unimore/kernel-hacking-2024-linux-steffo
unimore/kernel-hacking-2024-linux-steffo
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[SPARC64]: Kill all %pstate changes in context switch code.

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They are totally unnecessary because:

1) Interrupts are already disabled when switch_to()
   runs.

2) We don't use hard-coded alternate globals any longer.

This found a case in rtrap, which still assumed alternate
global %g6 was current_thread_info(), and that is fixed
by this changeset as well.

Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
David S. Miller 2006-02-05 21:59:03 -08:00
parent 936f482af1
commit 314981ac71
2 changed files with 4 additions and 6 deletions
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5
arch/sparc64/kernel/rtrap.S
View file

@ -224,7 +224,8 @@ rt_continue: ldx [%sp + PTREGS_OFF + PT_V9_G1], %g1
ldx [%sp + PTREGS_OFF + PT_V9_G4], %g4
ldx [%sp + PTREGS_OFF + PT_V9_G5], %g5
brz,pt %l3, 1f
nop
mov %g6, %l2
/* Must do this before thread reg is clobbered below. */
LOAD_PER_CPU_BASE(%g5, %g6, %i0, %i1, %i2)
1:
@ -238,6 +239,8 @@ rt_continue: ldx [%sp + PTREGS_OFF + PT_V9_G1], %g1
SET_GL(1)
.previous
mov %l2, %g6
ldx [%sp + PTREGS_OFF + PT_V9_I0], %i0
ldx [%sp + PTREGS_OFF + PT_V9_I1], %i1

5
include/asm-sparc64/system.h
View file

@ -213,7 +213,6 @@ do { if (test_thread_flag(TIF_PERFCTR)) { \
task_thread_info(next); \
__asm__ __volatile__( \
"mov %%g4, %%g7\n\t" \
"wrpr %%g0, 0x95, %%pstate\n\t" \
"stx %%i6, [%%sp + 2047 + 0x70]\n\t" \
"stx %%i7, [%%sp + 2047 + 0x78]\n\t" \
"rdpr %%wstate, %%o5\n\t" \
@ -227,14 +226,10 @@ do { if (test_thread_flag(TIF_PERFCTR)) { \
"ldx [%%g6 + %3], %%o6\n\t" \
"ldub [%%g6 + %2], %%o5\n\t" \
"ldub [%%g6 + %4], %%o7\n\t" \
"mov %%g6, %%l2\n\t" \
"wrpr %%o5, 0x0, %%wstate\n\t" \
"ldx [%%sp + 2047 + 0x70], %%i6\n\t" \
"ldx [%%sp + 2047 + 0x78], %%i7\n\t" \
"wrpr %%g0, 0x94, %%pstate\n\t" \
"mov %%l2, %%g6\n\t" \
"ldx [%%g6 + %6], %%g4\n\t" \
"wrpr %%g0, 0x96, %%pstate\n\t" \
"brz,pt %%o7, 1f\n\t" \
" mov %%g7, %0\n\t" \
"b,a ret_from_syscall\n\t" \