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[PowerPC] Ensure ppc32 cpu_switch routines set up Secure-PLT.

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This is a correctness fix needed to enable the ifunc conversion of the pmap
in D24993.

Since we are making function calls that may need to go through the PLT, ensure
r30 is set up correctly.

This fixes crashes when booting with D24993 applied.

Reviewed by:	jhibbits (in IRC)
Sponsored by:	Tag1 Consulting, Inc.
This commit is contained in:
Brandon Bergren 2020-05-26 02:27:10 +00:00
parent b04748bef2
commit 8ef0c667f4
1 changed files with 6 additions and 0 deletions
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6
sys/powerpc/powerpc/swtch32.S
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@ -92,6 +92,11 @@ ENTRY(cpu_switch)
mflr %r16 /* Save the link register */
stw %r16,PCB_LR(%r6)
stw %r1,PCB_SP(%r6) /* Save the stack pointer */
bl 1f
1:
mflr %r30 /* Prepare for secure-PLT calls */
addis %r30, %r30, (_GLOBAL_OFFSET_TABLE_-1b)@ha
addi %r30, %r30, (_GLOBAL_OFFSET_TABLE_-1b)@l
mr %r14,%r3 /* Copy the old thread ptr... */
mr %r2,%r4 /* and the new thread ptr in curthread */
@ -129,6 +134,7 @@ cpu_switchin:
mflr %r6
addis %r6,%r6,(_GLOBAL_OFFSET_TABLE_-1b)@ha
addi %r6,%r6,(_GLOBAL_OFFSET_TABLE_-1b)@l
mr %r30, %r6 /* Prepare for secure-PLT calls */
lwz %r6,blocked_lock@got(%r6)
blocked_loop:
lwz %r7,TD_LOCK(%r2)