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sparc: Save/restore only non-volatile context

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The _CPU_Context_switch() is a normal function call.  The following
registers are volatile (the caller must assume that the register
contents are destroyed by the callee) according to "SYSTEM V APPLICATION
BINARY INTERFACE - SPARC Processor Supplement", Third Edition: g1, o0,
o1, o2, o3, o4, o5.  Drop these registers from the context.

Ensure that offset defines match the structure offsets.
This commit is contained in:
Sebastian Huber
2014-02-05 11:36:05 +01:00
parent 62c5c4a564
commit 97cf623d4a
3 changed files with 78 additions and 79 deletions
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19
c/src/lib/libbsp/sparc/shared/irq_asm.S
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@@ -52,9 +52,7 @@
.align 4
PUBLIC(_CPU_Context_switch)
SYM(_CPU_Context_switch):
! skip g0
st %g1, [%o0 + G1_OFFSET] ! save the global registers
std %g2, [%o0 + G2_OFFSET]
std %g2, [%o0 + G2_OFFSET] ! save the global registers
std %g4, [%o0 + G4_OFFSET]
std %g6, [%o0 + G6_OFFSET]
@@ -68,10 +66,7 @@ SYM(_CPU_Context_switch):
std %i4, [%o0 + I4_OFFSET]
std %i6, [%o0 + I6_FP_OFFSET]
std %o0, [%o0 + O0_OFFSET] ! save the output registers
std %o2, [%o0 + O2_OFFSET]
std %o4, [%o0 + O4_OFFSET]
std %o6, [%o0 + O6_SP_OFFSET]
std %o6, [%o0 + O6_SP_OFFSET] ! save the output registers
! o3 = self per-CPU control
GET_SELF_CPU_CONTROL %o3, %o4
@@ -190,9 +185,7 @@ done_flushing:
nop
nop
! skip g0
ld [%o1 + G1_OFFSET], %g1 ! restore the global registers
ldd [%o1 + G2_OFFSET], %g2
ldd [%o1 + G2_OFFSET], %g2 ! restore the global registers
ldd [%o1 + G4_OFFSET], %g4
ldd [%o1 + G6_OFFSET], %g6
@@ -213,11 +206,7 @@ done_flushing:
ldd [%o1 + I4_OFFSET], %i4
ldd [%o1 + I6_FP_OFFSET], %i6
ldd [%o1 + O2_OFFSET], %o2 ! restore the output registers
ldd [%o1 + O4_OFFSET], %o4
ldd [%o1 + O6_SP_OFFSET], %o6
! do o0/o1 last to avoid destroying heir context pointer
ldd [%o1 + O0_OFFSET], %o0 ! overwrite heir pointer
ldd [%o1 + O6_SP_OFFSET], %o6 ! restore the output registers
jmp %o7 + 8 ! return
nop ! delay slot