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Move the CR0.WP manipulation KPI to x86.

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This should allow to avoid some #ifdefs in the common x86/ code.

Requested by:	markj
Sponsored by:	The FreeBSD Foundation
MFC after:	1 week
This commit is contained in:
kib 2018-03-20 20:20:49 +00:00
parent f8478f0d43
commit 0a1d8bb0a4
4 changed files with 28 additions and 27 deletions
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25
sys/amd64/amd64/machdep.c
View File

@ -2597,31 +2597,6 @@ clear_pcb_flags(struct pcb *pcb, const u_int flags)
: "cc", "memory");
}
/*
* Enable and restore kernel text write permissions.
* Callers must ensure that disable_wp()/restore_wp() are executed
* without rescheduling on the same core.
*/
bool
disable_wp(void)
{
u_int cr0;
cr0 = rcr0();
if ((cr0 & CR0_WP) == 0)
return (false);
load_cr0(cr0 & ~CR0_WP);
return (true);
}
void
restore_wp(bool old_wp)
{
if (old_wp)
load_cr0(rcr0() | CR0_WP);
}
#ifdef KDB
/*

2
sys/amd64/include/md_var.h
View File

@ -53,8 +53,6 @@ void amd64_conf_fast_syscall(void);
void amd64_db_resume_dbreg(void);
void amd64_lower_shared_page(struct sysentvec *);
void amd64_syscall(struct thread *td, int traced);
bool disable_wp(void);
void restore_wp(bool old_wp);
void doreti_iret(void) __asm(__STRING(doreti_iret));
void doreti_iret_fault(void) __asm(__STRING(doreti_iret_fault));
void ld_ds(void) __asm(__STRING(ld_ds));

2
sys/x86/include/x86_var.h
View File

@ -119,6 +119,8 @@ void busdma_swi(void);
bool cpu_mwait_usable(void);
void cpu_probe_amdc1e(void);
void cpu_setregs(void);
bool disable_wp(void);
void restore_wp(bool old_wp);
void dump_add_page(vm_paddr_t);
void dump_drop_page(vm_paddr_t);
void finishidentcpu(void);

26
sys/x86/x86/cpu_machdep.c
View File

@ -621,3 +621,29 @@ hw_ibrs_disable_handler(SYSCTL_HANDLER_ARGS)
SYSCTL_PROC(_hw, OID_AUTO, ibrs_disable, CTLTYPE_INT | CTLFLAG_RWTUN |
CTLFLAG_NOFETCH | CTLFLAG_MPSAFE, NULL, 0, hw_ibrs_disable_handler, "I",
"Disable Indirect Branch Restricted Speculation");
/*
* Enable and restore kernel text write permissions.
* Callers must ensure that disable_wp()/restore_wp() are executed
* without rescheduling on the same core.
*/
bool
disable_wp(void)
{
u_int cr0;
cr0 = rcr0();
if ((cr0 & CR0_WP) == 0)
return (false);
load_cr0(cr0 & ~CR0_WP);
return (true);
}
void
restore_wp(bool old_wp)
{
if (old_wp)
load_cr0(rcr0() | CR0_WP);
}