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riscv: add ARCH_HAS_SET_DIRECT_MAP support
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Add set_direct_map_*() functions for setting the direct map alias for
the page to its default permissions and to an invalid state that cannot
be cached in a TLB. (See d253ca0 ("x86/mm/cpa: Add set_direct_map_*()
functions")) Add a similar implementation for RISC-V.

Signed-off-by: Zong Li <[email protected]>
Signed-off-by: Palmer Dabbelt <[email protected]>
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zongbox authored and palmer-dabbelt committed Mar 26, 2020
1 parent d3ab332 commit 395a21f
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Showing 3 changed files with 28 additions and 0 deletions.
1 change: 1 addition & 0 deletions arch/riscv/Kconfig
Original file line number Diff line number Diff line change
Expand Up @@ -59,6 +59,7 @@ config RISCV
select HAVE_EBPF_JIT if 64BIT
select EDAC_SUPPORT
select ARCH_HAS_GIGANTIC_PAGE
select ARCH_HAS_SET_DIRECT_MAP
select ARCH_HAS_SET_MEMORY
select ARCH_WANT_HUGE_PMD_SHARE if 64BIT
select SPARSEMEM_STATIC if 32BIT
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3 changes: 3 additions & 0 deletions arch/riscv/include/asm/set_memory.h
Original file line number Diff line number Diff line change
Expand Up @@ -21,4 +21,7 @@ static inline int set_memory_x(unsigned long addr, int numpages) { return 0; }
static inline int set_memory_nx(unsigned long addr, int numpages) { return 0; }
#endif

int set_direct_map_invalid_noflush(struct page *page);
int set_direct_map_default_noflush(struct page *page);

#endif /* _ASM_RISCV_SET_MEMORY_H */
24 changes: 24 additions & 0 deletions arch/riscv/mm/pageattr.c
Original file line number Diff line number Diff line change
Expand Up @@ -148,3 +148,27 @@ int set_memory_nx(unsigned long addr, int numpages)
{
return __set_memory(addr, numpages, __pgprot(0), __pgprot(_PAGE_EXEC));
}

int set_direct_map_invalid_noflush(struct page *page)
{
unsigned long start = (unsigned long)page_address(page);
unsigned long end = start + PAGE_SIZE;
struct pageattr_masks masks = {
.set_mask = __pgprot(0),
.clear_mask = __pgprot(_PAGE_PRESENT)
};

return walk_page_range(&init_mm, start, end, &pageattr_ops, &masks);
}

int set_direct_map_default_noflush(struct page *page)
{
unsigned long start = (unsigned long)page_address(page);
unsigned long end = start + PAGE_SIZE;
struct pageattr_masks masks = {
.set_mask = PAGE_KERNEL,
.clear_mask = __pgprot(0)
};

return walk_page_range(&init_mm, start, end, &pageattr_ops, &masks);
}

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