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authorAl Viro <viro@zeniv.linux.org.uk>2010-09-25 16:07:14 -0400
committerLinus Torvalds <torvalds@linux-foundation.org>2010-09-25 17:38:13 -0400
commit77edffb652b33a565e099ff0a1687762f03eb46a (patch)
tree1e6e9586fc563d867c8737feb855575314deaff7 /arch/alpha
parent56162badadb91aae93843d8d6558c7d7780e3cb2 (diff)
alpha: fix hae_cache race in RESTORE_ALL
We want interrupts disabled on all paths leading to RESTORE_ALL; otherwise, we are risking an IRQ coming between the updates of alpha_mv->hae_cache and *alpha_mv->hae_register and set_hae() within the IRQ getting badly confused. RESTORE_ALL used to play with disabling IRQ itself, but that got removed back in 2002, without making sure we had them disabled on all paths. It's cheaper to make sure we have them disabled than to revert to original variant... Remove the detritus left from that commit back in 2002; we used to need a reload of $0 and $1 since swpipl would change those, but doing that had become pointless when we stopped doing swpipl in there... Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'arch/alpha')
-rw-r--r--arch/alpha/kernel/entry.S11
1 files changed, 7 insertions, 4 deletions
diff --git a/arch/alpha/kernel/entry.S b/arch/alpha/kernel/entry.S
index ab1ee0ab082b..d1273c1a1364 100644
--- a/arch/alpha/kernel/entry.S
+++ b/arch/alpha/kernel/entry.S
@@ -73,8 +73,6 @@
73 ldq $20, HAE_REG($19); \ 73 ldq $20, HAE_REG($19); \
74 stq $21, HAE_CACHE($19); \ 74 stq $21, HAE_CACHE($19); \
75 stq $21, 0($20); \ 75 stq $21, 0($20); \
76 ldq $0, 0($sp); \
77 ldq $1, 8($sp); \
7899:; \ 7699:; \
79 ldq $19, 72($sp); \ 77 ldq $19, 72($sp); \
80 ldq $20, 80($sp); \ 78 ldq $20, 80($sp); \
@@ -316,7 +314,7 @@ ret_from_sys_call:
316 cmovne $26, 0, $19 /* $19 = 0 => non-restartable */ 314 cmovne $26, 0, $19 /* $19 = 0 => non-restartable */
317 ldq $0, SP_OFF($sp) 315 ldq $0, SP_OFF($sp)
318 and $0, 8, $0 316 and $0, 8, $0
319 beq $0, restore_all 317 beq $0, ret_to_kernel
320ret_to_user: 318ret_to_user:
321 /* Make sure need_resched and sigpending don't change between 319 /* Make sure need_resched and sigpending don't change between
322 sampling and the rti. */ 320 sampling and the rti. */
@@ -329,6 +327,11 @@ restore_all:
329 RESTORE_ALL 327 RESTORE_ALL
330 call_pal PAL_rti 328 call_pal PAL_rti
331 329
330ret_to_kernel:
331 lda $16, 7
332 call_pal PAL_swpipl
333 br restore_all
334
332 .align 3 335 .align 3
333$syscall_error: 336$syscall_error:
334 /* 337 /*
@@ -657,7 +660,7 @@ kernel_thread:
657 /* We don't actually care for a3 success widgetry in the kernel. 660 /* We don't actually care for a3 success widgetry in the kernel.
658 Not for positive errno values. */ 661 Not for positive errno values. */
659 stq $0, 0($sp) /* $0 */ 662 stq $0, 0($sp) /* $0 */
660 br restore_all 663 br ret_to_kernel
661.end kernel_thread 664.end kernel_thread
662 665
663/* 666/*