Add the rt linux 4.1.3-rt3 as base

[kvmfornfv.git] / kernel / arch / arm / kernel / patch.c

diff --git a/kernel/arch/arm/kernel/patch.c b/kernel/arch/arm/kernel/patch.c
new file mode 100644 (file)
index 0000000..69bda1a
--- /dev/null
+++ b/kernel/arch/arm/kernel/patch.c
@@ -0,0 +1,128 @@
+#include <linux/kernel.h>
+#include <linux/spinlock.h>
+#include <linux/kprobes.h>
+#include <linux/mm.h>
+#include <linux/stop_machine.h>
+
+#include <asm/cacheflush.h>
+#include <asm/fixmap.h>
+#include <asm/smp_plat.h>
+#include <asm/opcodes.h>
+#include <asm/patch.h>
+
+struct patch {
+       void *addr;
+       unsigned int insn;
+};
+
+static DEFINE_SPINLOCK(patch_lock);
+
+static void __kprobes *patch_map(void *addr, int fixmap, unsigned long *flags)
+       __acquires(&patch_lock)
+{
+       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);
+       else
+               __acquire(&patch_lock);
+
+       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)
+       __releases(&patch_lock)
+{
+       clear_fixmap(fixmap);
+
+       if (flags)
+               spin_unlock_irqrestore(&patch_lock, *flags);
+       else
+               __release(&patch_lock);
+}
+
+void __kprobes __patch_text_real(void *addr, unsigned int insn, bool remap)
+{
+       bool thumb2 = IS_ENABLED(CONFIG_THUMB2_KERNEL);
+       unsigned int uintaddr = (uintptr_t) addr;
+       bool twopage = false;
+       unsigned long flags;
+       void *waddr = addr;
+       int size;
+
+       if (remap)
+               waddr = patch_map(addr, FIX_TEXT_POKE0, &flags);
+       else
+               __acquire(&patch_lock);
+
+       if (thumb2 && __opcode_is_thumb16(insn)) {
+               *(u16 *)waddr = __opcode_to_mem_thumb16(insn);
+               size = sizeof(u16);
+       } else if (thumb2 && (uintaddr & 2)) {
+               u16 first = __opcode_thumb32_first(insn);
+               u16 second = __opcode_thumb32_second(insn);
+               u16 *addrh0 = waddr;
+               u16 *addrh1 = waddr + 2;
+
+               twopage = (uintaddr & ~PAGE_MASK) == PAGE_SIZE - 2;
+               if (twopage && remap)
+                       addrh1 = patch_map(addr + 2, FIX_TEXT_POKE1, NULL);
+
+               *addrh0 = __opcode_to_mem_thumb16(first);
+               *addrh1 = __opcode_to_mem_thumb16(second);
+
+               if (twopage && addrh1 != addr + 2) {
+                       flush_kernel_vmap_range(addrh1, 2);
+                       patch_unmap(FIX_TEXT_POKE1, NULL);
+               }
+
+               size = sizeof(u32);
+       } else {
+               if (thumb2)
+                       insn = __opcode_to_mem_thumb32(insn);
+               else
+                       insn = __opcode_to_mem_arm(insn);
+
+               *(u32 *)waddr = insn;
+               size = sizeof(u32);
+       }
+
+       if (waddr != addr) {
+               flush_kernel_vmap_range(waddr, twopage ? size / 2 : size);
+               patch_unmap(FIX_TEXT_POKE0, &flags);
+       } else
+               __release(&patch_lock);
+
+       flush_icache_range((uintptr_t)(addr),
+                          (uintptr_t)(addr) + size);
+}
+
+static int __kprobes patch_text_stop_machine(void *data)
+{
+       struct patch *patch = data;
+
+       __patch_text(patch->addr, patch->insn);
+
+       return 0;
+}
+
+void __kprobes patch_text(void *addr, unsigned int insn)
+{
+       struct patch patch = {
+               .addr = addr,
+               .insn = insn,
+       };
+
+       stop_machine(patch_text_stop_machine, &patch, NULL);
+}