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author | Christophe Leroy <christophe.leroy@csgroup.eu> | 2021-12-24 14:07:40 +0300 |
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committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-04-08 15:24:04 +0300 |
commit | f4b0b5a0f3c1d50476b89f54fa2015bce72dd63d (patch) | |
tree | 18ad6e2f02838add1a0fb4e8959586f241caa6a9 /arch/powerpc/mm | |
parent | a29341e48601d7bb3d68bd75fc50988cf382abc9 (diff) | |
download | linux-f4b0b5a0f3c1d50476b89f54fa2015bce72dd63d.tar.xz |
powerpc: Add set_memory_{p/np}() and remove set_memory_attr()
commit f222ab83df92acf72691a2021e1f0d99880dcdf1 upstream.
set_memory_attr() was implemented by commit 4d1755b6a762 ("powerpc/mm:
implement set_memory_attr()") because the set_memory_xx() couldn't
be used at that time to modify memory "on the fly" as explained it
the commit.
But set_memory_attr() uses set_pte_at() which leads to warnings when
CONFIG_DEBUG_VM is selected, because set_pte_at() is unexpected for
updating existing page table entries.
The check could be bypassed by using __set_pte_at() instead,
as it was the case before commit c988cfd38e48 ("powerpc/32:
use set_memory_attr()") but since commit 9f7853d7609d ("powerpc/mm:
Fix set_memory_*() against concurrent accesses") it is now possible
to use set_memory_xx() functions to update page table entries
"on the fly" because the update is now atomic.
For DEBUG_PAGEALLOC we need to clear and set back _PAGE_PRESENT.
Add set_memory_np() and set_memory_p() for that.
Replace all uses of set_memory_attr() by the relevant set_memory_xx()
and remove set_memory_attr().
Fixes: c988cfd38e48 ("powerpc/32: use set_memory_attr()")
Cc: stable@vger.kernel.org
Reported-by: Maxime Bizon <mbizon@freebox.fr>
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Tested-by: Maxime Bizon <mbizon@freebox.fr>
Reviewed-by: Russell Currey <ruscur@russell.cc>
Depends-on: 9f7853d7609d ("powerpc/mm: Fix set_memory_*() against concurrent accesses")
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/cda2b44b55c96f9ac69fa92e68c01084ec9495c5.1640344012.git.christophe.leroy@csgroup.eu
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch/powerpc/mm')
-rw-r--r-- | arch/powerpc/mm/pageattr.c | 39 | ||||
-rw-r--r-- | arch/powerpc/mm/pgtable_32.c | 24 |
2 files changed, 17 insertions, 46 deletions
diff --git a/arch/powerpc/mm/pageattr.c b/arch/powerpc/mm/pageattr.c index edea388e9d3f..3bb9d168e3b3 100644 --- a/arch/powerpc/mm/pageattr.c +++ b/arch/powerpc/mm/pageattr.c @@ -48,6 +48,12 @@ static int change_page_attr(pte_t *ptep, unsigned long addr, void *data) case SET_MEMORY_X: pte = pte_mkexec(pte); break; + case SET_MEMORY_NP: + pte_update(&init_mm, addr, ptep, _PAGE_PRESENT, 0, 0); + break; + case SET_MEMORY_P: + pte_update(&init_mm, addr, ptep, 0, _PAGE_PRESENT, 0); + break; default: WARN_ON_ONCE(1); break; @@ -96,36 +102,3 @@ int change_memory_attr(unsigned long addr, int numpages, long action) return apply_to_existing_page_range(&init_mm, start, size, change_page_attr, (void *)action); } - -/* - * Set the attributes of a page: - * - * This function is used by PPC32 at the end of init to set final kernel memory - * protection. It includes changing the maping of the page it is executing from - * and data pages it is using. - */ -static int set_page_attr(pte_t *ptep, unsigned long addr, void *data) -{ - pgprot_t prot = __pgprot((unsigned long)data); - - spin_lock(&init_mm.page_table_lock); - - set_pte_at(&init_mm, addr, ptep, pte_modify(*ptep, prot)); - flush_tlb_kernel_range(addr, addr + PAGE_SIZE); - - spin_unlock(&init_mm.page_table_lock); - - return 0; -} - -int set_memory_attr(unsigned long addr, int numpages, pgprot_t prot) -{ - unsigned long start = ALIGN_DOWN(addr, PAGE_SIZE); - unsigned long sz = numpages * PAGE_SIZE; - - if (numpages <= 0) - return 0; - - return apply_to_existing_page_range(&init_mm, start, sz, set_page_attr, - (void *)pgprot_val(prot)); -} diff --git a/arch/powerpc/mm/pgtable_32.c b/arch/powerpc/mm/pgtable_32.c index fde1ed445ca4..f28859771440 100644 --- a/arch/powerpc/mm/pgtable_32.c +++ b/arch/powerpc/mm/pgtable_32.c @@ -138,10 +138,12 @@ void mark_initmem_nx(void) unsigned long numpages = PFN_UP((unsigned long)_einittext) - PFN_DOWN((unsigned long)_sinittext); - if (v_block_mapped((unsigned long)_sinittext)) + if (v_block_mapped((unsigned long)_sinittext)) { mmu_mark_initmem_nx(); - else - set_memory_attr((unsigned long)_sinittext, numpages, PAGE_KERNEL); + } else { + set_memory_nx((unsigned long)_sinittext, numpages); + set_memory_rw((unsigned long)_sinittext, numpages); + } } #ifdef CONFIG_STRICT_KERNEL_RWX @@ -155,18 +157,14 @@ void mark_rodata_ro(void) return; } - numpages = PFN_UP((unsigned long)_etext) - - PFN_DOWN((unsigned long)_stext); - - set_memory_attr((unsigned long)_stext, numpages, PAGE_KERNEL_ROX); /* - * mark .rodata as read only. Use __init_begin rather than __end_rodata - * to cover NOTES and EXCEPTION_TABLE. + * mark .text and .rodata as read only. Use __init_begin rather than + * __end_rodata to cover NOTES and EXCEPTION_TABLE. */ numpages = PFN_UP((unsigned long)__init_begin) - - PFN_DOWN((unsigned long)__start_rodata); + PFN_DOWN((unsigned long)_stext); - set_memory_attr((unsigned long)__start_rodata, numpages, PAGE_KERNEL_RO); + set_memory_ro((unsigned long)_stext, numpages); // mark_initmem_nx() should have already run by now ptdump_check_wx(); @@ -182,8 +180,8 @@ void __kernel_map_pages(struct page *page, int numpages, int enable) return; if (enable) - set_memory_attr(addr, numpages, PAGE_KERNEL); + set_memory_p(addr, numpages); else - set_memory_attr(addr, numpages, __pgprot(0)); + set_memory_np(addr, numpages); } #endif /* CONFIG_DEBUG_PAGEALLOC */ |