diff options
| author | Michael Ellerman <mpe@ellerman.id.au> | 2021-09-03 22:54:12 +1000 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2021-09-03 22:54:12 +1000 |
| commit | a3314262eede9c909a0c797f16f25f941d12c78d (patch) | |
| tree | 4ec2b6857f839e9f4c86c9a08c9ccc4528ed0e9f /arch/powerpc/mm | |
| parent | e432fe97f3e5de325b40021e505cce53877586c5 (diff) | |
| parent | 787c70f2f9990b5a197320152d2fc32cd8a6ad1a (diff) | |
Merge branch 'fixes' into next
Merge our fixes branch into next.
That lets us resolve a conflict in arch/powerpc/sysdev/xive/common.c.
Between cbc06f051c52 ("powerpc/xive: Do not skip CPU-less nodes when
creating the IPIs"), which moved request_irq() out of xive_init_ipis(),
and 17df41fec5b8 ("powerpc: use IRQF_NO_DEBUG for IPIs") which added
IRQF_NO_DEBUG to that request_irq() call, which has now moved.
Diffstat (limited to 'arch/powerpc/mm')
| -rw-r--r-- | arch/powerpc/mm/pageattr.c | 23 |
1 files changed, 10 insertions, 13 deletions
diff --git a/arch/powerpc/mm/pageattr.c b/arch/powerpc/mm/pageattr.c index 0876216ceee6..edea388e9d3f 100644 --- a/arch/powerpc/mm/pageattr.c +++ b/arch/powerpc/mm/pageattr.c @@ -18,16 +18,12 @@ /* * Updates the attributes of a page in three steps: * - * 1. invalidate the page table entry - * 2. flush the TLB - * 3. install the new entry with the updated attributes - * - * Invalidating the pte means there are situations where this will not work - * when in theory it should. - * For example: - * - removing write from page whilst it is being executed - * - setting a page read-only whilst it is being read by another CPU + * 1. take the page_table_lock + * 2. install the new entry with the updated attributes + * 3. flush the TLB * + * This sequence is safe against concurrent updates, and also allows updating the + * attributes of a page currently being executed or accessed. */ static int change_page_attr(pte_t *ptep, unsigned long addr, void *data) { @@ -36,9 +32,7 @@ static int change_page_attr(pte_t *ptep, unsigned long addr, void *data) spin_lock(&init_mm.page_table_lock); - /* invalidate the PTE so it's safe to modify */ - pte = ptep_get_and_clear(&init_mm, addr, ptep); - flush_tlb_kernel_range(addr, addr + PAGE_SIZE); + pte = ptep_get(ptep); /* modify the PTE bits as desired, then apply */ switch (action) { @@ -59,11 +53,14 @@ static int change_page_attr(pte_t *ptep, unsigned long addr, void *data) break; } - set_pte_at(&init_mm, addr, ptep, pte); + pte_update(&init_mm, addr, ptep, ~0UL, pte_val(pte), 0); /* See ptesync comment in radix__set_pte_at() */ if (radix_enabled()) asm volatile("ptesync": : :"memory"); + + flush_tlb_kernel_range(addr, addr + PAGE_SIZE); + spin_unlock(&init_mm.page_table_lock); return 0; |