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To prevent various race conditions in the RAS code, store and restore the

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values in ARM_RAS_START and ARM_RAS_END at context switch time.

MFC after:	1 week
This commit is contained in:
Olivier Houchard 2009-02-12 23:23:30 +00:00
parent b2e1580e4d
commit a43268a746
4 changed files with 23 additions and 4 deletions
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2
sys/arm/arm/genassym.c
View File

@ -96,6 +96,8 @@ ASSYM(TD_FRAME, offsetof(struct thread, td_frame));
ASSYM(TD_MD, offsetof(struct thread, td_md));
ASSYM(TD_LOCK, offsetof(struct thread, td_lock));
ASSYM(MD_TP, offsetof(struct mdthread, md_tp));
ASSYM(MD_RAS_START, offsetof(struct mdthread, md_ras_start));
ASSYM(MD_RAS_END, offsetof(struct mdthread, md_ras_end));
ASSYM(TF_R0, offsetof(struct trapframe, tf_r0));
ASSYM(TF_R1, offsetof(struct trapframe, tf_r1));

20
sys/arm/arm/swtch.S
View File

@ -205,8 +205,12 @@ ENTRY(cpu_throw)
/* Set the new tp */
ldr r6, [r5, #(TD_MD + MD_TP)]
ldr r5, =ARM_TP_ADDRESS
strt r6, [r5]
ldr r4, =ARM_TP_ADDRESS
str r6, [r4]
ldr r6, [r5, #(TD_MD + MD_RAS_START)]
str r6, [r4, #4] /* ARM_RAS_START */
ldr r6, [r5, #(TD_MD + MD_RAS_END)]
str r6, [r4, #4] /* ARM_RAS_END */
/* Hook in a new pcb */
ldr r6, .Lcurpcb
@ -265,12 +269,20 @@ ENTRY(cpu_switch)
*/
/* Store the old tp */
ldr r3, =ARM_TP_ADDRESS
ldrt r9, [r3]
ldr r9, [r3]
str r9, [r0, #(TD_MD + MD_TP)]
ldr r9, [r3, #4]
str r9, [r0, #(TD_MD + MD_RAS_START)]
ldr r9, [r3, #8]
str r9, [r0, #(TD_MD + MD_RAS_END)]
/* Set the new tp */
ldr r9, [r1, #(TD_MD + MD_TP)]
strt r9, [r3]
str r9, [r3]
ldr r9, [r1, #(TD_MD + MD_RAS_START)]
str r9, [r3, #4]
ldr r9, [r1, #(TD_MD + MD_RAS_END)]
str r9, [r3, #8]
/* Get the user structure for the new process in r9 */
ldr r9, [r1, #(TD_PCB)]

2
sys/arm/include/proc.h
View File

@ -51,6 +51,8 @@ struct mdthread {
int md_ptrace_instr;
int md_ptrace_addr;
void *md_tp;
void *md_ras_start;
void *md_ras_end;
};
struct mdproc {

3
sys/arm/include/sysarch.h
View File

@ -42,6 +42,9 @@
* The ARM_TP_ADDRESS points to a special purpose page, which is used as local
* store for the ARM per-thread data and Restartable Atomic Sequences support.
* Put it just above the "high" vectors' page.
* the cpu_switch() code assumes ARM_RAS_START is ARM_TP_ADDRESS + 4, and
* ARM_RAS_END is ARM_TP_ADDRESS + 8, so if that ever changes, be sure to
* update the cpu_switch() (and cpu_throw()) code as well.
*/
#define ARM_TP_ADDRESS (ARM_VECTORS_HIGH + 0x1000)
#define ARM_RAS_START (ARM_TP_ADDRESS + 4)