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author | Jason Gunthorpe | 2018-09-06 00:21:22 +0200 |
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committer | Jason Gunthorpe | 2018-09-06 00:21:22 +0200 |
commit | 2c910cb75e1fe6de52d95c8e32caedd1629a33a5 (patch) | |
tree | 94a0eea6f8cde689d11e7583ddd0a930b8785ab4 /arch/x86/mm/pageattr.c | |
parent | RDMA/core: Replace open-coded variant of get_device (diff) | |
parent | RDMA/uverbs: Use device.groups to initialize device attributes (diff) | |
download | kernel-qcow2-linux-2c910cb75e1fe6de52d95c8e32caedd1629a33a5.tar.gz kernel-qcow2-linux-2c910cb75e1fe6de52d95c8e32caedd1629a33a5.tar.xz kernel-qcow2-linux-2c910cb75e1fe6de52d95c8e32caedd1629a33a5.zip |
Merge branch 'uverbs_dev_cleanups' into rdma.git for-next
For dependencies, branch based on rdma.git 'for-rc' of
https://git.kernel.org/pub/scm/linux/kernel/git/rdma/rdma.git/
Pull 'uverbs_dev_cleanups' from Leon Romanovsky:
====================
Reuse the char device code interfaces to simplify ib_uverbs_device
creation and destruction. As part of this series, we are sending fix to
cleanup path, which was discovered during internal review,
The fix definitely can go to -rc, but it means that this series will be
dependent on rdma-rc.
====================
* branch 'uverbs_dev_cleanups':
RDMA/uverbs: Use device.groups to initialize device attributes
RDMA/uverbs: Use cdev_device_add() instead of cdev_add()
RDMA/core: Depend on device_add() to add device attributes
RDMA/uverbs: Fix error cleanup path of ib_uverbs_add_one()
Resolved conflict in ib_device_unregister_sysfs()
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
Diffstat (limited to 'arch/x86/mm/pageattr.c')
-rw-r--r-- | arch/x86/mm/pageattr.c | 25 |
1 files changed, 24 insertions, 1 deletions
diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c index 8d6c34fe49be..51a5a69ecac9 100644 --- a/arch/x86/mm/pageattr.c +++ b/arch/x86/mm/pageattr.c @@ -1420,6 +1420,29 @@ static int __change_page_attr_set_clr(struct cpa_data *cpa, int checkalias) return 0; } +/* + * Machine check recovery code needs to change cache mode of poisoned + * pages to UC to avoid speculative access logging another error. But + * passing the address of the 1:1 mapping to set_memory_uc() is a fine + * way to encourage a speculative access. So we cheat and flip the top + * bit of the address. This works fine for the code that updates the + * page tables. But at the end of the process we need to flush the cache + * and the non-canonical address causes a #GP fault when used by the + * CLFLUSH instruction. + * + * But in the common case we already have a canonical address. This code + * will fix the top bit if needed and is a no-op otherwise. + */ +static inline unsigned long make_addr_canonical_again(unsigned long addr) +{ +#ifdef CONFIG_X86_64 + return (long)(addr << 1) >> 1; +#else + return addr; +#endif +} + + static int change_page_attr_set_clr(unsigned long *addr, int numpages, pgprot_t mask_set, pgprot_t mask_clr, int force_split, int in_flag, @@ -1465,7 +1488,7 @@ static int change_page_attr_set_clr(unsigned long *addr, int numpages, * Save address for cache flush. *addr is modified in the call * to __change_page_attr_set_clr() below. */ - baddr = *addr; + baddr = make_addr_canonical_again(*addr); } /* Must avoid aliasing mappings in the highmem code */ |