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arm64: Use the Linux sigframe to restore registers

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When returning from a Linux signal use the Linux sigframe to find the
register values to restore.

Remove the FreeBSD ucontext from the stack as it's now unneeded.

Reviewed by:	dchagin, emaste
Sponsored by:	Arm Ltd
Differential Revision:	https://reviews.freebsd.org/D42360
This commit is contained in:
Andrew Turner 2023-10-25 10:50:11 +01:00
parent cb0259b6df
commit 070a4ff82a
2 changed files with 89 additions and 10 deletions
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1
sys/arm64/linux/linux_sigframe.h
View file

@ -76,7 +76,6 @@ struct l_sigframe {
/* frame_record */
uint64_t fp;
uint64_t lr;
ucontext_t uc;
};
#define LINUX_MINSIGSTKSZ roundup(sizeof(struct l_sigframe), 16)

98
sys/arm64/linux/linux_sysvec.c
View file

@ -187,28 +187,109 @@ linux_exec_setregs(struct thread *td, struct image_params *imgp,
bzero(&pcb->pcb_dbg_regs, sizeof(pcb->pcb_dbg_regs));
}
static bool
linux_parse_sigreturn_ctx(struct thread *td, struct l_sigcontext *sc)
{
struct l_fpsimd_context *fpsimd;
struct _l_aarch64_ctx *ctx;
int offset;
offset = 0;
while (1) {
/* The offset must be 16 byte aligned */
if ((offset & 15) != 0)
return (false);
/* Check for buffer overflow of the ctx */
if ((offset + sizeof(*ctx)) >
sizeof(sc->__reserved))
return (false);
ctx = (struct _l_aarch64_ctx *)&sc->__reserved[offset];
/* Check for buffer overflow of the data */
if ((offset + ctx->size) > sizeof(sc->__reserved))
return (false);
switch(ctx->magic) {
case 0:
if (ctx->size != 0)
return (false);
return (true);
case L_ESR_MAGIC:
/* Ignore */
break;
#ifdef VFP
case L_FPSIMD_MAGIC:
fpsimd = (struct l_fpsimd_context *)ctx;
/*
* Discard any vfp state for the current thread, we
* are about to override it.
*/
critical_enter();
vfp_discard(td);
critical_exit();
td->td_pcb->pcb_fpustate.vfp_fpcr = fpsimd->fpcr;
td->td_pcb->pcb_fpustate.vfp_fpsr = fpsimd->fpsr;
memcpy(td->td_pcb->pcb_fpustate.vfp_regs,
fpsimd->vregs, sizeof(fpsimd->vregs));
break;
#endif
default:
return (false);
}
offset += ctx->size;
}
}
int
linux_rt_sigreturn(struct thread *td, struct linux_rt_sigreturn_args *args)
{
struct l_rt_sigframe *sf;
struct l_sigframe *frame;
ucontext_t uc;
struct trapframe *tf;
sigset_t bmask;
int error;
sf = malloc(sizeof(*sf), M_LINUX, M_WAITOK | M_ZERO);
tf = td->td_frame;
frame = (struct l_sigframe *)tf->tf_sp;
if (copyin((void *)&frame->uc, &uc, sizeof(uc)))
return (EFAULT);
error = set_mcontext(td, &uc.uc_mcontext);
if (error != 0)
error = copyin((void *)&frame->sf, sf, sizeof(*sf));
if (error != 0) {
free(sf, M_LINUX);
return (error);
}
memcpy(tf->tf_x, sf->sf_uc.uc_sc.regs, sizeof(tf->tf_x));
tf->tf_lr = sf->sf_uc.uc_sc.regs[30];
tf->tf_sp = sf->sf_uc.uc_sc.sp;
tf->tf_elr = sf->sf_uc.uc_sc.pc;
if ((sf->sf_uc.uc_sc.pstate & PSR_M_MASK) != PSR_M_EL0t ||
(sf->sf_uc.uc_sc.pstate & PSR_AARCH32) != 0 ||
(sf->sf_uc.uc_sc.pstate & PSR_DAIF) !=
(td->td_frame->tf_spsr & PSR_DAIF))
goto einval;
tf->tf_spsr = sf->sf_uc.uc_sc.pstate;
if (!linux_parse_sigreturn_ctx(td, &sf->sf_uc.uc_sc))
goto einval;
/* Restore signal mask. */
kern_sigprocmask(td, SIG_SETMASK, &uc.uc_sigmask, NULL, 0);
linux_to_bsd_sigset(&sf->sf_uc.uc_sigmask, &bmask);
kern_sigprocmask(td, SIG_SETMASK, &bmask, NULL, 0);
free(sf, M_LINUX);
return (EJUSTRETURN);
einval:
free(sf, M_LINUX);
return (EINVAL);
}
static void
@ -310,7 +391,6 @@ linux_rt_sendsig(sig_t catcher, ksiginfo_t *ksi, sigset_t *mask)
}
memcpy(&frame->sf.sf_uc.uc_stack, &uc_stack, sizeof(uc_stack));
memcpy(&frame->uc, &uc, sizeof(uc));
/* Copy the sigframe out to the user's stack. */
if (copyout(frame, fp, sizeof(*fp)) != 0) {