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authorMax Filippov <jcmvbkbc@gmail.com>2015-10-16 17:01:04 +0300
committerMax Filippov <jcmvbkbc@gmail.com>2015-11-03 17:19:38 +0300
commitab45fb145096799dabd18afc58bb5f97171017cd (patch)
treec2aacf7f7c4a8961a239cb4ee215610b3eeb0d51 /arch/xtensa/kernel/vectors.S
parenta9df9338c1a32e7cdc8c6c6fa7c73f0a63a1ca56 (diff)
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xtensa: fix secondary core boot in SMP
There are multiple factors adding to the issue in different configurations: - commit 17290231df16eeee ("xtensa: add fixup for double exception raised in window overflow") added function window_overflow_restore_a0_fixup to double exception vector overlapping reset vector location of secondary processor cores. - on MMUv2 cores RESET_VECTOR1_VADDR may point to uncached kernel memory making code overlapping depend on cache type and size, so that without cache or with WT cache reset vector code overwrites double exception code, making issue even harder to detect. - on MMUv3 cores RESET_VECTOR1_VADDR may point to unmapped area, as MMUv3 cores change virtual address map to match MMUv2 layout, but reset vector virtual address is given for the original MMUv3 mapping. - physical memory region of the secondary reset vector is not reserved in the physical memory map, and thus may be allocated and overwritten at arbitrary moment. Fix it as follows: - move window_overflow_restore_a0_fixup code to .text section. - define RESET_VECTOR1_VADDR so that it points to reset vector in the cacheable MMUv2 map for cores with MMU. - reserve reset vector region in the physical memory map. Drop separate literal section and build mxhead.S with text section literals. Cc: <stable@vger.kernel.org> Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
Diffstat (limited to 'arch/xtensa/kernel/vectors.S')
-rw-r--r--arch/xtensa/kernel/vectors.S4
1 files changed, 3 insertions, 1 deletions
diff --git a/arch/xtensa/kernel/vectors.S b/arch/xtensa/kernel/vectors.S
index abcdb52..fc25318 100644
--- a/arch/xtensa/kernel/vectors.S
+++ b/arch/xtensa/kernel/vectors.S
@@ -478,6 +478,9 @@ _DoubleExceptionVector_handle_exception:
ENDPROC(_DoubleExceptionVector)
+ .end literal_prefix
+
+ .text
/*
* Fixup handler for TLB miss in double exception handler for window owerflow.
* We get here with windowbase set to the window that was being spilled and
@@ -587,7 +590,6 @@ ENTRY(window_overflow_restore_a0_fixup)
ENDPROC(window_overflow_restore_a0_fixup)
- .end literal_prefix
/*
* Debug interrupt vector
*
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