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- Small cleanups to the Giant handling in trap().

Browse source 
- Only release Giant in trap() if we locked it, otherwise we could release
  Giant in a kernel trap if we didn't get it for a page fault and the
  previous frame had grabbed the lock.
- Only get Giant for !MP safe syscalls.
This commit is contained in:
John Baldwin 2001-10-17 22:04:45 +00:00
parent c006932186
commit 05724cdd08
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=85082
1 changed files with 17 additions and 9 deletions
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26
sys/ia64/ia64/trap.c
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@ -302,11 +302,10 @@ trap(int vector, int imm, struct trapframe *framep)
*/
if (user) {
mtx_lock(&Giant);
if ((i = unaligned_fixup(framep, td)) == 0) {
mtx_unlock(&Giant);
goto out;
}
i = unaligned_fixup(framep, td);
mtx_unlock(&Giant);
if (i == 0)
goto out;
ucode = framep->tf_cr_ifa; /* VA */
break;
}
@ -478,6 +477,7 @@ trap(int vector, int imm, struct trapframe *framep)
} else if (rv == KERN_PROTECTION_FAILURE)
rv = KERN_INVALID_ADDRESS;
}
mtx_unlock(&Giant);
if (rv == KERN_SUCCESS)
goto out;
@ -520,10 +520,10 @@ trap(int vector, int imm, struct trapframe *framep)
#endif
trapsignal(p, i, ucode);
out:
if (user)
if (user) {
userret(td, framep, sticks);
if (mtx_owned(&Giant))
mtx_unlock(&Giant);
mtx_assert(&Giant, MA_NOTOWNED);
}
return;
dopanic:
@ -568,7 +568,6 @@ syscall(int code, u_int64_t *args, struct trapframe *framep)
td->td_frame = framep;
sticks = td->td_kse->ke_sticks;
mtx_lock(&Giant);
/*
* Skip past the break instruction. Remember old address in case
* we have to restart.
@ -610,6 +609,11 @@ syscall(int code, u_int64_t *args, struct trapframe *framep)
else
callp = &p->p_sysent->sv_table[code];
/*
* Try to run the syscall without Giant if the syscall is MP safe.
*/
if ((callp->sys_narg & SYS_MPSAFE) == 0)
mtx_lock(&Giant);
#ifdef KTRACE
if (KTRPOINT(p, KTR_SYSCALL))
ktrsyscall(p->p_tracep, code, (callp->sy_narg & SYF_ARGMASK), args);
@ -654,7 +658,11 @@ syscall(int code, u_int64_t *args, struct trapframe *framep)
if (KTRPOINT(p, KTR_SYSRET))
ktrsysret(p->p_tracep, code, error, td->td_retval[0]);
#endif
mtx_unlock(&Giant);
/*
* Release Giant if we had to get it.
*/
if ((callp->sy_narg & SYF_MPSAFE) == 0)
mtx_unlock(&Giant);
/*
* This works because errno is findable through the