[PATCH v3 3/7] arm: use fixmap for text patching when text is RO
From: Stephen Boyd <hidden>
Date: 2014-08-12 21:39:12
Also in:
lkml
On 08/12/14 11:24, Kees Cook wrote:
quoted hunk ↗ jump to hunk
diff --git a/arch/arm/kernel/patch.c b/arch/arm/kernel/patch.c index 07314af47733..03dd4e39c833 100644 --- a/arch/arm/kernel/patch.c +++ b/arch/arm/kernel/patch.c@@ -13,21 +16,69 @@ struct patch { unsigned int insn; }; -void __kprobes __patch_text(void *addr, unsigned int insn) +static DEFINE_SPINLOCK(patch_lock); + +static void __kprobes *patch_map(void *addr, int fixmap, unsigned long *flags) +{ + unsigned int uintaddr = (uintptr_t) addr; + bool module = !core_kernel_text(uintaddr); + struct page *page; + + if (module && IS_ENABLED(CONFIG_DEBUG_SET_MODULE_RONX)) + page = vmalloc_to_page(addr); + else if (!module && IS_ENABLED(CONFIG_DEBUG_RODATA)) + page = virt_to_page(addr); + else + return addr; + + if (flags) + spin_lock_irqsave(&patch_lock, *flags); + + set_fixmap(fixmap, page_to_phys(page)); + + return (void *) (__fix_to_virt(fixmap) + (uintaddr & ~PAGE_MASK)); +} + +static void __kprobes patch_unmap(int fixmap, unsigned long *flags) +{ + clear_fixmap(fixmap); + + if (flags) + spin_unlock_irqrestore(&patch_lock, *flags); +}
Has the kbuildbot complained about this one yet? CHECK arch/arm/kernel/patch.c arch/arm/kernel/patch.c:47:39: warning: context imbalance in 'patch_unmap' - unexpected unlock I guess we're going to ignore it. -- Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation