handler
* directly, only returning via the trampoline. Note the
* trampoline version numbers are coordinated with machine-
* dependent code in libc.
*/
tf->tf_r0 = sig;
tf->tf_r1 = (register_t)&fp->sf_si;
tf->tf_r2 = (register_t)&fp->sf_uc;
/* the trampoline uses r5 as the uc address */
tf->tf_r5 = (register_t)&fp->sf_uc;
tf->tf_pc = (register_t)catcher;
tf->tf_usr_sp = (register_t)fp;
sysent = p->p_sysent;
if (sysent->sv_sigcode_base != 0)
tf->tf_usr_lr = (register_t)sysent->sv_sigcode_base;
else
tf->tf_usr_lr = (register_t)(sysent->sv_psstrings -
*(sysent->sv_szsigcode));
/* Set the mode to enter in the signal handler */
#if __ARM_ARCH >= 7
if ((register_t)catcher & 1)
tf->tf_spsr |= PSR_T;
else
tf->tf_spsr &= ~PSR_T;
#endif
CTR3(KTR_SIG, "sendsig: return td=%p pc=%#x sp=%#x", td, tf->tf_usr_lr,
tf->tf_usr_sp);
PROC_LOCK(p);
mtx_lock(&psp->ps_mtx);
}
struct kva_md_info kmi;
/*
@ -488,6 +389,47 @@ exec_setregs(struct thread *td, struct image_params *imgp, u_long stack)
tf->tf_spsr = PSR_USR32_MODE;
}
#ifdef VFP
/*
* Get machine VFP context.
*/
static void
get_vfpcontext(struct thread *td, mcontext_vfp_t *vfp)
{
struct pcb *curpcb;
curpcb = curthread->td_pcb;
critical_enter();
vfp_store(&curpcb->pcb_vfpstate, false);
memcpy(vfp->mcv_reg, curpcb->pcb_vfpstate.reg,
sizeof(vfp->mcv_reg));
vfp->mcv_fpscr = curpcb->pcb_vfpstate.fpscr;
critical_exit();
}
/*
* Set machine VFP context.
*/
static void
set_vfpcontext(struct thread *td, mcontext_vfp_t *vfp)
{
struct pcb *curpcb;
curpcb = curthread->td_pcb;
critical_enter();
vfp_discard(td);
memcpy(curpcb->pcb_vfpstate.reg, vfp->mcv_reg,
sizeof(curpcb->pcb_vfpstate.reg));
curpcb->pcb_vfpstate.fpscr = vfp->mcv_fpscr;
critical_exit();
}
#endif
/*
* Get machine context.
*/
@ -520,6 +462,10 @@ get_mcontext(struct thread *td, mcontext_t *mcp, int clear_ret)
gr[_REG_LR] = tf->tf_usr_lr;
gr[_REG_PC] = tf->tf_pc;
mcp->mc_vfp_size = 0;
mcp->mc_vfp_ptr = NULL;
memset(&mcp->mc_spare, 0, sizeof(mcp->mc_spare));
return (0);
}
@ -532,9 +478,29 @@ get_mcontext(struct thread *td, mcontext_t *mcp, int clear_ret)
int
set_mcontext(struct thread *td, mcontext_t *mcp)
{
mcontext_vfp_t mc_vfp, *vfp;
struct trapframe *tf = td->td_frame;
const __greg_t *gr = mcp->__gregs;
#ifdef WITNESS
if (mcp->mc_vfp_size != 0 && mcp->mc_vfp_size != sizeof(mc_vfp)) {
printf("%s: %s: Malformed mc_vfp_size: %d (0x%08X)\n",
td->td_proc->p_comm, __func__,
mcp->mc_vfp_size, mcp->mc_vfp_size);
} else if (mcp->mc_vfp_size != 0 && mcp->mc_vfp_ptr == NULL) {
printf("%s: %s: c_vfp_size != 0 but mc_vfp_ptr == NULL\n",
td->td_proc->p_comm, __func__);
}
#endif
if (mcp->mc_vfp_size == sizeof(mc_vfp) && mcp->mc_vfp_ptr != NULL) {
if (copyin(mcp->mc_vfp_ptr, &mc_vfp, sizeof(mc_vfp)) != 0)
return (EFAULT);
vfp = &mc_vfp;
} else {
vfp = NULL;
}
tf->tf_r0 = gr[_REG_R0];
tf->tf_r1 = gr[_REG_R1];
tf->tf_r2 = gr[_REG_R2];
@ -552,10 +518,120 @@ set_mcontext(struct thread *td, mcontext_t *mcp)
tf->tf_usr_lr = gr[_REG_LR];
tf->tf_pc = gr[_REG_PC];
tf->tf_spsr = gr[_REG_CPSR];
#ifdef VFP
if (vfp != NULL)
set_vfpcontext(td, vfp);
#endif
return (0);
}
void
sendsig(catcher, ksi, mask)
sig_t catcher;
ksiginfo_t *ksi;
sigset_t *mask;
{
struct thread *td;
struct proc *p;
struct trapframe *tf;
struct sigframe *fp, frame;
struct sigacts *psp;
struct sysentvec *sysent;
int onstack;
int sig;
int code;
td = curthread;
p = td->td_proc;
PROC_LOCK_ASSERT(p, MA_OWNED);
sig = ksi->ksi_signo;
code = ksi->ksi_code;
psp = p->p_sigacts;
mtx_assert(&psp->ps_mtx, MA_OWNED);
