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Commit e0037df3 authored by Andrea Shepard's avatar Andrea Shepard Committed by David S. Miller
Browse files

sparc64: Fix race in arch/sparc64/kernel/trampoline.S 



Make arch/sparc64/kernel/trampoline.S in 2.6.27.1 lock prom_entry_lock
when calling the PROM.  This prevents a race condition that I observed
causing a hang on startup on a 12-CPU E4500.

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Signed-off-by: default avatarAndrea Shepard <andrea@persephoneslair.org>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 2515ddc6

arch/sparc64/kernel/trampoline.S

+14 −4
Original line number Original line Diff line number Diff line
@@ -328,6 +328,12 @@ after_lock_tlb: 




	wrpr		%g0, 0, %wstate

	wrpr		%g0, 0, %wstate





	sethi		%hi(prom_entry_lock), %g2

1:	ldstub		[%g2 + %lo(prom_entry_lock)], %g1

	membar		#StoreLoad | #StoreStore

	brnz,pn		%g1, 1b

	 nop



	/* As a hack, put &init_thread_union into %g6.

	/* As a hack, put &init_thread_union into %g6.

	 * prom_world() loads from here to restore the %asi

	 * prom_world() loads from here to restore the %asi

	 * register.

	 * register.
@@ -337,7 +343,7 @@ after_lock_tlb: 




	sethi		%hi(is_sun4v), %o0

	sethi		%hi(is_sun4v), %o0

	lduw		[%o0 + %lo(is_sun4v)], %o0

	lduw		[%o0 + %lo(is_sun4v)], %o0

	brz,pt		%o0, 1f

	brz,pt		%o0, 2f

	 nop

	 nop





	TRAP_LOAD_TRAP_BLOCK(%g2, %g3)

	TRAP_LOAD_TRAP_BLOCK(%g2, %g3)
@@ -369,10 +375,10 @@ after_lock_tlb: 
	call		%o1

	call		%o1

	 add		%sp, (2047 + 128), %o0

	 add		%sp, (2047 + 128), %o0





	ba,pt		%xcc, 2f

	ba,pt		%xcc, 3f

	 nop

	 nop





1:	sethi		%hi(sparc64_ttable_tl0), %o0

2:	sethi		%hi(sparc64_ttable_tl0), %o0

	set		prom_set_trap_table_name, %g2

	set		prom_set_trap_table_name, %g2

	stx		%g2, [%sp + 2047 + 128 + 0x00]

	stx		%g2, [%sp + 2047 + 128 + 0x00]

	mov		1, %g2

	mov		1, %g2
@@ -386,7 +392,11 @@ after_lock_tlb: 
	call		%o1

	call		%o1

	 add		%sp, (2047 + 128), %o0

	 add		%sp, (2047 + 128), %o0





2:	ldx		[%l0], %g6

3:	sethi		%hi(prom_entry_lock), %g2

	stb		%g0, [%g2 + %lo(prom_entry_lock)]

	membar		#StoreStore | #StoreLoad



	ldx		[%l0], %g6

	ldx		[%g6 + TI_TASK], %g4

	ldx		[%g6 + TI_TASK], %g4





	mov		1, %g5

	mov		1, %g5