From 77edffb652b33a565e099ff0a1687762f03eb46a Mon Sep 17 00:00:00 2001 From: Al Viro Date: Sat, 25 Sep 2010 21:07:14 +0100 Subject: [PATCH] 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 Signed-off-by: Linus Torvalds --- arch/alpha/kernel/entry.S | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-) diff --git a/arch/alpha/kernel/entry.S b/arch/alpha/kernel/entry.S index ab1ee0a..d1273c1 100644 --- a/arch/alpha/kernel/entry.S +++ b/arch/alpha/kernel/entry.S @@ -73,8 +73,6 @@ ldq $20, HAE_REG($19); \ stq $21, HAE_CACHE($19); \ stq $21, 0($20); \ - ldq $0, 0($sp); \ - ldq $1, 8($sp); \ 99:; \ ldq $19, 72($sp); \ ldq $20, 80($sp); \ @@ -316,7 +314,7 @@ ret_from_sys_call: cmovne $26, 0, $19 /* $19 = 0 => non-restartable */ ldq $0, SP_OFF($sp) and $0, 8, $0 - beq $0, restore_all + beq $0, ret_to_kernel ret_to_user: /* Make sure need_resched and sigpending don't change between sampling and the rti. */ @@ -329,6 +327,11 @@ restore_all: RESTORE_ALL call_pal PAL_rti +ret_to_kernel: + lda $16, 7 + call_pal PAL_swpipl + br restore_all + .align 3 $syscall_error: /* @@ -657,7 +660,7 @@ kernel_thread: /* We don't actually care for a3 success widgetry in the kernel. Not for positive errno values. */ stq $0, 0($sp) /* $0 */ - br restore_all + br ret_to_kernel .end kernel_thread /* -- 2.7.4