tf = td->td_frame;
onstack = sigonstack(tf->tf_usr_sp);
CTR4(KTR_SIG, "sendsig: td=%p (%s) catcher=%p sig=%d", td, p->p_comm,
catcher, sig);
/* Allocate and validate space for the signal handler context. */
if ((td->td_pflags & TDP_ALTSTACK) != 0 && !(onstack) &&
SIGISMEMBER(psp->ps_sigonstack, sig)) {
fp = (struct sigframe *)((uintptr_t)td->td_sigstk.ss_sp +
td->td_sigstk.ss_size);
#if defined(COMPAT_43)
td->td_sigstk.ss_flags |= SS_ONSTACK;
#endif
} else
fp = (struct sigframe *)td->td_frame->tf_usr_sp;
/* make room on the stack */
fp--;
/* make the stack aligned */
fp = (struct sigframe *)STACKALIGN(fp);
/* Populate the siginfo frame. */
get_mcontext(td, &frame.sf_uc.uc_mcontext, 0);
#ifdef VFP
get_vfpcontext(td, &frame.sf_vfp);
frame.sf_uc.uc_mcontext.mc_vfp_size = sizeof(fp->sf_vfp);
frame.sf_uc.uc_mcontext.mc_vfp_ptr = &fp->sf_vfp;
#else
frame.sf_uc.uc_mcontext.mc_vfp_size = 0;
frame.sf_uc.uc_mcontext.mc_vfp_ptr = NULL;
#endif
frame.sf_si = ksi->ksi_info;
frame.sf_uc.uc_sigmask = *mask;
frame.sf_uc.uc_stack.ss_flags = (td->td_pflags & TDP_ALTSTACK )
? ((onstack) ? SS_ONSTACK : 0) : SS_DISABLE;
frame.sf_uc.uc_stack = td->td_sigstk;
mtx_unlock(&psp->ps_mtx);
PROC_UNLOCK(td->td_proc);
/* Copy the sigframe out to the user's stack. */
if (copyout(&frame, fp, sizeof(*fp)) != 0) {
/* Process has trashed its stack. Kill it. */
CTR2(KTR_SIG, "sendsig: sigexit td=%p fp=%p", td, fp);
PROC_LOCK(p);
sigexit(td, SIGILL);
}
/*
* Build context to run handler in. We invoke the handler
* directly, only returning via the trampoline. Note the
* trampoline version numbers are coordinated with machine-
* dependent code in libc.
*/
tf->tf_r0 = sig;
tf->tf_r1 = (register_t)&fp->sf_si;
tf->tf_r2 = (register_t)&fp->sf_uc;
/* the trampoline uses r5 as the uc address */
tf->tf_r5 = (register_t)&fp->sf_uc;
tf->tf_pc = (register_t)catcher;
tf->tf_usr_sp = (register_t)fp;
sysent = p->p_sysent;
if (sysent->sv_sigcode_base != 0)
tf->tf_usr_lr = (register_t)sysent->sv_sigcode_base;
else
tf->tf_usr_lr = (register_t)(sysent->sv_psstrings -
*(sysent->sv_szsigcode));
/* Set the mode to enter in the signal handler */
#if __ARM_ARCH >= 7
if ((register_t)catcher & 1)
tf->tf_spsr |= PSR_T;
else
tf->tf_spsr &= ~PSR_T;
#endif
CTR3(KTR_SIG, "sendsig: return td=%p pc=%#x sp=%#x", td, tf->tf_usr_lr,
tf->tf_usr_sp);
PROC_LOCK(p);
mtx_lock(&psp->ps_mtx);
}
int
sys_sigreturn(td, uap)
struct thread *td;
@ -578,7 +654,7 @@ sys_sigreturn(td, uap)
if ((spsr & PSR_MODE) != PSR_USR32_MODE ||
(spsr & (PSR_I | PSR_F)) != 0)
return (EINVAL);
/* Restore register context. */
/* Restore register context. */
set_mcontext(td, &uc.uc_mcontext);
/* Restore signal mask. */

1
sys/arm/include/frame.h
View File

@ -94,6 +94,7 @@ struct trapframe {
struct sigframe {
siginfo_t sf_si; /* actual saved siginfo */
ucontext_t sf_uc; /* actual saved ucontext */
mcontext_vfp_t sf_vfp; /* actual saved VFP context */
};

13
sys/arm/include/ucontext.h
View File

@ -63,6 +63,14 @@ typedef __greg_t __gregset_t[_NGREG];
#define _REG_LR _REG_R14
#define _REG_PC _REG_R15
/*
* Floating point register state
*/
typedef struct {
__uint64_t mcv_reg[32];
__uint32_t mcv_fpscr;
} mcontext_vfp_t;
typedef struct {
__gregset_t __gregs;
@ -70,7 +78,10 @@ typedef struct {
* Originally, rest of this structure was named __fpu, 35 * 4 bytes
* long, never accessed from kernel.
*/
unsigned int mc_spare[35];
size_t mc_vfp_size;
void *mc_vfp_ptr;
unsigned int mc_spare[33];
} mcontext_t;
#define UC_
#endif /* !_MACHINE_MCONTEXT_H_ */