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| author | Kirill A. Shutemov <kirill.shutemov@linux.intel.com> | 2023-03-12 14:26:01 +0300 |
|---|---|---|
| committer | Dave Hansen <dave.hansen@linux.intel.com> | 2023-03-16 13:08:39 -0700 |
| commit | 74c228d20a51ddb1354409fdbed7b72427339d7b (patch) | |
| tree | 524713f7708b7ffd19da588b367a19796503c04f /arch/x86/mm/init.c | |
| parent | 428e106ae1ad4e45d3fd6978a753db475d0d0ec9 (diff) | |
| download | lwn-74c228d20a51ddb1354409fdbed7b72427339d7b.tar.gz lwn-74c228d20a51ddb1354409fdbed7b72427339d7b.zip | |
x86/uaccess: Provide untagged_addr() and remove tags before address check
untagged_addr() is a helper used by the core-mm to strip tag bits and
get the address to the canonical shape based on rules of the current
thread. It only handles userspace addresses.
The untagging mask is stored in per-CPU variable and set on context
switching to the task.
The tags must not be included into check whether it's okay to access the
userspace address. Strip tags in access_ok().
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Alexander Potapenko <glider@google.com>
Link: https://lore.kernel.org/all/20230312112612.31869-7-kirill.shutemov%40linux.intel.com
Diffstat (limited to 'arch/x86/mm/init.c')
| -rw-r--r-- | arch/x86/mm/init.c | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c index cb258f58fdc8..659b6c0f7910 100644 --- a/arch/x86/mm/init.c +++ b/arch/x86/mm/init.c @@ -1048,6 +1048,11 @@ __visible DEFINE_PER_CPU_ALIGNED(struct tlb_state, cpu_tlbstate) = { .cr4 = ~0UL, /* fail hard if we screw up cr4 shadow initialization */ }; +#ifdef CONFIG_ADDRESS_MASKING +DEFINE_PER_CPU(u64, tlbstate_untag_mask); +EXPORT_PER_CPU_SYMBOL(tlbstate_untag_mask); +#endif + void update_cache_mode_entry(unsigned entry, enum page_cache_mode cache) { /* entry 0 MUST be WB (hardwired to speed up translations) */ |