openrisc: fix SMP tlb flush NULL pointer dereference

Throughout the OpenRISC kernel port VMA is passed as NULL when flushing kernel tlb entries. Somehow this was missed when I was testing c28b274 ("openrisc: Implement proper SMP tlb flushing") and now the SMP kernel fails to completely boot. In OpenRISC VMA is used only to determine which cores need to have their TLB entries flushed. This patch updates the logic to flush tlbs on all cores when the VMA is passed as NULL. Also, we update places VMA is passed as NULL to use flush_tlb_kernel_range instead. Now, the only place VMA is passed as NULL is in the implementation of flush_tlb_kernel_range. Fixes: c28b274 ("openrisc: Implement proper SMP tlb flushing") Reported-by: Jan Henrik Weinstock <[email protected]> Signed-off-by: Stafford Horne <[email protected]>
majek · Nov 3, 2021 · 27dff9a · 27dff9a
1 parent 210893c
commit 27dff9a
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Showing 2 changed files with 6 additions and 4 deletions.
diff --git a/arch/openrisc/kernel/dma.c b/arch/openrisc/kernel/dma.c
@@ -33,7 +33,7 @@ page_set_nocache(pte_t *pte, unsigned long addr,
 	 * Flush the page out of the TLB so that the new page flags get
 	 * picked up next time there's an access
 	 */
-	flush_tlb_page(NULL, addr);
+	flush_tlb_kernel_range(addr, addr + PAGE_SIZE);
 
 	/* Flush page out of dcache */
 	for (cl = __pa(addr); cl < __pa(next); cl += cpuinfo->dcache_block_size)
@@ -56,7 +56,7 @@ page_clear_nocache(pte_t *pte, unsigned long addr,
 	 * Flush the page out of the TLB so that the new page flags get
 	 * picked up next time there's an access
 	 */
-	flush_tlb_page(NULL, addr);
+	flush_tlb_kernel_range(addr, addr + PAGE_SIZE);
 
 	return 0;
 }

diff --git a/arch/openrisc/kernel/smp.c b/arch/openrisc/kernel/smp.c
@@ -272,7 +272,7 @@ static inline void ipi_flush_tlb_range(void *info)
 	local_flush_tlb_range(NULL, fd->addr1, fd->addr2);
 }
 
-static void smp_flush_tlb_range(struct cpumask *cmask, unsigned long start,
+static void smp_flush_tlb_range(const struct cpumask *cmask, unsigned long start,
 				unsigned long end)
 {
 	unsigned int cpuid;
@@ -320,7 +320,9 @@ void flush_tlb_page(struct vm_area_struct *vma, unsigned long uaddr)
 void flush_tlb_range(struct vm_area_struct *vma,
 		     unsigned long start, unsigned long end)
 {
-	smp_flush_tlb_range(mm_cpumask(vma->vm_mm), start, end);
+	const struct cpumask *cmask = vma ? mm_cpumask(vma->vm_mm)
+					  : cpu_online_mask;
+	smp_flush_tlb_range(cmask, start, end);
 }
 
 /* Instruction cache invalidate - performed on each cpu */