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Do not save/restore the TLS pointer on context switch for armv6. The

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pointer cannot be changed directly by userland code on armv6 (it can be on
armv4), so there's no need to save/restore.

Submitted by:	Michal Meloun
This commit is contained in:
ian 2015-03-23 22:42:42 +00:00
parent 8533535e11
commit 22da00a29e
3 changed files with 12 additions and 18 deletions
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11
sys/arm/arm/swtch.S
View File

@ -255,7 +255,7 @@ ENTRY(cpu_switch)
mov r4, r0 /* Save the old thread. */
#ifdef ARM_TP_ADDRESS
/* Store the old tp */
/* Store the old tp; userland can change it on armv4. */
ldr r3, =ARM_TP_ADDRESS
ldr r9, [r3]
str r9, [r0, #(TD_MD + MD_TP)]
@ -272,11 +272,10 @@ ENTRY(cpu_switch)
ldr r9, [r1, #(TD_MD + MD_RAS_END)]
str r9, [r3, #8]
#else
/* Store the old tp */
mrc p15, 0, r9, c13, c0, 3
str r9, [r0, #(TD_MD + MD_TP)]
/* Set the new tp */
/*
* Set new tp. No need to store the old one first, userland can't
* change it directly on armv6.
*/
ldr r9, [r1, #(TD_MD + MD_TP)]
mcr p15, 0, r9, c13, c0, 3
#endif

15
sys/arm/arm/sys_machdep.c
View File

@ -84,13 +84,11 @@ static int
arm32_set_tp(struct thread *td, void *args)
{
if (td != curthread)
td->td_md.md_tp = (register_t)args;
else
td->td_md.md_tp = (register_t)args;
#ifndef ARM_TP_ADDRESS
set_tls(args);
set_tls(args);
#else
*(register_t *)ARM_TP_ADDRESS = (register_t)args;
*(register_t *)ARM_TP_ADDRESS = (register_t)args;
#endif
return (0);
}
@ -99,13 +97,10 @@ static int
arm32_get_tp(struct thread *td, void *args)
{
if (td != curthread)
td->td_retval[0] = td->td_md.md_tp;
else
#ifndef ARM_TP_ADDRESS
td->td_retval[0] = (register_t)get_tls();
td->td_retval[0] = td->td_md.md_tp;
#else
td->td_retval[0] = *(register_t *)ARM_TP_ADDRESS;
td->td_retval[0] = *(register_t *)ARM_TP_ADDRESS;
#endif
return (0);
}

4
sys/arm/arm/vm_machdep.c
View File

@ -145,7 +145,7 @@ cpu_fork(register struct thread *td1, register struct proc *p2,
#ifdef ARM_TP_ADDRESS
td2->td_md.md_tp = *(register_t *)ARM_TP_ADDRESS;
#else
td2->td_md.md_tp = (register_t) get_tls();
td2->td_md.md_tp = td1->td_md.md_tp;
#endif
}
@ -274,7 +274,7 @@ cpu_set_user_tls(struct thread *td, void *tls_base)
#ifdef ARM_TP_ADDRESS
*(register_t *)ARM_TP_ADDRESS = (register_t)tls_base;
#else
set_tls((void *)tls_base);
set_tls(tls_base);
#endif
critical_exit();
}