Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
iommupt: Add basic support for SW bits in the page table
SW bits can be placed on items, including table entries, single OA's and
individual items within a contiguous OA. They are guaranteed to be ignored
by the HW. The API is very basic since the only use case so far is a
single bit.
Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
authored by
Jason Gunthorpe
and committed by
Joerg Roedel
bcc64b57
36ae67b1
+91
+29
drivers/iommu/generic_pt/pt_common.h
+29
drivers/iommu/generic_pt/pt_common.h
···
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}
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/**
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* pt_max_sw_bit() - Return the maximum software bit usable for any level and
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* entry
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* @common: Page table
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*
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* The swbit can be passed as bitnr to the other sw_bit functions.
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*/
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static inline unsigned int pt_max_sw_bit(struct pt_common *common);
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/**
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* pt_test_sw_bit_acquire() - Read a software bit in an item
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* @pts: Entry to set
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*
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* Software bits are ignored by HW and can be used for any purpose by the
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* software. This does a test bit and acquire operation.
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*/
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static inline bool pt_test_sw_bit_acquire(struct pt_state *pts,
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unsigned int bitnr);
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/**
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* pt_set_sw_bit_release() - Set a software bit in an item
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* @pts: Entry to set
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*
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* Software bits are ignored by HW and can be used for any purpose by the
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* software. This does a set bit and release operation.
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*/
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static inline void pt_set_sw_bit_release(struct pt_state *pts,
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unsigned int bitnr);
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/**
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* pt_load_entry() - Read from the location pts points at into the pts
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* @pts: Table index to load
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*
+62
drivers/iommu/generic_pt/pt_fmt_defaults.h
+62
drivers/iommu/generic_pt/pt_fmt_defaults.h
···
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#define pt_clear_entries pt_clear_entries
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#endif
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/* If not supplied then SW bits are not supported */
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#ifdef pt_sw_bit
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static inline bool pt_test_sw_bit_acquire(struct pt_state *pts,
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unsigned int bitnr)
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{
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/* Acquire, pairs with pt_set_sw_bit_release() */
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smp_mb();
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/* For a contiguous entry the sw bit is only stored in the first item. */
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return pts->entry & pt_sw_bit(bitnr);
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}
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#define pt_test_sw_bit_acquire pt_test_sw_bit_acquire
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+
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static inline void pt_set_sw_bit_release(struct pt_state *pts,
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unsigned int bitnr)
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{
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#if !IS_ENABLED(CONFIG_GENERIC_ATOMIC64)
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if (PT_ITEM_WORD_SIZE == sizeof(u64)) {
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u64 *entryp = pt_cur_table(pts, u64) + pts->index;
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u64 old_entry = pts->entry;
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u64 new_entry;
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+
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do {
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new_entry = old_entry | pt_sw_bit(bitnr);
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} while (!try_cmpxchg64_release(entryp, &old_entry, new_entry));
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pts->entry = new_entry;
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return;
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}
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#endif
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if (PT_ITEM_WORD_SIZE == sizeof(u32)) {
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u32 *entryp = pt_cur_table(pts, u32) + pts->index;
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u32 old_entry = pts->entry;
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u32 new_entry;
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+
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do {
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new_entry = old_entry | pt_sw_bit(bitnr);
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} while (!try_cmpxchg_release(entryp, &old_entry, new_entry));
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pts->entry = new_entry;
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} else
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BUILD_BUG();
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}
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#define pt_set_sw_bit_release pt_set_sw_bit_release
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#else
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static inline unsigned int pt_max_sw_bit(struct pt_common *common)
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{
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return 0;
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}
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extern void __pt_no_sw_bit(void);
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static inline bool pt_test_sw_bit_acquire(struct pt_state *pts,
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unsigned int bitnr)
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{
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__pt_no_sw_bit();
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return false;
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}
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+
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static inline void pt_set_sw_bit_release(struct pt_state *pts,
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unsigned int bitnr)
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{
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__pt_no_sw_bit();
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}
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#endif
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/*
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* Format can call in the pt_install_leaf_entry() to check the arguments are all
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* aligned correctly.