From a3483c3dd18c136785a31406fe27210649fc4fba Mon Sep 17 00:00:00 2001 From: Christophe Leroy Date: Thu, 2 Dec 2021 13:00:20 +0100 Subject: [PATCH] powerpc/code-patching: Fix unmap_patch_area() error handling pXd_offset() doesn't return NULL. When the base is NULL, it still adds the offset. Use pXd_none() to check validity instead. It also improves performance by folding out none existing levels as pXd_none() always returns 0 in that case. Such an error is unexpected, use WARN_ON() so that the caller doesn't have to worry about it, and drop the returned value. And now that unmap_patch_area() doesn't return error, we can take into account the error returned by __patch_instruction(). While at it, remove the 'inline' property which is useless. Signed-off-by: Christophe Leroy Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/299804b117fae35c786c827536c91f25352e279b.1638446239.git.christophe.leroy@csgroup.eu --- arch/powerpc/lib/code-patching.c | 30 +++++++++++++----------------- 1 file changed, 13 insertions(+), 17 deletions(-) diff --git a/arch/powerpc/lib/code-patching.c b/arch/powerpc/lib/code-patching.c index 380c55d2e41a..740ba0dc5da0 100644 --- a/arch/powerpc/lib/code-patching.c +++ b/arch/powerpc/lib/code-patching.c @@ -94,7 +94,7 @@ static int map_patch_area(void *addr, unsigned long text_poke_addr) return map_kernel_page(text_poke_addr, (pfn << PAGE_SHIFT), PAGE_KERNEL); } -static inline int unmap_patch_area(unsigned long addr) +static void unmap_patch_area(unsigned long addr) { pte_t *ptep; pmd_t *pmdp; @@ -103,32 +103,30 @@ static inline int unmap_patch_area(unsigned long addr) pgd_t *pgdp; pgdp = pgd_offset_k(addr); - if (unlikely(!pgdp)) - return -EINVAL; + if (WARN_ON(pgd_none(*pgdp))) + return; p4dp = p4d_offset(pgdp, addr); - if (unlikely(!p4dp)) - return -EINVAL; + if (WARN_ON(p4d_none(*p4dp))) + return; pudp = pud_offset(p4dp, addr); - if (unlikely(!pudp)) - return -EINVAL; + if (WARN_ON(pud_none(*pudp))) + return; pmdp = pmd_offset(pudp, addr); - if (unlikely(!pmdp)) - return -EINVAL; + if (WARN_ON(pmd_none(*pmdp))) + return; ptep = pte_offset_kernel(pmdp, addr); - if (unlikely(!ptep)) - return -EINVAL; + if (WARN_ON(pte_none(*ptep))) + return; /* * In hash, pte_clear flushes the tlb, in radix, we have to */ pte_clear(&init_mm, addr, ptep); flush_tlb_kernel_range(addr, addr + PAGE_SIZE); - - return 0; } static int do_patch_instruction(u32 *addr, ppc_inst_t instr) @@ -156,11 +154,9 @@ static int do_patch_instruction(u32 *addr, ppc_inst_t instr) patch_addr = (u32 *)(text_poke_addr + (kaddr & ~PAGE_MASK)); - __patch_instruction(addr, instr, patch_addr); + err = __patch_instruction(addr, instr, patch_addr); - err = unmap_patch_area(text_poke_addr); - if (err) - pr_warn("failed to unmap %lx\n", text_poke_addr); + unmap_patch_area(text_poke_addr); out: local_irq_restore(flags);